use chrono::{DateTime, Local, NaiveDate, NaiveDateTime, NaiveTime};
use deadpool_postgres::{ManagerConfig, Pool, PoolError, RecyclingMethod, Runtime};
use futures::{SinkExt, StreamExt};
use openssl::ssl::{SslConnector, SslFiletype, SslMethod, SslVerifyMode};
use percent_encoding::percent_decode_str;
use rustls::client::danger::{HandshakeSignatureValid, ServerCertVerified, ServerCertVerifier};
use rustls::client::verify_server_cert_signed_by_trust_anchor;
use rustls::crypto::{verify_tls12_signature, verify_tls13_signature, CryptoProvider};
use rustls::pki_types::{CertificateDer, PrivateKeyDer, ServerName, UnixTime};
use rustls::server::ParsedCertificate;
use sqlparser::ast::{SetExpr, Statement};
use sqlparser::dialect::PostgreSqlDialect;
use sqlparser::parser::Parser;
use std::collections::{BTreeMap, BTreeSet, HashMap};
use std::fmt::Write as _;
use std::fs::File;
use std::future::Future;
use std::io::BufReader;
use std::pin::Pin;
use std::str::FromStr;
use std::sync::atomic::AtomicBool;
use std::sync::{Arc, Mutex, OnceLock, Weak};
use std::time::{Duration, Instant};
use tokio::task::JoinHandle;
use tokio_postgres::config::SslMode;
use tokio_postgres::tls::{MakeTlsConnect, TlsConnect};
use tokio_postgres::types::{FromSql, Kind, Type};
use tokio_postgres::{AsyncMessage, NoTls, Row, SimpleQueryMessage, Socket};
use tokio_util::sync::CancellationToken;

use super::file_validator::validate_file_path;
use crate::query::{await_stream_with_progress_timeout, DbOperationBudget, StreamProgressClock};
use crate::sql::starts_with_executable_sql_keyword;
use crate::types::{
    ColumnInfo, CompletionAssistantCandidate, CompletionAssistantCandidateKind, CompletionAssistantMatchMode,
    CompletionAssistantObjectKind, CompletionAssistantRequest, CompletionAssistantResponse, ConstraintInfo,
    CustomTypeDdl, CustomTypeDetails, CustomTypeDomainConstraint, CustomTypeKind, CustomTypeMember,
    CustomTypeProperties, DatabaseInfo, DatabaseStorageInfo, ExtensionInfo, ForeignKeyInfo, FunctionInfo, IndexInfo,
    ObjectInfo, ObjectStatistics, OwnerInfo, QueryMessage, QueryResult, RuleInfo, SchemaInfo, SequenceInfo,
    SpatialColumnBuilder, TableInfo, TriggerInfo,
};

pub(crate) const GAUSSDB_COMPATIBILITY_SQL: &str =
    "SELECT datcompatibility FROM pg_catalog.pg_database WHERE datname = current_database()";

pub async fn gaussdb_identifier_quote(pool: &Pool) -> Option<String> {
    let timeout = super::connection_timeout();
    let client = checkout_postgres_client(pool, None, timeout).await.ok()?;
    let row = tokio::time::timeout(timeout, client.query_opt(GAUSSDB_COMPATIBILITY_SQL, &[])).await.ok()?.ok()??;
    let compatibility_mode = row.try_get::<_, String>(0).ok()?;
    gaussdb_identifier_quote_for_compatibility_mode(&compatibility_mode).map(str::to_string)
}

pub(crate) fn gaussdb_identifier_quote_for_compatibility_mode(compatibility_mode: &str) -> Option<&'static str> {
    match compatibility_mode.trim().to_ascii_uppercase().as_str() {
        "M" | "B" | "MYSQL" => Some("`"),
        "A" | "PG" | "ORA" | "POSTGRESQL" => Some("\""),
        _ => None,
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PostgresTablePrivilegeInfo {
    pub grantor: String,
    pub grantee: String,
    pub privilege_type: String,
    pub is_grantable: bool,
    pub column_name: Option<String>,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PostgresTableAccessInfo {
    pub owner: String,
    pub owner_default_privileges: Vec<String>,
    pub privileges: Vec<PostgresTablePrivilegeInfo>,
}

#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub struct PostgresTablePartitionInfo {
    pub is_partition: bool,
    pub parent_schema: Option<String>,
    pub parent_table: Option<String>,
    pub bound: Option<String>,
    pub key: Option<String>,
    /// True when this relation is itself a foreign table (relkind 'f'),
    /// whether or not it is also a partition. A partition backed by a
    /// foreign server must be declared with `CREATE FOREIGN TABLE ...
    /// SERVER`, not `CREATE TABLE`.
    pub is_foreign: bool,
    pub foreign_server: Option<String>,
    pub foreign_options: Vec<(String, String)>,
}

/// The state of a partition-local column DEFAULT relative to the parent's
/// default for the same column (a partition with no entry in the owning
/// `column_defaults` map simply inherits the parent's default unchanged).
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum PostgresColumnDefaultState {
    /// This partition's own default differs from (or has no counterpart in)
    /// the parent's default — declared via `column WITH OPTIONS DEFAULT ...`.
    Overridden,
    /// The parent has a default for this column, but this partition
    /// explicitly ran `ALTER TABLE ONLY ... ALTER COLUMN ... DROP DEFAULT`
    /// to remove its own (otherwise auto-inherited-at-creation) copy —
    /// replayed as a standalone `ALTER TABLE ONLY ... DROP DEFAULT;`.
    Dropped,
}

#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub struct PostgresTablePartitionLocalObjects {
    pub has_primary_key: bool,
    pub foreign_keys: BTreeSet<String>,
    pub indexes: BTreeSet<String>,
    /// CHECK constraints with a local definition on this partition, as
    /// reported by pg_constraint.conislocal. A merged constraint may remain
    /// local even when coninhcount is greater than zero.
    pub check_constraints: BTreeSet<String>,
    /// Columns with a local override or explicit drop of the parent's
    /// default; a column absent from this map is purely inherited.
    pub column_defaults: BTreeMap<String, PostgresColumnDefaultState>,
}

fn pg_temporal_to_json_value(row: &Row, idx: usize) -> Option<serde_json::Value> {
    if let Ok(v) = row.try_get::<_, DateTime<Local>>(idx) {
        return Some(serde_json::Value::String(format_pg_timestamptz(v)));
    }
    if let Ok(v) = row.try_get::<_, NaiveDateTime>(idx) {
        return Some(serde_json::Value::String(v.to_string()));
    }
    if let Ok(v) = row.try_get::<_, NaiveDate>(idx) {
        return Some(serde_json::Value::String(v.to_string()));
    }
    if let Ok(v) = row.try_get::<_, NaiveTime>(idx) {
        return Some(serde_json::Value::String(v.to_string()));
    }
    None
}

struct PgSystemU32(u32);

impl<'a> FromSql<'a> for PgSystemU32 {
    fn from_sql(_: &Type, raw: &'a [u8]) -> Result<Self, Box<dyn std::error::Error + Sync + Send>> {
        let bytes: [u8; 4] = raw.try_into().map_err(|_| "expected 4 bytes for PostgreSQL system u32")?;
        Ok(Self(u32::from_be_bytes(bytes)))
    }

    fn accepts(ty: &Type) -> bool {
        matches!(*ty, Type::XID | Type::CID)
    }
}

/// A `FromSql` adapter that accepts any PostgreSQL type and reads its raw
/// bytes as a UTF-8 string. This is used as a last-resort fallback to handle
/// custom types (enums, domains, etc.) that tokio_postgres cannot map to
/// built-in Rust types in the binary protocol.
struct PgAnyString(String);

impl<'a> FromSql<'a> for PgAnyString {
    fn from_sql(_: &Type, raw: &'a [u8]) -> Result<Self, Box<dyn std::error::Error + Sync + Send>> {
        std::str::from_utf8(raw)
            .map(|s| PgAnyString(s.to_string()))
            .map_err(|e| Box::new(e) as Box<dyn std::error::Error + Sync + Send>)
    }

    fn accepts(_: &Type) -> bool {
        true
    }
}

struct PgNumeric(String);

impl<'a> FromSql<'a> for PgNumeric {
    fn from_sql(_: &Type, raw: &'a [u8]) -> Result<Self, Box<dyn std::error::Error + Sync + Send>> {
        decode_pg_numeric_bytes(raw).map(Self).ok_or_else(|| "invalid PostgreSQL numeric binary value".into())
    }

    fn accepts(ty: &Type) -> bool {
        *ty == Type::NUMERIC
    }
}

fn decode_pg_numeric_bytes(raw: &[u8]) -> Option<String> {
    const POSITIVE: u16 = 0x0000;
    const NEGATIVE: u16 = 0x4000;
    const NAN: u16 = 0xC000;
    const POSITIVE_INFINITY: u16 = 0xD000;
    const NEGATIVE_INFINITY: u16 = 0xF000;

    let digit_count = usize::from(u16::from_be_bytes(raw.get(0..2)?.try_into().ok()?));
    let weight = i16::from_be_bytes(raw.get(2..4)?.try_into().ok()?);
    let sign = u16::from_be_bytes(raw.get(4..6)?.try_into().ok()?);
    let scale = usize::from(u16::from_be_bytes(raw.get(6..8)?.try_into().ok()?));
    let expected_len = digit_count.checked_mul(2)?.checked_add(8)?;
    if raw.len() != expected_len {
        return None;
    }
    match sign {
        NAN => return Some("NaN".to_string()),
        POSITIVE_INFINITY => return Some("Infinity".to_string()),
        NEGATIVE_INFINITY => return Some("-Infinity".to_string()),
        POSITIVE | NEGATIVE => {}
        _ => return None,
    }

    let digits = raw[8..].chunks_exact(2).map(|chunk| u16::from_be_bytes([chunk[0], chunk[1]])).collect::<Vec<_>>();
    if digits.iter().any(|digit| *digit > 9999) {
        return None;
    }

    let integer_groups = if weight >= 0 { usize::try_from(weight).ok()?.checked_add(1)? } else { 0 };
    let fractional_groups = scale.checked_add(3)? / 4;
    let mut text = String::with_capacity(integer_groups.saturating_mul(4).max(1).saturating_add(scale + 2));
    if sign == NEGATIVE && digits.iter().any(|digit| *digit != 0) {
        text.push('-');
    }
    if integer_groups == 0 {
        text.push('0');
    } else {
        for group_index in 0..integer_groups {
            let digit = digits.get(group_index).copied().unwrap_or(0);
            if group_index == 0 {
                write!(&mut text, "{digit}").ok()?;
            } else {
                write!(&mut text, "{digit:04}").ok()?;
            }
        }
    }
    if scale > 0 {
        text.push('.');
        let fractional_start = text.len();
        for group_index in 0..fractional_groups {
            let digit_index = i32::from(weight) + 1 + i32::try_from(group_index).ok()?;
            let digit = usize::try_from(digit_index).ok().and_then(|index| digits.get(index)).copied().unwrap_or(0);
            write!(&mut text, "{digit:04}").ok()?;
        }
        text.truncate(fractional_start + scale);
    }
    Some(text)
}

/// PostgreSQL `money` is sent in the binary protocol as a signed 64-bit
/// integer scaled by 100 (the smallest unit of the currency). It is not
/// decoded by `rust_decimal`, so attempting to read it as `Decimal` produces
/// NULL in the result grid.
struct PgMoney(i64);

impl<'a> FromSql<'a> for PgMoney {
    fn from_sql(_: &Type, raw: &'a [u8]) -> Result<Self, Box<dyn std::error::Error + Sync + Send>> {
        let bytes: [u8; 8] = raw.try_into().map_err(|_| "expected 8 bytes for PostgreSQL money")?;
        Ok(Self(i64::from_be_bytes(bytes)))
    }

    fn accepts(ty: &Type) -> bool {
        *ty == Type::MONEY
    }
}

fn format_pg_money(value: i64) -> String {
    let negative = value < 0;
    let absolute = (value as i128).abs();
    let formatted = format!("{}.{:02}", absolute / 100, absolute % 100);
    if negative {
        format!("-{formatted}")
    } else {
        formatted
    }
}

/// A `FromSql` adapter that accepts any PostgreSQL type and returns the raw
/// bytes unchanged. Used to decode custom types like pgvector whose binary
/// format we handle ourselves.
struct PgRawBytes(Vec<u8>);

impl<'a> FromSql<'a> for PgRawBytes {
    fn from_sql(_: &Type, raw: &'a [u8]) -> Result<Self, Box<dyn std::error::Error + Sync + Send>> {
        Ok(PgRawBytes(raw.to_vec()))
    }

    fn accepts(_: &Type) -> bool {
        true
    }
}

#[derive(Clone, Copy, Debug, PartialEq)]
struct PgPoint {
    x: f64,
    y: f64,
}

impl<'a> FromSql<'a> for PgPoint {
    fn from_sql(_: &Type, raw: &'a [u8]) -> Result<Self, Box<dyn std::error::Error + Sync + Send>> {
        decode_pg_point_bytes(raw).ok_or_else(|| "expected 16 bytes for PostgreSQL point".into())
    }

    fn accepts(ty: &Type) -> bool {
        *ty == Type::POINT
    }
}

fn decode_pg_point_bytes(raw: &[u8]) -> Option<PgPoint> {
    let raw: [u8; 16] = raw.try_into().ok()?;
    Some(PgPoint {
        x: f64::from_be_bytes(raw[0..8].try_into().ok()?),
        y: f64::from_be_bytes(raw[8..16].try_into().ok()?),
    })
}

fn format_pg_float(value: f64) -> String {
    if value == f64::INFINITY {
        "Infinity".to_string()
    } else if value == f64::NEG_INFINITY {
        "-Infinity".to_string()
    } else {
        value.to_string()
    }
}

fn format_pg_point(point: PgPoint) -> String {
    format!("({},{})", format_pg_float(point.x), format_pg_float(point.y))
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
struct PgInterval {
    microseconds: i64,
    days: i32,
    months: i32,
}

impl<'a> FromSql<'a> for PgInterval {
    fn from_sql(_: &Type, raw: &'a [u8]) -> Result<Self, Box<dyn std::error::Error + Sync + Send>> {
        decode_pg_interval_bytes(raw).ok_or_else(|| "expected 16 bytes for PostgreSQL interval".into())
    }

    fn accepts(ty: &Type) -> bool {
        *ty == Type::INTERVAL
    }
}

fn decode_pg_interval_bytes(raw: &[u8]) -> Option<PgInterval> {
    let raw: [u8; 16] = raw.try_into().ok()?;
    Some(PgInterval {
        microseconds: i64::from_be_bytes(raw[0..8].try_into().ok()?),
        days: i32::from_be_bytes(raw[8..12].try_into().ok()?),
        months: i32::from_be_bytes(raw[12..16].try_into().ok()?),
    })
}

fn push_pg_interval_component(parts: &mut Vec<String>, value: i64, singular: &str, plural: &str) {
    if value == 0 {
        return;
    }
    let unit = if value.abs() == 1 { singular } else { plural };
    parts.push(format!("{value} {unit}"));
}

fn format_pg_interval_time(microseconds: i64) -> String {
    let signed_microseconds = i128::from(microseconds);
    let sign = if signed_microseconds < 0 { "-" } else { "" };
    let absolute_microseconds = signed_microseconds.abs();
    let hours = absolute_microseconds / 3_600_000_000;
    let minutes = absolute_microseconds / 60_000_000 % 60;
    let seconds = absolute_microseconds / 1_000_000 % 60;
    let fraction = absolute_microseconds % 1_000_000;
    let mut formatted = format!("{sign}{hours:02}:{minutes:02}:{seconds:02}");
    if fraction != 0 {
        let fraction = format!("{fraction:06}");
        formatted.push('.');
        formatted.push_str(fraction.trim_end_matches('0'));
    }
    formatted
}

fn format_pg_interval(interval: PgInterval) -> String {
    let total_months = i64::from(interval.months);
    let years = total_months / 12;
    let months = total_months % 12;
    let mut parts = Vec::with_capacity(4);
    push_pg_interval_component(&mut parts, years, "year", "years");
    push_pg_interval_component(&mut parts, months, "mon", "mons");
    push_pg_interval_component(&mut parts, i64::from(interval.days), "day", "days");
    parts.push(format_pg_interval_time(interval.microseconds));
    parts.join(" ")
}

struct PgDateRange(String);

impl<'a> FromSql<'a> for PgDateRange {
    fn from_sql(_: &Type, raw: &'a [u8]) -> Result<Self, Box<dyn std::error::Error + Sync + Send>> {
        decode_pg_daterange_bytes(raw).map(Self).ok_or_else(|| "invalid PostgreSQL daterange binary value".into())
    }

    fn accepts(ty: &Type) -> bool {
        *ty == Type::DATE_RANGE
    }
}

const PG_RANGE_EMPTY: u8 = 0b0000_0001;
const PG_RANGE_LOWER_INCLUSIVE: u8 = 0b0000_0010;
const PG_RANGE_UPPER_INCLUSIVE: u8 = 0b0000_0100;
const PG_RANGE_LOWER_UNBOUNDED: u8 = 0b0000_1000;
const PG_RANGE_UPPER_UNBOUNDED: u8 = 0b0001_0000;
const PG_RANGE_KNOWN_FLAGS: u8 = PG_RANGE_EMPTY
    | PG_RANGE_LOWER_INCLUSIVE
    | PG_RANGE_UPPER_INCLUSIVE
    | PG_RANGE_LOWER_UNBOUNDED
    | PG_RANGE_UPPER_UNBOUNDED;

fn decode_pg_date_bound(raw: &[u8], cursor: &mut usize, unbounded: bool) -> Option<String> {
    if unbounded {
        return Some(String::new());
    }

    let length = read_i32_be(raw, cursor)?;
    if length != 4 {
        return None;
    }
    let days = read_i32_be(raw, cursor)?;
    match days {
        i32::MIN => Some("-infinity".to_string()),
        i32::MAX => Some("infinity".to_string()),
        days => NaiveDate::from_ymd_opt(2000, 1, 1)?
            .checked_add_signed(chrono::Duration::days(i64::from(days)))
            .map(|date| date.to_string()),
    }
}

fn decode_pg_daterange_bytes(raw: &[u8]) -> Option<String> {
    let (&flags, _) = raw.split_first()?;
    if flags & !PG_RANGE_KNOWN_FLAGS != 0 {
        return None;
    }
    if flags == PG_RANGE_EMPTY {
        return (raw.len() == 1).then(|| "empty".to_string());
    }
    if flags & PG_RANGE_EMPTY != 0 {
        return None;
    }

    let lower_unbounded = flags & PG_RANGE_LOWER_UNBOUNDED != 0;
    let upper_unbounded = flags & PG_RANGE_UPPER_UNBOUNDED != 0;
    if (lower_unbounded && flags & PG_RANGE_LOWER_INCLUSIVE != 0)
        || (upper_unbounded && flags & PG_RANGE_UPPER_INCLUSIVE != 0)
    {
        return None;
    }

    let mut cursor = 1;
    let lower = decode_pg_date_bound(raw, &mut cursor, lower_unbounded)?;
    let upper = decode_pg_date_bound(raw, &mut cursor, upper_unbounded)?;
    if cursor != raw.len() {
        return None;
    }

    let lower_delimiter = if flags & PG_RANGE_LOWER_INCLUSIVE != 0 { '[' } else { '(' };
    let upper_delimiter = if flags & PG_RANGE_UPPER_INCLUSIVE != 0 { ']' } else { ')' };
    Some(format!("{lower_delimiter}{lower},{upper}{upper_delimiter}"))
}

/// Decode pgvector binary format into a Vec<f32>.
///
/// pgvector binary layout (big-endian):
/// - 2 bytes: dimensions (uint16)
/// - 2 bytes: unused (padding)
/// - N*4 bytes: IEEE 754 f32 values
fn decode_pgvector_bytes(raw: &[u8]) -> Option<Vec<f32>> {
    if raw.len() < 4 {
        return None;
    }
    let dims = u16::from_be_bytes([raw[0], raw[1]]) as usize;
    let expected_len = 4 + dims * 4;
    if raw.len() != expected_len {
        return None;
    }
    let floats: Vec<f32> =
        raw[4..].chunks_exact(4).map(|chunk| f32::from_be_bytes([chunk[0], chunk[1], chunk[2], chunk[3]])).collect();
    Some(floats)
}

fn pg_u32_number(v: u32) -> serde_json::Value {
    serde_json::Value::Number(serde_json::Number::from(v))
}

fn pg_system_u32_to_json(row: &Row, idx: usize) -> Option<serde_json::Value> {
    if let Ok(v) = row.try_get::<_, u32>(idx) {
        return Some(pg_u32_number(v));
    }
    row.try_get::<_, PgSystemU32>(idx).ok().map(|v| pg_u32_number(v.0))
}

fn pg_optional_array_to_json<T>(
    values: Vec<Option<T>>,
    map_value: impl Fn(T) -> serde_json::Value,
) -> serde_json::Value {
    serde_json::Value::Array(
        values.into_iter().map(|value| value.map(&map_value).unwrap_or(serde_json::Value::Null)).collect(),
    )
}

fn pg_json_array_values_to_json(values: Vec<Option<serde_json::Value>>) -> serde_json::Value {
    pg_optional_array_to_json(values, |value| serde_json::Value::String(value.to_string()))
}

fn pg_float_number(v: f64) -> serde_json::Value {
    serde_json::Number::from_f64(v).map(serde_json::Value::Number).unwrap_or(serde_json::Value::Null)
}

fn decode_pg_network_address_bytes(raw: &[u8], force_cidr_output: bool) -> Option<String> {
    let family = *raw.first()?;
    let bits = *raw.get(1)?;
    let is_cidr = *raw.get(2)? != 0;
    let addr_len = *raw.get(3)? as usize;
    let addr = raw.get(4..)?;
    if addr.len() != addr_len {
        return None;
    }

    let (address, host_bits) = match (family, addr_len) {
        (2, 4) => {
            let bytes: [u8; 4] = addr.try_into().ok()?;
            (std::net::IpAddr::V4(std::net::Ipv4Addr::from(bytes)).to_string(), 32)
        }
        (3, 16) => {
            let bytes: [u8; 16] = addr.try_into().ok()?;
            (std::net::IpAddr::V6(std::net::Ipv6Addr::from(bytes)).to_string(), 128)
        }
        _ => return None,
    };

    if bits > host_bits {
        return None;
    }

    if force_cidr_output || is_cidr || bits != host_bits {
        Some(format!("{address}/{bits}"))
    } else {
        Some(address)
    }
}

fn decode_pg_macaddr_bytes(raw: &[u8]) -> Option<String> {
    if !matches!(raw.len(), 6 | 8) {
        return None;
    }
    Some(raw.iter().map(|byte| format!("{byte:02x}")).collect::<Vec<_>>().join(":"))
}

fn decode_pg_bit_string_bytes(raw: &[u8]) -> Option<String> {
    let mut cursor = 0;
    let bit_len = read_i32_be(raw, &mut cursor)?;
    if bit_len < 0 {
        return None;
    }
    let bit_len = bit_len as usize;
    let data = raw.get(cursor..)?;
    if data.len() != bit_len.div_ceil(8) {
        return None;
    }

    let mut bits = String::with_capacity(bit_len);
    for index in 0..bit_len {
        let byte = data[index / 8];
        let bit = (byte >> (7 - (index % 8))) & 1;
        bits.push(if bit == 1 { '1' } else { '0' });
    }
    Some(bits)
}

fn pg_network_address_to_json_value(row: &Row, idx: usize, force_cidr_output: bool) -> Option<serde_json::Value> {
    row.try_get::<_, PgRawBytes>(idx)
        .ok()
        .and_then(|raw| decode_pg_network_address_bytes(&raw.0, force_cidr_output))
        .map(serde_json::Value::String)
}

fn pg_macaddr_to_json_value(row: &Row, idx: usize) -> Option<serde_json::Value> {
    row.try_get::<_, PgRawBytes>(idx)
        .ok()
        .and_then(|raw| decode_pg_macaddr_bytes(&raw.0))
        .map(serde_json::Value::String)
}

fn pg_bit_string_to_json_value(row: &Row, idx: usize) -> Option<serde_json::Value> {
    row.try_get::<_, PgRawBytes>(idx)
        .ok()
        .and_then(|raw| decode_pg_bit_string_bytes(&raw.0))
        .map(serde_json::Value::String)
}

fn pg_network_address_array_to_json_value(row: &Row, idx: usize, force_cidr_output: bool) -> Option<serde_json::Value> {
    row.try_get::<_, Vec<Option<PgRawBytes>>>(idx).ok().map(|values| {
        pg_optional_array_to_json(values, |raw| {
            decode_pg_network_address_bytes(&raw.0, force_cidr_output)
                .map(serde_json::Value::String)
                .unwrap_or_else(|| super::binary_value_to_json(&raw.0))
        })
    })
}

fn pg_macaddr_array_to_json_value(row: &Row, idx: usize) -> Option<serde_json::Value> {
    row.try_get::<_, Vec<Option<PgRawBytes>>>(idx).ok().map(|values| {
        pg_optional_array_to_json(values, |raw| {
            decode_pg_macaddr_bytes(&raw.0)
                .map(serde_json::Value::String)
                .unwrap_or_else(|| super::binary_value_to_json(&raw.0))
        })
    })
}

fn pg_bit_string_array_to_json_value(row: &Row, idx: usize) -> Option<serde_json::Value> {
    row.try_get::<_, Vec<Option<PgRawBytes>>>(idx).ok().map(|values| {
        pg_optional_array_to_json(values, |raw| {
            decode_pg_bit_string_bytes(&raw.0)
                .map(serde_json::Value::String)
                .unwrap_or_else(|| super::binary_value_to_json(&raw.0))
        })
    })
}

fn pg_array_to_json_value(row: &Row, idx: usize) -> Option<serde_json::Value> {
    if let Ok(values) = row.try_get::<_, Vec<Option<serde_json::Value>>>(idx) {
        return Some(pg_json_array_values_to_json(values));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<String>>>(idx) {
        return Some(pg_optional_array_to_json(values, serde_json::Value::String));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<bool>>>(idx) {
        return Some(pg_optional_array_to_json(values, serde_json::Value::Bool));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<PgNumeric>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| serde_json::Value::String(v.0)));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<uuid::Uuid>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| serde_json::Value::String(v.to_string())));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<DateTime<Local>>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| serde_json::Value::String(format_pg_timestamptz(v))));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<NaiveDateTime>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| serde_json::Value::String(v.to_string())));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<NaiveDate>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| serde_json::Value::String(v.to_string())));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<NaiveTime>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| serde_json::Value::String(v.to_string())));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<u32>>>(idx) {
        return Some(pg_optional_array_to_json(values, pg_u32_number));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<i8>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| serde_json::Value::Number(v.into())));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<i16>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| serde_json::Value::Number(v.into())));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<i32>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| serde_json::Value::Number(v.into())));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<i64>>>(idx) {
        return Some(pg_optional_array_to_json(values, super::safe_i64_to_json));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<f32>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| pg_float_number(v as f64)));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<f64>>>(idx) {
        return Some(pg_optional_array_to_json(values, pg_float_number));
    }
    if let Ok(values) = row.try_get::<_, Vec<Option<PgAnyString>>>(idx) {
        return Some(pg_optional_array_to_json(values, |v| serde_json::Value::String(v.0)));
    }
    None
}

fn format_pg_timestamptz(value: DateTime<Local>) -> String {
    value.to_rfc3339()
}

/// 时间类型解码失败后的回退目标，与原 if 链中时间分支之后的匹配顺序一一对应。
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub(crate) enum PgTemporalFallback {
    /// 数组类型名（下划线开头）落到通用数组解码。
    GenericArray,
    /// `VECTOR(...)` 形式的类型名落到 pgvector 解码。
    Vector,
    /// 其余落到通用试探链。
    Probe,
}

/// 每列一次的类型分类结果，避免在逐单元格路径上重复 `to_uppercase` 与字符串比较链。
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub(crate) enum PgColType {
    Bytea,
    Json,
    Bool,
    Point,
    Interval,
    DateRange,
    Temporal { fallback: PgTemporalFallback },
    Numeric,
    Money,
    Uuid,
    Inet { cidr: bool },
    MacAddr,
    BitString,
    TsVector,
    SystemU32,
    InetArray { cidr: bool },
    MacAddrArray,
    BitStringArray,
    GenericArray,
    Vector,
    Geometry,
    Other,
}

fn pg_scalar_type_requires_text_protocol(oid: u32, col_type: PgColType) -> bool {
    Type::from_oid(oid).is_none() && !matches!(col_type, PgColType::Vector | PgColType::Geometry)
}

/// PostgreSQL `reg*` types are OID-backed, but their useful representation is
/// the catalog name returned by the text protocol (for example `regtype`
/// returns `integer`). Decoding their binary payload as a generic value leaves
/// the raw four-byte OID on the UI boundary, which is rendered as gibberish.
fn pg_type_is_reg_type(pg_type: &Type) -> bool {
    matches!(
        pg_type.oid(),
        oid if [
            Type::REGPROC.oid(),
            Type::REGPROCEDURE.oid(),
            Type::REGOPER.oid(),
            Type::REGOPERATOR.oid(),
            Type::REGCLASS.oid(),
            Type::REGTYPE.oid(),
            Type::REGNAMESPACE.oid(),
            Type::REGROLE.oid(),
            Type::REGCOLLATION.oid(),
            Type::REGCONFIG.oid(),
            Type::REGDICTIONARY.oid(),
            Type::REGPROC_ARRAY.oid(),
            Type::REGPROCEDURE_ARRAY.oid(),
            Type::REGOPER_ARRAY.oid(),
            Type::REGOPERATOR_ARRAY.oid(),
            Type::REGCLASS_ARRAY.oid(),
            Type::REGTYPE_ARRAY.oid(),
            Type::REGNAMESPACE_ARRAY.oid(),
            Type::REGROLE_ARRAY.oid(),
            Type::REGCOLLATION_ARRAY.oid(),
            Type::REGCONFIG_ARRAY.oid(),
            Type::REGDICTIONARY_ARRAY.oid(),
        ]
        .contains(&oid)
    )
}

fn pg_type_requires_text_protocol(pg_type: &Type, col_type: PgColType) -> bool {
    if pg_type.oid() == Type::RECORD.oid() || pg_type.oid() == Type::RECORD_ARRAY.oid() || pg_type_is_reg_type(pg_type)
    {
        return true;
    }

    match pg_type.kind() {
        Kind::Enum(_) => false,
        Kind::Array(element_type) => Type::from_oid(element_type.oid()).is_none(),
        Kind::Simple => pg_scalar_type_requires_text_protocol(pg_type.oid(), col_type),
        _ => Type::from_oid(pg_type.oid()).is_none(),
    }
}

pub(crate) fn classify_pg_type(type_name: &str) -> PgColType {
    let upper = type_name.to_uppercase();

    if upper == "BYTEA" {
        return PgColType::Bytea;
    }
    if upper == "JSON" || upper == "JSONB" {
        return PgColType::Json;
    }
    if upper == "BOOL" {
        return PgColType::Bool;
    }
    if upper == "POINT" {
        return PgColType::Point;
    }
    if upper == "INTERVAL" {
        return PgColType::Interval;
    }
    if upper == "DATERANGE" {
        return PgColType::DateRange;
    }
    if upper.contains("TIMESTAMP")
        || upper == "DATE"
        || upper == "TIME"
        || upper == "TIMETZ"
        || upper.contains("INTERVAL")
    {
        let fallback = if upper.starts_with('_') {
            PgTemporalFallback::GenericArray
        } else if upper.starts_with("VECTOR(") {
            PgTemporalFallback::Vector
        } else {
            PgTemporalFallback::Probe
        };
        return PgColType::Temporal { fallback };
    }
    if upper == "MONEY" {
        return PgColType::Money;
    }
    if upper == "NUMERIC" || upper == "DECIMAL" {
        return PgColType::Numeric;
    }
    if upper == "UUID" {
        return PgColType::Uuid;
    }
    if matches!(upper.as_str(), "INET" | "CIDR") {
        return PgColType::Inet { cidr: upper == "CIDR" };
    }
    if matches!(upper.as_str(), "MACADDR" | "MACADDR8") {
        return PgColType::MacAddr;
    }
    if matches!(upper.as_str(), "BIT" | "VARBIT") {
        return PgColType::BitString;
    }
    if upper == "TSVECTOR" {
        return PgColType::TsVector;
    }
    if matches!(upper.as_str(), "OID" | "XID" | "CID") {
        return PgColType::SystemU32;
    }
    if matches!(upper.as_str(), "_INET" | "_CIDR") {
        return PgColType::InetArray { cidr: upper == "_CIDR" };
    }
    if matches!(upper.as_str(), "_MACADDR" | "_MACADDR8") {
        return PgColType::MacAddrArray;
    }
    if matches!(upper.as_str(), "_BIT" | "_VARBIT") {
        return PgColType::BitStringArray;
    }
    if upper.starts_with('_') {
        return PgColType::GenericArray;
    }
    if upper == "VECTOR" || upper.starts_with("VECTOR(") {
        return PgColType::Vector;
    }
    if upper == "GEOMETRY" || upper == "GEOGRAPHY" {
        return PgColType::Geometry;
    }
    PgColType::Other
}

pub(crate) fn classify_pg_column_types(column_types: &[String]) -> Vec<PgColType> {
    column_types.iter().map(|type_name| classify_pg_type(type_name)).collect()
}

pub(crate) fn pg_value_to_json_classified(row: &Row, idx: usize, col_type: PgColType) -> serde_json::Value {
    match col_type {
        PgColType::Bytea => row
            .try_get::<_, Vec<u8>>(idx)
            .map(|bytes| super::binary_value_to_json(&bytes))
            .unwrap_or(serde_json::Value::Null),
        PgColType::Json => {
            if let Ok(v) = row.try_get::<_, serde_json::Value>(idx) {
                return serde_json::Value::String(v.to_string());
            }
            if let Ok(v) = row.try_get::<_, String>(idx) {
                return serde_json::Value::String(v);
            }
            serde_json::Value::Null
        }
        PgColType::Bool => pg_bool_value_to_json(row, idx),
        PgColType::Point => row
            .try_get::<_, PgPoint>(idx)
            .map(|point| serde_json::Value::String(format_pg_point(point)))
            .unwrap_or(serde_json::Value::Null),
        PgColType::Interval => row
            .try_get::<_, PgInterval>(idx)
            .map(|interval| serde_json::Value::String(format_pg_interval(interval)))
            .unwrap_or_else(|_| pg_fallback_value_to_json(row, idx)),
        PgColType::DateRange => row
            .try_get::<_, PgDateRange>(idx)
            .map(|range| serde_json::Value::String(range.0))
            .unwrap_or_else(|_| pg_fallback_value_to_json(row, idx)),
        PgColType::Temporal { fallback } => {
            if let Some(v) = pg_temporal_to_json_value(row, idx) {
                return v;
            }
            match fallback {
                PgTemporalFallback::GenericArray => pg_array_to_json_value(row, idx).unwrap_or(serde_json::Value::Null),
                PgTemporalFallback::Vector => pg_vector_value_to_json(row, idx),
                PgTemporalFallback::Probe => pg_fallback_value_to_json(row, idx),
            }
        }
        PgColType::Numeric => {
            row.try_get::<_, PgNumeric>(idx).map(|v| serde_json::Value::String(v.0)).unwrap_or(serde_json::Value::Null)
        }
        PgColType::Money => row
            .try_get::<_, PgMoney>(idx)
            .map(|v| serde_json::Value::String(format_pg_money(v.0)))
            .unwrap_or(serde_json::Value::Null),
        PgColType::Uuid => row
            .try_get::<_, uuid::Uuid>(idx)
            .map(|v| serde_json::Value::String(v.to_string()))
            .unwrap_or(serde_json::Value::Null),
        PgColType::Inet { cidr } => pg_network_address_to_json_value(row, idx, cidr).unwrap_or(serde_json::Value::Null),
        PgColType::MacAddr => pg_macaddr_to_json_value(row, idx).unwrap_or(serde_json::Value::Null),
        PgColType::BitString => pg_bit_string_to_json_value(row, idx).unwrap_or(serde_json::Value::Null),
        PgColType::TsVector => row
            .try_get::<_, PgRawBytes>(idx)
            .ok()
            .and_then(|raw| decode_tsvector_bytes(&raw.0))
            .map(serde_json::Value::String)
            .unwrap_or(serde_json::Value::Null),
        PgColType::SystemU32 => pg_system_u32_to_json(row, idx).unwrap_or(serde_json::Value::Null),
        PgColType::InetArray { cidr } => {
            pg_network_address_array_to_json_value(row, idx, cidr).unwrap_or(serde_json::Value::Null)
        }
        PgColType::MacAddrArray => pg_macaddr_array_to_json_value(row, idx).unwrap_or(serde_json::Value::Null),
        PgColType::BitStringArray => pg_bit_string_array_to_json_value(row, idx).unwrap_or(serde_json::Value::Null),
        PgColType::GenericArray => pg_array_to_json_value(row, idx).unwrap_or(serde_json::Value::Null),
        PgColType::Vector => pg_vector_value_to_json(row, idx),
        PgColType::Geometry => {
            if let Ok(PgRawBytes(raw)) = row.try_get::<_, PgRawBytes>(idx) {
                return super::wkb::wkb_to_wkt(&raw)
                    .map(serde_json::Value::String)
                    .unwrap_or_else(|| super::binary_value_to_json(&raw));
            }
            serde_json::Value::Null
        }
        PgColType::Other => pg_fallback_value_to_json(row, idx),
    }
}

fn pg_value_to_json_with_srid(row: &Row, idx: usize, col_type: PgColType) -> (serde_json::Value, Option<u32>) {
    if col_type != PgColType::Geometry {
        return (pg_value_to_json_classified(row, idx, col_type), None);
    }
    if let Ok(PgRawBytes(raw)) = row.try_get::<_, PgRawBytes>(idx) {
        return match super::wkb::decode_wkb_geometry(&raw) {
            Some(geometry) => (serde_json::Value::String(geometry.wkt), geometry.srid),
            None => (super::binary_value_to_json(&raw), None),
        };
    }
    (serde_json::Value::Null, None)
}

fn pg_text_fallback_value(value: &str, col_type: Option<PgColType>) -> (serde_json::Value, Option<u32>) {
    let (value, srid, _) = pg_text_fallback_value_with_spatial(value, col_type);
    (value, srid)
}

fn pg_text_fallback_value_with_spatial(
    value: &str,
    col_type: Option<PgColType>,
) -> (serde_json::Value, Option<u32>, bool) {
    match col_type {
        Some(PgColType::Geometry) => decode_pg_text_wkb(value)
            .map(|geometry| (serde_json::Value::String(geometry.wkt), geometry.srid, true))
            .or_else(|| split_pg_ewkt(value, false).map(|(value, srid)| (value, srid, true)))
            .unwrap_or_else(|| (serde_json::Value::String(value.to_string()), None, true)),
        Some(_) => (serde_json::Value::String(value.to_string()), None, false),
        None => decode_pg_text_wkb(value)
            .map(|geometry| (serde_json::Value::String(geometry.wkt), geometry.srid, true))
            .or_else(|| split_pg_ewkt(value, true).map(|(value, srid)| (value, srid, true)))
            .unwrap_or_else(|| (serde_json::Value::String(value.to_string()), None, false)),
    }
}

fn decode_pg_text_wkb(value: &str) -> Option<super::wkb::DecodedGeometry> {
    let trimmed = value.trim();
    let hex = trimmed
        .strip_prefix("0x")
        .or_else(|| trimmed.strip_prefix("0X"))
        .or_else(|| trimmed.strip_prefix("\\x"))
        .or_else(|| trimmed.strip_prefix("\\X"))
        .unwrap_or(trimmed);
    if hex.len() < 10 || !hex.len().is_multiple_of(2) || !matches!(&hex[..2], "00" | "01") || !hex.is_ascii() {
        return None;
    }
    let bytes = hex
        .as_bytes()
        .chunks_exact(2)
        .map(|pair| {
            let text = std::str::from_utf8(pair).ok()?;
            u8::from_str_radix(text, 16).ok()
        })
        .collect::<Option<Vec<_>>>()?;
    super::wkb::decode_wkb_geometry(&bytes)
}

fn split_pg_ewkt(value: &str, require_recognizable_wkt: bool) -> Option<(serde_json::Value, Option<u32>)> {
    let rest = value.strip_prefix("SRID=")?;
    let (srid, wkt) = rest.split_once(';')?;
    let srid = srid.parse::<i64>().ok().and_then(|value| u32::try_from(value).ok())?;
    if require_recognizable_wkt && !is_recognizable_wkt(wkt) {
        return None;
    }
    Some((serde_json::Value::String(wkt.to_string()), (srid != 0).then_some(srid)))
}

fn is_recognizable_wkt(value: &str) -> bool {
    let trimmed = value.trim_start();
    const TYPES: [&str; 7] =
        ["POINT", "LINESTRING", "POLYGON", "MULTIPOINT", "MULTILINESTRING", "MULTIPOLYGON", "GEOMETRYCOLLECTION"];
    TYPES.iter().any(|geometry_type| {
        trimmed
            .get(..geometry_type.len())
            .filter(|prefix| prefix.eq_ignore_ascii_case(geometry_type))
            .and_then(|_| trimmed.as_bytes().get(geometry_type.len()))
            .is_some_and(|next| next.is_ascii_whitespace() || *next == b'(')
    })
}

/// Serialize a pgvector `vector` component with f32 shortest round-trip decimal text.
///
/// Casting through `f64` (or fixed fractional rounding) either expands binary noise or
/// truncates remaining single-precision digits; formatting via `f32` display keeps the
/// full float4 value that pgvector stores.
fn pg_vector_element_number(v: f32) -> serde_json::Value {
    v.to_string().parse().map(serde_json::Value::Number).unwrap_or(serde_json::Value::Null)
}

fn pg_vector_value_to_json(row: &Row, idx: usize) -> serde_json::Value {
    if let Ok(PgRawBytes(raw)) = row.try_get::<_, PgRawBytes>(idx) {
        if let Some(floats) = decode_pgvector_bytes(&raw) {
            return serde_json::Value::Array(floats.into_iter().map(pg_vector_element_number).collect());
        }
    }
    serde_json::Value::Null
}

fn pg_fallback_value_to_json(row: &Row, idx: usize) -> serde_json::Value {
    row.try_get::<_, String>(idx)
        .map(serde_json::Value::String)
        .or_else(|e| pg_system_u32_to_json(row, idx).ok_or(e))
        .or_else(|_| row.try_get::<_, i64>(idx).map(super::safe_i64_to_json))
        .or_else(|_| row.try_get::<_, i32>(idx).map(|v| serde_json::Value::Number(v.into())))
        .or_else(|_| row.try_get::<_, i16>(idx).map(|v| serde_json::Value::Number(v.into())))
        .or_else(|_| row.try_get::<_, i8>(idx).map(|v| serde_json::Value::Number(v.into())))
        .or_else(|e| pg_array_to_json_value(row, idx).ok_or(e))
        .or_else(|_| {
            row.try_get::<_, f64>(idx).map(|v| {
                serde_json::Number::from_f64(v).map(serde_json::Value::Number).unwrap_or(serde_json::Value::Null)
            })
        })
        .or_else(|_| {
            row.try_get::<_, f32>(idx).map(|v| {
                serde_json::Number::from_f64((v as f64 * 1_000_000.0).round() / 1_000_000.0)
                    .map(serde_json::Value::Number)
                    .unwrap_or(serde_json::Value::Null)
            })
        })
        .or_else(|_| row.try_get::<_, bool>(idx).map(serde_json::Value::Bool))
        .or_else(|_| row.try_get::<_, uuid::Uuid>(idx).map(|v| serde_json::Value::String(v.to_string())))
        .or_else(|e| pg_temporal_to_json_value(row, idx).ok_or(e))
        .or_else(|_| row.try_get::<_, Vec<u8>>(idx).map(|bytes| super::binary_value_to_json(&bytes)))
        .or_else(|_| row.try_get::<_, PgAnyString>(idx).map(|v| serde_json::Value::String(v.0)))
        .or_else(|_| row.try_get::<_, PgRawBytes>(idx).map(|v| super::binary_value_to_json(&v.0)))
        .unwrap_or(serde_json::Value::Null)
}

fn decode_tsvector_bytes(raw: &[u8]) -> Option<String> {
    let mut cursor = 0;
    let count = read_i32_be(raw, &mut cursor)?;
    if count < 0 {
        return None;
    }

    let mut entries = Vec::with_capacity(count as usize);
    for _ in 0..count {
        let start = cursor;
        while cursor < raw.len() && raw[cursor] != 0 {
            cursor += 1;
        }
        if cursor >= raw.len() {
            return None;
        }
        let lexeme = std::str::from_utf8(&raw[start..cursor]).ok()?;
        cursor += 1;

        let position_count = read_u16_be(raw, &mut cursor)? as usize;
        let mut positions = Vec::with_capacity(position_count);
        for _ in 0..position_count {
            let encoded = read_u16_be(raw, &mut cursor)?;
            let position = encoded & 0x3fff;
            let weight = match encoded >> 14 {
                3 => "A",
                2 => "B",
                1 => "C",
                _ => "",
            };
            positions.push(format!("{position}{weight}"));
        }

        let mut entry = format!("'{}'", escape_tsvector_lexeme(lexeme));
        if !positions.is_empty() {
            entry.push(':');
            entry.push_str(&positions.join(","));
        }
        entries.push(entry);
    }

    if cursor == raw.len() {
        Some(entries.join(" "))
    } else {
        None
    }
}

fn read_i32_be(raw: &[u8], cursor: &mut usize) -> Option<i32> {
    let bytes: [u8; 4] = raw.get(*cursor..*cursor + 4)?.try_into().ok()?;
    *cursor += 4;
    Some(i32::from_be_bytes(bytes))
}

fn read_u16_be(raw: &[u8], cursor: &mut usize) -> Option<u16> {
    let bytes: [u8; 2] = raw.get(*cursor..*cursor + 2)?.try_into().ok()?;
    *cursor += 2;
    Some(u16::from_be_bytes(bytes))
}

fn escape_tsvector_lexeme(value: &str) -> String {
    value.replace('\\', "\\\\").replace('\'', "''")
}

fn pg_error_to_string(err: tokio_postgres::Error) -> String {
    err.as_db_error().map(ToString::to_string).unwrap_or_else(|| err.to_string())
}

/// Tries each SQL tier in `tiers` in order (most-capable first), via `run`,
/// returning the first tier that succeeds. Every driver-compat query in this
/// module (a "does this server have the newer catalog column" primary/compat
/// split, occasionally with a further information_schema fallback) used to
/// hand-roll this same try/log/combine-errors shape once per query; this is
/// the shared version.
///
/// If every tier fails, all of their errors are logged together at debug
/// level (so a fallback firing in production is diagnosable) and the last
/// tier's error is returned to the caller, since it's usually the most
/// specific one for whatever the connected server actually is.
async fn query_with_compat_fallback<T, F, Fut>(
    log_context: &str,
    tiers: &[&'static str],
    mut run: F,
) -> Result<T, String>
where
    F: FnMut(&'static str) -> Fut,
    Fut: std::future::Future<Output = Result<T, tokio_postgres::Error>>,
{
    let mut errors: Vec<String> = Vec::new();
    for sql in tiers {
        match run(sql).await {
            Ok(value) => return Ok(value),
            Err(error) => errors.push(pg_error_to_string(error)),
        }
    }
    log::debug!("[postgres][{log_context}:compat-failed] {}", errors.join("; "));
    Err(errors.into_iter().next_back().unwrap_or_else(|| format!("[postgres][{log_context}] no SQL tiers configured")))
}

fn pg_db_error_to_string(err: &tokio_postgres::error::DbError) -> String {
    format!("{err} (SQLSTATE {})", err.code().code())
}

fn pg_error_from_sources(err: &(dyn std::error::Error + 'static)) -> Option<String> {
    let mut current = Some(err);
    while let Some(source) = current {
        if let Some(pg_error) = source.downcast_ref::<tokio_postgres::Error>() {
            if let Some(db_error) = pg_error.as_db_error() {
                return Some(pg_db_error_to_string(db_error));
            }
        }
        if let Some(db_error) = source.downcast_ref::<tokio_postgres::error::DbError>() {
            return Some(pg_db_error_to_string(db_error));
        }
        current = source.source();
    }
    None
}

fn error_with_sources_to_string(err: &(dyn std::error::Error + 'static)) -> String {
    let mut messages = vec![err.to_string()];
    let mut current = err.source();
    while let Some(source) = current {
        let message = source.to_string();
        if !messages.iter().any(|existing| existing == &message) {
            messages.push(message);
        }
        current = source.source();
    }
    messages.join(": ")
}

fn pg_pool_error_to_string(err: PoolError) -> String {
    pg_error_from_sources(&err).unwrap_or_else(|| error_with_sources_to_string(&err))
}

fn should_retry_postgres_text_query(err: &tokio_postgres::Error) -> bool {
    let message = err.as_db_error().map(ToString::to_string).unwrap_or_else(|| err.to_string()).to_ascii_lowercase();
    should_retry_postgres_text_query_message(&message)
}

fn should_retry_postgres_text_query_message(message: &str) -> bool {
    message.contains("no binary output function")
        || message.contains("no binary send function")
        || message.contains("cannot display a value of type")
}

fn should_retry_postgres_stale_cache(err: &tokio_postgres::Error) -> bool {
    if let Some(db_error) = err.as_db_error() {
        return should_retry_postgres_stale_cache_fields(
            Some(db_error.code().code()),
            db_error.routine(),
            db_error.message(),
        );
    }
    should_retry_postgres_stale_cache_fields(None, None, &err.to_string())
}

fn should_retry_postgres_stale_cache_fields(sqlstate: Option<&str>, routine: Option<&str>, message: &str) -> bool {
    let structured_match = sqlstate == Some("0A000")
        && routine.is_some_and(|routine| routine.eq_ignore_ascii_case("RevalidateCachedQuery"));
    structured_match || message.to_ascii_lowercase().contains("cached plan must not change result type")
}

fn should_fallback_postgres_missing_prepared_statement(err: &tokio_postgres::Error) -> bool {
    if let Some(db_error) = err.as_db_error() {
        return should_fallback_postgres_missing_prepared_statement_fields(
            Some(db_error.code().code()),
            db_error.message(),
        );
    }
    should_fallback_postgres_missing_prepared_statement_fields(None, &err.to_string())
}

fn should_fallback_postgres_missing_prepared_statement_fields(sqlstate: Option<&str>, message: &str) -> bool {
    if sqlstate == Some("26000") {
        return true;
    }
    let message = message.to_ascii_lowercase();
    message.contains("prepared statement") && message.contains("does not exist")
}

fn postgres_unnamed_statement_clients() -> &'static Mutex<HashMap<usize, Weak<deadpool_postgres::StatementCache>>> {
    static CLIENTS: OnceLock<Mutex<HashMap<usize, Weak<deadpool_postgres::StatementCache>>>> = OnceLock::new();
    CLIENTS.get_or_init(|| Mutex::new(HashMap::new()))
}

fn postgres_client_uses_unnamed_statements(client: &deadpool_postgres::Client) -> bool {
    let statement_cache = &client.statement_cache;
    let key = Arc::as_ptr(statement_cache) as usize;
    let mut clients = postgres_unnamed_statement_clients().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
    match clients.get(&key).and_then(Weak::upgrade) {
        Some(cached) if Arc::ptr_eq(&cached, statement_cache) => true,
        _ => {
            clients.remove(&key);
            false
        }
    }
}

fn mark_postgres_client_unnamed_statements(client: &deadpool_postgres::Client) {
    let statement_cache = &client.statement_cache;
    let key = Arc::as_ptr(statement_cache) as usize;
    let mut clients = postgres_unnamed_statement_clients().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
    clients.retain(|_, cached| cached.strong_count() > 0);
    clients.insert(key, Arc::downgrade(statement_cache));
}

fn postgres_typed_params<'a>(
    params: &[&'a (dyn tokio_postgres::types::ToSql + Sync)],
    param_types: &[Type],
) -> Option<Vec<(&'a (dyn tokio_postgres::types::ToSql + Sync), Type)>> {
    (params.len() == param_types.len()).then(|| params.iter().copied().zip(param_types.iter().cloned()).collect())
}

async fn postgres_query_unnamed(
    client: &deadpool_postgres::Client,
    sql: &str,
) -> Result<tokio_postgres::RowStream, tokio_postgres::Error> {
    client.query_typed_raw(sql, std::iter::empty::<(&(dyn tokio_postgres::types::ToSql + Sync), Type)>()).await
}

async fn postgres_query_cached(
    client: &deadpool_postgres::Client,
    sql: &str,
    params: &[&(dyn tokio_postgres::types::ToSql + Sync)],
) -> Result<Vec<Row>, tokio_postgres::Error> {
    if postgres_client_uses_unnamed_statements(client) && params.is_empty() {
        return client.query_typed(sql, &[]).await;
    }
    let stmt = client.prepare_cached(sql).await?;
    if postgres_client_uses_unnamed_statements(client) {
        let Some(typed_params) = postgres_typed_params(params, stmt.params()) else {
            return client.query(&stmt, params).await;
        };
        return client.query_typed(sql, &typed_params).await;
    }
    match client.query(&stmt, params).await {
        Ok(rows) => Ok(rows),
        Err(err) if should_fallback_postgres_missing_prepared_statement(&err) => {
            let Some(typed_params) = postgres_typed_params(params, stmt.params()) else {
                return Err(err);
            };
            log::warn!(
                "[postgres][metadata:missing_prepared_statement] downgrading connection to unnamed statements: {}",
                pg_error_to_string(err)
            );
            mark_postgres_client_unnamed_statements(client);
            client.query_typed(sql, &typed_params).await
        }
        Err(err) if should_retry_postgres_stale_cache(&err) => {
            // Metadata queries can be cached while a table/view definition is
            // changed from another session. Evict and retry once with fresh
            // statement/type metadata instead of surfacing PostgreSQL's stale
            // cached-plan error to the UI.
            log::warn!("[postgres][metadata:stale_cache] evicting cached statement: {}", pg_error_to_string(err));
            client.statement_cache.remove(sql, &[]);
            client.clear_type_cache();
            let stmt = client.prepare_cached(sql).await?;
            client.query(&stmt, params).await
        }
        Err(err) => Err(err),
    }
}

async fn postgres_query_one_cached(
    client: &deadpool_postgres::Client,
    sql: &str,
    params: &[&(dyn tokio_postgres::types::ToSql + Sync)],
) -> Result<Row, tokio_postgres::Error> {
    if postgres_client_uses_unnamed_statements(client) && params.is_empty() {
        return client.query_typed_one(sql, &[]).await;
    }
    let stmt = client.prepare_cached(sql).await?;
    if postgres_client_uses_unnamed_statements(client) {
        let Some(typed_params) = postgres_typed_params(params, stmt.params()) else {
            return client.query_one(&stmt, params).await;
        };
        return client.query_typed_one(sql, &typed_params).await;
    }
    match client.query_one(&stmt, params).await {
        Ok(row) => Ok(row),
        Err(err) if should_fallback_postgres_missing_prepared_statement(&err) => {
            let Some(typed_params) = postgres_typed_params(params, stmt.params()) else {
                return Err(err);
            };
            log::warn!(
                "[postgres][metadata_one:missing_prepared_statement] downgrading connection to unnamed statements: {}",
                pg_error_to_string(err)
            );
            mark_postgres_client_unnamed_statements(client);
            client.query_typed_one(sql, &typed_params).await
        }
        Err(err) if should_retry_postgres_stale_cache(&err) => {
            // Same stale-cache protection as postgres_query_cached, for scalar
            // catalog probes such as pg_proc feature detection.
            log::warn!("[postgres][metadata:stale_cache] evicting cached statement: {}", pg_error_to_string(err));
            client.statement_cache.remove(sql, &[]);
            client.clear_type_cache();
            let stmt = client.prepare_cached(sql).await?;
            client.query_one(&stmt, params).await
        }
        Err(err) => Err(err),
    }
}

#[allow(clippy::large_enum_variant)]
enum PreparedSelectOutcome {
    Complete(Box<QueryResult>),
    TextFallback { column_types: Vec<String>, unsupported_type: String },
}

struct PreparedSelectMetadata {
    columns: Vec<String>,
    column_types: Vec<String>,
    column_classes: Vec<PgColType>,
    unsupported_type: Option<String>,
}

fn prepared_select_metadata(columns: &[tokio_postgres::Column]) -> PreparedSelectMetadata {
    let column_names: Vec<String> = columns.iter().map(|c| c.name().to_string()).collect();
    let column_types: Vec<String> = columns.iter().map(|c| c.type_().name().to_string()).collect();
    let column_classes = classify_pg_column_types(&column_types);
    let unsupported_type = columns.iter().zip(&column_classes).find_map(|(column, col_type)| {
        let pg_type = column.type_();
        pg_type_requires_text_protocol(pg_type, *col_type).then(|| pg_type.name().to_string())
    });
    PreparedSelectMetadata { columns: column_names, column_types, column_classes, unsupported_type }
}

async fn prepare_select_with_metadata(
    client: &deadpool_postgres::Client,
    sql: &str,
) -> Result<(tokio_postgres::Statement, PreparedSelectMetadata), tokio_postgres::Error> {
    let mut stmt = client.prepare_cached(sql).await?;
    let mut metadata = prepared_select_metadata(stmt.columns());
    if metadata.unsupported_type.is_some() {
        stmt = client.prepare(sql).await?;
        metadata = prepared_select_metadata(stmt.columns());
    }
    Ok((stmt, metadata))
}

enum PostgresSelectStreamOutcome {
    Binary { stream: tokio_postgres::RowStream, metadata: PreparedSelectMetadata },
    TextFallback { column_types: Vec<String>, unsupported_type: String },
}

fn postgres_select_stream_outcome(stream: tokio_postgres::RowStream) -> PostgresSelectStreamOutcome {
    let metadata = prepared_select_metadata(stream.columns());
    if let Some(unsupported_type) = metadata.unsupported_type.clone() {
        return PostgresSelectStreamOutcome::TextFallback { column_types: metadata.column_types, unsupported_type };
    }
    PostgresSelectStreamOutcome::Binary { stream, metadata }
}

async fn prepare_unnamed_select_metadata(
    client: &deadpool_postgres::Client,
    sql: &str,
) -> Result<PreparedSelectMetadata, tokio_postgres::Error> {
    // query_typed_raw sends Describe and Execute together. If its result has an
    // unknown user-defined type, tokio-postgres then resolves that type with a
    // second query on the same connection before returning the RowStream. A
    // large result can fill the connection buffers and block that type lookup.
    // Describe once without executing so custom types are cached before the
    // actual unnamed stream starts. The stream remains unnamed to tolerate
    // server-side prepared statement loss in snapshot/proxy environments.
    let stmt = client.prepare(sql).await?;
    Ok(prepared_select_metadata(stmt.columns()))
}

async fn start_postgres_select_stream(
    client: &deadpool_postgres::Client,
    sql: &str,
    force_unnamed: bool,
) -> Result<PostgresSelectStreamOutcome, tokio_postgres::Error> {
    if force_unnamed || postgres_client_uses_unnamed_statements(client) {
        let metadata = prepare_unnamed_select_metadata(client, sql).await?;
        if let Some(unsupported_type) = metadata.unsupported_type {
            return Ok(PostgresSelectStreamOutcome::TextFallback {
                column_types: metadata.column_types,
                unsupported_type,
            });
        }
        return postgres_query_unnamed(client, sql).await.map(postgres_select_stream_outcome);
    }

    let (stmt, metadata) = prepare_select_with_metadata(client, sql).await?;
    if let Some(unsupported_type) = metadata.unsupported_type {
        return Ok(PostgresSelectStreamOutcome::TextFallback { column_types: metadata.column_types, unsupported_type });
    }

    let params: Vec<&(dyn tokio_postgres::types::ToSql + Sync)> = Vec::new();
    match client.query_raw(&stmt, params).await {
        Ok(stream) => Ok(postgres_select_stream_outcome(stream)),
        Err(err) if should_fallback_postgres_missing_prepared_statement(&err) => {
            // Bind failed before execution. Downgrade this physical connection
            // so later queries do not repeat the named-statement round trip.
            log::warn!(
                "[postgres][prepared_statement:missing] downgrading connection to unnamed statements: {}",
                pg_error_to_string(err)
            );
            mark_postgres_client_unnamed_statements(client);
            postgres_query_unnamed(client, sql).await.map(postgres_select_stream_outcome)
        }
        Err(err) => Err(err),
    }
}

async fn execute_select_prepared(
    client: &deadpool_postgres::Client,
    sql: &str,
    start: Instant,
    row_limit: usize,
    progress_clock: Option<&StreamProgressClock>,
    force_unnamed: bool,
) -> Result<PreparedSelectOutcome, tokio_postgres::Error> {
    let stream_start = Instant::now();
    let stream_outcome = start_postgres_select_stream(client, sql, force_unnamed).await?;
    if let Some(progress_clock) = progress_clock {
        progress_clock.mark();
    }
    log::info!(
        "[postgres][select:stream_ready] elapsed_ms={} total_ms={}",
        stream_start.elapsed().as_millis(),
        start.elapsed().as_millis()
    );
    let (stream, metadata) = match stream_outcome {
        PostgresSelectStreamOutcome::Binary { stream, metadata } => (stream, metadata),
        PostgresSelectStreamOutcome::TextFallback { column_types, unsupported_type } => {
            return Ok(PreparedSelectOutcome::TextFallback { column_types, unsupported_type });
        }
    };
    let PreparedSelectMetadata { columns, column_types, column_classes, unsupported_type: _ } = metadata;
    if let Some(progress_clock) = progress_clock {
        progress_clock.mark();
    }
    log::info!(
        "[postgres][select:metadata_ready] total_ms={} column_count={}",
        start.elapsed().as_millis(),
        columns.len()
    );
    tokio::pin!(stream);
    let mut result_rows: Vec<Vec<serde_json::Value>> = Vec::new();
    let mut spatial_values: Vec<Vec<Option<u32>>> = Vec::new();
    let mut spatial_columns = SpatialColumnBuilder::new(
        column_classes
            .iter()
            .enumerate()
            .filter_map(|(index, col_type)| (*col_type == PgColType::Geometry).then_some(index)),
    );
    let mut truncated = false;

    let rows_start = Instant::now();
    while let Some(row_result) = stream.next().await {
        if let Some(progress_clock) = progress_clock {
            progress_clock.mark();
        }
        if result_rows.len() >= row_limit {
            truncated = true;
            break;
        }
        let row = row_result?;
        let mut values = Vec::with_capacity(row.columns().len());
        let mut row_srids = vec![None; row.columns().len()];
        for (i, row_srid) in row_srids.iter_mut().enumerate() {
            let col_type = column_classes.get(i).copied().unwrap_or(PgColType::Other);
            let (value, srid) = pg_value_to_json_with_srid(&row, i, col_type);
            if col_type == PgColType::Geometry {
                spatial_columns.observe(i, srid);
                *row_srid = srid;
            }
            values.push(value);
        }
        result_rows.push(values);
        spatial_values.push(row_srids);
    }
    log::info!(
        "[postgres][select:rows:done] elapsed_ms={} total_ms={} row_count={} truncated={}",
        rows_start.elapsed().as_millis(),
        start.elapsed().as_millis(),
        result_rows.len(),
        truncated
    );

    let (spatial_columns, spatial_values) = spatial_columns.finish_with_values(spatial_values);
    Ok(PreparedSelectOutcome::Complete(Box::new(QueryResult {
        columns,
        column_types,
        column_sortables: Vec::new(),
        spatial_columns,
        spatial_values,
        rows: result_rows,
        affected_rows: 0,
        execution_time_ms: start.elapsed().as_millis(),
        truncated,
        session_id: None,
        has_more: false,
        elasticsearch_raw_body: None,
        messages: Vec::new(),
    })))
}

fn matching_pg_text_column_types(columns: &[String], prepared: Option<Vec<String>>) -> Vec<String> {
    prepared.filter(|types| types.len() == columns.len()).unwrap_or_default()
}

async fn execute_select_text(
    client: &deadpool_postgres::Client,
    sql: &str,
    start: Instant,
    row_limit: usize,
    prepared_column_types: Option<Vec<String>>,
    progress_clock: Option<&StreamProgressClock>,
) -> Result<QueryResult, String> {
    let stream = client.simple_query_raw(sql).await.map_err(pg_error_to_string)?;
    if let Some(progress_clock) = progress_clock {
        progress_clock.mark();
    }
    tokio::pin!(stream);
    let mut columns: Vec<String> = Vec::new();
    let mut result_rows: Vec<Vec<serde_json::Value>> = Vec::new();
    let mut spatial_values: Vec<Vec<Option<u32>>> = Vec::new();
    let column_classes =
        prepared_column_types.as_ref().map(|types| classify_pg_column_types(types)).unwrap_or_default();
    let mut spatial_columns = SpatialColumnBuilder::new(
        column_classes
            .iter()
            .enumerate()
            .filter_map(|(index, col_type)| (*col_type == PgColType::Geometry).then_some(index)),
    );
    let mut truncated = false;

    while let Some(message) = stream.next().await {
        if let Some(progress_clock) = progress_clock {
            progress_clock.mark();
        }
        match message {
            Ok(SimpleQueryMessage::RowDescription(cols)) => {
                columns = cols.iter().map(|c| c.name().to_string()).collect();
            }
            Ok(SimpleQueryMessage::Row(row)) => {
                if columns.is_empty() {
                    columns = row.columns().iter().map(|c| c.name().to_string()).collect();
                }
                if result_rows.len() >= row_limit {
                    truncated = true;
                    break;
                }
                let mut values = Vec::with_capacity(row.len());
                let mut row_srids = vec![None; row.len()];
                for (i, row_srid) in row_srids.iter_mut().enumerate() {
                    match row.try_get(i).map_err(pg_error_to_string)? {
                        Some(value) => {
                            let (decoded, srid, is_spatial) =
                                pg_text_fallback_value_with_spatial(value, column_classes.get(i).copied());
                            values.push(decoded);
                            if is_spatial {
                                spatial_columns.observe(i, srid);
                                *row_srid = srid;
                            }
                        }
                        None => {
                            values.push(serde_json::Value::Null);
                        }
                    }
                }
                result_rows.push(values);
                spatial_values.push(row_srids);
            }
            Err(_) if result_rows.len() >= row_limit => {
                truncated = true;
                break;
            }
            Err(err) => return Err(pg_error_to_string(err)),
            Ok(SimpleQueryMessage::CommandComplete(_)) => {}
            Ok(_) => {}
        }
    }

    let (spatial_columns, spatial_values) = spatial_columns.finish_with_values(spatial_values);
    Ok(QueryResult {
        column_types: matching_pg_text_column_types(&columns, prepared_column_types),
        columns,
        column_sortables: Vec::new(),
        spatial_columns,
        spatial_values,
        rows: result_rows,
        affected_rows: 0,
        execution_time_ms: start.elapsed().as_millis(),
        truncated,
        session_id: None,
        has_more: false,
        elasticsearch_raw_body: None,
        messages: Vec::new(),
    })
}

async fn finish_prepared_select(
    client: &deadpool_postgres::Client,
    sql: &str,
    start: Instant,
    row_limit: usize,
    outcome: PreparedSelectOutcome,
    progress_clock: Option<&StreamProgressClock>,
) -> Result<QueryResult, String> {
    match outcome {
        PreparedSelectOutcome::Complete(result) => Ok(*result),
        PreparedSelectOutcome::TextFallback { column_types, unsupported_type } => {
            log::info!(
                "[postgres][select:text_fallback] unsupported_type={} switching_to=simple_query",
                unsupported_type
            );
            execute_select_text(client, sql, start, row_limit, Some(column_types), progress_clock).await
        }
    }
}

pub(crate) async fn execute_select_query(
    client: &deadpool_postgres::Client,
    sql: &str,
    start: Instant,
    row_limit: usize,
) -> Result<QueryResult, String> {
    execute_select_query_with_progress(client, sql, start, row_limit, None, false).await
}

pub(crate) async fn execute_select_query_unnamed(
    client: &deadpool_postgres::Client,
    sql: &str,
    start: Instant,
    row_limit: usize,
) -> Result<QueryResult, String> {
    execute_select_query_with_progress(client, sql, start, row_limit, None, true).await
}

async fn execute_select_query_with_progress(
    client: &deadpool_postgres::Client,
    sql: &str,
    start: Instant,
    row_limit: usize,
    progress_clock: Option<&StreamProgressClock>,
    force_unnamed: bool,
) -> Result<QueryResult, String> {
    match execute_select_prepared(client, sql, start, row_limit, progress_clock, force_unnamed).await {
        Ok(outcome) => finish_prepared_select(client, sql, start, row_limit, outcome, progress_clock).await,
        Err(err) if should_retry_postgres_stale_cache(&err) => {
            // The cached prepared statement is stale (e.g. the view or table
            // schema changed since the statement was prepared). Evict the
            // stale entry and retry with a fresh server-side prepare.
            log::warn!("[postgres][select:stale_cache] evicting cached statement: {}", pg_error_to_string(err));
            client.statement_cache.remove(sql, &[]);
            match execute_select_prepared(client, sql, start, row_limit, progress_clock, force_unnamed).await {
                Ok(outcome) => finish_prepared_select(client, sql, start, row_limit, outcome, progress_clock).await,
                Err(err) if should_retry_postgres_text_query(&err) => {
                    execute_select_text(client, sql, start, row_limit, None, progress_clock).await
                }
                Err(err) => Err(pg_error_to_string(err)),
            }
        }
        Err(err) if should_retry_postgres_text_query(&err) => {
            execute_select_text(client, sql, start, row_limit, None, progress_clock).await
        }
        Err(err) => Err(pg_error_to_string(err)),
    }
}

pub enum PostgresQueryStreamItem {
    Columns { columns: Vec<String>, column_types: Vec<String> },
    Row(Vec<serde_json::Value>),
}

enum PostgresQueryStreamError {
    Postgres { err: tokio_postgres::Error, emitted: bool },
    TextFallback { column_types: Vec<String>, unsupported_type: String },
    Export(String),
}

impl PostgresQueryStreamError {
    fn into_string(self) -> String {
        match self {
            Self::Postgres { err, .. } => pg_error_to_string(err),
            Self::TextFallback { unsupported_type, .. } => {
                format!("PostgreSQL type {unsupported_type} requires text protocol")
            }
            Self::Export(err) => err,
        }
    }
}

async fn stream_select_query_prepared(
    client: &deadpool_postgres::Client,
    sql: &str,
    row_limit: Option<usize>,
    on_item: &mut impl FnMut(PostgresQueryStreamItem) -> Result<(), String>,
    force_unnamed: bool,
) -> Result<u64, PostgresQueryStreamError> {
    let stream_outcome = start_postgres_select_stream(client, sql, force_unnamed)
        .await
        .map_err(|err| PostgresQueryStreamError::Postgres { err, emitted: false })?;
    let (stream, metadata) = match stream_outcome {
        PostgresSelectStreamOutcome::Binary { stream, metadata } => (stream, metadata),
        PostgresSelectStreamOutcome::TextFallback { column_types, unsupported_type } => {
            return Err(PostgresQueryStreamError::TextFallback { column_types, unsupported_type });
        }
    };
    let PreparedSelectMetadata { columns, column_types, column_classes, unsupported_type: _ } = metadata;
    tokio::pin!(stream);
    let mut rows_streamed = 0_u64;
    let mut columns_emitted = false;
    while let Some(row_result) = stream.next().await {
        if row_limit.is_some_and(|limit| rows_streamed as usize >= limit) {
            break;
        }
        let row = row_result
            .map_err(|err| PostgresQueryStreamError::Postgres { err, emitted: columns_emitted || rows_streamed > 0 })?;
        if !columns_emitted {
            on_item(PostgresQueryStreamItem::Columns { columns: columns.clone(), column_types: column_types.clone() })
                .map_err(PostgresQueryStreamError::Export)?;
            columns_emitted = true;
        }
        let values = (0..row.columns().len())
            .map(|i| pg_value_to_json_classified(&row, i, column_classes.get(i).copied().unwrap_or(PgColType::Other)))
            .collect();
        on_item(PostgresQueryStreamItem::Row(values)).map_err(PostgresQueryStreamError::Export)?;
        rows_streamed += 1;
    }
    if !columns_emitted {
        on_item(PostgresQueryStreamItem::Columns { columns, column_types })
            .map_err(PostgresQueryStreamError::Export)?;
    }
    Ok(rows_streamed)
}

async fn stream_select_query_text(
    client: &deadpool_postgres::Client,
    sql: &str,
    row_limit: Option<usize>,
    prepared_column_types: Option<Vec<String>>,
    on_item: &mut impl FnMut(PostgresQueryStreamItem) -> Result<(), String>,
) -> Result<u64, String> {
    let stream = client.simple_query_raw(sql).await.map_err(pg_error_to_string)?;
    tokio::pin!(stream);
    let mut columns: Vec<String> = Vec::new();
    let column_classes =
        prepared_column_types.as_ref().map(|types| classify_pg_column_types(types)).unwrap_or_default();
    let mut rows_streamed = 0_u64;
    while let Some(message) = stream.next().await {
        match message.map_err(pg_error_to_string)? {
            SimpleQueryMessage::RowDescription(cols) => {
                columns = cols.iter().map(|c| c.name().to_string()).collect();
                let column_types = matching_pg_text_column_types(&columns, prepared_column_types.clone());
                on_item(PostgresQueryStreamItem::Columns { columns: columns.clone(), column_types })?;
            }
            SimpleQueryMessage::Row(row) => {
                if row_limit.is_some_and(|limit| rows_streamed as usize >= limit) {
                    break;
                }
                if columns.is_empty() {
                    columns = row.columns().iter().map(|c| c.name().to_string()).collect();
                    let column_types = matching_pg_text_column_types(&columns, prepared_column_types.clone());
                    on_item(PostgresQueryStreamItem::Columns { columns: columns.clone(), column_types })?;
                }
                let mut values = Vec::with_capacity(row.len());
                for i in 0..row.len() {
                    values.push(match row.try_get(i).map_err(pg_error_to_string)? {
                        Some(value) => pg_text_fallback_value(value, column_classes.get(i).copied()).0,
                        None => serde_json::Value::Null,
                    });
                }
                on_item(PostgresQueryStreamItem::Row(values))?;
                rows_streamed += 1;
            }
            SimpleQueryMessage::CommandComplete(_) => {}
            _ => {}
        }
    }
    Ok(rows_streamed)
}

#[cfg(test)]
pub(crate) async fn stream_select_query_inner_unnamed(
    client: &deadpool_postgres::Client,
    sql: &str,
    row_limit: Option<usize>,
    on_item: &mut impl FnMut(PostgresQueryStreamItem) -> Result<(), String>,
) -> Result<u64, String> {
    stream_select_query_inner_with_mode(client, sql, row_limit, on_item, true).await
}

pub(crate) async fn stream_select_query_inner_unnamed_with_cancel(
    client: &deadpool_postgres::Client,
    sql: &str,
    row_limit: Option<usize>,
    on_item: &mut impl FnMut(PostgresQueryStreamItem) -> Result<(), String>,
    cancel_token: Option<&CancellationToken>,
    budget: &DbOperationBudget,
    cancel_context: Option<&PostgresCancelContext>,
) -> Result<u64, String> {
    if cancel_token.is_some_and(CancellationToken::is_cancelled) {
        return Err(crate::query::canceled_error());
    }
    let pg_cancel_token = client.cancel_token();
    let progress_clock = Arc::new(StreamProgressClock::new());
    let progress_clock_for_stream = progress_clock.clone();
    let mut on_stream_item = |item| {
        let row_received = matches!(&item, PostgresQueryStreamItem::Row(_));
        on_item(item)?;
        if row_received {
            progress_clock_for_stream.mark();
        }
        Ok(())
    };
    let timeout_error =
        format!("Query timed out after {} seconds", budget.query_timeout.map_or(0, |timeout| timeout.as_secs()));
    let stream = stream_select_query_inner_with_mode(client, sql, row_limit, &mut on_stream_item, true);
    tokio::pin!(stream);
    let result = await_stream_with_progress_timeout(
        stream.as_mut(),
        budget.query_timeout,
        progress_clock,
        cancel_token,
        timeout_error.clone(),
    )
    .await;

    if result.as_ref().is_err_and(|error| error == &timeout_error || error == crate::query::QUERY_CANCELED) {
        let original_error = result.as_ref().expect_err("timeout or cancellation result").clone();
        cancel_postgres_query(pg_cancel_token, cancel_context, budget.cancel_timeout).await;
        if tokio::time::timeout(budget.cleanup_timeout, stream.as_mut()).await.is_err() {
            return Err(format!(
                "{}; PostgreSQL stream cleanup timed out after {} seconds",
                original_error,
                budget.cleanup_timeout.as_secs()
            ));
        }
    }

    result
}

async fn stream_select_query_inner_with_mode(
    client: &deadpool_postgres::Client,
    sql: &str,
    row_limit: Option<usize>,
    on_item: &mut impl FnMut(PostgresQueryStreamItem) -> Result<(), String>,
    force_unnamed: bool,
) -> Result<u64, String> {
    match stream_select_query_prepared(client, sql, row_limit, on_item, force_unnamed).await {
        Ok(rows) => Ok(rows),
        Err(PostgresQueryStreamError::TextFallback { column_types, unsupported_type }) => {
            log::info!(
                "[postgres][stream:text_fallback] unsupported_type={} switching_to=simple_query",
                unsupported_type
            );
            stream_select_query_text(client, sql, row_limit, Some(column_types), on_item).await
        }
        Err(PostgresQueryStreamError::Postgres { err, emitted: false }) if should_retry_postgres_stale_cache(&err) => {
            // The cached prepared statement can become stale after schema changes.
            // Evict and retry once, matching the normal query execution path.
            log::warn!("[postgres][stream:stale_cache] evicting cached statement: {}", pg_error_to_string(err));
            client.statement_cache.remove(sql, &[]);
            match stream_select_query_prepared(client, sql, row_limit, on_item, force_unnamed).await {
                Ok(rows) => Ok(rows),
                Err(PostgresQueryStreamError::Postgres { err, emitted: false })
                    if should_retry_postgres_text_query(&err) =>
                {
                    stream_select_query_text(client, sql, row_limit, None, on_item).await
                }
                Err(PostgresQueryStreamError::TextFallback { column_types, unsupported_type }) => {
                    log::info!(
                        "[postgres][stream:text_fallback] unsupported_type={} switching_to=simple_query",
                        unsupported_type
                    );
                    stream_select_query_text(client, sql, row_limit, Some(column_types), on_item).await
                }
                Err(err) => Err(err.into_string()),
            }
        }
        Err(PostgresQueryStreamError::Postgres { err, emitted: false }) if should_retry_postgres_text_query(&err) => {
            stream_select_query_text(client, sql, row_limit, None, on_item).await
        }
        Err(err) => Err(err.into_string()),
    }
}

pub async fn stream_query_rows(
    pool: &Pool,
    sql: &str,
    max_rows: Option<usize>,
    cancelled: &AtomicBool,
    mut on_row: impl FnMut(&[serde_json::Value]) -> Result<(), String>,
) -> Result<u64, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    match stream_query_rows_on_client(&client, sql, max_rows, cancelled, &mut on_row).await {
        Ok(rows) => Ok(rows),
        Err(error) if should_retry_postgres_text_query_message(&error.to_ascii_lowercase()) => {
            stream_query_rows_text_on_client(&client, sql, max_rows, cancelled, None, &mut on_row).await
        }
        Err(error) => Err(error),
    }
}

async fn stream_query_rows_on_client(
    client: &deadpool_postgres::Client,
    sql: &str,
    max_rows: Option<usize>,
    cancelled: &AtomicBool,
    on_row: &mut impl FnMut(&[serde_json::Value]) -> Result<(), String>,
) -> Result<u64, String> {
    let stream_outcome = start_postgres_select_stream(client, sql, false).await.map_err(pg_error_to_string)?;
    let (stream, metadata) = match stream_outcome {
        PostgresSelectStreamOutcome::Binary { stream, metadata } => (stream, metadata),
        PostgresSelectStreamOutcome::TextFallback { column_types, unsupported_type } => {
            log::info!(
                "[postgres][row_stream:text_fallback] unsupported_type={} switching_to=simple_query",
                unsupported_type
            );
            let column_classes = classify_pg_column_types(&column_types);
            return stream_query_rows_text_on_client(client, sql, max_rows, cancelled, Some(&column_classes), on_row)
                .await;
        }
    };
    let PreparedSelectMetadata { column_classes, .. } = metadata;
    tokio::pin!(stream);
    let row_limit = max_rows.unwrap_or(usize::MAX);
    let mut rows_exported = 0_u64;

    while let Some(row_result) = stream.next().await {
        if cancelled.load(std::sync::atomic::Ordering::SeqCst) {
            return Err(crate::query::canceled_error());
        }
        if rows_exported as usize >= row_limit {
            break;
        }
        let row = row_result.map_err(pg_error_to_string)?;
        let values: Vec<serde_json::Value> = (0..row.columns().len())
            .map(|i| pg_value_to_json_classified(&row, i, column_classes.get(i).copied().unwrap_or(PgColType::Other)))
            .collect();
        on_row(&values)?;
        rows_exported += 1;
    }

    Ok(rows_exported)
}

async fn stream_query_rows_text_on_client(
    client: &deadpool_postgres::Client,
    sql: &str,
    max_rows: Option<usize>,
    cancelled: &AtomicBool,
    column_classes: Option<&[PgColType]>,
    on_row: &mut impl FnMut(&[serde_json::Value]) -> Result<(), String>,
) -> Result<u64, String> {
    let stream = client.simple_query_raw(sql).await.map_err(pg_error_to_string)?;
    tokio::pin!(stream);
    let row_limit = max_rows.unwrap_or(usize::MAX);
    let mut rows_exported = 0_u64;

    while let Some(message) = stream.next().await {
        if cancelled.load(std::sync::atomic::Ordering::SeqCst) {
            return Err(crate::query::canceled_error());
        }
        if rows_exported as usize >= row_limit {
            break;
        }
        let message = message.map_err(pg_error_to_string)?;
        if let SimpleQueryMessage::Row(row) = message {
            let mut values = Vec::with_capacity(row.len());
            for i in 0..row.len() {
                values.push(match row.try_get(i).map_err(pg_error_to_string)? {
                    Some(value) => {
                        pg_text_fallback_value(value, column_classes.and_then(|classes| classes.get(i)).copied()).0
                    }
                    None => serde_json::Value::Null,
                });
            }
            on_row(&values)?;
            rows_exported += 1;
        }
    }

    Ok(rows_exported)
}

pub async fn connect(url: &str, fallback_timeout: Duration) -> Result<Pool, String> {
    connect_with_max_connections(url, fallback_timeout, 10).await
}

/// Creates a PostgreSQL pool with an explicit checkout bound.
///
/// Session-scoped DBX pools use a single connection so temporary tables and
/// other connection-local state cannot migrate between physical clients.
pub async fn connect_with_max_connections(
    url: &str,
    fallback_timeout: Duration,
    max_connections: usize,
) -> Result<Pool, String> {
    #[cfg(all(windows, target_vendor = "win7"))]
    {
        connect_with_optional_local_timezone_with_max_connections(url, fallback_timeout, None, max_connections).await
    }

    #[cfg(not(all(windows, target_vendor = "win7")))]
    {
        let timezone = iana_time_zone::get_timezone().unwrap_or_else(|_| "UTC".to_string());
        connect_with_local_timezone_with_max_connections(url, fallback_timeout, &timezone, max_connections).await
    }
}

/// Test-only thin wrappers (the library now connects through
/// `connect_with_max_connections`, which carries the pool bound).
#[cfg(test)]
async fn connect_with_local_timezone(url: &str, fallback_timeout: Duration, timezone: &str) -> Result<Pool, String> {
    connect_with_local_timezone_with_max_connections(url, fallback_timeout, timezone, 10).await
}

async fn connect_with_local_timezone_with_max_connections(
    url: &str,
    fallback_timeout: Duration,
    timezone: &str,
    max_connections: usize,
) -> Result<Pool, String> {
    connect_with_optional_local_timezone_with_max_connections(url, fallback_timeout, Some(timezone), max_connections)
        .await
}

/// Identity of one physical backend connection for notice attribution:
/// (server address, server port, backend PID). The PID alone is not unique
/// across different servers, so the server's own address/port disambiguate
/// (`inet_server_addr()` is NULL for Unix sockets, hence the fallback).
type PostgresConnectionKey = (String, String, String);

const POSTGRES_CONNECTION_IDENTITY_SQL: &str = "SELECT pg_backend_pid()::text, \
     COALESCE(host(inet_server_addr()), 'unix'), \
     COALESCE(inet_server_port()::text, current_setting('port'))";

fn postgres_connection_key_from_row(row: &Row) -> Option<PostgresConnectionKey> {
    Some((row.try_get::<_, String>(1).ok()?, row.try_get::<_, String>(2).ok()?, row.try_get::<_, String>(0).ok()?))
}

/// Notice buffers for live connections, keyed by connection identity. Entries
/// are weak so they disappear once the pooled connection (and its driver
/// task) is dropped.
type PostgresNoticeBuffers = HashMap<PostgresConnectionKey, Weak<Mutex<Vec<QueryMessage>>>>;

fn postgres_notice_buffers() -> &'static Mutex<PostgresNoticeBuffers> {
    static BUFFERS: OnceLock<Mutex<PostgresNoticeBuffers>> = OnceLock::new();
    BUFFERS.get_or_init(|| Mutex::new(HashMap::new()))
}

/// Connection identity cache, keyed by the per-physical-connection statement
/// cache pointer (same identity pattern as `postgres_single_schema_clients`).
/// The `Weak` guards against pointer reuse: a new connection whose
/// `StatementCache` lands on a freed entry's address fails the `ptr_eq` check
/// and is treated as a miss. The value is `None` when the identity query
/// failed, so it is issued at most once per physical connection — it must
/// never be retried from `drain_postgres_notices`, which can run inside the
/// read-only transaction used for EXPLAIN, where a failing query would abort
/// the user's statement.
type PostgresClientKeys = HashMap<usize, (Weak<deadpool_postgres::StatementCache>, Option<PostgresConnectionKey>)>;

fn postgres_client_keys() -> &'static Mutex<PostgresClientKeys> {
    static KEYS: OnceLock<Mutex<PostgresClientKeys>> = OnceLock::new();
    KEYS.get_or_init(|| Mutex::new(HashMap::new()))
}

/// Establishes connections like deadpool's `ConfigConnectImpl`, but drives
/// each connection with a task that captures `NoticeResponse` messages
/// (`RAISE NOTICE`/`WARNING`, etc.) into a per-backend buffer instead of
/// discarding them. Query execution drains the buffer so notices are
/// attached to the `QueryResult` of the statement that raised them.
struct NoticeCapturingConnect<T>
where
    T: MakeTlsConnect<Socket> + Clone + Sync + Send + 'static,
    T::Stream: Sync + Send,
    T::TlsConnect: Sync + Send,
    <T::TlsConnect as TlsConnect<Socket>>::Future: Send,
{
    tls: T,
}

impl<T> deadpool_postgres::Connect for NoticeCapturingConnect<T>
where
    T: MakeTlsConnect<Socket> + Clone + Sync + Send + 'static,
    T::Stream: Sync + Send,
    T::TlsConnect: Sync + Send,
    <T::TlsConnect as TlsConnect<Socket>>::Future: Send,
{
    fn connect(
        &self,
        pg_config: &tokio_postgres::Config,
    ) -> Pin<
        Box<dyn Future<Output = Result<(tokio_postgres::Client, JoinHandle<()>), tokio_postgres::Error>> + Send + '_>,
    > {
        let tls = self.tls.clone();
        let pg_config = pg_config.clone();
        Box::pin(async move {
            let (client, mut connection) = pg_config.connect(tls).await?;
            // No query can complete before the connection is being driven, so
            // the notice buffer is handed to the driver task through a slot
            // that is filled once the backend PID is known.
            let notice_buffer = Arc::new(Mutex::new(None::<Arc<Mutex<Vec<QueryMessage>>>>));
            let task_buffer = Arc::clone(&notice_buffer);
            let conn_task = tokio::spawn(async move {
                loop {
                    match std::future::poll_fn(|cx| connection.poll_message(cx)).await {
                        Some(Ok(AsyncMessage::Notice(error))) => {
                            let message = QueryMessage {
                                severity: error.severity().to_string(),
                                message: error.message().to_string(),
                                code: Some(error.code().code().to_string()),
                                detail: error.detail().map(str::to_string),
                                hint: error.hint().map(str::to_string),
                            };
                            let buffer = task_buffer.lock().unwrap_or_else(|poisoned| poisoned.into_inner()).clone();
                            match buffer {
                                Some(buffer) => {
                                    buffer.lock().unwrap_or_else(|poisoned| poisoned.into_inner()).push(message);
                                }
                                None => {
                                    log::info!("[postgres][notice] {}: {}", message.severity, message.message);
                                }
                            }
                        }
                        // LISTEN/NOTIFY messages are not surfaced anywhere.
                        Some(Ok(_)) => {}
                        Some(Err(err)) => {
                            log::warn!("[postgres] connection driver error: {err}");
                            break;
                        }
                        None => break,
                    }
                }
            });

            // Best-effort: without the connection identity, notices cannot be
            // attributed to query results on this connection and are logged
            // by the driver task instead. Never fail the connection over this.
            if let Ok(row) = client.query_one(POSTGRES_CONNECTION_IDENTITY_SQL, &[]).await {
                if let Some(key) = postgres_connection_key_from_row(&row) {
                    let buffer = Arc::new(Mutex::new(Vec::new()));
                    let mut buffers = postgres_notice_buffers().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
                    buffers.retain(|_, weak| weak.strong_count() > 0);
                    buffers.insert(key, Arc::downgrade(&buffer));
                    drop(buffers);
                    *notice_buffer.lock().unwrap_or_else(|poisoned| poisoned.into_inner()) = Some(buffer);
                }
            }

            Ok((client, conn_task))
        })
    }
}

/// Cached identity lookup. `Some(Some(key))` = resolved, `Some(None)` =
/// identity query failed before (do not retry), `None` = never seen (or the
/// entry belonged to a dropped connection whose address was reused).
fn cached_postgres_client_key(client: &deadpool_postgres::Client) -> Option<Option<PostgresConnectionKey>> {
    let cache_key = Arc::as_ptr(&client.statement_cache) as usize;
    let mut keys = postgres_client_keys().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
    match keys.get(&cache_key) {
        Some((cached, key)) if cached.upgrade().is_some_and(|cached| Arc::ptr_eq(&cached, &client.statement_cache)) => {
            Some(key.clone())
        }
        Some(_) => {
            keys.remove(&cache_key);
            None
        }
        None => None,
    }
}

/// Best-effort identity resolution. Failures are cached as `None` so the
/// identity query runs at most once per physical connection.
async fn resolve_postgres_client_key(client: &deadpool_postgres::Client) -> Option<PostgresConnectionKey> {
    if let Some(key) = cached_postgres_client_key(client) {
        return key;
    }
    let key: Option<PostgresConnectionKey> = client
        .query_one(POSTGRES_CONNECTION_IDENTITY_SQL, &[])
        .await
        .ok()
        .and_then(|row| postgres_connection_key_from_row(&row));
    let mut keys = postgres_client_keys().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
    keys.retain(|_, (cached, _)| cached.strong_count() > 0);
    let cache_key = Arc::as_ptr(&client.statement_cache) as usize;
    keys.insert(cache_key, (Arc::downgrade(&client.statement_cache), key.clone()));
    key
}

async fn postgres_client_key(client: &deadpool_postgres::Client) -> Option<PostgresConnectionKey> {
    resolve_postgres_client_key(client).await
}

fn take_notices_for_key(key: &PostgresConnectionKey) -> Vec<QueryMessage> {
    let buffer = {
        let mut buffers = postgres_notice_buffers().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
        buffers.retain(|_, weak| weak.strong_count() > 0);
        buffers.get(key).and_then(Weak::upgrade)
    };
    let Some(buffer) = buffer else {
        return Vec::new();
    };
    let notices = std::mem::take(&mut *buffer.lock().unwrap_or_else(|poisoned| poisoned.into_inner()));
    notices
}

async fn drain_postgres_notices(client: &deadpool_postgres::Client) -> Vec<QueryMessage> {
    match postgres_client_key(client).await {
        Some(key) => take_notices_for_key(&key),
        None => Vec::new(),
    }
}

#[cfg(test)]
async fn connect_with_optional_local_timezone(
    url: &str,
    fallback_timeout: Duration,
    timezone: Option<&str>,
) -> Result<Pool, String> {
    connect_with_optional_local_timezone_with_max_connections(url, fallback_timeout, timezone, 10).await
}

async fn connect_with_optional_local_timezone_with_max_connections(
    url: &str,
    fallback_timeout: Duration,
    timezone: Option<&str>,
    max_connections: usize,
) -> Result<Pool, String> {
    let url_with_keepalive = inject_postgres_keepalive_params(url);
    let _ = rustls::crypto::aws_lc_rs::default_provider().install_default();
    let timeout = super::parse_connect_timeout_with_fallback(url, fallback_timeout);

    let first_attempt = connect_postgres_pool_attempt(&url_with_keepalive, timeout, max_connections).await;
    let (pool, client) = match first_attempt {
        Err(error) if postgres_error_should_retry_without_tls(&error) => {
            let Some(fallback_url) = postgres_ssl_fallback_url(&url_with_keepalive) else {
                return Err(error);
            };
            log::info!("PostgreSQL TLS handshake failed in sslmode=prefer; retrying without TLS");
            connect_postgres_pool_attempt(&fallback_url, timeout, max_connections).await?
        }
        result => result?,
    };

    // Creating the physical connection and applying session defaults are two
    // sequential network phases. Give each phase the configured connection
    // timeout instead of sharing one deadline that can expire during the
    // optional SET timezone round-trip on higher-latency tunnels.
    if !pg_url_has_timezone_setting(url) {
        if let Some(timezone) = timezone {
            postgres_session_setup_with_timeout(timeout, set_automatic_postgres_timezone(&client, timezone)).await?;
        }
    }

    drop(client);
    Ok(pool)
}

async fn connect_postgres_pool_attempt(
    url: &str,
    timeout: Duration,
    max_connections: usize,
) -> Result<(Pool, deadpool_postgres::Client), String> {
    let postgres_url = postgres_connection_url(url)?;
    super::with_connection_timeout("PostgreSQL", timeout, async {
        let pg_config = tokio_postgres::Config::from_str(&postgres_url.url)
            .map_err(|e| format!("Invalid PostgreSQL connection URL: {e}"))?;

        // Fast recycling only checks whether the connection is already closed
        // instead of issuing a validation query on every checkout, saving one
        // round-trip per query. Connections that went stale without being
        // observed are caught when the query runs and recovered by the
        // executor's ReconnectAndRetry path (see pool_error_action / do_execute
        // in query.rs).
        let mgr_config = ManagerConfig { recycling_method: RecyclingMethod::Fast };
        let mgr = if postgres_url.legacy_tls {
            log::info!("PostgreSQL legacy TLS compatibility enabled");
            let tls = postgres_openssl_connector(
                &postgres_url.ssl_files,
                postgres_url.accepts_invalid_certs,
                postgres_url.verifies_hostname,
            )?;
            deadpool_postgres::Manager::from_connect(pg_config.clone(), NoticeCapturingConnect { tls }, mgr_config)
        } else {
            let tls_config = postgres_tls_config(
                &pg_config,
                &postgres_url.ssl_files,
                postgres_url.accepts_invalid_certs,
                postgres_url.verifies_hostname,
            )?;
            deadpool_postgres::Manager::from_connect(
                pg_config.clone(),
                NoticeCapturingConnect { tls: tokio_postgres_rustls::MakeRustlsConnect::new(tls_config) },
                mgr_config,
            )
        };
        let pool = Pool::builder(mgr)
            .max_size(max_connections.max(1))
            .runtime(Runtime::Tokio1)
            .wait_timeout(Some(timeout))
            .create_timeout(Some(timeout))
            .recycle_timeout(Some(timeout))
            .build()
            .map_err(|e| format!("Failed to create PostgreSQL pool: {e}"))?;

        // Verify connectivity. Explicit connection options are handled by
        // PostgreSQL during startup and must remain strict.
        let client =
            pool.get().await.map_err(|e| format!("PostgreSQL connection failed: {}", pg_pool_error_to_string(e)))?;
        Ok((pool, client))
    })
    .await
}

fn postgres_error_should_retry_without_tls(error: &str) -> bool {
    error.to_ascii_lowercase().contains("tls handshake")
}

fn postgres_ssl_fallback_url(url: &str) -> Option<String> {
    let parsed = postgres_connection_url(url).ok()?;
    let pg_config = tokio_postgres::Config::from_str(&parsed.url).ok()?;
    if pg_config.get_ssl_mode() != SslMode::Prefer {
        return None;
    }

    let (base, fragment) = url.split_once('#').map_or((url, None), |(base, fragment)| (base, Some(fragment)));
    let (prefix, query) = base.split_once('?').map_or((base, None), |(prefix, query)| (prefix, Some(query)));
    let mut params = Vec::new();
    let mut inserted_sslmode = false;
    for param in query.into_iter().flat_map(|query| query.split('&')).filter(|param| !param.is_empty()) {
        let is_sslmode = param.split_once('=').is_some_and(|(key, _)| key.trim().eq_ignore_ascii_case("sslmode"));
        if is_sslmode {
            if !inserted_sslmode {
                params.push("sslmode=disable".to_string());
                inserted_sslmode = true;
            }
        } else {
            params.push(param.to_string());
        }
    }
    if !inserted_sslmode {
        params.insert(0, "sslmode=disable".to_string());
    }

    let mut fallback = format!("{prefix}?{}", params.join("&"));
    if let Some(fragment) = fragment {
        fallback.push('#');
        fallback.push_str(fragment);
    }
    Some(fallback)
}

async fn postgres_session_setup_with_timeout<T, F>(timeout: Duration, future: F) -> Result<T, String>
where
    F: Future<Output = Result<T, String>>,
{
    super::with_connection_timeout("PostgreSQL session setup", timeout, future).await
}

async fn set_automatic_postgres_timezone(client: &deadpool_postgres::Client, timezone: &str) -> Result<(), String> {
    let candidates = postgres_timezone_candidates(timezone);
    for (index, candidate) in candidates.iter().enumerate() {
        let sql = format!("SET timezone = '{}'", candidate.replace('\'', "''"));
        match client.execute(&sql, &[]).await {
            Ok(_) => {
                if *candidate != timezone {
                    log::warn!(
                        "PostgreSQL does not recognize local timezone '{timezone}'; using compatible alias '{candidate}'"
                    );
                }
                return Ok(());
            }
            Err(error) if postgres_timezone_error_is_nonfatal(&error) => {
                let detail = pg_error_to_string(error);
                if index + 1 == candidates.len() {
                    // A connected server may have older tzdata or only partial PostgreSQL compatibility.
                    // Keep its session default rather than making optional local display alignment fatal.
                    log::warn!(
                        "PostgreSQL connected, but automatic local timezone '{timezone}' was rejected; \
                         keeping the server default timezone: {detail}"
                    );
                    return Ok(());
                }
            }
            Err(error) => {
                return Err(format!("PostgreSQL SET timezone failed after connecting: {}", pg_error_to_string(error)));
            }
        }
    }

    Ok(())
}

fn postgres_timezone_error_is_nonfatal(error: &tokio_postgres::Error) -> bool {
    let Some(db_error) = error.as_db_error() else {
        return false;
    };
    // SET failures reported as ordinary SQL errors are optional session setup.
    // FATAL/PANIC responses mean the connection itself is not safe to return.
    !matches!(
        db_error.parsed_severity(),
        Some(tokio_postgres::error::Severity::Fatal | tokio_postgres::error::Severity::Panic)
    ) && !matches!(db_error.severity().to_ascii_uppercase().as_str(), "FATAL" | "PANIC")
}

fn postgres_timezone_candidates(timezone: &str) -> Vec<&str> {
    let legacy_alias = match timezone {
        "Asia/Saigon" => Some("Asia/Ho_Chi_Minh"),
        "Asia/Ho_Chi_Minh" => Some("Asia/Saigon"),
        "Europe/Kyiv" => Some("Europe/Kiev"),
        "Europe/Kiev" => Some("Europe/Kyiv"),
        "Asia/Calcutta" => Some("Asia/Kolkata"),
        "Asia/Kolkata" => Some("Asia/Calcutta"),
        _ => None,
    };
    std::iter::once(timezone).chain(legacy_alias).collect()
}

#[derive(Debug, Default, Clone, PartialEq, Eq)]
pub struct PostgresSslFiles {
    pub sslcert: Option<String>,
    pub sslkey: Option<String>,
    pub sslrootcert: Option<String>,
}

/// TLS context info, used to reconstruct the TLS connector when cancelling a query.
#[derive(Debug, Clone)]
pub struct PostgresCancelContext {
    pub ssl_files: PostgresSslFiles,
    pub accepts_invalid_certs: bool,
    pub verifies_hostname: bool,
    pub ssl_mode: SslMode,
    pub legacy_tls: bool,
}

/// Build a TLS cancel context from the connection URL.
/// Returns None if URL parsing fails or sslmode=disable (no TLS cancel needed).
pub fn build_postgres_cancel_context(url: &str) -> Option<PostgresCancelContext> {
    let postgres_url = postgres_connection_url(url).ok()?;
    let pg_config = tokio_postgres::Config::from_str(&postgres_url.url).ok()?;
    if pg_config.get_ssl_mode() == SslMode::Disable {
        return None;
    }
    Some(PostgresCancelContext {
        ssl_files: postgres_url.ssl_files,
        accepts_invalid_certs: postgres_url.accepts_invalid_certs,
        verifies_hostname: postgres_url.verifies_hostname,
        ssl_mode: pg_config.get_ssl_mode(),
        legacy_tls: postgres_url.legacy_tls,
    })
}

/// Reconstruct a TLS connector from the cancel context, used for TLS connection cancellation.
fn make_rustls_connect_from_context(
    ctx: &PostgresCancelContext,
) -> Result<tokio_postgres_rustls::MakeRustlsConnect, String> {
    // Build a minimal pg_config solely for ssl_mode determination
    let mut pg_config = tokio_postgres::Config::new();
    pg_config.ssl_mode(ctx.ssl_mode);
    let tls_config = postgres_tls_config(&pg_config, &ctx.ssl_files, ctx.accepts_invalid_certs, ctx.verifies_hostname)?;
    Ok(tokio_postgres_rustls::MakeRustlsConnect::new(tls_config))
}

fn make_openssl_connect_from_context(
    ctx: &PostgresCancelContext,
) -> Result<postgres_openssl::MakeTlsConnector, String> {
    postgres_openssl_connector(&ctx.ssl_files, ctx.accepts_invalid_certs, ctx.verifies_hostname)
}

#[derive(Debug, Clone, PartialEq, Eq)]
struct PostgresConnectionUrl {
    url: String,
    ssl_files: PostgresSslFiles,
    accepts_invalid_certs: bool,
    verifies_hostname: bool,
    legacy_tls: bool,
}

/// Inject TCP keepalive parameters into the PostgreSQL URL (only when the user has not explicitly specified them).
/// Default parameters shorten half-open connection detection time, suitable for desktop/VPN/NAT environments.
fn inject_postgres_keepalive_params(url: &str) -> String {
    let (base, fragment) = url.split_once('#').map_or((url, ""), |(base, fragment)| (base, fragment));
    let query = base.split('?').nth(1);
    let has_keepalives = query
        .map(|q| q.split('&').any(|p| p.split('=').next().is_some_and(|k| k.eq_ignore_ascii_case("keepalives"))))
        .unwrap_or(false);
    if has_keepalives {
        return url.to_string(); // User has explicitly configured keepalive
    }
    let separator = if base.contains('?') { "&" } else { "?" };
    let injected =
        format!("{base}{separator}keepalives=1&keepalives_idle=30&keepalives_interval=10&keepalives_retries=3");
    if fragment.is_empty() {
        injected
    } else {
        format!("{injected}#{fragment}")
    }
}

fn postgres_connection_url(url: &str) -> Result<PostgresConnectionUrl, String> {
    let Some(query_start) = url.find('?') else {
        let pg_config =
            tokio_postgres::Config::from_str(url).map_err(|e| format!("Invalid PostgreSQL connection URL: {e}"))?;
        return Ok(PostgresConnectionUrl {
            url: url.to_string(),
            ssl_files: PostgresSslFiles::default(),
            accepts_invalid_certs: postgres_sslmode_accepts_invalid_certs(pg_config.get_ssl_mode()),
            verifies_hostname: false,
            legacy_tls: false,
        });
    };

    let prefix = &url[..query_start];
    let suffix = &url[query_start + 1..];
    let (query_string, fragment) = suffix.split_once('#').map_or((suffix, ""), |(query, fragment)| (query, fragment));
    let mut ssl_files = PostgresSslFiles::default();
    let mut kept_params = Vec::new();
    let mut accepts_invalid_certs = true;
    let mut verifies_hostname = false;
    let mut legacy_tls = false;

    for param in query_string.split('&') {
        if param.is_empty() {
            continue;
        }

        let Some((key, value)) = param.split_once('=') else {
            kept_params.push(param.to_string());
            continue;
        };

        if key.eq_ignore_ascii_case("legacy_tls") {
            legacy_tls = matches!(value.trim().to_ascii_lowercase().as_str(), "1" | "true" | "yes" | "on");
        } else if key.eq_ignore_ascii_case("sslcert")
            || key.eq_ignore_ascii_case("sslkey")
            || key.eq_ignore_ascii_case("sslrootcert")
        {
            let decoded = percent_decode_str(value)
                .decode_utf8()
                .map_err(|_| format!("Invalid URL encoding in {key}"))?
                .into_owned();
            validate_file_path(&decoded, |_| false).map_err(|e| format!("{key}: {e}"))?;

            if key.eq_ignore_ascii_case("sslcert") {
                ssl_files.sslcert = Some(decoded);
            } else if key.eq_ignore_ascii_case("sslkey") {
                ssl_files.sslkey = Some(decoded);
            } else {
                ssl_files.sslrootcert = Some(decoded);
            }
        } else if key.eq_ignore_ascii_case("channel_binding") {
            // channel_binding=require fails when the server does not offer
            // SCRAM-SHA-256-PLUS (e.g. Neon). Normalize require→prefer so
            // channel binding is used when available but does not cause a
            // hard failure when the server doesn't support it.
            match value.to_ascii_lowercase().as_str() {
                "require" => kept_params.push("channel_binding=prefer".to_string()),
                _ => kept_params.push(param.to_string()),
            }
        } else if key.eq_ignore_ascii_case("sslmode") {
            match value.to_ascii_lowercase().as_str() {
                "verify-ca" => {
                    accepts_invalid_certs = false;
                    kept_params.push("sslmode=require".to_string());
                }
                "verify-full" | "verify_identity" | "verify-identity" => {
                    accepts_invalid_certs = false;
                    verifies_hostname = true;
                    kept_params.push("sslmode=require".to_string());
                }
                "disable" => {
                    accepts_invalid_certs = false;
                    kept_params.push(param.to_string());
                }
                "prefer" | "require" => {
                    accepts_invalid_certs = true;
                    kept_params.push(param.to_string());
                }
                _ => kept_params.push(param.to_string()),
            }
        } else {
            kept_params.push(param.to_string());
        }
    }

    let mut sanitized_url = prefix.to_string();
    if !kept_params.is_empty() {
        sanitized_url.push('?');
        sanitized_url.push_str(&kept_params.join("&"));
    }
    if !fragment.is_empty() {
        sanitized_url.push('#');
        sanitized_url.push_str(fragment);
    }

    Ok(PostgresConnectionUrl { url: sanitized_url, ssl_files, accepts_invalid_certs, verifies_hostname, legacy_tls })
}

fn postgres_openssl_connector(
    ssl_files: &PostgresSslFiles,
    accepts_invalid_certs: bool,
    verifies_hostname: bool,
) -> Result<postgres_openssl::MakeTlsConnector, String> {
    let mut builder = SslConnector::builder(SslMethod::tls_client())
        .map_err(|e| format!("Failed to initialize PostgreSQL legacy TLS: {e}"))?;

    if accepts_invalid_certs {
        builder.set_verify(SslVerifyMode::NONE);
    } else {
        builder.set_verify(SslVerifyMode::PEER);
        if let Some(path) = ssl_files.sslrootcert.as_deref() {
            builder
                .set_ca_file(path)
                .map_err(|e| format!("sslrootcert: failed to load CA certificate from {path}: {e}"))?;
        }
    }

    match (ssl_files.sslcert.as_deref(), ssl_files.sslkey.as_deref()) {
        (Some(cert_path), Some(key_path)) => {
            builder
                .set_certificate_chain_file(cert_path)
                .map_err(|e| format!("sslcert: failed to load certificate from {cert_path}: {e}"))?;
            builder
                .set_private_key_file(key_path, SslFiletype::PEM)
                .map_err(|e| format!("sslkey: failed to load private key from {key_path}: {e}"))?;
            builder.check_private_key().map_err(|e| format!("sslkey: private key does not match sslcert: {e}"))?;
        }
        (Some(_), None) => return Err("PostgreSQL sslcert requires sslkey".to_string()),
        (None, Some(_)) => return Err("PostgreSQL sslkey requires sslcert".to_string()),
        (None, None) => {}
    }

    let mut connector = postgres_openssl::MakeTlsConnector::new(builder.build());
    connector.set_callback(move |config, _| {
        config.set_verify_hostname(verifies_hostname);
        Ok(())
    });
    Ok(connector)
}

fn postgres_tls_config(
    pg_config: &tokio_postgres::Config,
    ssl_files: &PostgresSslFiles,
    accepts_invalid_certs: bool,
    verifies_hostname: bool,
) -> Result<rustls::ClientConfig, String> {
    if pg_config.get_ssl_mode() != SslMode::Disable && accepts_invalid_certs {
        let provider = Arc::new(rustls::crypto::aws_lc_rs::default_provider());
        let builder = rustls::ClientConfig::builder()
            .dangerous()
            .with_custom_certificate_verifier(Arc::new(NoPostgresCertVerification { provider }));
        return postgres_tls_client_auth(builder, ssl_files);
    }

    let root_store = postgres_root_cert_store(ssl_files)?;
    let builder = if verifies_hostname {
        rustls::ClientConfig::builder().with_root_certificates(root_store)
    } else {
        let provider = Arc::new(rustls::crypto::aws_lc_rs::default_provider());
        rustls::ClientConfig::builder().dangerous().with_custom_certificate_verifier(Arc::new(
            PostgresCaOnlyCertVerification { provider, roots: Arc::new(root_store) },
        ))
    };
    postgres_tls_client_auth(builder, ssl_files)
}

fn postgres_root_cert_store(ssl_files: &PostgresSslFiles) -> Result<rustls::RootCertStore, String> {
    let mut root_store = rustls::RootCertStore::empty();
    if let Some(path) = ssl_files.sslrootcert.as_deref() {
        let certs = read_postgres_pem_certs("sslrootcert", path)?;
        let (valid_count, _) = root_store.add_parsable_certificates(certs);
        if valid_count == 0 {
            return Err(format!("sslrootcert: no valid CA certificates found in {path}"));
        }
    } else {
        root_store.extend(webpki_roots::TLS_SERVER_ROOTS.iter().cloned());
    }
    Ok(root_store)
}

fn postgres_tls_client_auth(
    builder: rustls::ConfigBuilder<rustls::ClientConfig, rustls::client::WantsClientCert>,
    ssl_files: &PostgresSslFiles,
) -> Result<rustls::ClientConfig, String> {
    match (ssl_files.sslcert.as_deref(), ssl_files.sslkey.as_deref()) {
        (Some(cert_path), Some(key_path)) => {
            let certs = read_postgres_pem_certs("sslcert", cert_path)?;
            if certs.is_empty() {
                return Err(format!("sslcert: no certificates found in {cert_path}"));
            }
            let private_key = read_postgres_private_key(key_path)?;
            let provider = rustls::crypto::aws_lc_rs::default_provider();
            let signing_key = provider
                .key_provider
                .load_private_key(private_key)
                .map_err(|e| format!("PostgreSQL client private key is invalid: {e}"))?;
            // rustls' convenience builder parses the leaf with webpki while matching keys,
            // which rejects otherwise usable X.509 v1 client certificates before TLS starts.
            let certified_key = rustls::sign::CertifiedKey::new(certs, signing_key);
            Ok(builder.with_client_cert_resolver(Arc::new(rustls::sign::SingleCertAndKey::from(certified_key))))
        }
        (Some(_), None) => Err("PostgreSQL sslcert requires sslkey".to_string()),
        (None, Some(_)) => Err("PostgreSQL sslkey requires sslcert".to_string()),
        (None, None) => Ok(builder.with_no_client_auth()),
    }
}

fn read_postgres_pem_certs(label: &str, path: &str) -> Result<Vec<CertificateDer<'static>>, String> {
    let file = File::open(path).map_err(|e| format!("{label}: failed to open {path}: {e}"))?;
    let mut reader = BufReader::new(file);
    rustls_pemfile::certs(&mut reader)
        .collect::<Result<Vec<_>, _>>()
        .map_err(|e| format!("{label}: failed to read PEM certificates from {path}: {e}"))
}

fn read_postgres_private_key(path: &str) -> Result<PrivateKeyDer<'static>, String> {
    let file = File::open(path).map_err(|e| format!("sslkey: failed to open {path}: {e}"))?;
    let mut reader = BufReader::new(file);
    rustls_pemfile::private_key(&mut reader)
        .map_err(|e| format!("sslkey: failed to read PEM private key from {path}: {e}"))?
        .ok_or_else(|| format!("sslkey: no private key found in {path}"))
}

fn postgres_sslmode_accepts_invalid_certs(ssl_mode: SslMode) -> bool {
    matches!(ssl_mode, SslMode::Prefer | SslMode::Require)
}

#[derive(Debug)]
struct NoPostgresCertVerification {
    provider: Arc<CryptoProvider>,
}

impl ServerCertVerifier for NoPostgresCertVerification {
    fn verify_server_cert(
        &self,
        _end_entity: &CertificateDer<'_>,
        _intermediates: &[CertificateDer<'_>],
        _server_name: &ServerName<'_>,
        _ocsp_response: &[u8],
        _now: UnixTime,
    ) -> Result<ServerCertVerified, rustls::Error> {
        Ok(ServerCertVerified::assertion())
    }

    fn verify_tls12_signature(
        &self,
        _message: &[u8],
        cert: &CertificateDer<'_>,
        _dss: &rustls::DigitallySignedStruct,
    ) -> Result<HandshakeSignatureValid, rustls::Error> {
        self.accept_tls_signature_for_unverified_cert(cert)
    }

    fn verify_tls13_signature(
        &self,
        _message: &[u8],
        cert: &CertificateDer<'_>,
        _dss: &rustls::DigitallySignedStruct,
    ) -> Result<HandshakeSignatureValid, rustls::Error> {
        self.accept_tls_signature_for_unverified_cert(cert)
    }

    fn supported_verify_schemes(&self) -> Vec<rustls::SignatureScheme> {
        self.provider.signature_verification_algorithms.supported_schemes()
    }
}

impl NoPostgresCertVerification {
    fn accept_tls_signature_for_unverified_cert(
        &self,
        _cert: &CertificateDer<'_>,
    ) -> Result<HandshakeSignatureValid, rustls::Error> {
        // PostgreSQL sslmode=prefer/require does not authenticate the server certificate.
        // Avoid rustls' default signature helpers here because they parse the certificate
        // before chain verification and reject legacy server certificates that libpq/JDBC
        // still accept in these non-verifying modes.
        Ok(HandshakeSignatureValid::assertion())
    }
}

#[derive(Debug)]
struct PostgresCaOnlyCertVerification {
    provider: Arc<CryptoProvider>,
    roots: Arc<rustls::RootCertStore>,
}

impl ServerCertVerifier for PostgresCaOnlyCertVerification {
    fn verify_server_cert(
        &self,
        end_entity: &CertificateDer<'_>,
        intermediates: &[CertificateDer<'_>],
        _server_name: &ServerName<'_>,
        _ocsp_response: &[u8],
        now: UnixTime,
    ) -> Result<ServerCertVerified, rustls::Error> {
        let cert = ParsedCertificate::try_from(end_entity)?;
        verify_server_cert_signed_by_trust_anchor(
            &cert,
            &self.roots,
            intermediates,
            now,
            self.provider.signature_verification_algorithms.all,
        )?;
        Ok(ServerCertVerified::assertion())
    }

    fn verify_tls12_signature(
        &self,
        message: &[u8],
        cert: &CertificateDer<'_>,
        dss: &rustls::DigitallySignedStruct,
    ) -> Result<HandshakeSignatureValid, rustls::Error> {
        verify_tls12_signature(message, cert, dss, &self.provider.signature_verification_algorithms)
    }

    fn verify_tls13_signature(
        &self,
        message: &[u8],
        cert: &CertificateDer<'_>,
        dss: &rustls::DigitallySignedStruct,
    ) -> Result<HandshakeSignatureValid, rustls::Error> {
        verify_tls13_signature(message, cert, dss, &self.provider.signature_verification_algorithms)
    }

    fn supported_verify_schemes(&self) -> Vec<rustls::SignatureScheme> {
        self.provider.signature_verification_algorithms.supported_schemes()
    }
}

/// Check whether the user's connection URL already specifies a timezone via
/// the `options` parameter so we don't overwrite it with the local timezone.
fn pg_url_has_timezone_setting(url: &str) -> bool {
    let Some(query) = url.split_once('?').map(|(_, query)| query.split('#').next().unwrap_or(query)) else {
        return false;
    };

    query.split('&').any(|parameter| {
        let (raw_key, raw_value) = parameter.split_once('=').unwrap_or((parameter, ""));
        let key = percent_decode_str(raw_key).decode_utf8_lossy();
        if !key.eq_ignore_ascii_case("options") {
            return false;
        }

        let options = percent_decode_str(raw_value).decode_utf8_lossy().to_ascii_lowercase();
        options.split_ascii_whitespace().any(|token| {
            let option = token.trim_start_matches('-');
            option.starts_with("timezone=") || option.starts_with("time_zone=")
        })
    })
}

#[cfg(test)]
fn validate_postgres_ssl_paths(url: &str) -> Result<(), String> {
    postgres_connection_url(url).map(|_| ())
}

fn list_databases_sql() -> &'static str {
    "SELECT datname \
     FROM pg_database \
     WHERE datallowconn = true \
     ORDER BY datname"
}

fn database_metadata_sql() -> &'static str {
    "SELECT d.datname, \
            CASE \
              WHEN has_database_privilege(d.datname, 'CONNECT') \
                OR COALESCE(( \
                  SELECT pg_has_role(current_user, r.oid, 'MEMBER') \
                  FROM pg_roles r \
                  WHERE r.rolname = 'pg_read_all_stats' \
                ), false) \
              THEN pg_database_size(d.oid) \
              ELSE NULL \
            END AS size_bytes, \
            obj_description(d.oid, 'pg_database') AS comment, \
            pg_encoding_to_char(d.encoding) AS default_charset \
     FROM pg_database d \
     WHERE datallowconn = true \
     ORDER BY d.datname"
}

fn database_storage_sql() -> &'static str {
    "SELECT d.datname, \
            CASE \
              WHEN has_database_privilege(d.datname, 'CONNECT') \
                OR COALESCE(( \
                  SELECT pg_has_role(current_user, r.oid, 'MEMBER') \
                  FROM pg_roles r \
                  WHERE r.rolname = 'pg_read_all_stats' \
                ), false) \
              THEN pg_database_size(d.oid) \
              ELSE NULL \
            END AS size_bytes \
     FROM pg_database d \
     WHERE d.datallowconn = true \
       AND d.datname = ANY($1::text[]) \
     ORDER BY d.datname"
}

pub async fn list_databases(pool: &Pool) -> Result<Vec<DatabaseInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, list_databases_sql(), &[]).await.map_err(|e| e.to_string())?;

    Ok(rows.iter().map(|row| DatabaseInfo { name: pg_row_try_string(row, 0), ..Default::default() }).collect())
}

pub async fn list_database_metadata(pool: &Pool) -> Result<Vec<DatabaseInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, database_metadata_sql(), &[]).await.map_err(|e| e.to_string())?;
    Ok(rows
        .iter()
        .map(|row| DatabaseInfo {
            name: pg_row_try_string(row, 0),
            size_bytes: row.try_get::<_, Option<i64>>(1).ok().flatten(),
            comment: row.try_get::<_, Option<String>>(2).ok().flatten().filter(|value| !value.trim().is_empty()),
            default_charset: row
                .try_get::<_, Option<String>>(3)
                .ok()
                .flatten()
                .filter(|value| !value.trim().is_empty()),
            ..Default::default()
        })
        .collect())
}

pub async fn list_database_storage(pool: &Pool, database_names: &[String]) -> Result<Vec<DatabaseStorageInfo>, String> {
    if database_names.is_empty() {
        return Ok(Vec::new());
    }
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows =
        postgres_query_cached(&client, database_storage_sql(), &[&database_names]).await.map_err(|e| e.to_string())?;
    Ok(rows
        .iter()
        .map(|row| DatabaseStorageInfo {
            name: pg_row_try_string(row, 0),
            size_bytes: row.try_get::<_, Option<i64>>(1).ok().flatten(),
        })
        .collect())
}

pub async fn list_tables(pool: &Pool, schema: &str) -> Result<Vec<TableInfo>, String> {
    list_tables_filtered(pool, schema, None, None, None).await
}

pub async fn list_tables_filtered(
    pool: &Pool,
    schema: &str,
    filter: Option<&str>,
    limit: Option<usize>,
    offset: Option<usize>,
) -> Result<Vec<TableInfo>, String> {
    list_tables_filtered_by_kind(pool, schema, filter, limit, offset, false).await
}

/// Lists only table-like relations, excluding views and materialized views while
/// retaining server-side filtering and pagination.
pub async fn list_table_objects_filtered(
    pool: &Pool,
    schema: &str,
    filter: Option<&str>,
    limit: Option<usize>,
    offset: Option<usize>,
) -> Result<Vec<TableInfo>, String> {
    list_tables_filtered_by_kind(pool, schema, filter, limit, offset, true).await
}

async fn list_tables_filtered_by_kind(
    pool: &Pool,
    schema: &str,
    filter: Option<&str>,
    limit: Option<usize>,
    offset: Option<usize>,
    table_objects_only: bool,
) -> Result<Vec<TableInfo>, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let filter = filter.unwrap_or("").trim();
    let filter_pattern = like_contains_pattern(filter);
    let fuzzy_filter_pattern =
        if crate::sql::fuzzy_filter_enabled(filter) { like_fuzzy_pattern(filter) } else { String::new() };
    let limit_param = limit.and_then(|value| i64::try_from(value).ok());
    let offset_param = offset.and_then(|value| i64::try_from(value).ok()).unwrap_or(0);
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let sql = if table_objects_only {
        postgres_table_objects_sql(limit_param, offset_param)
    } else {
        postgres_tables_sql(limit_param, offset_param)
    };
    let params: &[(&(dyn tokio_postgres::types::ToSql + Sync), Type)] =
        &[(&schema, Type::VARCHAR), (&filter_pattern, Type::VARCHAR), (&fuzzy_filter_pattern, Type::VARCHAR)];
    // The pagination literals make this SQL vary by page. Use an unnamed typed
    // query so each load stays one round trip without growing the statement cache.
    let rows = client.query_typed(&sql, params).await.map_err(|e| e.to_string())?;

    Ok(rows
        .iter()
        .map(|row| TableInfo {
            name: pg_row_try_string(row, 0),
            table_type: pg_row_try_string(row, 1),
            comment: row.try_get::<_, Option<String>>(2).ok().flatten().filter(|s| !s.is_empty()),
            parent_schema: row.try_get::<_, Option<String>>(3).ok().flatten().filter(|s| !s.is_empty()),
            parent_name: row.try_get::<_, Option<String>>(4).ok().flatten().filter(|s| !s.is_empty()),
        })
        .collect())
}

pub async fn completion_assistant_search(
    pool: &Pool,
    request: &CompletionAssistantRequest,
) -> Result<CompletionAssistantResponse, String> {
    let schema = request.schema.as_deref().or(request.parent_schema.as_deref());
    let routine_schema = schema.unwrap_or("public");
    let limit = request.max_results.unwrap_or(100).clamp(1, 1000);
    let kinds = if request.object_kinds.is_empty() {
        vec![CompletionAssistantObjectKind::Table, CompletionAssistantObjectKind::View]
    } else {
        request.object_kinds.clone()
    };
    let pattern = postgres_completion_like_pattern(&request.mask, request.match_mode.as_ref());
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let mut candidates = Vec::new();

    if kinds.iter().any(|kind| matches!(kind, CompletionAssistantObjectKind::Schema)) {
        for row in postgres_query_cached(
            &client,
            "SELECT nspname FROM pg_catalog.pg_namespace \
             WHERE nspname NOT LIKE 'pg_%' AND nspname <> 'information_schema' \
               AND ($1 = '%%' OR nspname ILIKE $1 ESCAPE '~') \
             ORDER BY nspname LIMIT $2",
            &[&pattern, &(limit as i64)],
        )
        .await
        .map_err(|e| e.to_string())?
        {
            let schema_name: String = pg_row_try_string(&row, 0);
            candidates.push(CompletionAssistantCandidate {
                name: schema_name.clone(),
                kind: CompletionAssistantCandidateKind::Schema,
                database: Some(request.database.clone()),
                schema: Some(schema_name),
                parent_schema: None,
                parent_name: None,
                comment: None,
                data_type: None,
                signature: None,
            });
        }
    }

    if candidates.len() < limit && kinds.iter().any(CompletionAssistantObjectKind::is_table_like) {
        let relkinds = postgres_completion_relkinds(&kinds);
        let rows = postgres_query_cached(
            &client,
            postgres_completion_tables_sql(),
            &[&schema, &pattern, &relkinds, &((limit - candidates.len()) as i64)],
        )
        .await
        .map_err(|e| e.to_string())?;
        for row in rows {
            let table_type: String = pg_row_try_string(&row, 2);
            candidates.push(CompletionAssistantCandidate {
                name: pg_row_try_string(&row, 0),
                kind: if table_type.contains("VIEW") {
                    CompletionAssistantCandidateKind::View
                } else {
                    CompletionAssistantCandidateKind::Table
                },
                database: Some(request.database.clone()),
                schema: Some(pg_row_try_string(&row, 1)),
                parent_schema: row.try_get::<_, Option<String>>(4).ok().flatten(),
                parent_name: row.try_get::<_, Option<String>>(5).ok().flatten(),
                comment: row.try_get::<_, Option<String>>(3).ok().flatten(),
                data_type: None,
                signature: None,
            });
        }
    }

    if candidates.len() < limit && kinds.iter().any(CompletionAssistantObjectKind::is_routine_like) {
        let has_proc_prokind = postgres_proc_has_prokind(&client).await?;
        let rows = if has_proc_prokind {
            let prokinds = postgres_completion_prokinds(&kinds);
            postgres_query_cached(
                &client,
                postgres_completion_routines_sql(true),
                &[&routine_schema, &pattern, &prokinds, &((limit - candidates.len()) as i64)],
            )
            .await
            .map_err(|e| e.to_string())?
        } else if kinds.iter().any(|kind| {
            matches!(kind, CompletionAssistantObjectKind::Function | CompletionAssistantObjectKind::Routine)
        }) {
            postgres_query_cached(
                &client,
                postgres_completion_routines_sql(false),
                &[&routine_schema, &pattern, &((limit - candidates.len()) as i64)],
            )
            .await
            .map_err(|e| e.to_string())?
        } else {
            Vec::new()
        };
        for row in rows {
            let routine_type: String = pg_row_try_string(&row, 2);
            candidates.push(CompletionAssistantCandidate {
                name: pg_row_try_string(&row, 0),
                kind: if routine_type == "PROCEDURE" {
                    CompletionAssistantCandidateKind::Procedure
                } else {
                    CompletionAssistantCandidateKind::Function
                },
                database: Some(request.database.clone()),
                schema: Some(pg_row_try_string(&row, 1)),
                parent_schema: None,
                parent_name: None,
                comment: row.try_get::<_, Option<String>>(3).ok().flatten(),
                data_type: row.try_get::<_, Option<String>>(4).ok().flatten(),
                signature: row.try_get::<_, Option<String>>(5).ok().flatten(),
            });
        }
    }

    if candidates.len() < limit && kinds.iter().any(|kind| matches!(kind, CompletionAssistantObjectKind::Sequence)) {
        let rows = postgres_query_cached(
            &client,
            postgres_completion_sequences_sql(),
            &[&schema, &pattern, &request.case_sensitive, &((limit - candidates.len()) as i64)],
        )
        .await
        .map_err(|e| e.to_string())?;
        for row in rows {
            candidates.push(CompletionAssistantCandidate {
                name: pg_row_try_string(&row, 0),
                kind: CompletionAssistantCandidateKind::Sequence,
                database: Some(request.database.clone()),
                schema: Some(pg_row_try_string(&row, 1)),
                parent_schema: None,
                parent_name: None,
                comment: row.try_get::<_, Option<String>>(2).ok().flatten(),
                data_type: None,
                signature: None,
            });
        }
    }

    if candidates.len() < limit && kinds.iter().any(|kind| matches!(kind, CompletionAssistantObjectKind::Column)) {
        let table = request.parent_name.as_deref().unwrap_or("");
        if !table.is_empty() {
            // Unqualified PostgreSQL objects resolve through search_path, so column
            // metadata must use the same visible relation instead of assuming public.
            let resolved_schema = match schema {
                Some(schema) => Some(schema.to_string()),
                None => postgres_query_cached(&client, postgres_visible_table_schema_sql(), &[&table])
                    .await
                    .map_err(|e| e.to_string())?
                    .first()
                    .map(|row| pg_row_try_string(row, 0)),
            };
            let Some(resolved_schema) = resolved_schema else {
                return Ok(CompletionAssistantResponse { incomplete: false, candidates, fallback_used: false });
            };
            let rows = postgres_query_cached(
                &client,
                postgres_completion_columns_sql(),
                &[&resolved_schema, &table, &pattern, &((limit - candidates.len()) as i64)],
            )
            .await
            .map_err(|e| e.to_string())?;
            for row in rows {
                candidates.push(CompletionAssistantCandidate {
                    name: pg_row_try_string(&row, 0),
                    kind: CompletionAssistantCandidateKind::Column,
                    database: Some(request.database.clone()),
                    schema: Some(resolved_schema.clone()),
                    parent_schema: Some(resolved_schema.clone()),
                    parent_name: Some(table.to_string()),
                    comment: row.try_get::<_, Option<String>>(2).ok().flatten(),
                    data_type: Some(pg_row_try_string(&row, 1)),
                    signature: None,
                });
            }
        }
    }

    Ok(CompletionAssistantResponse { incomplete: candidates.len() >= limit, candidates, fallback_used: false })
}

fn postgres_completion_tables_sql() -> &'static str {
    "SELECT c.relname, n.nspname, \
            CASE c.relkind WHEN 'v' THEN 'VIEW' WHEN 'm' THEN 'VIEW' ELSE 'TABLE' END AS table_type, \
            obj_description(c.oid) AS table_comment, \
            CASE WHEN pc.relkind = 'p' THEN pn.nspname ELSE NULL END AS parent_schema, \
            CASE WHEN pc.relkind = 'p' THEN pc.relname ELSE NULL END AS parent_name \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     LEFT JOIN pg_catalog.pg_inherits i ON i.inhrelid = c.oid \
     LEFT JOIN pg_catalog.pg_class pc ON pc.oid = i.inhparent \
     LEFT JOIN pg_catalog.pg_namespace pn ON pn.oid = pc.relnamespace \
     WHERE ($1::text IS NOT NULL AND n.nspname = $1 \
            OR $1::text IS NULL AND pg_catalog.pg_table_is_visible(c.oid)) \
       AND c.relkind::text = ANY($3::text[]) \
       AND ($2 = '%%' OR c.relname ILIKE $2 ESCAPE '~') \
     ORDER BY c.relname LIMIT $4"
}

fn postgres_completion_routines_sql(has_proc_prokind: bool) -> &'static str {
    if has_proc_prokind {
        return "SELECT p.proname, n.nspname, CASE p.prokind WHEN 'p' THEN 'PROCEDURE' ELSE 'FUNCTION' END, \
            obj_description(p.oid) AS routine_comment, COALESCE(pg_get_function_result(p.oid), '') AS data_type, \
            pg_get_function_identity_arguments(p.oid) AS signature \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 AND p.prokind::text = ANY($3::text[]) \
       AND ($2 = '%%' OR p.proname ILIKE $2 ESCAPE '~') \
     ORDER BY p.proname LIMIT $4";
    }

    "SELECT p.proname, n.nspname, 'FUNCTION'::text, \
            obj_description(p.oid) AS routine_comment, COALESCE(pg_get_function_result(p.oid), '') AS data_type, \
            pg_get_function_identity_arguments(p.oid) AS signature \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 \
       AND ($2 = '%%' OR p.proname ILIKE $2 ESCAPE '~') \
     ORDER BY p.proname LIMIT $3"
}

fn postgres_completion_sequences_sql() -> &'static str {
    "SELECT c.relname, n.nspname, obj_description(c.oid) AS sequence_comment \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE ($1::text IS NOT NULL AND n.nspname = $1 \
            OR $1::text IS NULL AND pg_catalog.pg_table_is_visible(c.oid)) \
       AND c.relkind = 'S' \
       AND pg_catalog.has_schema_privilege(n.oid, 'USAGE') \
       AND CASE WHEN c.relkind = 'S' \
                THEN pg_catalog.has_sequence_privilege(c.oid, 'USAGE, SELECT, UPDATE') \
                ELSE FALSE END \
       AND ($2 = '%%' OR CASE WHEN $3 THEN c.relname LIKE $2 ESCAPE '~' \
                              ELSE c.relname ILIKE $2 ESCAPE '~' END) \
     ORDER BY c.relname LIMIT $4"
}

fn postgres_completion_columns_sql() -> &'static str {
    "SELECT a.attname, pg_catalog.format_type(a.atttypid, a.atttypmod), col_description(c.oid, a.attnum) \
     FROM pg_catalog.pg_attribute a \
     JOIN pg_catalog.pg_class c ON c.oid = a.attrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 AND c.relname = $2 AND a.attnum > 0 AND NOT a.attisdropped \
       AND ($3 = '%%' OR a.attname ILIKE $3 ESCAPE '~') \
     ORDER BY a.attnum LIMIT $4"
}

fn postgres_visible_table_schema_sql() -> &'static str {
    "SELECT n.nspname FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE c.relname = $1 AND pg_catalog.pg_table_is_visible(c.oid) \
     LIMIT 1"
}

fn postgres_completion_relkinds(kinds: &[CompletionAssistantObjectKind]) -> Vec<String> {
    let mut relkinds = Vec::new();
    if kinds.iter().any(|kind| matches!(kind, CompletionAssistantObjectKind::Table)) {
        relkinds.extend(["r", "p", "f"].into_iter().map(str::to_string));
    }
    if kinds.iter().any(|kind| matches!(kind, CompletionAssistantObjectKind::View)) {
        relkinds.extend(["v", "m"].into_iter().map(str::to_string));
    }
    relkinds
}

fn postgres_completion_prokinds(kinds: &[CompletionAssistantObjectKind]) -> Vec<String> {
    let mut prokinds = Vec::new();
    if kinds
        .iter()
        .any(|kind| matches!(kind, CompletionAssistantObjectKind::Procedure | CompletionAssistantObjectKind::Routine))
    {
        prokinds.push("p".to_string());
    }
    if kinds
        .iter()
        .any(|kind| matches!(kind, CompletionAssistantObjectKind::Function | CompletionAssistantObjectKind::Routine))
    {
        prokinds.push("f".to_string());
    }
    prokinds
}

fn postgres_completion_like_pattern(value: &str, mode: Option<&CompletionAssistantMatchMode>) -> String {
    if value.trim().is_empty() || value == "%" {
        return "%%".to_string();
    }
    let escaped = value.trim().replace('~', "~~").replace('%', "~%").replace('_', "~_");
    match mode.unwrap_or(&CompletionAssistantMatchMode::Prefix) {
        CompletionAssistantMatchMode::Prefix => format!("{escaped}%"),
        CompletionAssistantMatchMode::Contains => format!("%{escaped}%"),
    }
}

pub async fn get_table_comment(pool: &Pool, schema: &str, table: &str) -> Result<Option<String>, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, postgres_table_comment_sql(), &[&schema, &table])
        .await
        .map_err(|e| e.to_string())?;
    Ok(rows.first().and_then(|row| row.try_get::<_, Option<String>>(0).ok().flatten()).filter(|s| !s.is_empty()))
}

pub async fn get_table_partition_info(
    pool: &Pool,
    schema: &str,
    table: &str,
) -> Result<PostgresTablePartitionInfo, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let relation_rows = postgres_query_cached(&client, postgres_table_partition_relation_sql(), &[&schema, &table])
        .await
        .map_err(|e| e.to_string())?;
    let Some(relation) = relation_rows.first() else {
        return Ok(PostgresTablePartitionInfo::default());
    };
    let relkind = relation.try_get::<_, String>(0).unwrap_or_default();
    let is_partition = relation.try_get::<_, bool>(1).unwrap_or(false);
    let is_foreign = relkind == "f";
    if relkind != "p" && !is_foreign && !is_partition {
        return Ok(PostgresTablePartitionInfo::default());
    }

    let params: [&(dyn tokio_postgres::types::ToSql + Sync); 2] = [&schema, &table];
    let rows = query_with_compat_fallback(
        "get_table_partition_info",
        &[postgres_table_partition_info_sql(), postgres_table_partition_info_compat_sql()],
        |sql| postgres_query_cached(&client, sql, &params),
    )
    .await?;
    let Some(row) = rows.first() else {
        return Ok(PostgresTablePartitionInfo { is_partition, is_foreign, ..Default::default() });
    };
    let foreign_options = row
        .try_get::<_, Option<Vec<String>>>(5)
        .ok()
        .flatten()
        .unwrap_or_default()
        .into_iter()
        .filter_map(|option| option.split_once('=').map(|(key, value)| (key.to_string(), value.to_string())))
        .collect();
    Ok(PostgresTablePartitionInfo {
        is_partition,
        parent_schema: row.try_get::<_, Option<String>>(0).ok().flatten().filter(|value| !value.is_empty()),
        parent_table: row.try_get::<_, Option<String>>(1).ok().flatten().filter(|value| !value.is_empty()),
        bound: row.try_get::<_, Option<String>>(2).ok().flatten().filter(|value| !value.is_empty()),
        key: row.try_get::<_, Option<String>>(3).ok().flatten().filter(|value| !value.is_empty()),
        is_foreign,
        foreign_server: row.try_get::<_, Option<String>>(4).ok().flatten().filter(|value| !value.is_empty()),
        foreign_options,
    })
}

pub async fn get_table_partition_key(pool: &Pool, schema: &str, table: &str) -> Result<Option<String>, String> {
    Ok(get_table_partition_info(pool, schema, table).await?.key)
}

/// Classifies one row of `postgres_table_partition_local_objects_sql` (or its
/// `_for_relations` sibling, which has the same `object_kind`/`object_name`/
/// `object_type` columns plus a leading `relid`) into `entry`. Shared so a
/// future local-object kind, or a fix to how a kind is recognized, can't be
/// applied to only one of the two query paths.
fn apply_partition_local_object_row(
    entry: &mut PostgresTablePartitionLocalObjects,
    object_kind: &str,
    object_name: String,
    object_type: &str,
) {
    match object_kind {
        "constraint" if object_type == "p" => entry.has_primary_key = true,
        "constraint" if object_type == "f" && !object_name.is_empty() => {
            entry.foreign_keys.insert(object_name);
        }
        "check" if !object_name.is_empty() => {
            entry.check_constraints.insert(object_name);
        }
        "index" if !object_name.is_empty() => {
            entry.indexes.insert(object_name);
        }
        "column_default" if !object_name.is_empty() => {
            let state = if object_type == "dropped" {
                PostgresColumnDefaultState::Dropped
            } else {
                PostgresColumnDefaultState::Overridden
            };
            entry.column_defaults.insert(object_name, state);
        }
        _ => {}
    }
}

pub async fn get_table_partition_local_objects(
    pool: &Pool,
    schema: &str,
    table: &str,
) -> Result<PostgresTablePartitionLocalObjects, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, postgres_table_partition_local_objects_sql(), &[&schema, &table])
        .await
        .map_err(|e| e.to_string())?;
    let mut result = PostgresTablePartitionLocalObjects::default();
    for row in rows {
        let object_kind = row.try_get::<_, String>(0).unwrap_or_default();
        let object_name = row.try_get::<_, String>(1).unwrap_or_default();
        let object_type = row.try_get::<_, Option<String>>(2).ok().flatten().unwrap_or_default();
        apply_partition_local_object_row(&mut result, &object_kind, object_name, &object_type);
    }
    Ok(result)
}

/// One relation in a partition tree, as discovered by
/// `fetch_postgres_partition_tree`.
#[derive(Debug, Clone)]
pub struct PostgresPartitionTreeNode {
    pub oid: i64,
    pub schema: String,
    pub table: String,
    pub parent_oid: Option<i64>,
    pub parent_schema: Option<String>,
    pub parent_table: Option<String>,
    pub partition_info: PostgresTablePartitionInfo,
}

fn postgres_partition_tree_sql() -> &'static str {
    "WITH RECURSIVE tree AS ( \
       SELECT c.oid::bigint AS oid, n.nspname::text AS schema, c.relname::text AS relname, \
              ap.oid::bigint AS parent_oid, an.nspname::text COLLATE \"C\" AS parent_schema, ap.relname::text COLLATE \"C\" AS parent_relname, \
              c.relkind::text AS relkind, ARRAY[c.oid]::bigint[] AS path \
       FROM pg_catalog.pg_class c \
       JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
       LEFT JOIN pg_catalog.pg_inherits ai ON ai.inhrelid = c.oid AND c.relispartition \
       LEFT JOIN pg_catalog.pg_class ap ON ap.oid = ai.inhparent \
       LEFT JOIN pg_catalog.pg_namespace an ON an.oid = ap.relnamespace \
       WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r','p','f') \
       UNION ALL \
       SELECT c.oid::bigint, n.nspname::text, c.relname::text, tree.oid, tree.schema, tree.relname, c.relkind::text, \
              tree.path || c.oid::bigint \
       FROM pg_catalog.pg_inherits i \
       JOIN pg_catalog.pg_class c ON c.oid = i.inhrelid AND c.relispartition \
       JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
       JOIN tree ON tree.oid = i.inhparent \
       WHERE NOT c.oid = ANY(tree.path) \
     ) \
     SELECT t.oid, t.schema, t.relname, t.parent_oid, t.parent_schema, t.parent_relname, t.relkind, \
            pg_catalog.pg_get_expr(c.relpartbound, c.oid, true) AS partition_bound, \
            CASE WHEN t.relkind = 'p' THEN pg_catalog.pg_get_partkeydef(c.oid) ELSE NULL END AS partition_key, \
            fs.srvname AS foreign_server, \
            ft.ftoptions AS foreign_options \
     FROM tree t \
     JOIN pg_catalog.pg_class c ON c.oid = t.oid \
     LEFT JOIN pg_catalog.pg_foreign_table ft ON ft.ftrelid = c.oid \
     LEFT JOIN pg_catalog.pg_foreign_server fs ON fs.oid = ft.ftserver \
     ORDER BY t.oid"
}

/// 9.x 没有 relispartition/relpartbound/pg_get_partkeydef，主查询会用到一个
/// 不存在的列，直接报错；旧式 INHERITS 子表在 9.x 按普通表处理，
/// 这里只返回请求的关系本身。
///
/// Pre-10 servers lack the declarative-partition catalog (relispartition /
/// relpartbound / pg_get_partkeydef) the primary query needs; old-style
/// INHERITS children are plain tables there, so just the requested relation
/// is returned.
fn postgres_partition_tree_compat_sql() -> &'static str {
    "SELECT c.oid::bigint AS oid, n.nspname::text AS schema, c.relname::text AS relname, \
            NULL::bigint AS parent_oid, NULL::text AS parent_schema, NULL::text AS parent_relname, \
            c.relkind::text AS relkind, \
            NULL::text AS partition_bound, NULL::text AS partition_key, \
            fs.srvname AS foreign_server, \
            ft.ftoptions AS foreign_options \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     LEFT JOIN pg_catalog.pg_foreign_table ft ON ft.ftrelid = c.oid \
     LEFT JOIN pg_catalog.pg_foreign_server fs ON fs.oid = ft.ftserver \
     WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r','p','f')"
}

/// The whole partition tree rooted at (schema, table) — the root itself plus
/// every descendant partition at any depth — plus each node's partition info,
/// in a single round trip. Used by `pg_ddl_with_partitions` instead of
/// recursing per-relation (which reruns the full metadata query chain once
/// per node and scales the request count linearly with tree size).
pub async fn fetch_postgres_partition_tree(
    pool: &Pool,
    schema: &str,
    table: &str,
) -> Result<Vec<PostgresPartitionTreeNode>, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let params: [&(dyn tokio_postgres::types::ToSql + Sync); 2] = [&schema, &table];
    let rows = query_with_compat_fallback(
        "fetch_postgres_partition_tree",
        &[postgres_partition_tree_sql(), postgres_partition_tree_compat_sql()],
        |sql| postgres_query_cached(&client, sql, &params),
    )
    .await?;
    Ok(rows
        .into_iter()
        .filter_map(|row| {
            let oid = row.try_get::<_, i64>(0).ok()?;
            let node_schema = row.try_get::<_, String>(1).ok()?;
            let node_table = row.try_get::<_, String>(2).ok()?;
            let parent_oid = row.try_get::<_, Option<i64>>(3).ok().flatten();
            let parent_schema = row.try_get::<_, Option<String>>(4).ok().flatten();
            let parent_table = row.try_get::<_, Option<String>>(5).ok().flatten();
            let relkind = row.try_get::<_, String>(6).unwrap_or_default();
            let is_foreign = relkind == "f";
            let foreign_options = row
                .try_get::<_, Option<Vec<String>>>(10)
                .ok()
                .flatten()
                .unwrap_or_default()
                .into_iter()
                .filter_map(|option| option.split_once('=').map(|(key, value)| (key.to_string(), value.to_string())))
                .collect();
            let partition_info = PostgresTablePartitionInfo {
                is_partition: parent_oid.is_some(),
                parent_schema: parent_schema.clone().filter(|value| !value.is_empty()),
                parent_table: parent_table.clone().filter(|value| !value.is_empty()),
                bound: row.try_get::<_, Option<String>>(7).ok().flatten().filter(|value| !value.is_empty()),
                key: row.try_get::<_, Option<String>>(8).ok().flatten().filter(|value| !value.is_empty()),
                is_foreign,
                foreign_server: row.try_get::<_, Option<String>>(9).ok().flatten().filter(|value| !value.is_empty()),
                foreign_options,
            };
            Some(PostgresPartitionTreeNode {
                oid,
                schema: node_schema,
                table: node_table,
                parent_oid,
                parent_schema,
                parent_table,
                partition_info,
            })
        })
        .collect())
}

/// Batched sibling of get_columns, fetching every relation through at most
/// two OID-scoped catalog queries. The compatibility tier avoids PostgreSQL
/// 12+ catalog fields so PostgreSQL 10-compatible servers remain bounded.
pub async fn get_columns_for_relations(
    pool: &Pool,
    relations: &[(i64, String, String)],
) -> Result<HashMap<i64, Vec<ColumnInfo>>, String> {
    let oids: Vec<i64> = relations.iter().map(|(oid, _, _)| *oid).collect();
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let tiers = postgres_columns_for_relations_query_tiers();
    query_with_compat_fallback("get_columns_for_relations", &tiers, |sql| {
        get_columns_for_relations_with_sql(&client, sql, &oids)
    })
    .await
}

async fn get_columns_for_relations_with_sql(
    client: &deadpool_postgres::Client,
    sql: &str,
    oids: &[i64],
) -> Result<HashMap<i64, Vec<ColumnInfo>>, tokio_postgres::Error> {
    let rows = postgres_query_cached(client, sql, &[&oids]).await?;
    let mut result: HashMap<i64, Vec<ColumnInfo>> = HashMap::new();
    for row in &rows {
        let Ok(relid) = row.try_get::<_, i64>(0) else { continue };
        result.entry(relid).or_default().push(column_info_from_row_offset(row, 1));
    }
    Ok(result)
}

fn postgres_columns_for_relations_query_tiers() -> [&'static str; 2] {
    [postgres_columns_for_relations_sql(), postgres_columns_for_relations_compat_sql()]
}

// Sibling of `POSTGRES_COLUMNS_SQL`/`POSTGRES_COLUMNS_COMPAT_SQL` below (~line
// 4880): same column list and detection logic (identity/serial inference,
// numeric precision/scale, enum values), batched by oid instead of a single
// (schema, table) pair. Kept as a separate literal rather than sharing a
// fragment — `pg_class` needs the `c` alias here for the oid filter, which
// pushes `information_schema.columns` to `ic` instead of the single-relation
// version's `c`, and every column's position in the SELECT list is relied on
// positionally by `column_info_from_row_offset`. A change to one almost
// certainly needs the same change in the other.
fn postgres_columns_for_relations_sql() -> &'static str {
    "SELECT c.oid::bigint AS relid, a.attname AS column_name, \
             format_type(a.atttypid, a.atttypmod) AS full_type, \
             COALESCE(ic.is_nullable = 'YES', NOT a.attnotnull) AS is_nullable, \
             CASE WHEN a.attgenerated <> '' THEN NULL ELSE pg_get_expr(ad.adbin, ad.adrelid) END AS column_default, \
             EXISTS ( \
               SELECT 1 FROM pg_constraint co \
               JOIN pg_index i ON i.indrelid = co.conrelid AND co.conindid = i.indexrelid \
               WHERE co.conrelid = a.attrelid AND co.contype = 'p' \
               AND a.attnum = ANY(i.indkey) \
             ) AS is_pk, \
             col_description(a.attrelid, a.attnum) AS column_comment, \
             CASE a.attidentity \
               WHEN 'd' THEN 'generated by default as identity' || CASE WHEN pseq.seqstart IS NOT NULL THEN format(' (start with %s increment by %s)', pseq.seqstart, pseq.seqincrement) ELSE '' END \
               WHEN 'a' THEN 'generated always as identity' || CASE WHEN pseq.seqstart IS NOT NULL THEN format(' (start with %s increment by %s)', pseq.seqstart, pseq.seqincrement) ELSE '' END \
               ELSE CASE a.attgenerated \
                 WHEN 's' THEN 'generated always as (' || pg_get_expr(ad.adbin, ad.adrelid) || ') stored' \
                 WHEN 'v' THEN 'generated always as (' || pg_get_expr(ad.adbin, ad.adrelid) || ') virtual' \
                 ELSE CASE WHEN a.atttypid IN (20, 21, 23) AND dep.deptype = 'a' \
                   AND pseq.seqrelid IS NOT NULL \
                   AND pg_get_expr(ad.adbin, ad.adrelid) = format('nextval(%L::regclass)', dep.objid::regclass::text) \
                 THEN CASE a.atttypid \
                   WHEN 21 THEN 'smallserial' \
                   WHEN 23 THEN 'serial' \
                   WHEN 20 THEN 'bigserial' \
                 END ELSE NULL END \
               END \
             END AS column_extra, \
             CASE WHEN t.typname = 'numeric' AND a.atttypmod > 0 \
               THEN ((a.atttypmod - 4) >> 16) & 65535 ELSE NULL END AS numeric_precision, \
             CASE WHEN t.typname = 'numeric' AND a.atttypmod > 0 \
               THEN (a.atttypmod - 4) & 65535 ELSE NULL END AS numeric_scale, \
             CASE WHEN t.typname IN ('varchar', 'bpchar') AND a.atttypmod > 0 \
               THEN a.atttypmod - 4 ELSE NULL END AS character_maximum_length, \
             CASE WHEN enum_t.oid IS NULL THEN NULL \
               ELSE COALESCE((SELECT array_to_json(array_agg(e.enumlabel ORDER BY e.enumsortorder))::text \
                              FROM pg_enum e WHERE e.enumtypid = enum_t.oid), '[]') END AS enum_values \
             FROM pg_attribute a \
             JOIN pg_class c ON c.oid = a.attrelid \
             JOIN pg_namespace n ON n.oid = c.relnamespace \
             JOIN pg_type t ON t.oid = a.atttypid \
             LEFT JOIN pg_type enum_t ON enum_t.oid = CASE WHEN t.typtype = 'd' THEN t.typbasetype WHEN t.typtype = 'e' THEN t.oid ELSE NULL END AND enum_t.typtype = 'e' \
             LEFT JOIN pg_attrdef ad ON ad.adrelid = a.attrelid AND ad.adnum = a.attnum \
             LEFT JOIN LATERAL ( \
               SELECT sequence_dep.objid, sequence_dep.deptype \
               FROM pg_catalog.pg_depend sequence_dep \
               JOIN pg_catalog.pg_class sequence_class \
                 ON sequence_class.oid = sequence_dep.objid AND sequence_class.relkind = 'S' \
               WHERE sequence_dep.classid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                 AND sequence_dep.objsubid = 0 \
                 AND sequence_dep.refclassid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                 AND sequence_dep.refobjid = a.attrelid AND sequence_dep.refobjsubid = a.attnum \
                 AND ((a.attidentity <> '' AND sequence_dep.deptype = 'i') OR (a.attidentity = '' \
                   AND sequence_dep.deptype = 'a' AND EXISTS ( \
                     SELECT 1 FROM pg_catalog.pg_depend serial_default_dep \
                     WHERE serial_default_dep.classid = 'pg_catalog.pg_attrdef'::pg_catalog.regclass \
                       AND serial_default_dep.objid = ad.oid AND serial_default_dep.objsubid = 0 \
                       AND serial_default_dep.refclassid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                       AND serial_default_dep.refobjid = sequence_dep.objid \
                       AND serial_default_dep.refobjsubid = 0 AND serial_default_dep.deptype = 'n' \
                   ))) \
               ORDER BY sequence_dep.objid \
               LIMIT 1 \
             ) dep ON TRUE \
             LEFT JOIN pg_sequence pseq ON pseq.seqrelid = dep.objid \
             LEFT JOIN information_schema.columns ic \
               ON ic.table_schema = n.nspname AND ic.table_name = c.relname AND ic.column_name = a.attname \
             WHERE c.oid = ANY($1::bigint[]) \
             AND a.attnum > 0 AND NOT a.attisdropped \
             ORDER BY c.oid, a.attnum"
}

// Compat-tier sibling of `POSTGRES_COLUMNS_COMPAT_SQL` (~line 4938) — see the
// note on `postgres_columns_for_relations_sql` above.
fn postgres_columns_for_relations_compat_sql() -> &'static str {
    "SELECT c.oid::bigint AS relid, a.attname AS column_name, \
             format_type(a.atttypid, a.atttypmod) AS full_type, \
             COALESCE(ic.is_nullable = 'YES', NOT a.attnotnull) AS is_nullable, \
             pg_get_expr(ad.adbin, ad.adrelid) AS column_default, \
             EXISTS ( \
               SELECT 1 FROM pg_constraint co \
               JOIN pg_index i ON i.indrelid = co.conrelid AND co.conindid = i.indexrelid \
               WHERE co.conrelid = a.attrelid AND co.contype = 'p' \
               AND a.attnum = ANY(i.indkey) \
             ) AS is_pk, \
             col_description(a.attrelid, a.attnum) AS column_comment, \
             CASE WHEN a.atttypid IN (20, 21, 23) AND serial_seq.oid IS NOT NULL \
               AND pg_get_expr(ad.adbin, ad.adrelid) = format('nextval(%L::regclass)', serial_seq.oid::regclass::text) \
             THEN CASE a.atttypid \
               WHEN 21 THEN 'smallserial' \
               WHEN 23 THEN 'serial' \
               WHEN 20 THEN 'bigserial' \
             END ELSE NULL END AS column_extra, \
             CASE WHEN t.typname = 'numeric' AND a.atttypmod > 0 \
               THEN ((a.atttypmod - 4) >> 16) & 65535 ELSE NULL END AS numeric_precision, \
             CASE WHEN t.typname = 'numeric' AND a.atttypmod > 0 \
               THEN (a.atttypmod - 4) & 65535 ELSE NULL END AS numeric_scale, \
             CASE WHEN t.typname IN ('varchar', 'bpchar') AND a.atttypmod > 0 \
               THEN a.atttypmod - 4 ELSE NULL END AS character_maximum_length, \
             NULL::text AS enum_values \
             FROM pg_attribute a \
             JOIN pg_class c ON c.oid = a.attrelid \
             JOIN pg_namespace n ON n.oid = c.relnamespace \
             JOIN pg_type t ON t.oid = a.atttypid \
             LEFT JOIN pg_attrdef ad ON ad.adrelid = a.attrelid AND ad.adnum = a.attnum \
             LEFT JOIN pg_catalog.pg_class serial_seq ON serial_seq.oid = ( \
               SELECT sequence_dep.objid \
               FROM pg_catalog.pg_depend sequence_dep \
               JOIN pg_catalog.pg_class sequence_class \
                 ON sequence_class.oid = sequence_dep.objid AND sequence_class.relkind = 'S' \
               WHERE sequence_dep.classid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                 AND sequence_dep.objsubid = 0 \
                 AND sequence_dep.refclassid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                 AND sequence_dep.refobjid = a.attrelid AND sequence_dep.refobjsubid = a.attnum \
                 AND sequence_dep.deptype = 'a' AND EXISTS ( \
                   SELECT 1 FROM pg_catalog.pg_depend serial_default_dep \
                   WHERE serial_default_dep.classid = 'pg_catalog.pg_attrdef'::pg_catalog.regclass \
                     AND serial_default_dep.objid = ad.oid AND serial_default_dep.objsubid = 0 \
                     AND serial_default_dep.refclassid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                     AND serial_default_dep.refobjid = sequence_dep.objid \
                     AND serial_default_dep.refobjsubid = 0 AND serial_default_dep.deptype = 'n' \
                 ) \
               ORDER BY sequence_dep.objid \
               LIMIT 1 \
             ) AND serial_seq.relkind = 'S' \
             LEFT JOIN information_schema.columns ic \
               ON ic.table_schema = n.nspname AND ic.table_name = c.relname AND ic.column_name = a.attname \
             WHERE c.oid = ANY($1::bigint[]) \
             AND a.attnum > 0 AND NOT a.attisdropped \
             ORDER BY c.oid, a.attnum"
}

/// Same field layout as `column_info_from_row`, offset by one leading `relid`
/// column.
fn column_info_from_row_offset(row: &Row, offset: usize) -> ColumnInfo {
    let full_type = row.try_get::<_, Option<String>>(offset + 1).ok().flatten().unwrap_or_default();
    ColumnInfo {
        name: pg_row_try_string(row, offset),
        data_type: full_type,
        is_nullable: pg_row_try_bool(row, offset + 2).unwrap_or(true),
        column_default: row.try_get::<_, Option<String>>(offset + 3).ok().flatten(),
        is_primary_key: pg_row_try_bool(row, offset + 4).unwrap_or(false),
        extra: row.try_get::<_, Option<String>>(offset + 6).ok().flatten(),
        comment: row.try_get::<_, Option<String>>(offset + 5).ok().flatten(),
        numeric_precision: row.try_get::<_, Option<i32>>(offset + 7).ok().flatten(),
        numeric_scale: row.try_get::<_, Option<i32>>(offset + 8).ok().flatten(),
        character_maximum_length: row.try_get::<_, Option<i32>>(offset + 9).ok().flatten(),
        enum_values: parse_enum_values_from_row(row, offset + 10),
        ..Default::default()
    }
}

/// Batched sibling of list_indexes, using a modern and a PostgreSQL 10
/// compatible OID-scoped tier so the request count stays bounded.
pub async fn list_indexes_for_relations(
    pool: &Pool,
    relations: &[(i64, String, String)],
) -> Result<HashMap<i64, Vec<IndexInfo>>, String> {
    let oids: Vec<i64> = relations.iter().map(|(oid, _, _)| *oid).collect();
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let tiers = postgres_indexes_for_relations_query_tiers();
    query_with_compat_fallback("list_indexes_for_relations", &tiers, |sql| {
        list_indexes_for_relations_with_sql(&client, sql, &oids)
    })
    .await
}

async fn list_indexes_for_relations_with_sql(
    client: &deadpool_postgres::Client,
    sql: &str,
    oids: &[i64],
) -> Result<HashMap<i64, Vec<IndexInfo>>, tokio_postgres::Error> {
    let rows = postgres_query_cached(client, sql, &[&oids]).await?;
    let mut result: HashMap<i64, Vec<IndexInfo>> = HashMap::new();
    for row in &rows {
        let Ok(relid) = row.try_get::<_, i64>(0) else { continue };
        let all_cols: Vec<String> = row.try_get::<_, Vec<String>>(2).unwrap_or_default();
        let all_opclasses: Vec<Option<String>> = row.try_get::<_, Vec<Option<String>>>(3).unwrap_or_default();
        let nkeyatts = row.try_get::<_, Option<i16>>(8).ok().flatten().unwrap_or(all_cols.len() as i16) as usize;
        let split_at = nkeyatts.min(all_cols.len());
        let key_cols = all_cols[..split_at].to_vec();
        let key_opclasses = if all_opclasses.len() == all_cols.len() {
            all_opclasses[..split_at].to_vec()
        } else {
            vec![None; split_at]
        };
        let included = if split_at < all_cols.len() { all_cols[split_at..].to_vec() } else { vec![] };
        let all_is_expr: Vec<bool> = row.try_get::<_, Vec<bool>>(11).unwrap_or_default();
        let key_is_expression =
            if all_is_expr.len() == all_cols.len() { all_is_expr[..split_at].to_vec() } else { Vec::new() };
        result.entry(relid).or_default().push(IndexInfo {
            name: pg_row_try_string(row, 1),
            columns: key_cols,
            is_unique: pg_row_try_bool(row, 4).unwrap_or(false),
            is_primary: pg_row_try_bool(row, 5).unwrap_or(false),
            filter: row.try_get::<_, Option<String>>(6).ok().flatten(),
            index_type: row.try_get::<_, Option<String>>(7).ok().flatten(),
            included_columns: if included.is_empty() { None } else { Some(included) },
            comment: row.try_get::<_, Option<String>>(10).ok().flatten(),
            key_is_expression,
            column_opclasses: key_opclasses,
        });
    }
    Ok(result)
}

fn postgres_indexes_for_relations_query_tiers() -> [&'static str; 2] {
    [postgres_indexes_for_relations_sql(), postgres_indexes_for_relations_compat_sql()]
}

// Sibling of `POSTGRES_INDEXES_SQL`/`POSTGRES_INDEXES_COMPAT_SQL` (~line
// 6042): same index-detection logic, batched by oid instead of a single
// (schema, table) pair. Not merged into a shared fragment for the same
// reason as the columns queries above — an alias would need renaming to
// line up, and result columns are read positionally.
fn postgres_indexes_for_relations_sql() -> &'static str {
    "SELECT t.oid::bigint AS relid, i.relname AS index_name, \
             array_agg(COALESCE(a.attname, pg_get_indexdef(ix.indexrelid, k.n::int, false)) ORDER BY k.n) AS columns, \
             array_agg(CASE WHEN oc.opcdefault THEN NULL ELSE quote_ident(opcns.nspname) || '.' || quote_ident(oc.opcname) END ORDER BY k.n) AS column_opclasses, \
             (ix.indisunique AND ix.indisvalid) AS is_unique, \
             ix.indisprimary AS is_primary, \
             pg_get_expr(ix.indpred, ix.indrelid) AS filter_expr, \
             am.amname AS index_type, \
             ix.indnkeyatts AS nkeyatts, \
             ix.indkey AS indkey, \
             obj_description(i.oid, 'pg_class') AS index_comment, \
             array_agg(a.attname IS NULL ORDER BY k.n) AS key_is_expression \
             FROM pg_index ix \
             JOIN pg_class t ON t.oid = ix.indrelid \
             JOIN pg_class i ON i.oid = ix.indexrelid \
             JOIN pg_am am ON am.oid = i.relam \
             JOIN LATERAL unnest(ix.indkey, ix.indclass) WITH ORDINALITY AS k(attnum, class_oid, n) ON true \
             LEFT JOIN pg_attribute a ON a.attrelid = t.oid AND a.attnum = k.attnum AND k.attnum > 0 \
             LEFT JOIN pg_opclass oc ON oc.oid = k.class_oid \
             LEFT JOIN pg_namespace opcns ON opcns.oid = oc.opcnamespace \
             WHERE t.oid = ANY($1::bigint[]) \
             GROUP BY t.oid, i.relname, i.oid, ix.indisunique, ix.indisvalid, ix.indisprimary, ix.indpred, ix.indrelid, am.amname, ix.indnkeyatts, ix.indkey \
             ORDER BY t.oid, i.relname"
}

// Compat-tier sibling of `POSTGRES_INDEXES_COMPAT_SQL` (~line 6063) — see the
// note on `postgres_indexes_for_relations_sql` above.
fn postgres_indexes_for_relations_compat_sql() -> &'static str {
    "SELECT t.oid::bigint AS relid, i.relname AS index_name, \
             ARRAY( \
               SELECT COALESCE(a.attname, pg_get_indexdef(ix.indexrelid, pos.n, false)) \
               FROM generate_series(1, array_length(string_to_array(ix.indkey::text, ' '), 1)) AS pos(n) \
               LEFT JOIN pg_attribute a \
                 ON a.attrelid = t.oid \
                AND a.attnum = (string_to_array(ix.indkey::text, ' '))[pos.n]::int2 \
                AND a.attnum > 0 \
               ORDER BY pos.n \
             ) AS columns, \
             ARRAY( \
               SELECT CASE WHEN oc.opcdefault THEN NULL \
                           ELSE oc.opcname \
                      END \
               FROM generate_series(1, array_length(string_to_array(ix.indkey::text, ' '), 1)) AS pos(n) \
               LEFT JOIN pg_attribute a \
                 ON a.attrelid = t.oid \
                AND a.attnum = (string_to_array(ix.indkey::text, ' '))[pos.n]::int2 \
                AND a.attnum > 0 \
               LEFT JOIN pg_opclass oc \
                 ON oc.oid = (string_to_array(ix.indclass::text, ' '))[pos.n]::oid \
               ORDER BY pos.n \
             ) AS column_opclasses, \
             (ix.indisunique AND ix.indisvalid) AS is_unique, \
             ix.indisprimary AS is_primary, \
             pg_get_expr(ix.indpred, ix.indrelid) AS filter_expr, \
             am.amname AS index_type, \
             NULL::smallint AS nkeyatts, \
             ix.indkey AS indkey, \
             obj_description(i.oid, 'pg_class') AS index_comment, \
             ARRAY( \
               SELECT a.attname IS NULL \
               FROM generate_series(1, array_length(string_to_array(ix.indkey::text, ' '), 1)) AS pos(n) \
               LEFT JOIN pg_attribute a \
                 ON a.attrelid = t.oid \
                AND a.attnum = (string_to_array(ix.indkey::text, ' '))[pos.n]::int2 \
                AND a.attnum > 0 \
               ORDER BY pos.n \
             ) AS key_is_expression \
             FROM pg_index ix \
             JOIN pg_class t ON t.oid = ix.indrelid \
             JOIN pg_class i ON i.oid = ix.indexrelid \
             JOIN pg_am am ON am.oid = i.relam \
             WHERE t.oid = ANY($1::bigint[]) \
             ORDER BY t.oid, i.relname"
}

/// Batched sibling of `list_foreign_keys`, keyed by `(schema, table)`.
pub async fn list_foreign_keys_for_relations(
    pool: &Pool,
    relations: &[(String, String)],
) -> Result<HashMap<(String, String), Vec<ForeignKeyInfo>>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let schemas: Vec<&str> = relations.iter().map(|(schema, _)| schema.as_str()).collect();
    let tables: Vec<&str> = relations.iter().map(|(_, table)| table.as_str()).collect();
    let tiers = postgres_foreign_keys_for_relations_query_tiers();
    query_with_compat_fallback("list_foreign_keys_for_relations", &tiers, |sql| {
        list_foreign_keys_for_relations_with_sql(&client, sql, &schemas, &tables)
    })
    .await
}

async fn list_foreign_keys_for_relations_with_sql(
    client: &deadpool_postgres::Client,
    sql: &str,
    schemas: &[&str],
    tables: &[&str],
) -> Result<HashMap<(String, String), Vec<ForeignKeyInfo>>, tokio_postgres::Error> {
    let rows = postgres_query_cached(client, sql, &[&schemas, &tables]).await?;
    let mut result: HashMap<(String, String), Vec<ForeignKeyInfo>> = HashMap::new();
    for row in &rows {
        let key = (pg_row_try_string(row, 0), pg_row_try_string(row, 1));
        result.entry(key).or_default().push(ForeignKeyInfo {
            name: pg_row_try_string(row, 2),
            column: pg_row_try_string(row, 3),
            ref_schema: Some(pg_row_try_string(row, 4)),
            ref_table: pg_row_try_string(row, 5),
            ref_column: pg_row_try_string(row, 6),
            on_update: postgres_fk_action_label(pg_row_try_optional_text(row, 7)),
            on_delete: postgres_fk_action_label(pg_row_try_optional_text(row, 8)),
        });
    }
    Ok(result)
}

fn postgres_foreign_keys_for_relations_query_tiers() -> [&'static str; 2] {
    [postgres_foreign_keys_for_relations_sql(), postgres_foreign_keys_for_relations_compat_sql()]
}

fn postgres_foreign_keys_for_relations_sql() -> &'static str {
    "SELECT rel.rel_schema, rel.rel_table, \
     con.conname AS constraint_name, \
     a.attname AS column_name, \
     ref_n.nspname AS ref_schema, \
     ref_c.relname AS ref_table, \
     ref_a.attname AS ref_column, \
     con.confupdtype::text AS on_update_raw, \
     con.confdeltype::text AS on_delete_raw \
     FROM unnest($1::text[], $2::text[]) AS rel(rel_schema, rel_table) \
     JOIN pg_catalog.pg_constraint con ON true \
     JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     JOIN pg_catalog.pg_class ref_c ON ref_c.oid = con.confrelid \
     JOIN pg_catalog.pg_namespace ref_n ON ref_n.oid = ref_c.relnamespace \
     JOIN LATERAL unnest(con.conkey) WITH ORDINALITY AS fk(attnum, ord) ON true \
     JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid AND a.attnum = fk.attnum AND NOT a.attisdropped \
     JOIN LATERAL unnest(con.confkey) WITH ORDINALITY AS pk(attnum, ord) ON pk.ord = fk.ord \
     JOIN pg_catalog.pg_attribute ref_a ON ref_a.attrelid = ref_c.oid AND ref_a.attnum = pk.attnum AND NOT ref_a.attisdropped \
     WHERE con.contype = 'f' AND n.nspname = rel.rel_schema AND c.relname = rel.rel_table \
     ORDER BY rel.rel_schema, rel.rel_table, con.conname, fk.ord"
}

// PostgreSQL 9.3 and older only accept one array argument to unnest(). Pair
// the schema/table arrays through their shared subscript so the fallback stays
// one bounded query and preserves each relation tuple's position.
// WITH ORDINALITY is equally unavailable before 9.4, so pair conkey/confkey
// positions with generate_series over the array length plus plain subscripts —
// the same pre-9.4 technique the index compat SQL relies on.
fn postgres_foreign_keys_for_relations_compat_sql() -> &'static str {
    "SELECT rel.rel_schema, rel.rel_table, \
     con.conname AS constraint_name, \
     a.attname AS column_name, \
     ref_n.nspname AS ref_schema, \
     ref_c.relname AS ref_table, \
     ref_a.attname AS ref_column, \
     con.confupdtype::text AS on_update_raw, \
     con.confdeltype::text AS on_delete_raw \
     FROM ( \
       SELECT ($1::text[])[rel.i] AS rel_schema, ($2::text[])[rel.i] AS rel_table \
       FROM generate_subscripts($1::text[], 1) AS rel(i) \
     ) AS rel \
     JOIN pg_catalog.pg_constraint con ON true \
     JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     JOIN pg_catalog.pg_class ref_c ON ref_c.oid = con.confrelid \
     JOIN pg_catalog.pg_namespace ref_n ON ref_n.oid = ref_c.relnamespace \
     CROSS JOIN generate_series(1, array_length(con.conkey, 1)) AS fk(ord) \
     JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid AND a.attnum = (con.conkey)[fk.ord] AND NOT a.attisdropped \
     JOIN pg_catalog.pg_attribute ref_a ON ref_a.attrelid = ref_c.oid AND ref_a.attnum = (con.confkey)[fk.ord] AND NOT ref_a.attisdropped \
     WHERE con.contype = 'f' AND n.nspname = rel.rel_schema AND c.relname = rel.rel_table \
     ORDER BY rel.rel_schema, rel.rel_table, con.conname, fk.ord"
}

/// Batched sibling of `get_table_comment`.
pub async fn get_table_comments_for_relations(
    pool: &Pool,
    oids: &[i64],
) -> Result<HashMap<i64, Option<String>>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(
        &client,
        "SELECT c.oid::bigint AS relid, obj_description(c.oid) AS table_comment \
         FROM pg_catalog.pg_class c WHERE c.oid = ANY($1::bigint[])",
        &[&oids],
    )
    .await
    .map_err(|e| e.to_string())?;
    let mut result: HashMap<i64, Option<String>> = HashMap::new();
    for row in &rows {
        let Ok(relid) = row.try_get::<_, i64>(0) else { continue };
        let comment = row.try_get::<_, Option<String>>(1).ok().flatten().filter(|s| !s.is_empty());
        result.insert(relid, comment);
    }
    Ok(result)
}

/// Batched sibling of `list_trigger_definitions`, with the same pre-13
/// `tgparentid` capability probe.
pub async fn list_trigger_definitions_for_relations(
    pool: &Pool,
    oids: &[i64],
) -> Result<HashMap<i64, Vec<String>>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let sql = if postgres_trigger_has_tgparentid(&client).await? {
        postgres_trigger_definitions_for_relations_sql()
    } else {
        postgres_trigger_definitions_for_relations_sql_without_tgparentid()
    };
    let rows = postgres_query_cached(&client, sql, &[&oids]).await.map_err(|e| e.to_string())?;
    let mut result: HashMap<i64, Vec<String>> = HashMap::new();
    for row in &rows {
        let Ok(relid) = row.try_get::<_, i64>(0) else { continue };
        let definition = pg_row_try_string(row, 1);
        if !definition.trim().is_empty() {
            result.entry(relid).or_default().push(definition);
        }
    }
    Ok(result)
}

fn postgres_trigger_definitions_for_relations_sql() -> &'static str {
    "SELECT t.tgrelid::bigint AS relid, pg_catalog.pg_get_triggerdef(t.oid, true) AS trigger_definition \
     FROM pg_catalog.pg_trigger t \
     WHERE t.tgrelid = ANY($1::bigint[]) AND NOT t.tgisinternal AND t.tgparentid = 0 \
     ORDER BY t.tgrelid, t.tgname, t.oid"
}

fn postgres_trigger_definitions_for_relations_sql_without_tgparentid() -> &'static str {
    "SELECT t.tgrelid::bigint AS relid, pg_catalog.pg_get_triggerdef(t.oid, true) AS trigger_definition \
     FROM pg_catalog.pg_trigger t \
     WHERE t.tgrelid = ANY($1::bigint[]) AND NOT t.tgisinternal \
     ORDER BY t.tgrelid, t.tgname, t.oid"
}

/// Batched sibling of `list_check_constraints`.
pub async fn list_check_constraints_for_relations(
    pool: &Pool,
    oids: &[i64],
) -> Result<HashMap<i64, Vec<(String, String)>>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(
        &client,
        "SELECT con.conrelid::bigint AS relid, con.conname, pg_catalog.pg_get_constraintdef(con.oid, true) AS definition \
         FROM pg_catalog.pg_constraint con \
         WHERE con.conrelid = ANY($1::bigint[]) AND con.contype = 'c' \
         ORDER BY con.conrelid, con.conname",
        &[&oids],
    )
    .await
    .map_err(|e| e.to_string())?;
    let mut result: HashMap<i64, Vec<(String, String)>> = HashMap::new();
    for row in &rows {
        let Ok(relid) = row.try_get::<_, i64>(0) else { continue };
        let name = pg_row_try_string(row, 1);
        let definition = pg_row_try_string(row, 2);
        if !name.is_empty() && !definition.is_empty() {
            result.entry(relid).or_default().push((name, definition));
        }
    }
    Ok(result)
}

/// Batched sibling of `get_table_partition_local_objects`.
pub async fn get_table_partition_local_objects_for_relations(
    pool: &Pool,
    oids: &[i64],
) -> Result<HashMap<i64, PostgresTablePartitionLocalObjects>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let tiers = postgres_table_partition_local_objects_for_relations_query_tiers();
    query_with_compat_fallback("get_table_partition_local_objects_for_relations", &tiers, |sql| {
        get_table_partition_local_objects_for_relations_with_sql(&client, sql, oids)
    })
    .await
}

async fn get_table_partition_local_objects_for_relations_with_sql(
    client: &deadpool_postgres::Client,
    sql: &str,
    oids: &[i64],
) -> Result<HashMap<i64, PostgresTablePartitionLocalObjects>, tokio_postgres::Error> {
    let rows = postgres_query_cached(client, sql, &[&oids]).await?;
    let mut result: HashMap<i64, PostgresTablePartitionLocalObjects> = HashMap::new();
    for row in &rows {
        let Ok(relid) = row.try_get::<_, i64>(0) else { continue };
        let object_kind = row.try_get::<_, String>(1).unwrap_or_default();
        let object_name = row.try_get::<_, String>(2).unwrap_or_default();
        let object_type = row.try_get::<_, Option<String>>(3).ok().flatten().unwrap_or_default();
        apply_partition_local_object_row(result.entry(relid).or_default(), &object_kind, object_name, &object_type);
    }
    Ok(result)
}

fn postgres_table_partition_local_objects_for_relations_query_tiers() -> [&'static str; 2] {
    [
        postgres_table_partition_local_objects_for_relations_sql(),
        postgres_table_partition_local_objects_for_relations_compat_sql(),
    ]
}

fn postgres_table_partition_local_objects_for_relations_sql() -> &'static str {
    "SELECT con.conrelid::bigint AS relid, 'constraint'::text AS object_kind, con.conname AS object_name, con.contype::text AS object_type \
     FROM pg_catalog.pg_constraint con \
     WHERE con.conrelid = ANY($1::bigint[]) AND con.contype IN ('p','f') \
       AND COALESCE(NULLIF(pg_catalog.row_to_json(con)->>'conparentid', '')::oid, 0) = 0 \
     UNION ALL \
     SELECT con.conrelid::bigint, 'check'::text AS object_kind, con.conname AS object_name, NULL::text AS object_type \
     FROM pg_catalog.pg_constraint con \
     WHERE con.conrelid = ANY($1::bigint[]) AND con.contype = 'c' AND con.conislocal \
     UNION ALL \
     SELECT ix.indrelid::bigint, 'index'::text AS object_kind, idx.relname AS object_name, NULL::text AS object_type \
     FROM pg_catalog.pg_index ix \
     JOIN pg_catalog.pg_class idx ON idx.oid = ix.indexrelid \
     WHERE ix.indrelid = ANY($1::bigint[]) \
       AND NOT EXISTS (SELECT 1 FROM pg_catalog.pg_inherits i WHERE i.inhrelid = idx.oid) \
     UNION ALL \
     SELECT a.attrelid::bigint, 'column_default'::text AS object_kind, a.attname AS object_name, \
            CASE WHEN ad.oid IS NOT NULL THEN 'overridden' ELSE 'dropped' END AS object_type \
     FROM pg_catalog.pg_attribute a \
     JOIN pg_catalog.pg_inherits i ON i.inhrelid = a.attrelid \
     JOIN pg_catalog.pg_attribute pa \
       ON pa.attrelid = i.inhparent AND pa.attname = a.attname AND pa.attnum > 0 AND NOT pa.attisdropped \
     LEFT JOIN pg_catalog.pg_attrdef ad ON ad.adrelid = a.attrelid AND ad.adnum = a.attnum \
     LEFT JOIN pg_catalog.pg_attrdef pad ON pad.adrelid = pa.attrelid AND pad.adnum = pa.attnum \
     WHERE a.attrelid = ANY($1::bigint[]) AND a.attnum > 0 AND NOT a.attisdropped \
       AND ( \
         (ad.oid IS NOT NULL AND (pad.oid IS NULL \
              OR pg_catalog.pg_get_expr(ad.adbin, ad.adrelid) \
                 IS DISTINCT FROM pg_catalog.pg_get_expr(pad.adbin, pad.adrelid))) \
         OR (ad.oid IS NULL AND pad.oid IS NOT NULL) \
       ) \
     ORDER BY relid, object_kind, object_name"
}

// PostgreSQL 9.2 has row_to_json(), but not the JSON ->> operator used above
// to probe conparentid without directly referencing that newer catalog
// column. Pre-11 servers do not have parent-linked constraint clones, so the
// compatibility tier can omit only that filter and keep the same batched
// result shape.
fn postgres_table_partition_local_objects_for_relations_compat_sql() -> &'static str {
    "SELECT con.conrelid::bigint AS relid, 'constraint'::text AS object_kind, con.conname AS object_name, con.contype::text AS object_type \
     FROM pg_catalog.pg_constraint con \
     WHERE con.conrelid = ANY($1::bigint[]) AND con.contype IN ('p','f') \
     UNION ALL \
     SELECT con.conrelid::bigint, 'check'::text AS object_kind, con.conname AS object_name, NULL::text AS object_type \
     FROM pg_catalog.pg_constraint con \
     WHERE con.conrelid = ANY($1::bigint[]) AND con.contype = 'c' AND con.conislocal \
     UNION ALL \
     SELECT ix.indrelid::bigint, 'index'::text AS object_kind, idx.relname AS object_name, NULL::text AS object_type \
     FROM pg_catalog.pg_index ix \
     JOIN pg_catalog.pg_class idx ON idx.oid = ix.indexrelid \
     WHERE ix.indrelid = ANY($1::bigint[]) \
       AND NOT EXISTS (SELECT 1 FROM pg_catalog.pg_inherits i WHERE i.inhrelid = idx.oid) \
     UNION ALL \
     SELECT a.attrelid::bigint, 'column_default'::text AS object_kind, a.attname AS object_name, \
            CASE WHEN ad.oid IS NOT NULL THEN 'overridden' ELSE 'dropped' END AS object_type \
     FROM pg_catalog.pg_attribute a \
     JOIN pg_catalog.pg_inherits i ON i.inhrelid = a.attrelid \
     JOIN pg_catalog.pg_attribute pa \
       ON pa.attrelid = i.inhparent AND pa.attname = a.attname AND pa.attnum > 0 AND NOT pa.attisdropped \
     LEFT JOIN pg_catalog.pg_attrdef ad ON ad.adrelid = a.attrelid AND ad.adnum = a.attnum \
     LEFT JOIN pg_catalog.pg_attrdef pad ON pad.adrelid = pa.attrelid AND pad.adnum = pa.attnum \
     WHERE a.attrelid = ANY($1::bigint[]) AND a.attnum > 0 AND NOT a.attisdropped \
       AND ( \
         (ad.oid IS NOT NULL AND (pad.oid IS NULL \
              OR pg_catalog.pg_get_expr(ad.adbin, ad.adrelid) \
                 IS DISTINCT FROM pg_catalog.pg_get_expr(pad.adbin, pad.adrelid))) \
         OR (ad.oid IS NULL AND pad.oid IS NOT NULL) \
       ) \
     ORDER BY relid, object_kind, object_name"
}

/// CHECK constraints on a table, as (name, definition) pairs (definition
/// includes the leading `CHECK` keyword, e.g. `CHECK (id > 0)`).
pub async fn list_check_constraints(pool: &Pool, schema: &str, table: &str) -> Result<Vec<(String, String)>, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, postgres_check_constraints_sql(), &[&schema, &table])
        .await
        .map_err(|e| e.to_string())?;
    Ok(rows
        .into_iter()
        .filter_map(|row| {
            let name = row.try_get::<_, String>(0).ok()?;
            let definition = row.try_get::<_, String>(1).ok()?;
            (!name.is_empty() && !definition.is_empty()).then_some((name, definition))
        })
        .collect())
}

fn postgres_check_constraints_sql() -> &'static str {
    "SELECT con.conname, pg_catalog.pg_get_constraintdef(con.oid, true) AS definition \
     FROM pg_catalog.pg_constraint con \
     JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 AND c.relname = $2 AND con.contype = 'c' \
     ORDER BY con.conname"
}

/// All constraints on a table (primary key, foreign key, unique, check,
/// exclude, and — on PG 18+ — not-null), as full `ConstraintInfo` records.
/// `pg_constraint.contype` letters are expanded to display labels and the
/// `conkey`/`confkey` attribute numbers are resolved to column names.
/// PostgreSQL has no per-constraint disabled state, so `enabled` is always
/// true; a `NOT VALID` constraint (e.g. an added-but-unvalidated CHECK or
/// FK) reports `valid = false` and surfaces the "Not validated" badge.
pub async fn list_constraints(pool: &Pool, schema: &str, table: &str) -> Result<Vec<ConstraintInfo>, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, postgres_constraints_sql(), &[&schema, &table])
        .await
        .map_err(|e| e.to_string())?;

    Ok(rows
        .iter()
        .map(|row| ConstraintInfo {
            name: pg_row_try_string(row, 0),
            constraint_type: postgres_constraint_type_label(&pg_row_try_string(row, 1)),
            definition: pg_row_try_string(row, 2),
            columns: row.try_get::<_, Vec<String>>(3).unwrap_or_default(),
            ref_schema: row.try_get::<_, Option<String>>(4).ok().flatten(),
            ref_table: row.try_get::<_, Option<String>>(5).ok().flatten(),
            ref_columns: row.try_get::<_, Vec<String>>(6).unwrap_or_default(),
            match_type: postgres_constraint_match_type(row.try_get::<_, Option<String>>(7).ok().flatten()),
            on_update: postgres_fk_action_label(row.try_get::<_, Option<String>>(8).ok().flatten()),
            on_delete: postgres_fk_action_label(row.try_get::<_, Option<String>>(9).ok().flatten()),
            deferrable: row.try_get::<_, bool>(10).unwrap_or(false),
            initially_deferred: row.try_get::<_, bool>(11).unwrap_or(false),
            enabled: true,
            valid: row.try_get::<_, bool>(12).unwrap_or(true),
        })
        .collect())
}

/// OpenGauss-compatible constraint metadata without PostgreSQL's array/LATERAL
/// dependencies. Older OpenGauss releases expose conkey/confkey as catalog
/// vectors but may reject WITH ORDINALITY or decode them differently on the
/// wire, so resolve attribute numbers in Rust.
pub async fn list_opengauss_constraints(pool: &Pool, schema: &str, table: &str) -> Result<Vec<ConstraintInfo>, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = match postgres_query_cached(&client, opengauss_constraints_sql(true), &[&schema, &table]).await {
        Ok(rows) => rows,
        Err(error) if is_missing_opengauss_constraint_column(&error, "convalidated") => {
            log::debug!(
                "[opengauss][constraints] convalidated unavailable; defaulting valid=true: {}",
                pg_error_to_string(error)
            );
            postgres_query_cached(&client, opengauss_constraints_sql(false), &[&schema, &table])
                .await
                .map_err(|e| e.to_string())?
        }
        Err(error) => return Err(error.to_string()),
    };
    if rows.is_empty() {
        return Ok(Vec::new());
    }

    let local_relation_oid =
        pg_row_try_u32(&rows[0], 13).ok_or("OpenGauss constraint metadata did not return a local relation OID")?;
    let local_attributes = opengauss_relation_attributes(&client, local_relation_oid).await?;
    let mut referenced_attributes: HashMap<u32, HashMap<i16, String>> = HashMap::new();
    let mut result = Vec::with_capacity(rows.len());

    for row in rows {
        let name = pg_row_try_string(&row, 0);
        let kind = pg_row_try_string(&row, 1);
        let column_numbers = parse_opengauss_attribute_numbers(&pg_row_try_string(&row, 3))
            .map_err(|error| format!("failed to parse OpenGauss constraint {name} columns: {error}"))?;
        let ref_column_numbers = parse_opengauss_attribute_numbers(&pg_row_try_string(&row, 6))
            .map_err(|error| format!("failed to parse OpenGauss constraint {name} referenced columns: {error}"))?;
        let referenced_relation_oid = pg_row_try_u32(&row, 14).filter(|oid| *oid != 0);
        let ref_columns = if kind == "f" {
            if let Some(oid) = referenced_relation_oid {
                if let std::collections::hash_map::Entry::Vacant(entry) = referenced_attributes.entry(oid) {
                    entry.insert(opengauss_relation_attributes(&client, oid).await?);
                }
                map_opengauss_attribute_names(&ref_column_numbers, referenced_attributes.get(&oid).unwrap())
            } else {
                Vec::new()
            }
        } else {
            Vec::new()
        };

        result.push(ConstraintInfo {
            name,
            constraint_type: postgres_constraint_type_label(&kind),
            definition: pg_row_try_string(&row, 2),
            columns: map_opengauss_attribute_names(&column_numbers, &local_attributes),
            ref_schema: row.try_get::<_, Option<String>>(4).ok().flatten(),
            ref_table: row.try_get::<_, Option<String>>(5).ok().flatten(),
            ref_columns,
            match_type: postgres_constraint_match_type(pg_row_try_optional_text(&row, 7)),
            on_update: postgres_fk_action_label(pg_row_try_optional_text(&row, 8)),
            on_delete: postgres_fk_action_label(pg_row_try_optional_text(&row, 9)),
            deferrable: pg_row_try_bool(&row, 10).unwrap_or(false),
            initially_deferred: pg_row_try_bool(&row, 11).unwrap_or(false),
            enabled: true,
            valid: pg_row_try_bool(&row, 12).unwrap_or(true),
        });
    }
    Ok(result)
}

fn opengauss_constraints_sql(include_validated: bool) -> &'static str {
    if include_validated {
        "SELECT COALESCE(con.conname, ''), \
                con.contype::text, \
                COALESCE(pg_catalog.pg_get_constraintdef(con.oid, true), ''), \
                COALESCE(con.conkey::text, ''), \
                refn.nspname, refc.relname, COALESCE(con.confkey::text, ''), \
                CASE WHEN con.contype = 'f' THEN con.confmatchtype::text END, \
                CASE WHEN con.contype = 'f' THEN con.confupdtype::text END, \
                CASE WHEN con.contype = 'f' THEN con.confdeltype::text END, \
                con.condeferrable, con.condeferred, con.convalidated, \
                con.conrelid::oid, con.confrelid::oid \
         FROM pg_catalog.pg_constraint con \
         JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
         JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
         LEFT JOIN pg_catalog.pg_class refc ON refc.oid = con.confrelid \
         LEFT JOIN pg_catalog.pg_namespace refn ON refn.oid = refc.relnamespace \
         WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r','p','f') \
         ORDER BY COALESCE(con.conname, '')"
    } else {
        "SELECT COALESCE(con.conname, ''), \
                con.contype::text, \
                COALESCE(pg_catalog.pg_get_constraintdef(con.oid, true), ''), \
                COALESCE(con.conkey::text, ''), \
                refn.nspname, refc.relname, COALESCE(con.confkey::text, ''), \
                CASE WHEN con.contype = 'f' THEN con.confmatchtype::text END, \
                CASE WHEN con.contype = 'f' THEN con.confupdtype::text END, \
                CASE WHEN con.contype = 'f' THEN con.confdeltype::text END, \
                con.condeferrable, con.condeferred, TRUE, \
                con.conrelid::oid, con.confrelid::oid \
         FROM pg_catalog.pg_constraint con \
         JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
         JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
         LEFT JOIN pg_catalog.pg_class refc ON refc.oid = con.confrelid \
         LEFT JOIN pg_catalog.pg_namespace refn ON refn.oid = refc.relnamespace \
         WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r','p','f') \
         ORDER BY COALESCE(con.conname, '')"
    }
}

async fn opengauss_relation_attributes(
    client: &tokio_postgres::Client,
    relation_oid: u32,
) -> Result<HashMap<i16, String>, String> {
    let rows = client
        .query(
            "SELECT a.attnum, a.attname::text FROM pg_catalog.pg_attribute a \
             WHERE a.attrelid = $1::oid AND a.attnum > 0 AND NOT a.attisdropped ORDER BY a.attnum",
            &[&relation_oid],
        )
        .await
        .map_err(|e| e.to_string())?;
    Ok(rows.iter().filter_map(|row| Some((row.try_get::<_, i16>(0).ok()?, pg_row_try_string(row, 1)))).collect())
}

fn parse_opengauss_attribute_numbers(raw: &str) -> Result<Vec<i16>, String> {
    let value = raw.trim().trim_matches(|character| matches!(character, '{' | '}' | '[' | ']'));
    if value.is_empty() {
        return Ok(Vec::new());
    }
    value
        .split(|character: char| character == ',' || character.is_whitespace())
        .filter(|part| !part.is_empty())
        .map(|part| part.parse::<i16>().map_err(|_| format!("invalid attribute number {part:?}")))
        .collect()
}

fn map_opengauss_attribute_names(numbers: &[i16], attributes: &HashMap<i16, String>) -> Vec<String> {
    numbers.iter().filter_map(|number| attributes.get(number).cloned()).collect()
}

fn pg_row_try_u32(row: &Row, idx: usize) -> Option<u32> {
    row.try_get::<_, u32>(idx)
        .ok()
        .or_else(|| row.try_get::<_, i64>(idx).ok().and_then(|value| u32::try_from(value).ok()))
        .or_else(|| pg_row_try_string(row, idx).parse::<u32>().ok())
}

fn pg_row_try_optional_text(row: &Row, idx: usize) -> Option<String> {
    if let Ok(value) = row.try_get::<_, Option<String>>(idx) {
        return value.filter(|value| !value.is_empty());
    }
    row.try_get::<_, PgRawBytes>(idx)
        .ok()
        .and_then(|value| String::from_utf8(value.0).ok())
        .filter(|value| !value.is_empty())
}

fn is_missing_opengauss_constraint_column(error: &tokio_postgres::Error, column: &str) -> bool {
    error.as_db_error().is_some_and(|db_error| {
        db_error.code().code() == "42703" && db_error.message().to_ascii_lowercase().contains(column)
    })
}

fn postgres_constraints_sql() -> &'static str {
    "SELECT con.conname, \
            con.contype::text, \
            pg_catalog.pg_get_constraintdef(con.oid, true) AS definition, \
            COALESCE(conkey.attnames, ARRAY[]::text[]) AS columns, \
            refn.nspname AS ref_schema, \
            refc.relname AS ref_table, \
            COALESCE(confkey.attnames, ARRAY[]::text[]) AS ref_columns, \
            CASE WHEN con.contype = 'f' THEN con.confmatchtype::text END AS match_type, \
            CASE WHEN con.contype = 'f' THEN con.confupdtype::text END AS on_update, \
            CASE WHEN con.contype = 'f' THEN con.confdeltype::text END AS on_delete, \
            con.condeferrable, \
            con.condeferred, \
            con.convalidated \
     FROM pg_catalog.pg_constraint con \
     JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     LEFT JOIN pg_catalog.pg_class refc ON refc.oid = con.confrelid \
     LEFT JOIN pg_catalog.pg_namespace refn ON refn.oid = refc.relnamespace \
     LEFT JOIN LATERAL ( \
         SELECT array_agg(a.attname::text ORDER BY ord.ord) AS attnames \
         FROM unnest(con.conkey) WITH ORDINALITY AS ord(attnum, ord) \
         JOIN pg_catalog.pg_attribute a ON a.attrelid = con.conrelid AND a.attnum = ord.attnum AND NOT a.attisdropped \
     ) conkey ON true \
     LEFT JOIN LATERAL ( \
         SELECT array_agg(a.attname::text ORDER BY ord.ord) AS attnames \
         FROM unnest(con.confkey) WITH ORDINALITY AS ord(attnum, ord) \
         JOIN pg_catalog.pg_attribute a ON a.attrelid = con.confrelid AND a.attnum = ord.attnum AND NOT a.attisdropped \
     ) confkey ON true \
     WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r','p','f') \
     ORDER BY con.conname"
}

/// Expand a `pg_constraint.contype` letter to a human-readable label.
fn postgres_constraint_type_label(contype: &str) -> String {
    match contype {
        "c" => "CHECK".to_string(),
        "f" => "FOREIGN KEY".to_string(),
        "p" => "PRIMARY KEY".to_string(),
        "u" => "UNIQUE".to_string(),
        "t" => "CONSTRAINT TRIGGER".to_string(),
        "x" => "EXCLUDE".to_string(),
        "n" => "NOT NULL".to_string(),
        _ => contype.to_string(),
    }
}

/// Normalize a `confupdtype`/`confdeltype` letter to an `information_schema`
/// style referential-action label.
fn postgres_fk_action_label(action: Option<String>) -> Option<String> {
    action
        .as_deref()
        .and_then(|value| match value {
            "a" => Some("NO ACTION"),
            "r" => Some("RESTRICT"),
            "c" => Some("CASCADE"),
            "n" => Some("SET NULL"),
            "d" => Some("SET DEFAULT"),
            _ => None,
        })
        .map(str::to_string)
}

/// Normalize a `confmatchtype` letter to a match-type label.
fn postgres_constraint_match_type(match_type: Option<String>) -> Option<String> {
    match_type
        .as_deref()
        .and_then(|value| match value {
            "f" => Some("FULL"),
            "p" => Some("PARTIAL"),
            "s" | "u" => Some("SIMPLE"),
            _ => None,
        })
        .map(str::to_string)
}

fn postgres_table_partition_relation_sql() -> &'static str {
    "SELECT c.relkind::text, \
            EXISTS ( \
              SELECT 1 FROM pg_catalog.pg_inherits i \
              WHERE i.inhrelid = c.oid \
                AND (SELECT parent.relkind FROM pg_catalog.pg_class parent WHERE parent.oid = i.inhparent) = 'p' \
            ) AS is_partition \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r','p','f') \
     LIMIT 1"
}

fn postgres_table_partition_info_sql() -> &'static str {
    "SELECT CASE WHEN c.relispartition THEN pn.nspname ELSE NULL END AS parent_schema, \
            CASE WHEN c.relispartition THEN pc.relname ELSE NULL END AS parent_table, \
            CASE WHEN c.relispartition THEN pg_catalog.pg_get_expr(c.relpartbound, c.oid, true) ELSE NULL END AS partition_bound, \
            CASE WHEN c.relkind = 'p' THEN pg_catalog.pg_get_partkeydef(c.oid) ELSE NULL END AS partition_key, \
            CASE WHEN c.relkind = 'f' THEN fs.srvname ELSE NULL END AS foreign_server, \
            CASE WHEN c.relkind = 'f' THEN ft.ftoptions ELSE NULL END AS foreign_options \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     LEFT JOIN pg_catalog.pg_inherits i ON i.inhrelid = c.oid \
     LEFT JOIN pg_catalog.pg_class pc ON pc.oid = i.inhparent \
     LEFT JOIN pg_catalog.pg_namespace pn ON pn.oid = pc.relnamespace \
     LEFT JOIN pg_catalog.pg_foreign_table ft ON ft.ftrelid = c.oid \
     LEFT JOIN pg_catalog.pg_foreign_server fs ON fs.oid = ft.ftserver \
     WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r','p','f') \
     ORDER BY i.inhseqno NULLS LAST \
     LIMIT 1"
}

/// 9.x 没有分区父表（也没有 relpartbound/pg_get_partkeydef），只保留
/// 外部表字段，其余列给 NULL，列序与主查询保持一致。
///
/// Pre-10 servers have no partition parent (nor the 10+ columns/functions);
/// only the foreign-table fields are kept, same column order as the primary.
fn postgres_table_partition_info_compat_sql() -> &'static str {
    "SELECT NULL::text AS parent_schema, NULL::text AS parent_table, NULL::text AS partition_bound, \
            NULL::text AS partition_key, \
            CASE WHEN c.relkind = 'f' THEN fs.srvname ELSE NULL END AS foreign_server, \
            CASE WHEN c.relkind = 'f' THEN ft.ftoptions ELSE NULL END AS foreign_options \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     LEFT JOIN pg_catalog.pg_foreign_table ft ON ft.ftrelid = c.oid \
     LEFT JOIN pg_catalog.pg_foreign_server fs ON fs.oid = ft.ftserver \
     WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r','p','f') \
     LIMIT 1"
}

fn postgres_table_partition_local_objects_sql() -> &'static str {
    "SELECT 'constraint'::text AS object_kind, con.conname AS object_name, con.contype::text AS object_type \
     FROM pg_catalog.pg_constraint con \
     JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 AND c.relname = $2 AND con.contype IN ('p','f') \
       AND COALESCE(NULLIF(pg_catalog.row_to_json(con)->>'conparentid', '')::oid, 0) = 0 \
     UNION ALL \
     SELECT 'check'::text AS object_kind, con.conname AS object_name, NULL::text AS object_type \
     FROM pg_catalog.pg_constraint con \
     JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 AND c.relname = $2 AND con.contype = 'c' AND con.conislocal \
     UNION ALL \
     SELECT 'index'::text AS object_kind, idx.relname AS object_name, NULL::text AS object_type \
     FROM pg_catalog.pg_index ix \
     JOIN pg_catalog.pg_class c ON c.oid = ix.indrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     JOIN pg_catalog.pg_class idx ON idx.oid = ix.indexrelid \
     WHERE n.nspname = $1 AND c.relname = $2 \
       AND NOT EXISTS (SELECT 1 FROM pg_catalog.pg_inherits i WHERE i.inhrelid = idx.oid) \
     UNION ALL \
     SELECT 'column_default'::text AS object_kind, a.attname AS object_name, \
            CASE WHEN ad.oid IS NOT NULL THEN 'overridden' ELSE 'dropped' END AS object_type \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid AND a.attnum > 0 AND NOT a.attisdropped \
     JOIN pg_catalog.pg_inherits i ON i.inhrelid = c.oid \
     JOIN pg_catalog.pg_attribute pa \
       ON pa.attrelid = i.inhparent AND pa.attname = a.attname AND pa.attnum > 0 AND NOT pa.attisdropped \
     LEFT JOIN pg_catalog.pg_attrdef ad ON ad.adrelid = a.attrelid AND ad.adnum = a.attnum \
     LEFT JOIN pg_catalog.pg_attrdef pad ON pad.adrelid = pa.attrelid AND pad.adnum = pa.attnum \
     WHERE n.nspname = $1 AND c.relname = $2 \
       AND ( \
         (ad.oid IS NOT NULL AND (pad.oid IS NULL \
              OR pg_catalog.pg_get_expr(ad.adbin, ad.adrelid) \
                 IS DISTINCT FROM pg_catalog.pg_get_expr(pad.adbin, pad.adrelid))) \
         OR (ad.oid IS NULL AND pad.oid IS NOT NULL) \
       ) \
     ORDER BY object_kind, object_name"
}

fn postgres_table_comment_sql() -> &'static str {
    "SELECT obj_description(c.oid) AS table_comment \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r','m','f','p') \
     LIMIT 1"
}

fn postgres_tables_sql(limit: Option<i64>, offset: i64) -> String {
    postgres_tables_sql_with_kind(limit, offset, false)
}

fn postgres_table_objects_sql(limit: Option<i64>, offset: i64) -> String {
    postgres_tables_sql_with_kind(limit, offset, true)
}

fn postgres_tables_sql_with_kind(limit: Option<i64>, offset: i64, table_objects_only: bool) -> String {
    // PostgreSQL-compatible servers do not agree on the inferred wire types
    // or accepted expression grammar for LIMIT/OFFSET parameters. These values
    // originate as usize and are converted to non-negative i64 literals.
    // Omitting an explicit ESCAPE keeps compatibility with servers that expose
    // only two-argument ILIKE; bound patterns use the default backslash escape.
    let pagination = match limit {
        Some(limit) => format!("LIMIT {limit} OFFSET {offset}"),
        None => format!("OFFSET {offset}"),
    };
    let relation_kinds = if table_objects_only { "'r','f','p'" } else { "'r','v','m','f','p'" };
    format!(
        "SELECT c.relname AS table_name, \
         CASE c.relkind WHEN 'r' THEN 'BASE TABLE' WHEN 'v' THEN 'VIEW' \
           WHEN 'm' THEN 'MATERIALIZED_VIEW' WHEN 'f' THEN 'FOREIGN TABLE' \
           WHEN 'p' THEN 'BASE TABLE' END AS table_type, \
         obj_description(c.oid) AS table_comment, \
         CASE WHEN pc.relkind = 'p' THEN pn.nspname ELSE NULL END AS parent_schema, \
         CASE WHEN pc.relkind = 'p' THEN pc.relname ELSE NULL END AS parent_name \
         FROM pg_catalog.pg_class c \
         JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
         LEFT JOIN pg_catalog.pg_inherits i ON i.inhrelid = c.oid \
         LEFT JOIN pg_catalog.pg_class pc ON pc.oid = i.inhparent \
         LEFT JOIN pg_catalog.pg_namespace pn ON pn.oid = pc.relnamespace \
         WHERE n.nspname = $1 AND c.relkind IN ({relation_kinds}) \
           AND ($2 = '%%' OR c.relname ILIKE $2 OR ($3 <> '' AND c.relname ILIKE $3)) \
         ORDER BY CASE WHEN pc.relkind = 'p' THEN 1 ELSE 0 END, c.relname \
         {pagination}"
    )
}

fn like_contains_pattern(value: &str) -> String {
    if value.is_empty() {
        return "%%".to_string();
    }

    let mut pattern = String::with_capacity(value.len() + 2);
    pattern.push('%');
    for ch in value.chars() {
        if ch == '\\' || ch == '%' || ch == '_' {
            pattern.push('\\');
        }
        pattern.push(ch);
    }
    pattern.push('%');
    pattern
}

fn like_fuzzy_pattern(value: &str) -> String {
    crate::sql::fuzzy_like_pattern_with_escape(value, |value| {
        let mut escaped = String::with_capacity(value.len() + 1);
        for ch in value.chars() {
            if ch == '\\' || ch == '%' || ch == '_' {
                escaped.push('\\');
            }
            escaped.push(ch);
        }
        escaped
    })
}

fn list_object_relations_sql(include_timestamps: bool) -> &'static str {
    if include_timestamps {
        return "SELECT c.relname AS object_name, \
       CASE c.relkind \
         WHEN 'v' THEN 'VIEW' \
         WHEN 'm' THEN 'MATERIALIZED_VIEW' \
         WHEN 'S' THEN 'SEQUENCE' \
         ELSE 'TABLE' \
       END AS object_type, \
       obj_description(c.oid) AS object_comment, \
       stat.creation::text AS created_at, \
       COALESCE( \
         CASE WHEN current_setting('track_commit_timestamp', true) = 'on' \
           THEN pg_xact_commit_timestamp(c.xmin)::text END, \
         stat.modification::text \
       ) AS updated_at, \
       CASE WHEN pc.relkind = 'p' THEN pn.nspname ELSE NULL END AS parent_schema, \
       CASE WHEN pc.relkind = 'p' THEN pc.relname ELSE NULL END AS parent_name, \
       NULL::text AS signature, \
       CASE c.relkind WHEN 'v' THEN 1 WHEN 'm' THEN 1 WHEN 'S' THEN 4 ELSE 0 END AS sort_order \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     LEFT JOIN pg_catalog.pg_inherits i ON i.inhrelid = c.oid \
     LEFT JOIN pg_catalog.pg_class pc ON pc.oid = i.inhparent \
     LEFT JOIN pg_catalog.pg_namespace pn ON pn.oid = pc.relnamespace \
     LEFT JOIN LATERAL pg_stat_file( \
       CASE WHEN c.relkind IN ('r','m','f','p') THEN pg_relation_filepath(c.oid) END, true \
     ) stat ON true \
     WHERE n.nspname = $1 AND c.relkind IN ('r','v','m','f','p','S')";
    }

    "SELECT c.relname AS object_name, \
       CASE c.relkind \
         WHEN 'v' THEN 'VIEW' \
         WHEN 'm' THEN 'MATERIALIZED_VIEW' \
         WHEN 'S' THEN 'SEQUENCE' \
         ELSE 'TABLE' \
       END AS object_type, \
       obj_description(c.oid) AS object_comment, \
       NULL::text AS created_at, \
       NULL::text AS updated_at, \
       CASE WHEN pc.relkind = 'p' THEN pn.nspname ELSE NULL END AS parent_schema, \
       CASE WHEN pc.relkind = 'p' THEN pc.relname ELSE NULL END AS parent_name, \
       NULL::text AS signature, \
       CASE c.relkind WHEN 'v' THEN 1 WHEN 'm' THEN 1 WHEN 'S' THEN 4 ELSE 0 END AS sort_order \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     LEFT JOIN pg_catalog.pg_inherits i ON i.inhrelid = c.oid \
     LEFT JOIN pg_catalog.pg_class pc ON pc.oid = i.inhparent \
     LEFT JOIN pg_catalog.pg_namespace pn ON pn.oid = pc.relnamespace \
     WHERE n.nspname = $1 AND c.relkind IN ('r','v','m','f','p','S')"
}

fn list_object_routines_sql(include_timestamps: bool, has_proc_prokind: bool, has_proc_prosp: bool) -> &'static str {
    if has_proc_prokind && has_proc_prosp {
        if include_timestamps {
            return "SELECT p.proname AS object_name, \
       CASE WHEN p.prokind = 'p' OR p.prosp THEN 'PROCEDURE' ELSE 'FUNCTION' END AS object_type, \
       obj_description(p.oid) AS object_comment, \
       NULL::text AS created_at, \
       CASE WHEN current_setting('track_commit_timestamp', true) = 'on' \
         THEN pg_xact_commit_timestamp(p.xmin)::text END AS updated_at, \
       NULL::text AS parent_schema, \
       NULL::text AS parent_name, \
       pg_get_function_identity_arguments(p.oid) AS signature, \
       CASE WHEN p.prokind = 'p' OR p.prosp THEN 2 ELSE 3 END AS sort_order \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 AND (p.prokind IN ('p','f') OR p.prosp)";
        }

        return "SELECT p.proname AS object_name, \
       CASE WHEN p.prokind = 'p' OR p.prosp THEN 'PROCEDURE' ELSE 'FUNCTION' END AS object_type, \
       obj_description(p.oid) AS object_comment, \
       NULL::text AS created_at, \
       NULL::text AS updated_at, \
       NULL::text AS parent_schema, \
       NULL::text AS parent_name, \
       pg_get_function_identity_arguments(p.oid) AS signature, \
       CASE WHEN p.prokind = 'p' OR p.prosp THEN 2 ELSE 3 END AS sort_order \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 AND (p.prokind IN ('p','f') OR p.prosp)";
    }

    if has_proc_prokind {
        if include_timestamps {
            return "SELECT p.proname AS object_name, \
       CASE p.prokind WHEN 'p' THEN 'PROCEDURE' ELSE 'FUNCTION' END AS object_type, \
       obj_description(p.oid) AS object_comment, \
       NULL::text AS created_at, \
       CASE WHEN current_setting('track_commit_timestamp', true) = 'on' \
         THEN pg_xact_commit_timestamp(p.xmin)::text END AS updated_at, \
       NULL::text AS parent_schema, \
       NULL::text AS parent_name, \
       pg_get_function_identity_arguments(p.oid) AS signature, \
       CASE p.prokind WHEN 'p' THEN 2 ELSE 3 END AS sort_order \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 AND p.prokind IN ('p','f')";
        }

        return "SELECT p.proname AS object_name, \
       CASE p.prokind WHEN 'p' THEN 'PROCEDURE' ELSE 'FUNCTION' END AS object_type, \
       obj_description(p.oid) AS object_comment, \
       NULL::text AS created_at, \
       NULL::text AS updated_at, \
       NULL::text AS parent_schema, \
       NULL::text AS parent_name, \
       pg_get_function_identity_arguments(p.oid) AS signature, \
       CASE p.prokind WHEN 'p' THEN 2 ELSE 3 END AS sort_order \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 AND p.prokind IN ('p','f')";
    }

    if has_proc_prosp {
        if include_timestamps {
            return "SELECT p.proname AS object_name, \
       CASE WHEN p.prosp THEN 'PROCEDURE' ELSE 'FUNCTION' END AS object_type, \
       obj_description(p.oid) AS object_comment, \
       NULL::text AS created_at, \
       CASE WHEN current_setting('track_commit_timestamp', true) = 'on' \
         THEN pg_xact_commit_timestamp(p.xmin)::text END AS updated_at, \
       NULL::text AS parent_schema, \
       NULL::text AS parent_name, \
       pg_get_function_identity_arguments(p.oid) AS signature, \
       CASE WHEN p.prosp THEN 2 ELSE 3 END AS sort_order \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 AND NOT p.proisagg AND NOT p.proiswindow";
        }

        return "SELECT p.proname AS object_name, \
       CASE WHEN p.prosp THEN 'PROCEDURE' ELSE 'FUNCTION' END AS object_type, \
       obj_description(p.oid) AS object_comment, \
       NULL::text AS created_at, \
       NULL::text AS updated_at, \
       NULL::text AS parent_schema, \
       NULL::text AS parent_name, \
       pg_get_function_identity_arguments(p.oid) AS signature, \
       CASE WHEN p.prosp THEN 2 ELSE 3 END AS sort_order \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 AND NOT p.proisagg AND NOT p.proiswindow";
    }

    if include_timestamps {
        return "SELECT p.proname AS object_name, \
       'FUNCTION' AS object_type, \
       obj_description(p.oid) AS object_comment, \
       NULL::text AS created_at, \
       CASE WHEN current_setting('track_commit_timestamp', true) = 'on' \
         THEN pg_xact_commit_timestamp(p.xmin)::text END AS updated_at, \
       NULL::text AS parent_schema, \
       NULL::text AS parent_name, \
       pg_get_function_identity_arguments(p.oid) AS signature, \
       3 AS sort_order \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 AND NOT p.proisagg AND NOT p.proiswindow";
    }

    "SELECT p.proname AS object_name, \
       'FUNCTION' AS object_type, \
       obj_description(p.oid) AS object_comment, \
       NULL::text AS created_at, \
       NULL::text AS updated_at, \
       NULL::text AS parent_schema, \
       NULL::text AS parent_name, \
       pg_get_function_identity_arguments(p.oid) AS signature, \
       3 AS sort_order \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 AND NOT p.proisagg AND NOT p.proiswindow"
}

fn redshift_routine_objects_sql() -> &'static str {
    "SELECT function_name AS object_name, \
       CASE function_type \
         WHEN 'STORED PROCEDURE' THEN 'PROCEDURE' \
         ELSE 'FUNCTION' \
       END AS object_type, \
       NULL::varchar AS object_comment, \
       NULL::varchar AS created_at, \
       NULL::varchar AS updated_at, \
       NULL::varchar AS parent_schema, \
       NULL::varchar AS parent_name, \
       argument_type AS signature, \
       CASE function_type WHEN 'STORED PROCEDURE' THEN 2 ELSE 3 END AS sort_order \
     FROM svv_redshift_functions \
     WHERE database_name = current_database() \
       AND schema_name = $1 \
       AND function_type IN ('STORED PROCEDURE', 'REGULAR FUNCTION') \
     ORDER BY sort_order, object_name"
}

/// SQL for listing user-defined types in one schema.
///
/// Only explicitly created types are returned: base types (b), standalone
/// composite types (c), domains (d), enums (e), ranges (r) and multiranges (m).
/// Relation auto-generated row types (table/view/materialized view/foreign
/// table/partitioned table) are excluded via `typrelid = 0 OR relkind = 'c'`,
/// and array companion types are excluded via `typelem = 0`. The type branch
/// has no usable timestamp/stat columns, so created_at/updated_at are always
/// NULL. Column order must match the relation and routine branches.
fn list_object_custom_types_sql() -> &'static str {
    "SELECT t.typname AS object_name, \
       'TYPE' AS object_type, \
       d.description AS object_comment, \
       NULL::text AS created_at, \
       NULL::text AS updated_at, \
       NULL::text AS parent_schema, \
       NULL::text AS parent_name, \
       (t.typtype::text || ':' || CASE \
         WHEN t.typtype = 'c' THEN CASE WHEN EXISTS ( \
           SELECT 1 FROM pg_catalog.pg_attribute a \
           WHERE a.attrelid = t.typrelid AND a.attnum > 0 AND NOT a.attisdropped \
         ) THEN '1' ELSE '0' END \
         WHEN t.typtype = 'e' THEN CASE WHEN EXISTS ( \
           SELECT 1 FROM pg_catalog.pg_enum e WHERE e.enumtypid = t.oid \
         ) THEN '1' ELSE '0' END \
         ELSE '0' \
       END) AS signature, \
       5 AS sort_order \
     FROM pg_catalog.pg_type t \
     JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace \
     LEFT JOIN pg_catalog.pg_class c ON c.oid = t.typrelid \
     LEFT JOIN pg_catalog.pg_description d \
       ON d.objoid = t.oid \
      AND d.classoid = 'pg_catalog.pg_type'::regclass \
      AND d.objsubid = 0 \
     WHERE n.nspname = $1 \
       AND t.typtype IN ('b', 'c', 'd', 'e', 'r', 'm') \
       AND t.typisdefined \
       AND t.typelem = 0 \
       AND (t.typrelid = 0 OR c.relkind = 'c') \
       AND n.nspname <> 'pg_catalog' \
       AND n.nspname <> 'information_schema' \
       AND n.nspname NOT LIKE 'pg_toast%' \
       AND n.nspname NOT LIKE 'pg_temp%'"
}

fn is_postgres_system_schema(schema: &str) -> bool {
    schema == "pg_catalog"
        || schema == "information_schema"
        || schema.starts_with("pg_toast")
        || schema.starts_with("pg_temp")
}

fn list_objects_sql(
    include_timestamps: bool,
    has_proc_prokind: bool,
    has_proc_prosp: bool,
    has_function_identity_arguments: bool,
    include_relations: bool,
    include_routines: bool,
    include_custom_types: bool,
) -> String {
    let mut parts: Vec<String> = Vec::new();
    if include_relations {
        parts.push(list_object_relations_sql(include_timestamps).to_string());
    }
    if include_routines {
        parts.push(list_object_routines_sql(include_timestamps, has_proc_prokind, has_proc_prosp).to_string());
    }
    if include_custom_types {
        parts.push(list_object_custom_types_sql().to_string());
    }
    let mut sql = parts.join(" UNION ALL ");
    if !parts.is_empty() {
        sql = format!("{sql} ORDER BY sort_order, object_name");
    }
    if has_function_identity_arguments {
        sql
    } else {
        // Redshift and older PostgreSQL-compatible servers may only expose the
        // older formatter. It includes argument names but still distinguishes
        // overloads instead of making the whole schema browser unavailable.
        sql.replace("pg_get_function_identity_arguments(p.oid)", "pg_get_function_arguments(p.oid)")
    }
}

fn postgres_has_function_identity_arguments_sql() -> &'static str {
    "SELECT EXISTS ( \
       SELECT 1 \
       FROM pg_catalog.pg_proc p \
       JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
       WHERE n.nspname = 'pg_catalog' \
         AND p.proname = 'pg_get_function_identity_arguments' \
     )"
}

async fn postgres_has_function_identity_arguments(client: &deadpool_postgres::Client) -> Result<bool, String> {
    let row = postgres_query_one_cached(client, postgres_has_function_identity_arguments_sql(), &[])
        .await
        .map_err(|e| e.to_string())?;
    Ok(pg_row_try_bool(&row, 0).unwrap_or(false))
}

fn postgres_proc_has_prokind_sql() -> &'static str {
    "SELECT EXISTS ( \
       SELECT 1 \
       FROM pg_catalog.pg_attribute \
       WHERE attrelid = 'pg_catalog.pg_proc'::regclass \
         AND attname = 'prokind' \
         AND NOT attisdropped \
     )"
}

async fn postgres_proc_has_prokind(client: &deadpool_postgres::Client) -> Result<bool, String> {
    let row =
        postgres_query_one_cached(client, postgres_proc_has_prokind_sql(), &[]).await.map_err(|e| e.to_string())?;
    Ok(pg_row_try_bool(&row, 0).unwrap_or(false))
}

fn postgres_trigger_has_tgparentid_sql() -> &'static str {
    "SELECT EXISTS ( \
       SELECT 1 \
       FROM pg_catalog.pg_attribute \
       WHERE attrelid = 'pg_catalog.pg_trigger'::regclass \
         AND attname = 'tgparentid' \
         AND NOT attisdropped \
     )"
}

/// PostgreSQL 13 added `pg_trigger.tgparentid`, tracking a partition's
/// automatically-cloned copy of its parent's trigger. Servers older than 13
/// lack the column (and never clone triggers onto partitions in the first
/// place, so `tgisinternal` alone is sufficient there).
async fn postgres_trigger_has_tgparentid(client: &deadpool_postgres::Client) -> Result<bool, String> {
    let row = postgres_query_one_cached(client, postgres_trigger_has_tgparentid_sql(), &[])
        .await
        .map_err(|e| e.to_string())?;
    Ok(pg_row_try_bool(&row, 0).unwrap_or(false))
}

fn postgres_proc_has_prosp_sql() -> &'static str {
    "SELECT EXISTS ( \
       SELECT 1 \
       FROM pg_catalog.pg_attribute \
       WHERE attrelid = 'pg_catalog.pg_proc'::regclass \
         AND attname = 'prosp' \
         AND NOT attisdropped \
     )"
}

async fn postgres_proc_has_prosp(client: &deadpool_postgres::Client) -> Result<bool, String> {
    let row = postgres_query_one_cached(client, postgres_proc_has_prosp_sql(), &[]).await.map_err(|e| e.to_string())?;
    Ok(pg_row_try_bool(&row, 0).unwrap_or(false))
}

async fn list_objects_rows(
    client: &deadpool_postgres::Client,
    schema: &str,
    include_timestamps: bool,
    has_proc_prokind: bool,
    has_proc_prosp: bool,
    has_function_identity_arguments: bool,
    include_relations: bool,
    include_routines: bool,
    include_custom_types: bool,
) -> Result<Vec<Row>, String> {
    let sql = list_objects_sql(
        include_timestamps,
        has_proc_prokind,
        has_proc_prosp,
        has_function_identity_arguments,
        include_relations,
        include_routines,
        include_custom_types,
    );
    if sql.is_empty() {
        // No branch was selected (e.g. an object_types filter the catalog
        // cannot serve); skip the round-trip instead of executing empty SQL.
        return Ok(Vec::new());
    }
    postgres_query_cached(client, &sql, &[&schema]).await.map_err(|e| e.to_string())
}

pub async fn list_objects(
    pool: &Pool,
    schema: &str,
    include_relations: bool,
    include_routines: bool,
    include_custom_types: bool,
) -> Result<Vec<ObjectInfo>, String> {
    // System schemas may be visible in the schema tree, but their catalog
    // types are implementation details and are never custom types.
    let include_custom_types = include_custom_types && !is_postgres_system_schema(schema);
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    // Routine catalog probes are only needed when the routine branch runs.
    // Skipping them for relation/type-only requests avoids three extra
    // pg_proc/pg_attribute round-trips and keeps compatible catalogs that lack
    // prokind/prosp from breaking a plain type listing.
    let (has_proc_prokind, has_proc_prosp, has_function_identity_arguments) = if include_routines {
        let has_proc_prokind = postgres_proc_has_prokind(&client).await?;
        // Some GaussDB-compatible catalogs expose prosp alongside, or instead of,
        // PostgreSQL 11's prokind. Treat prosp as an extra procedure signal.
        let has_proc_prosp = postgres_proc_has_prosp(&client).await?;
        let has_function_identity_arguments = postgres_has_function_identity_arguments(&client).await?;
        (has_proc_prokind, has_proc_prosp, has_function_identity_arguments)
    } else {
        (false, false, false)
    };
    let rows = match list_objects_rows(
        &client,
        schema,
        true,
        has_proc_prokind,
        has_proc_prosp,
        has_function_identity_arguments,
        include_relations,
        include_routines,
        include_custom_types,
    )
    .await
    {
        Ok(rows) => rows,
        Err(primary_error) => {
            log::debug!("[postgres][list_objects:timestamp-fallback] primary_error={}", primary_error);
            match list_objects_rows(
                &client,
                schema,
                false,
                has_proc_prokind,
                has_proc_prosp,
                has_function_identity_arguments,
                include_relations,
                include_routines,
                include_custom_types,
            )
            .await
            {
                Ok(rows) => rows,
                Err(fallback_error) => {
                    return Err(format!("{primary_error}; timestamp fallback failed: {fallback_error}"));
                }
            }
        }
    };

    Ok(object_rows_to_infos(&rows, schema))
}

pub async fn list_redshift_objects(
    pool: &Pool,
    schema: &str,
    include_relations: bool,
    include_routines: bool,
) -> Result<Vec<ObjectInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let mut rows = Vec::new();

    if include_relations {
        // Redshift does not support PostgreSQL's generic file, object-location,
        // or transaction-ID helpers, so skip the timestamp variant entirely.
        rows = list_objects_rows(&client, schema, false, false, false, false, true, false, false).await?;
    }

    if include_routines {
        let routine_rows = client
            .query_typed(redshift_routine_objects_sql(), &[(&schema, Type::VARCHAR)])
            .await
            .map_err(|error| format!("Redshift routine metadata query failed: {error}"))?;
        rows.extend(routine_rows);
    }

    Ok(object_rows_to_infos(&rows, schema))
}

fn object_rows_to_infos(rows: &[Row], schema: &str) -> Vec<ObjectInfo> {
    rows.iter()
        .map(|row| {
            let object_type = pg_row_try_string(row, 1);
            let raw_signature = row.try_get::<_, Option<String>>(7).ok().flatten();
            let (signature, custom_type_kind, has_members) = if object_type == "TYPE" {
                let (kind, has_members) = custom_type_list_metadata(raw_signature.as_deref());
                (None, kind, has_members)
            } else {
                (raw_signature, None, None)
            };
            ObjectInfo {
                name: pg_row_try_string(row, 0),
                object_type,
                schema: Some(schema.to_string()),
                valid: None,
                signature,
                custom_type_kind,
                has_members,
                comment: row.try_get::<_, Option<String>>(2).ok().flatten().filter(|s| !s.is_empty()),
                created_at: row.try_get::<_, Option<String>>(3).ok().flatten().filter(|s| !s.is_empty()),
                updated_at: row.try_get::<_, Option<String>>(4).ok().flatten().filter(|s| !s.is_empty()),
                parent_schema: row.try_get::<_, Option<String>>(5).ok().flatten().filter(|s| !s.is_empty()),
                parent_name: row.try_get::<_, Option<String>>(6).ok().flatten().filter(|s| !s.is_empty()),
                trigger: None,
                xugu_type_members_expandable: None,
            }
        })
        .collect()
}

fn custom_type_list_metadata(value: Option<&str>) -> (Option<String>, Option<bool>) {
    let Some((kind_code, has_members)) = value.and_then(|value| value.split_once(':')) else {
        return (None, None);
    };
    let kind = custom_type_kind_for(kind_code).map(|kind| kind.as_str().to_string());
    let has_members = match has_members {
        "1" => Some(true),
        "0" => Some(false),
        _ => None,
    };
    (kind, has_members)
}

/// General `pg_type` row for a user-defined type located by schema + name.
///
/// The query never interpolates user input: schema and name are bound as
/// parameters. Function OIDs are joined to `pg_proc` so the DDL generator and
/// the properties panel get human-readable names without extra round-trips.
struct CustomTypeGeneralInfo {
    oid: u32,
    typtype: String,
    typisdefined: bool,
    typbasetype: u32,
    typnotnull: bool,
    typrelid: u32,
    typelem: u32,
    typcollation: u32,
    typdefaultbin: Option<String>,
    typdefault: Option<String>,
    typlen: i16,
    typbyval: bool,
    typalign: String,
    typstorage: String,
    typtypmod: i32,
    input_function: Option<String>,
    output_function: Option<String>,
    receive_function: Option<String>,
    send_function: Option<String>,
    analyze_function: Option<String>,
    comment: Option<String>,
    relkind: Option<String>,
    collation: Option<String>,
}

fn custom_type_general_info_sql() -> &'static str {
    "SELECT t.oid, t.typtype::text, t.typisdefined, \
       t.typbasetype, t.typnotnull, t.typrelid, t.typelem, \
       t.typcollation, t.typdefaultbin, t.typdefault, \
       t.typlen, t.typbyval, t.typalign::text, t.typstorage::text, t.typtypmod, \
       pi.proname AS input_fn, po.proname AS output_fn, \
       pr.proname AS receive_fn, ps.proname AS send_fn, pa.proname AS analyze_fn, \
       d.description, \
       CASE WHEN t.typrelid != 0 THEN \
         (SELECT c.relkind::text FROM pg_catalog.pg_class c WHERE c.oid = t.typrelid) \
       END AS relkind, \
       CASE WHEN cl.oid IS NULL THEN NULL ELSE quote_ident(ncl.nspname) || '.' || quote_ident(cl.collname) END \
     FROM pg_catalog.pg_type t \
     JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace \
     LEFT JOIN pg_catalog.pg_description d \
       ON d.objoid = t.oid AND d.classoid = 'pg_catalog.pg_type'::regclass AND d.objsubid = 0 \
     LEFT JOIN pg_catalog.pg_proc pi ON pi.oid = t.typinput \
     LEFT JOIN pg_catalog.pg_proc po ON po.oid = t.typoutput \
     LEFT JOIN pg_catalog.pg_proc pr ON pr.oid = t.typreceive \
     LEFT JOIN pg_catalog.pg_proc ps ON ps.oid = t.typsend \
     LEFT JOIN pg_catalog.pg_proc pa ON pa.oid = t.typanalyze \
     LEFT JOIN pg_catalog.pg_collation cl ON cl.oid = t.typcollation \
     LEFT JOIN pg_catalog.pg_namespace ncl ON ncl.oid = cl.collnamespace \
     WHERE n.nspname = $1 AND t.typname = $2"
}

async fn custom_type_general_info(
    client: &deadpool_postgres::Client,
    schema: &str,
    name: &str,
) -> Result<CustomTypeGeneralInfo, String> {
    let rows = postgres_query_cached(client, custom_type_general_info_sql(), &[&schema, &name])
        .await
        .map_err(|e| format!("failed to locate custom type {schema}.{name}: {e}"))?;
    let row = rows.first().ok_or_else(|| format!("custom type {schema}.{name} does not exist"))?;
    Ok(CustomTypeGeneralInfo {
        oid: row.try_get::<_, u32>(0).unwrap_or(0),
        typtype: pg_row_try_string(row, 1),
        typisdefined: pg_row_try_bool(row, 2).unwrap_or(false),
        typbasetype: row.try_get::<_, u32>(3).unwrap_or(0),
        typnotnull: pg_row_try_bool(row, 4).unwrap_or(false),
        typrelid: row.try_get::<_, u32>(5).unwrap_or(0),
        typelem: row.try_get::<_, u32>(6).unwrap_or(0),
        typcollation: row.try_get::<_, u32>(7).unwrap_or(0),
        typdefaultbin: row.try_get::<_, Option<String>>(8).ok().flatten(),
        typdefault: row.try_get::<_, Option<String>>(9).ok().flatten(),
        typlen: row.try_get::<_, i16>(10).unwrap_or(-1),
        typbyval: pg_row_try_bool(row, 11).unwrap_or(false),
        typalign: pg_row_try_string(row, 12),
        typstorage: pg_row_try_string(row, 13),
        typtypmod: row.try_get::<_, i32>(14).unwrap_or(-1),
        input_function: row.try_get::<_, Option<String>>(15).ok().flatten(),
        output_function: row.try_get::<_, Option<String>>(16).ok().flatten(),
        receive_function: row.try_get::<_, Option<String>>(17).ok().flatten(),
        send_function: row.try_get::<_, Option<String>>(18).ok().flatten(),
        analyze_function: row.try_get::<_, Option<String>>(19).ok().flatten(),
        comment: row.try_get::<_, Option<String>>(20).ok().flatten(),
        relkind: row.try_get::<_, Option<String>>(21).ok().flatten(),
        collation: row.try_get::<_, Option<String>>(22).ok().flatten(),
    })
}

async fn custom_type_rendered_domain_default(
    client: &deadpool_postgres::Client,
    oid: u32,
) -> Result<Option<String>, String> {
    let rows = postgres_query_cached(
        client,
        "SELECT pg_catalog.pg_get_expr(t.typdefaultbin, 0) \
         FROM pg_catalog.pg_type t WHERE t.oid = $1",
        &[&oid],
    )
    .await
    .map_err(|error| format!("failed to render domain default: {error}"))?;
    Ok(rows
        .first()
        .and_then(|row| row.try_get::<_, Option<String>>(0).ok().flatten())
        .filter(|value| !value.is_empty()))
}

fn domain_default_from_render_result(result: Result<Option<String>, String>) -> (Option<String>, Option<String>) {
    match result {
        Ok(Some(value)) if !value.is_empty() => (Some(value), None),
        Ok(_) => (None, Some("default value could not be rendered; the generated DDL is incomplete".to_string())),
        Err(error) => {
            (None, Some(format!("default value could not be rendered; the generated DDL is incomplete: {error}")))
        }
    }
}

fn custom_type_kind_for(typtype: &str) -> Option<CustomTypeKind> {
    match typtype {
        "b" => Some(CustomTypeKind::Base),
        "c" => Some(CustomTypeKind::Composite),
        "d" => Some(CustomTypeKind::Domain),
        "e" => Some(CustomTypeKind::Enum),
        "r" => Some(CustomTypeKind::Range),
        "m" => Some(CustomTypeKind::Multirange),
        _ => None,
    }
}

async fn custom_type_enum_members(
    client: &deadpool_postgres::Client,
    oid: u32,
) -> Result<Vec<CustomTypeMember>, String> {
    let rows = postgres_query_cached(
        client,
        "SELECT e.enumlabel, e.enumsortorder \
         FROM pg_catalog.pg_enum e \
         WHERE e.enumtypid = $1 \
         ORDER BY e.enumsortorder",
        &[&oid],
    )
    .await
    .map_err(|e| format!("failed to read enum values: {e}"))?;
    Ok(rows
        .iter()
        .enumerate()
        .map(|(index, row)| CustomTypeMember {
            name: String::new(),
            data_type: String::new(),
            // enumsortorder is float4: ALTER TYPE ... ADD VALUE BEFORE/AFTER can
            // produce fractional values (1.5). Use the position after ORDER BY
            // instead so ordinals stay unique and stable for UI keys.
            ordinal: index as i32 + 1,
            nullable: None,
            default: None,
            comment: None,
            enum_value: Some(pg_row_try_string(row, 0)),
        })
        .collect())
}

async fn custom_type_composite_members(
    client: &deadpool_postgres::Client,
    typrelid: u32,
) -> Result<Vec<CustomTypeMember>, String> {
    let data_type =
        postgres_qualified_format_type_expression("at", "atn", "elem", "elem_n", "a.atttypid", "a.atttypmod");
    let rows = postgres_query_cached(
        client,
        &format!(
            "SELECT a.attname, {data_type} AS data_type, \
                a.attnum, NOT a.attnotnull AS nullable, a.atthasdef, \
                pg_get_expr(ad.adbin, ad.adrelid) AS default_expr, \
                col_description($1, a.attnum) AS comment \
         FROM pg_catalog.pg_attribute a \
         JOIN pg_catalog.pg_type at ON at.oid = a.atttypid \
         JOIN pg_catalog.pg_namespace atn ON atn.oid = at.typnamespace \
         LEFT JOIN pg_catalog.pg_type elem ON elem.oid = at.typelem \
         LEFT JOIN pg_catalog.pg_namespace elem_n ON elem_n.oid = elem.typnamespace \
         LEFT JOIN pg_catalog.pg_attrdef ad \
           ON ad.adrelid = a.attrelid AND ad.adnum = a.attnum \
         WHERE a.attrelid = $1 AND a.attnum > 0 AND NOT a.attisdropped \
         ORDER BY a.attnum"
        ),
        &[&typrelid],
    )
    .await
    .map_err(|e| format!("failed to read composite fields: {e}"))?;
    let mut members = Vec::with_capacity(rows.len());
    for row in rows {
        let name =
            row.try_get::<_, String>(0).map_err(|error| format!("failed to decode composite field name: {error}"))?;
        let data_type =
            row.try_get::<_, String>(1).map_err(|error| format!("failed to decode composite field type: {error}"))?;
        let ordinal =
            row.try_get::<_, i16>(2).map_err(|error| format!("failed to decode composite field ordinal: {error}"))?;
        if name.is_empty() || data_type.is_empty() {
            return Err("composite field name or type is empty".to_string());
        }
        let has_default = pg_row_try_bool(&row, 4).unwrap_or(false);
        members.push(CustomTypeMember {
            name,
            data_type,
            ordinal: ordinal as i32,
            nullable: pg_row_try_bool(&row, 3),
            default: if has_default { row.try_get::<_, Option<String>>(5).ok().flatten() } else { None },
            comment: row.try_get::<_, Option<String>>(6).ok().flatten(),
            enum_value: None,
        });
    }
    Ok(members)
}

/// Catalog-qualified type rendering for generated DDL. `format_type` omits a
/// user type's schema when it is on the current search path, so use it only
/// for pg_catalog types where it also preserves typmods. User-defined types
/// and their array companions retain an explicit, safely quoted schema.
fn postgres_qualified_format_type_expression(
    type_alias: &str,
    namespace_alias: &str,
    element_alias: &str,
    element_namespace_alias: &str,
    oid_expression: &str,
    typmod_expression: &str,
) -> String {
    format!(
        "CASE \
           WHEN {type_alias}.typelem <> 0 AND {element_namespace_alias}.nspname <> 'pg_catalog' \
             THEN quote_ident({element_namespace_alias}.nspname) || '.' || quote_ident({element_alias}.typname) || '[]' \
           WHEN {namespace_alias}.nspname <> 'pg_catalog' \
             THEN quote_ident({namespace_alias}.nspname) || '.' || quote_ident({type_alias}.typname) \
           ELSE format_type({oid_expression}, {typmod_expression}) \
         END"
    )
}

/// Domain-only attributes. Runs a category query that some compatible
/// catalogs (older openGauss/GaussDB) may reject; on failure the caller
/// degrades to missing attributes with a warning instead of failing the whole
/// details request.
async fn custom_type_domain_attributes(
    client: &deadpool_postgres::Client,
    info: &CustomTypeGeneralInfo,
    properties: &mut CustomTypeProperties,
) -> Vec<String> {
    let mut warnings = Vec::new();
    let base_type_expression =
        postgres_qualified_format_type_expression("t", "n", "elem", "elem_n", "t.oid", "$2::int4");
    let base_type = postgres_query_cached(
        client,
        &format!(
            "SELECT {base_type_expression} \
             FROM pg_catalog.pg_type t \
             JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace \
             LEFT JOIN pg_catalog.pg_type elem ON elem.oid = t.typelem \
             LEFT JOIN pg_catalog.pg_namespace elem_n ON elem_n.oid = elem.typnamespace \
             WHERE t.oid = $1"
        ),
        &[&info.typbasetype, &info.typtypmod],
    )
    .await
    .ok()
    .and_then(|rows| rows.first().map(|row| pg_row_try_string(row, 0)));
    if let Some(base) = base_type.filter(|value| !value.is_empty()) {
        properties.base_type = Some(base);
    }
    properties.not_null = Some(info.typnotnull);
    properties.default = info.typdefault.clone().filter(|value| !value.is_empty());
    if properties.default.is_none() && info.typdefaultbin.as_deref().is_some_and(|value| !value.is_empty()) {
        let (default, warning) =
            domain_default_from_render_result(custom_type_rendered_domain_default(client, info.oid).await);
        properties.default = default;
        if let Some(warning) = warning {
            warnings.push(warning);
        }
    }
    if info.typcollation != 0 {
        properties.collation = info.collation.clone();
    }
    match postgres_query_cached(
        client,
        "SELECT c.conname, pg_get_constraintdef(c.oid, true) AS definition \
         FROM pg_catalog.pg_constraint c \
         WHERE c.contypid = $1 \
         ORDER BY c.conname",
        &[&info.oid],
    )
    .await
    {
        Ok(rows) => {
            properties.domain_constraints.clear();
            for row in rows {
                let name = match row.try_get::<_, String>(0) {
                    Ok(value) => value,
                    Err(error) => {
                        warnings.push(format!("domain constraints could not be decoded (name): {error}"));
                        continue;
                    }
                };
                let definition = match row.try_get::<_, String>(1) {
                    Ok(value) => value,
                    Err(error) => {
                        warnings.push(format!("domain constraints could not be decoded ({name}): {error}"));
                        continue;
                    }
                };
                if !definition.is_empty() {
                    properties.domain_constraints.push(CustomTypeDomainConstraint { name, definition });
                }
            }
        }
        Err(error) => {
            warnings.push(format!("domain constraints could not be read: {error}"));
        }
    }
    warnings
}

/// Range/multirange attributes. Like the domain branch this is a category
/// extension: failures degrade to missing attributes with a warning. The
/// multirange companion name (PG 13+ `rngmultitypid`) is queried separately
/// because openGauss/GaussDB kernels predate that column.
async fn custom_type_range_attributes(
    client: &deadpool_postgres::Client,
    oid: u32,
    is_multirange: bool,
    properties: &mut CustomTypeProperties,
) -> Vec<String> {
    // pg_range.rngtypid always stores the RANGE oid. A multirange view must
    // first resolve its owning range through rngmultitypid.
    let range_oid_clause = if is_multirange { "WHERE r.rngmultitypid = $1" } else { "WHERE r.rngtypid = $1" };
    let subtype =
        postgres_qualified_format_type_expression("st", "stn", "elem", "elem_n", "r.rngsubtype", "NULL::integer");
    let rows = match postgres_query_cached(
        client,
        &format!(
            "SELECT {subtype} AS subtype, \
                CASE WHEN pcan.oid IS NULL THEN NULL ELSE quote_ident(ncan.nspname) || '.' || quote_ident(pcan.proname) END AS canonical_fn, \
                CASE WHEN pdiff.oid IS NULL THEN NULL ELSE quote_ident(ndiff.nspname) || '.' || quote_ident(pdiff.proname) END AS subdiff_fn, \
                CASE WHEN opc.oid IS NULL THEN NULL ELSE quote_ident(nopc.nspname) || '.' || quote_ident(opc.opcname) END AS subtype_opclass \
         FROM pg_catalog.pg_range r \
         JOIN pg_catalog.pg_type st ON st.oid = r.rngsubtype \
         JOIN pg_catalog.pg_namespace stn ON stn.oid = st.typnamespace \
         LEFT JOIN pg_catalog.pg_type elem ON elem.oid = st.typelem \
         LEFT JOIN pg_catalog.pg_namespace elem_n ON elem_n.oid = elem.typnamespace \
         LEFT JOIN pg_catalog.pg_proc pcan ON pcan.oid = r.rngcanonical \
         LEFT JOIN pg_catalog.pg_proc pdiff ON pdiff.oid = r.rngsubdiff \
         LEFT JOIN pg_catalog.pg_opclass opc ON opc.oid = r.rngsubopc \
         LEFT JOIN pg_catalog.pg_namespace ncan ON ncan.oid = pcan.pronamespace \
         LEFT JOIN pg_catalog.pg_namespace ndiff ON ndiff.oid = pdiff.pronamespace \
         LEFT JOIN pg_catalog.pg_namespace nopc ON nopc.oid = opc.opcnamespace \
         {range_oid_clause}"
        ),
        &[&oid],
    )
    .await
    {
        Ok(rows) => rows,
        Err(error) => return vec![format!("range attributes could not be read: {error}")],
    };
    let mut warnings = Vec::new();
    if let Some(row) = rows.first() {
        match row.try_get::<_, Option<String>>(0) {
            Ok(value) => properties.range_subtype = value.filter(|value| !value.is_empty()),
            Err(error) => warnings.push(format!("range subtype could not be read: {error}")),
        }
        match row.try_get::<_, Option<String>>(1) {
            Ok(value) => properties.range_canonical_function = value.filter(|value| !value.is_empty()),
            Err(error) => warnings.push(format!("range canonical function could not be read: {error}")),
        }
        match row.try_get::<_, Option<String>>(2) {
            Ok(value) => properties.range_subtype_diff_function = value.filter(|value| !value.is_empty()),
            Err(error) => warnings.push(format!("range subtype diff function could not be read: {error}")),
        }
        match row.try_get::<_, Option<String>>(3) {
            Ok(value) => properties.range_subtype_opclass = value.filter(|value| !value.is_empty()),
            Err(error) => warnings.push(format!("range subtype opclass could not be read: {error}")),
        }
    } else {
        warnings.push("range attributes returned no rows".to_string());
    }
    // Optional PG 13+ multirange companion; older kernels simply have no column.
    match postgres_query_cached(
        client,
        "SELECT mt.typname \
         FROM pg_catalog.pg_range r \
         JOIN pg_catalog.pg_type mt ON mt.oid = r.rngmultitypid \
         WHERE r.rngtypid = $1",
        &[&oid],
    )
    .await
    {
        Ok(rows) => {
            properties.range_multirange_name =
                rows.first().map(|row| pg_row_try_string(row, 0)).filter(|value| !value.is_empty());
        }
        Err(error) => warnings.push(format!("multirange companion could not be read: {error}")),
    }
    warnings
}

/// Generate normalized `CREATE TYPE` text for a user-defined type.
///
/// `complete` is only true when the text can be executed standalone in the
/// current schema. Multiranges (auto-generated companions) and base types
/// (whose I/O functions cannot be reconstructed from catalogs) are always
/// marked incomplete with visible warnings.
fn build_custom_type_ddl(
    schema: &str,
    name: &str,
    kind: CustomTypeKind,
    info: &CustomTypeGeneralInfo,
    members: &[CustomTypeMember],
    properties: &CustomTypeProperties,
    warnings: &[String],
) -> CustomTypeDdl {
    let qualified = format!("{}.{}", pg_quote_ident(schema), pg_quote_ident(name));
    match kind {
        CustomTypeKind::Enum => {
            let values = members
                .iter()
                .map(|member| member.enum_value.as_deref().unwrap_or_default())
                .map(pg_quote_literal)
                .collect::<Vec<_>>()
                .join(", ");
            CustomTypeDdl {
                sql: format!("CREATE TYPE {qualified} AS ENUM ({values});"),
                complete: true,
                warnings: warnings.to_vec(),
            }
        }
        CustomTypeKind::Composite => {
            let fields = members
                .iter()
                .map(|member| format!("{} {}", pg_quote_ident(&member.name), member.data_type))
                .collect::<Vec<_>>()
                .join(",\n  ");
            let mut sql = format!("CREATE TYPE {qualified} AS (\n  {fields}\n);");
            let comments = members
                .iter()
                .filter_map(|member| {
                    member.comment.as_ref().map(|comment| {
                        format!(
                            "COMMENT ON COLUMN {}.{} IS {};",
                            qualified,
                            pg_quote_ident(&member.name),
                            pg_quote_literal(comment)
                        )
                    })
                })
                .collect::<Vec<_>>()
                .join("\n");
            if !comments.is_empty() {
                sql = format!("{sql}\n{comments}");
            }
            CustomTypeDdl { sql, complete: true, warnings: warnings.to_vec() }
        }
        CustomTypeKind::Domain => {
            let mut warnings = warnings.to_vec();
            // A domain without a resolvable base type or constraints cannot be
            // rebuilt faithfully; mark it incomplete so the UI never presents
            // the truncated text as executable source.
            let mut complete = true;
            let base = match properties.base_type.as_deref().filter(|v| !v.is_empty()) {
                Some(base) => base.to_string(),
                None => {
                    complete = false;
                    warnings.push("base type could not be resolved; the generated DDL is incomplete".to_string());
                    "unknown".to_string()
                }
            };
            let mut parts = vec![format!("CREATE DOMAIN {qualified} AS {base}")];
            if let Some(collation) = properties.collation.as_deref().filter(|v| !v.is_empty()) {
                parts.push(format!("COLLATE {}", pg_quote_catalog_identifier(collation)));
            }
            if let Some(default) = properties.default.as_deref().filter(|v| !v.is_empty()) {
                parts.push(format!("DEFAULT {default}"));
            }
            if properties.not_null == Some(true) {
                parts.push("NOT NULL".to_string());
            }
            let incomplete_warning = warnings.iter().any(|warning| {
                warning.contains("domain constraints") || warning.contains("default value could not be rendered")
            });
            if incomplete_warning {
                complete = false;
            }
            for constraint in &properties.domain_constraints {
                let body = constraint.definition.trim().trim_start_matches("CHECK").trim();
                let constraint_name =
                    if constraint.name.is_empty() { format!("{name}_check") } else { constraint.name.clone() };
                parts.push(format!("CONSTRAINT {} CHECK {body}", pg_quote_ident(&constraint_name)));
            }
            CustomTypeDdl { sql: format!("{};", parts.join("\n  ")), complete, warnings }
        }
        CustomTypeKind::Range => {
            let mut args = Vec::new();
            if let Some(subtype) = properties.range_subtype.as_deref().filter(|v| !v.is_empty()) {
                args.push(format!("subtype = {subtype}"));
            }
            if let Some(opclass) = properties.range_subtype_opclass.as_deref().filter(|v| !v.is_empty()) {
                args.push(format!("subtype_opclass = {}", pg_quote_catalog_identifier(opclass)));
            }
            if let Some(value) = properties.range_canonical_function.as_deref().filter(|v| !v.is_empty()) {
                args.push(format!("canonical = {}", pg_quote_catalog_identifier(value)));
            }
            if let Some(value) = properties.range_subtype_diff_function.as_deref().filter(|v| !v.is_empty()) {
                args.push(format!("subtype_diff = {}", pg_quote_catalog_identifier(value)));
            }
            if let Some(value) = properties.range_multirange_name.as_deref().filter(|v| !v.is_empty()) {
                args.push(format!("multirange_type_name = {}", pg_quote_catalog_identifier(value)));
            }
            if properties.range_subtype.as_deref().is_none_or(|value| value.is_empty()) {
                let mut warnings = warnings.to_vec();
                warnings.push("range attributes could not be resolved".to_string());
                CustomTypeDdl {
                    sql: format!("CREATE TYPE {qualified} AS RANGE (subtype = unknown);"),
                    complete: false,
                    warnings,
                }
            } else {
                CustomTypeDdl {
                    sql: format!("CREATE TYPE {qualified} AS RANGE (\n  {}\n);", args.join(",\n  ")),
                    complete: true,
                    warnings: warnings.to_vec(),
                }
            }
        }
        CustomTypeKind::Multirange => {
            let mut all = warnings.to_vec();
            all.push(format!(
                "{} is the auto-generated multirange companion of a range type; it has no standalone CREATE statement",
                qualified
            ));
            CustomTypeDdl { sql: String::new(), complete: false, warnings: all }
        }
        CustomTypeKind::Base => {
            let mut all = warnings.to_vec();
            all.push(format!(
                "{} is a base type; its input/output functions ({}) cannot be rebuilt from catalogs",
                qualified,
                info.input_function.clone().unwrap_or_else(|| "unknown".to_string())
            ));
            CustomTypeDdl {
                sql: format!("CREATE TYPE {qualified};  -- base type attributes require manual reconstruction"),
                complete: false,
                warnings: all,
            }
        }
    }
}

/// Category-independent attribute assembly shared by all kinds.
fn custom_type_common_properties(info: &CustomTypeGeneralInfo) -> CustomTypeProperties {
    CustomTypeProperties {
        input_function: info.input_function.clone(),
        output_function: info.output_function.clone(),
        receive_function: info.receive_function.clone(),
        send_function: info.send_function.clone(),
        analyze_function: info.analyze_function.clone(),
        internallength: (info.typlen != -1 && info.typlen > 0).then_some(info.typlen as i32),
        passed_by_value: Some(info.typbyval),
        alignment: (!info.typalign.is_empty()).then(|| info.typalign.clone()),
        storage: (!info.typstorage.is_empty()).then(|| info.typstorage.clone()),
        ..Default::default()
    }
}

/// Fetch the read-only details of a user-defined type.
///
/// The caller must already have routed the connection to a verified
/// PostgreSQL-family database; this function validates that the target object
/// is an independent user-defined type (never a relation row type, an array
/// companion, an undefined type or a system-schema type).
pub async fn get_custom_type_details(pool: &Pool, schema: &str, name: &str) -> Result<CustomTypeDetails, String> {
    let schema = schema.trim();
    let name = name.trim();
    if schema.is_empty() || name.is_empty() {
        return Err("schema and type name are required".to_string());
    }
    if is_postgres_system_schema(schema) {
        return Err(format!("system schema {schema} is not supported for custom type details"));
    }
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let info = custom_type_general_info(&client, schema, name).await?;
    if !info.typisdefined {
        return Err(format!("custom type {schema}.{name} is not fully defined"));
    }
    if info.typelem != 0 {
        return Err(format!("custom type {schema}.{name} is an array companion type"));
    }
    let Some(kind) = custom_type_kind_for(&info.typtype) else {
        return Err(format!("custom type {schema}.{name} is a pseudo type (typtype={})", info.typtype));
    };
    if let Some(relkind) = info.relkind.as_deref() {
        if relkind != "c" {
            return Err(format!(
                "{schema}.{name} is the auto-generated row type of a relation, not an independent custom type"
            ));
        }
    }

    let mut members = Vec::new();
    let mut properties = custom_type_common_properties(&info);
    let mut warnings = Vec::new();
    match kind {
        CustomTypeKind::Enum => {
            members = custom_type_enum_members(&client, info.oid).await?;
        }
        CustomTypeKind::Composite => {
            members = custom_type_composite_members(&client, info.typrelid).await?;
        }
        CustomTypeKind::Domain => {
            warnings.extend(custom_type_domain_attributes(&client, &info, &mut properties).await);
        }
        CustomTypeKind::Range => {
            warnings.extend(custom_type_range_attributes(&client, info.oid, false, &mut properties).await);
        }
        CustomTypeKind::Multirange => {
            warnings.extend(custom_type_range_attributes(&client, info.oid, true, &mut properties).await);
        }
        CustomTypeKind::Base => {}
    }

    let ddl = build_custom_type_ddl(schema, name, kind, &info, &members, &properties, &warnings);
    Ok(CustomTypeDetails {
        name: name.to_string(),
        schema: schema.to_string(),
        kind,
        comment: info.comment.clone(),
        members,
        properties,
        ddl: Some(ddl),
    })
}

pub async fn list_object_statistics(pool: &Pool, schema: &str) -> Result<Vec<ObjectStatistics>, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(
        &client,
        "SELECT c.relname, \
                GREATEST(c.reltuples, 0)::bigint AS estimated_rows, \
                pg_catalog.pg_total_relation_size(c.oid)::bigint AS total_bytes \
         FROM pg_catalog.pg_class c \
         JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
         WHERE n.nspname = $1 AND c.relkind IN ('r','m','f','p') \
         ORDER BY c.relname",
        &[&schema],
    )
    .await
    .map_err(|e| e.to_string())?;
    Ok(rows
        .iter()
        .map(|row| ObjectStatistics {
            name: pg_row_try_string(row, 0),
            schema: Some(schema.to_string()),
            estimated_rows: row.try_get::<_, i64>(1).ok(),
            total_bytes: row.try_get::<_, i64>(2).ok(),
        })
        .collect())
}

pub async fn list_schemas(pool: &Pool) -> Result<Vec<String>, String> {
    list_schemas_with_system(pool, false).await
}

pub async fn list_schema_infos(pool: &Pool) -> Result<Vec<SchemaInfo>, String> {
    list_schema_infos_with_system(pool, false).await
}

pub async fn list_schemas_with_system(pool: &Pool, show_system_schemas: bool) -> Result<Vec<String>, String> {
    Ok(list_schema_infos_with_system(pool, show_system_schemas).await?.into_iter().map(|schema| schema.name).collect())
}

const POSTGRES_SCHEMA_INFOS_SQL: &str = "SELECT n.nspname AS schema_name, d.description AS schema_comment \
     FROM pg_catalog.pg_namespace n \
     LEFT JOIN pg_catalog.pg_description d \
       ON d.objoid = n.oid \
      AND d.objsubid = 0 \
      AND d.classoid = 'pg_namespace'::regclass \
     ORDER BY n.nspname";

const POSTGRES_SCHEMA_INFOS_HIDE_SYSTEM_SQL: &str = "SELECT n.nspname AS schema_name, d.description AS schema_comment \
     FROM pg_catalog.pg_namespace n \
     LEFT JOIN pg_catalog.pg_description d \
       ON d.objoid = n.oid \
      AND d.objsubid = 0 \
      AND d.classoid = 'pg_namespace'::regclass \
     WHERE n.nspname NOT IN ('information_schema', 'pg_catalog', 'pg_toast') \
     AND n.nspname NOT LIKE 'pg_toast_temp_%' \
     AND n.nspname NOT LIKE 'pg_temp_%' \
     ORDER BY n.nspname";

fn postgres_schema_infos_sql(show_system_schemas: bool) -> &'static str {
    if show_system_schemas {
        POSTGRES_SCHEMA_INFOS_SQL
    } else {
        POSTGRES_SCHEMA_INFOS_HIDE_SYSTEM_SQL
    }
}

pub async fn list_schema_infos_with_system(pool: &Pool, show_system_schemas: bool) -> Result<Vec<SchemaInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, postgres_schema_infos_sql(show_system_schemas), &[])
        .await
        .map_err(|e| e.to_string())?;

    Ok(rows
        .iter()
        .map(|row| SchemaInfo {
            name: pg_row_try_string(row, 0),
            comment: row.try_get::<_, Option<String>>(1).ok().flatten(),
        })
        .collect())
}

// Sibling of `postgres_columns_for_relations_sql`/`_compat_sql` above (~line
// 3086), for a single (schema, table) instead of a batch of oids — see the
// note there about why these aren't merged into a shared fragment.
const POSTGRES_COLUMNS_SQL: &str = "SELECT a.attname AS column_name, \
             format_type(a.atttypid, a.atttypmod) AS full_type, \
             COALESCE(c.is_nullable = 'YES', NOT a.attnotnull) AS is_nullable, \
             CASE WHEN a.attgenerated <> '' THEN NULL ELSE pg_get_expr(ad.adbin, ad.adrelid) END AS column_default, \
             EXISTS ( \
               SELECT 1 FROM pg_constraint co \
               JOIN pg_index i ON i.indrelid = co.conrelid AND co.conindid = i.indexrelid \
               WHERE co.conrelid = a.attrelid AND co.contype = 'p' \
               AND a.attnum = ANY(i.indkey) \
             ) AS is_pk, \
             col_description(a.attrelid, a.attnum) AS column_comment, \
             CASE a.attidentity \
               WHEN 'd' THEN 'generated by default as identity' || CASE WHEN pseq.seqstart IS NOT NULL THEN format(' (start with %s increment by %s)', pseq.seqstart, pseq.seqincrement) ELSE '' END \
               WHEN 'a' THEN 'generated always as identity' || CASE WHEN pseq.seqstart IS NOT NULL THEN format(' (start with %s increment by %s)', pseq.seqstart, pseq.seqincrement) ELSE '' END \
               ELSE CASE a.attgenerated \
                 WHEN 's' THEN 'generated always as (' || pg_get_expr(ad.adbin, ad.adrelid) || ') stored' \
                 WHEN 'v' THEN 'generated always as (' || pg_get_expr(ad.adbin, ad.adrelid) || ') virtual' \
                 ELSE CASE WHEN a.atttypid IN (20, 21, 23) AND dep.deptype = 'a' \
                   AND pseq.seqrelid IS NOT NULL \
                   AND pg_get_expr(ad.adbin, ad.adrelid) = format('nextval(%L::regclass)', dep.objid::regclass::text) \
                 THEN CASE a.atttypid \
                   WHEN 21 THEN 'smallserial' \
                   WHEN 23 THEN 'serial' \
                   WHEN 20 THEN 'bigserial' \
                 END ELSE NULL END \
               END \
             END AS column_extra, \
             CASE WHEN t.typname = 'numeric' AND a.atttypmod > 0 \
               THEN ((a.atttypmod - 4) >> 16) & 65535 ELSE NULL END AS numeric_precision, \
             CASE WHEN t.typname = 'numeric' AND a.atttypmod > 0 \
               THEN (a.atttypmod - 4) & 65535 ELSE NULL END AS numeric_scale, \
             CASE WHEN t.typname IN ('varchar', 'bpchar') AND a.atttypmod > 0 \
               THEN a.atttypmod - 4 ELSE NULL END AS character_maximum_length, \
             CASE WHEN enum_t.oid IS NULL THEN NULL \
               ELSE COALESCE((SELECT array_to_json(array_agg(e.enumlabel ORDER BY e.enumsortorder))::text \
                              FROM pg_enum e WHERE e.enumtypid = enum_t.oid), '[]') END AS enum_values \
             FROM pg_attribute a \
             JOIN pg_type t ON t.oid = a.atttypid \
             JOIN pg_class relation_class ON relation_class.oid = a.attrelid \
             JOIN pg_namespace relation_namespace ON relation_namespace.oid = relation_class.relnamespace \
             LEFT JOIN pg_type enum_t ON enum_t.oid = CASE WHEN t.typtype = 'd' THEN t.typbasetype WHEN t.typtype = 'e' THEN t.oid ELSE NULL END AND enum_t.typtype = 'e' \
             LEFT JOIN pg_attrdef ad ON ad.adrelid = a.attrelid AND ad.adnum = a.attnum \
             LEFT JOIN LATERAL ( \
               SELECT sequence_dep.objid, sequence_dep.deptype \
               FROM pg_catalog.pg_depend sequence_dep \
               JOIN pg_catalog.pg_class sequence_class \
                 ON sequence_class.oid = sequence_dep.objid AND sequence_class.relkind = 'S' \
               WHERE sequence_dep.classid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                 AND sequence_dep.objsubid = 0 \
                 AND sequence_dep.refclassid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                 AND sequence_dep.refobjid = a.attrelid AND sequence_dep.refobjsubid = a.attnum \
                 AND ((a.attidentity <> '' AND sequence_dep.deptype = 'i') OR (a.attidentity = '' \
                   AND sequence_dep.deptype = 'a' AND EXISTS ( \
                     SELECT 1 FROM pg_catalog.pg_depend serial_default_dep \
                     WHERE serial_default_dep.classid = 'pg_catalog.pg_attrdef'::pg_catalog.regclass \
                       AND serial_default_dep.objid = ad.oid AND serial_default_dep.objsubid = 0 \
                       AND serial_default_dep.refclassid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                       AND serial_default_dep.refobjid = sequence_dep.objid \
                       AND serial_default_dep.refobjsubid = 0 AND serial_default_dep.deptype = 'n' \
                   ))) \
               ORDER BY sequence_dep.objid \
               LIMIT 1 \
             ) dep ON TRUE \
             LEFT JOIN pg_sequence pseq ON pseq.seqrelid = dep.objid \
             LEFT JOIN information_schema.columns c \
               ON c.table_schema = relation_namespace.nspname AND c.table_name = relation_class.relname AND c.column_name = a.attname \
             WHERE a.attrelid = (CASE WHEN $1 = '' THEN quote_ident($2) ELSE quote_ident($1) || '.' || quote_ident($2) END)::regclass \
             AND a.attnum > 0 AND NOT a.attisdropped \
             ORDER BY a.attnum";

// Compat-tier sibling of `postgres_columns_for_relations_compat_sql` (~line
// 3148) — see the note on `POSTGRES_COLUMNS_SQL` above.
const POSTGRES_COLUMNS_COMPAT_SQL: &str = "SELECT a.attname AS column_name, \
             format_type(a.atttypid, a.atttypmod) AS full_type, \
             COALESCE(c.is_nullable = 'YES', NOT a.attnotnull) AS is_nullable, \
             pg_get_expr(ad.adbin, ad.adrelid) AS column_default, \
             EXISTS ( \
               SELECT 1 FROM pg_constraint co \
               JOIN pg_index i ON i.indrelid = co.conrelid AND co.conindid = i.indexrelid \
               WHERE co.conrelid = a.attrelid AND co.contype = 'p' \
               AND a.attnum = ANY(i.indkey) \
             ) AS is_pk, \
             col_description(a.attrelid, a.attnum) AS column_comment, \
             CASE WHEN a.atttypid IN (20, 21, 23) AND serial_seq.oid IS NOT NULL \
               AND pg_get_expr(ad.adbin, ad.adrelid) = format('nextval(%L::regclass)', serial_seq.oid::regclass::text) \
             THEN CASE a.atttypid \
               WHEN 21 THEN 'smallserial' \
               WHEN 23 THEN 'serial' \
               WHEN 20 THEN 'bigserial' \
             END ELSE NULL END AS column_extra, \
             CASE WHEN t.typname = 'numeric' AND a.atttypmod > 0 \
               THEN ((a.atttypmod - 4) >> 16) & 65535 ELSE NULL END AS numeric_precision, \
             CASE WHEN t.typname = 'numeric' AND a.atttypmod > 0 \
               THEN (a.atttypmod - 4) & 65535 ELSE NULL END AS numeric_scale, \
             CASE WHEN t.typname IN ('varchar', 'bpchar') AND a.atttypmod > 0 \
               THEN a.atttypmod - 4 ELSE NULL END AS character_maximum_length, \
             NULL::text AS enum_values \
             FROM pg_attribute a \
             JOIN pg_type t ON t.oid = a.atttypid \
             JOIN pg_class relation_class ON relation_class.oid = a.attrelid \
             JOIN pg_namespace relation_namespace ON relation_namespace.oid = relation_class.relnamespace \
             LEFT JOIN pg_attrdef ad ON ad.adrelid = a.attrelid AND ad.adnum = a.attnum \
             LEFT JOIN pg_catalog.pg_class serial_seq ON serial_seq.oid = ( \
               SELECT sequence_dep.objid \
               FROM pg_catalog.pg_depend sequence_dep \
               JOIN pg_catalog.pg_class sequence_class \
                 ON sequence_class.oid = sequence_dep.objid AND sequence_class.relkind = 'S' \
               WHERE sequence_dep.classid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                 AND sequence_dep.objsubid = 0 \
                 AND sequence_dep.refclassid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                 AND sequence_dep.refobjid = a.attrelid AND sequence_dep.refobjsubid = a.attnum \
                 AND sequence_dep.deptype = 'a' AND EXISTS ( \
                   SELECT 1 FROM pg_catalog.pg_depend serial_default_dep \
                   WHERE serial_default_dep.classid = 'pg_catalog.pg_attrdef'::pg_catalog.regclass \
                     AND serial_default_dep.objid = ad.oid AND serial_default_dep.objsubid = 0 \
                     AND serial_default_dep.refclassid = 'pg_catalog.pg_class'::pg_catalog.regclass \
                     AND serial_default_dep.refobjid = sequence_dep.objid \
                     AND serial_default_dep.refobjsubid = 0 AND serial_default_dep.deptype = 'n' \
                 ) \
               ORDER BY sequence_dep.objid \
               LIMIT 1 \
             ) AND serial_seq.relkind = 'S' \
             LEFT JOIN information_schema.columns c \
               ON c.table_schema = relation_namespace.nspname AND c.table_name = relation_class.relname AND c.column_name = a.attname \
             WHERE a.attrelid = (CASE WHEN $1 = '' THEN quote_ident($2) ELSE quote_ident($1) || '.' || quote_ident($2) END)::regclass \
             AND a.attnum > 0 AND NOT a.attisdropped \
             ORDER BY a.attnum";

const POSTGRES_COLUMNS_INFORMATION_SCHEMA_SQL: &str = "SELECT c.column_name, \
             CASE WHEN c.data_type = 'USER-DEFINED' THEN c.udt_name ELSE c.data_type END AS full_type, \
             c.is_nullable = 'YES' AS is_nullable, \
             c.column_default, \
             EXISTS ( \
               SELECT 1 FROM information_schema.table_constraints tc \
               JOIN information_schema.key_column_usage kcu \
                 ON kcu.constraint_catalog = tc.constraint_catalog \
                AND kcu.constraint_schema = tc.constraint_schema \
                AND kcu.constraint_name = tc.constraint_name \
                AND kcu.table_schema = tc.table_schema \
                AND kcu.table_name = tc.table_name \
               WHERE tc.constraint_type = 'PRIMARY KEY' \
                 AND tc.table_schema = c.table_schema \
                 AND tc.table_name = c.table_name \
                 AND kcu.column_name = c.column_name \
             ) AS is_pk, \
             NULL::text AS column_comment, \
             NULL::text AS column_extra, \
             CAST(c.numeric_precision AS int) AS numeric_precision, \
             CAST(c.numeric_scale AS int) AS numeric_scale, \
             CAST(c.character_maximum_length AS int) AS character_maximum_length, \
             NULL::text AS enum_values \
             FROM information_schema.columns c \
             WHERE c.table_schema = $1 AND c.table_name = $2 \
             ORDER BY c.ordinal_position";

fn parse_enum_values_from_row(row: &Row, index: usize) -> Option<Vec<String>> {
    let raw = row.try_get::<_, Option<String>>(index).ok().flatten()?;
    serde_json::from_str::<Vec<String>>(&raw).ok()
}

/// Decode a boolean column to JSON, tolerating databases (e.g. GaussDB) that
/// encode booleans as the ASCII bytes `t` (0x74) / `f` (0x66) in the binary
/// protocol instead of the standard PostgreSQL 0x00 / 0x01.
fn pg_bool_value_to_json(row: &Row, idx: usize) -> serde_json::Value {
    if let Some(v) = pg_row_try_bool(row, idx) {
        return serde_json::Value::Bool(v);
    }
    serde_json::Value::Null
}

/// Map raw boolean bytes to a Rust `bool`.
///
/// Standard PostgreSQL binary uses `[0x00]` / `[0x01]`; GaussDB sends the ASCII
/// text representation `[b't']` / `[b'f']` instead.
fn decode_bool_bytes(raw: &[u8]) -> Option<bool> {
    match raw {
        [0x00] => Some(false),
        [0x01] => Some(true),
        [b't'] | [b'T'] => Some(true),
        [b'f'] | [b'F'] => Some(false),
        _ => None,
    }
}

fn decode_bool_candidates(raw: Option<&[u8]>, standard: Option<bool>) -> Option<bool> {
    raw.and_then(decode_bool_bytes).or(standard)
}

/// Read a boolean column from a PostgreSQL row, tolerating databases that
/// encode booleans as integers (0/1) or text ('t'/'f') instead of the standard
/// `bool` OID.  Returns `None` when the column is NULL or truly unreadable.
fn pg_row_try_bool(row: &Row, idx: usize) -> Option<bool> {
    // GaussDB encodes boolean as ASCII 't' (0x74) / 'f' (0x66) in binary.
    let raw = row.try_get::<_, PgRawBytes>(idx).ok();
    let standard = row.try_get::<_, bool>(idx).ok();
    if let Some(v) = decode_bool_candidates(raw.as_ref().map(|value| value.0.as_slice()), standard) {
        return Some(v);
    }
    if let Ok(v) = row.try_get::<_, i32>(idx) {
        return Some(v != 0);
    }
    if let Ok(v) = row.try_get::<_, i16>(idx) {
        return Some(v != 0);
    }
    if let Ok(Some(v)) = row.try_get::<_, Option<String>>(idx) {
        match v.as_str() {
            "t" | "true" | "1" | "yes" | "YES" => return Some(true),
            "f" | "false" | "0" | "no" | "NO" => return Some(false),
            _ => return None,
        }
    }
    None
}

/// Read a String column from a PostgreSQL row, tolerating databases that
/// return text as other types.  Falls back to i64/i32/i16/bool formatting.
fn pg_row_try_string(row: &Row, idx: usize) -> String {
    if let Ok(v) = row.try_get::<_, String>(idx) {
        return v;
    }
    if let Ok(v) = row.try_get::<_, i64>(idx) {
        return v.to_string();
    }
    if let Ok(v) = row.try_get::<_, i32>(idx) {
        return v.to_string();
    }
    if let Ok(v) = row.try_get::<_, i16>(idx) {
        return v.to_string();
    }
    if let Some(v) = pg_row_try_bool(row, idx) {
        return v.to_string();
    }
    String::new()
}

fn column_info_from_row(row: &Row) -> ColumnInfo {
    column_info_from_row_offset(row, 0)
}

async fn get_columns_with_sql(
    client: &deadpool_postgres::Client,
    sql: &str,
    schema: &str,
    table: &str,
) -> Result<Vec<ColumnInfo>, tokio_postgres::Error> {
    let rows = postgres_query_cached(client, sql, &[&schema, &table]).await?;

    Ok(rows.iter().map(column_info_from_row).collect())
}

pub async fn get_columns(pool: &Pool, schema: &str, table: &str) -> Result<Vec<ColumnInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let tiers = [POSTGRES_COLUMNS_SQL, POSTGRES_COLUMNS_COMPAT_SQL, POSTGRES_COLUMNS_INFORMATION_SCHEMA_SQL];
    query_with_compat_fallback("get_columns", &tiers, |sql| get_columns_with_sql(&client, sql, schema, table)).await
}

fn pg_quote_literal(value: &str) -> String {
    format!("'{}'", value.replace('\'', "''"))
}

fn redshift_columns_sql(schema: &str, table: &str) -> String {
    format!(
        "SELECT c.column_name, \
                CASE WHEN c.data_type = 'USER-DEFINED' THEN c.udt_name ELSE c.data_type END AS full_type, \
                c.is_nullable, \
                c.column_default, \
                CAST(c.numeric_precision AS varchar) AS numeric_precision, \
                CAST(c.numeric_scale AS varchar) AS numeric_scale, \
                CAST(c.character_maximum_length AS varchar) AS character_maximum_length \
         FROM information_schema.columns c \
         WHERE c.table_schema = {} AND c.table_name = {} \
         ORDER BY c.ordinal_position",
        pg_quote_literal(schema),
        pg_quote_literal(table)
    )
}

fn query_result_text(row: &[serde_json::Value], index: usize) -> Option<String> {
    row.get(index).and_then(|value| match value {
        serde_json::Value::String(value) => Some(value.clone()),
        serde_json::Value::Number(value) => Some(value.to_string()),
        serde_json::Value::Bool(value) => Some(value.to_string()),
        serde_json::Value::Null | serde_json::Value::Array(_) | serde_json::Value::Object(_) => None,
    })
}

fn query_result_i32(row: &[serde_json::Value], index: usize) -> Option<i32> {
    query_result_text(row, index)?.parse().ok()
}

fn redshift_columns_from_query_result(result: QueryResult) -> Vec<ColumnInfo> {
    result
        .rows
        .into_iter()
        .filter_map(|row| {
            Some(ColumnInfo {
                name: query_result_text(&row, 0)?,
                data_type: query_result_text(&row, 1).unwrap_or_default(),
                is_nullable: query_result_text(&row, 2).is_none_or(|value| value.eq_ignore_ascii_case("YES")),
                column_default: query_result_text(&row, 3),
                is_primary_key: false,
                extra: None,
                comment: None,
                numeric_precision: query_result_i32(&row, 4),
                numeric_scale: query_result_i32(&row, 5),
                character_maximum_length: query_result_i32(&row, 6),
                enum_values: None,
                ..Default::default()
            })
        })
        .collect()
}

pub async fn get_redshift_columns(pool: &Pool, schema: &str, table: &str) -> Result<Vec<ColumnInfo>, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let result = execute_select_text(
        &client,
        &redshift_columns_sql(schema, table),
        Instant::now(),
        crate::query::MAX_ROWS,
        None,
        None,
    )
    .await?;
    Ok(redshift_columns_from_query_result(result))
}

pub(crate) fn pg_quote_ident(ident: &str) -> String {
    format!("\"{}\"", ident.replace('"', "\"\""))
}

fn pg_quote_catalog_identifier(ident: &str) -> String {
    let ident = ident.trim();
    if ident.starts_with('"') && ident.ends_with('"') && ident.contains("\".\"") {
        return ident.to_string();
    }
    if let Some((schema, name)) = ident.rsplit_once('.') {
        return format!("{}.{}", pg_quote_ident(schema), pg_quote_ident(name));
    }
    pg_quote_ident(ident)
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum PostgresSearchPathContext {
    Query,
    Transaction,
    LocalTransaction,
    LocalQueryTransaction,
}

#[derive(Debug, Clone, PartialEq, Eq)]
struct PostgresSearchPathBaseline {
    configured: String,
    first_resolved_schema: Option<String>,
    has_explicit_pg_catalog: bool,
}

type PostgresSearchPathBaselineEntry = (Weak<deadpool_postgres::StatementCache>, PostgresSearchPathBaseline);
type PostgresSearchPathBaselineCache = Mutex<HashMap<usize, PostgresSearchPathBaselineEntry>>;

pub(crate) fn postgres_set_search_path_sql(schema: &str, context: PostgresSearchPathContext) -> String {
    let (scope, suffix) = match context {
        // Ordinary queries and exports historically fall back to public for
        // extensions and helper functions after checking the selected schema.
        PostgresSearchPathContext::Query => ("", ", pg_catalog, public"),
        PostgresSearchPathContext::Transaction => ("", ", pg_catalog"),
        PostgresSearchPathContext::LocalTransaction => (" LOCAL", ", pg_catalog"),
        PostgresSearchPathContext::LocalQueryTransaction => (" LOCAL", ", pg_catalog, public"),
    };
    // PostgreSQL otherwise searches pg_catalog before every explicit path item.
    format!("SET{scope} search_path TO {}{suffix}", pg_quote_ident(schema))
}

fn postgres_set_single_schema_search_path_sql(schema: &str, context: PostgresSearchPathContext) -> String {
    let scope = if matches!(
        context,
        PostgresSearchPathContext::LocalTransaction | PostgresSearchPathContext::LocalQueryTransaction
    ) {
        " LOCAL"
    } else {
        ""
    };
    format!("SET{scope} search_path TO {}", pg_quote_ident(schema))
}

fn postgres_set_preserved_search_path_sql(
    schema: &str,
    context: PostgresSearchPathContext,
    baseline: &PostgresSearchPathBaseline,
) -> String {
    let scope = if matches!(
        context,
        PostgresSearchPathContext::LocalTransaction | PostgresSearchPathContext::LocalQueryTransaction
    ) {
        " LOCAL"
    } else {
        ""
    };
    let configured = baseline.configured.trim();
    let selected_schema = pg_quote_ident(schema);
    let mut path = if baseline.first_resolved_schema.as_deref() == Some(schema) {
        configured.to_string()
    } else if configured.is_empty() {
        selected_schema.clone()
    } else {
        format!("{selected_schema}, {configured}")
    };
    if path.is_empty() {
        path = selected_schema;
    }
    if !baseline.has_explicit_pg_catalog {
        path.push_str(", pg_catalog");
    }
    format!("SET{scope} search_path TO {path}")
}

fn postgres_requires_single_schema_search_path(error: &str) -> bool {
    error.to_ascii_lowercase().contains("does not support search_path with multiple names")
}

fn postgres_single_schema_clients() -> &'static Mutex<HashMap<usize, Weak<deadpool_postgres::StatementCache>>> {
    static CLIENTS: OnceLock<Mutex<HashMap<usize, Weak<deadpool_postgres::StatementCache>>>> = OnceLock::new();
    CLIENTS.get_or_init(|| Mutex::new(HashMap::new()))
}

fn postgres_client_uses_single_schema_search_path(client: &deadpool_postgres::Client) -> bool {
    let statement_cache = &client.statement_cache;
    let key = Arc::as_ptr(statement_cache) as usize;
    let mut clients = postgres_single_schema_clients().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
    match clients.get(&key).and_then(Weak::upgrade) {
        Some(cached) if Arc::ptr_eq(&cached, statement_cache) => true,
        _ => {
            clients.remove(&key);
            false
        }
    }
}

fn mark_postgres_client_single_schema_search_path(client: &deadpool_postgres::Client) {
    let statement_cache = &client.statement_cache;
    let key = Arc::as_ptr(statement_cache) as usize;
    let mut clients = postgres_single_schema_clients().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
    clients.retain(|_, cached| cached.strong_count() > 0);
    clients.insert(key, Arc::downgrade(statement_cache));
}

fn postgres_search_path_baselines() -> &'static PostgresSearchPathBaselineCache {
    static BASELINES: OnceLock<PostgresSearchPathBaselineCache> = OnceLock::new();
    BASELINES.get_or_init(|| Mutex::new(HashMap::new()))
}

fn cached_postgres_search_path_baseline(client: &deadpool_postgres::Client) -> Option<PostgresSearchPathBaseline> {
    let statement_cache = &client.statement_cache;
    let key = Arc::as_ptr(statement_cache) as usize;
    let mut baselines = postgres_search_path_baselines().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
    match baselines.get(&key) {
        Some((cached, baseline)) if cached.upgrade().is_some_and(|cached| Arc::ptr_eq(&cached, statement_cache)) => {
            Some(baseline.clone())
        }
        _ => {
            baselines.remove(&key);
            None
        }
    }
}

fn cache_postgres_search_path_baseline(client: &deadpool_postgres::Client, baseline: PostgresSearchPathBaseline) {
    let statement_cache = &client.statement_cache;
    let key = Arc::as_ptr(statement_cache) as usize;
    let mut baselines = postgres_search_path_baselines().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
    baselines.retain(|_, (cached, _)| cached.strong_count() > 0);
    baselines.insert(key, (Arc::downgrade(statement_cache), baseline));
}

async fn postgres_search_path_baseline(
    client: &deadpool_postgres::Client,
    timeout_duration: Duration,
) -> Result<PostgresSearchPathBaseline, String> {
    if let Some(baseline) = cached_postgres_search_path_baseline(client) {
        return Ok(baseline);
    }
    let row = tokio::time::timeout(
        timeout_duration,
        client.query_one(
            "SELECT current_setting('search_path'), (current_schemas(false))[1], \
                    'pg_catalog' = ANY(current_schemas(false))",
            &[],
        ),
    )
    .await
    .map_err(|_| format!("PostgreSQL schema.get timed out after {} seconds", timeout_duration.as_secs()))?
    .map_err(pg_error_to_string)?;
    let baseline = PostgresSearchPathBaseline {
        configured: row.try_get(0).map_err(|error| error.to_string())?,
        first_resolved_schema: row.try_get(1).map_err(|error| error.to_string())?,
        has_explicit_pg_catalog: row.try_get(2).map_err(|error| error.to_string())?,
    };
    cache_postgres_search_path_baseline(client, baseline.clone());
    Ok(baseline)
}

pub(crate) async fn set_postgres_search_path(
    client: &deadpool_postgres::Client,
    schema: &str,
    context: PostgresSearchPathContext,
    timeout_duration: Duration,
) -> Result<u64, String> {
    if postgres_client_uses_single_schema_search_path(client) {
        return execute_postgres_infra_statement(
            client,
            &postgres_set_single_schema_search_path_sql(schema, context),
            timeout_duration,
            "schema.set",
        )
        .await;
    }

    let primary_sql = match postgres_search_path_baseline(client, timeout_duration).await {
        Ok(baseline) => postgres_set_preserved_search_path_sql(schema, context, &baseline),
        Err(error) => {
            log::warn!("[postgres][schema.get:error] schema={schema} error={error}; using compatibility fallback");
            postgres_set_search_path_sql(schema, context)
        }
    };
    match execute_postgres_infra_statement(client, &primary_sql, timeout_duration, "schema.set").await {
        Ok(affected) => Ok(affected),
        Err(primary_error) if postgres_requires_single_schema_search_path(&primary_error) => {
            mark_postgres_client_single_schema_search_path(client);
            log::info!("[postgres][schema.set:single-schema-fallback] schema={schema}");
            execute_postgres_infra_statement(
                client,
                &postgres_set_single_schema_search_path_sql(schema, context),
                timeout_duration,
                "schema.set",
            )
            .await
            .map_err(|fallback_error| {
                format!("{primary_error}; single-schema search_path fallback failed: {fallback_error}")
            })
        }
        Err(error) => Err(error),
    }
}

fn query_result_row_limit(max_rows: Option<usize>) -> usize {
    max_rows.unwrap_or(crate::query::MAX_ROWS).max(1)
}

/// Returns whether a parsed DML statement produces a result set, or `None` when
/// the statement is not DML.
fn postgres_dml_statement_returns_rows(statement: &Statement) -> Option<bool> {
    match statement {
        Statement::Insert(insert) => Some(insert.returning.is_some()),
        Statement::Update(update) => Some(update.returning.is_some()),
        Statement::Delete(delete) => Some(delete.returning.is_some()),
        Statement::Merge(merge) => Some(merge.output.is_some()),
        _ => None,
    }
}

/// `WITH cte AS (...) UPDATE ...` parses as a query whose body is the wrapped
/// DML statement; returns that statement so its `RETURNING` clause can decide.
fn postgres_query_body_dml(body: &SetExpr) -> Option<&Statement> {
    match body {
        SetExpr::Insert(statement)
        | SetExpr::Update(statement)
        | SetExpr::Delete(statement)
        | SetExpr::Merge(statement) => Some(statement),
        _ => None,
    }
}

/// Returns whether PostgreSQL should execute this statement through the row
/// retrieval path. DML without `RETURNING` needs `execute` for its command
/// tag/affected-row count, while DML with `RETURNING` produces a result set.
pub(crate) fn postgres_statement_returns_rows(sql: &str) -> bool {
    if starts_with_executable_sql_keyword(sql, &["SELECT", "SHOW", "EXPLAIN", "TABLE"]) {
        return true;
    }

    // A leading `WITH` is usually a CTE query, but PostgreSQL also allows a CTE
    // to be followed directly by INSERT/UPDATE/DELETE/MERGE, which only returns
    // rows with `RETURNING`. The prefix alone cannot decide, so parse it and
    // keep the row-returning assumption whenever parsing does not say otherwise.
    let leads_with_cte = starts_with_executable_sql_keyword(sql, &["WITH"]);

    let Ok(statements) = Parser::parse_sql(&PostgreSqlDialect {}, sql) else {
        return leads_with_cte;
    };
    let [statement] = statements.as_slice() else {
        return leads_with_cte;
    };

    if let Some(returns_rows) = postgres_dml_statement_returns_rows(statement) {
        return returns_rows;
    }

    match statement {
        Statement::Query(query) => {
            postgres_query_body_dml(&query.body).and_then(postgres_dml_statement_returns_rows).unwrap_or(true)
        }
        _ => leads_with_cte,
    }
}

pub async fn execute_query(pool: &Pool, sql: &str) -> Result<QueryResult, String> {
    execute_query_with_max_rows(pool, sql, None).await
}

pub async fn execute_query_with_max_rows(
    pool: &Pool,
    sql: &str,
    max_rows: Option<usize>,
) -> Result<QueryResult, String> {
    let start = Instant::now();
    let row_limit = query_result_row_limit(max_rows);

    if postgres_statement_returns_rows(sql) {
        let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
        execute_select_query(&client, sql, start, row_limit).await
    } else {
        let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
        let affected = client.execute(sql, &[]).await.map_err(pg_error_to_string)?;
        clear_postgres_caches_after_ddl(pool, Some(&client), sql);

        Ok(QueryResult {
            columns: vec![],
            column_types: Vec::new(),
            column_sortables: Vec::new(),
            spatial_columns: vec![],
            spatial_values: vec![],
            rows: vec![],
            affected_rows: affected,
            execution_time_ms: start.elapsed().as_millis(),
            truncated: false,
            session_id: None,
            has_more: false,
            elasticsearch_raw_body: None,
            messages: Vec::new(),
        })
    }
}

pub async fn execute_query_with_max_rows_and_cancel(
    pool: &Pool,
    sql: &str,
    max_rows: Option<usize>,
    cancel_token: Option<CancellationToken>,
    budget: DbOperationBudget,
    cancel_context: Option<PostgresCancelContext>,
    prefer_text_protocol: bool,
) -> Result<QueryResult, String> {
    let client = checkout_postgres_client(pool, cancel_token.as_ref(), budget.checkout_timeout).await?;
    execute_postgres_user_query(
        &client,
        sql,
        max_rows,
        cancel_token,
        budget.query_timeout,
        budget.cancel_timeout,
        cancel_context,
        prefer_text_protocol,
    )
    .await
}

fn postgres_read_only_transaction_setup() -> Vec<(String, &'static str)> {
    vec![("BEGIN READ ONLY".to_string(), "explain_analyze.begin")]
}

fn postgres_read_only_transaction_cleanup_error(error: String) -> String {
    format!("PostgreSQL read-only transaction cleanup failed: {error}")
}

fn merge_postgres_operation_and_rollback_result<T>(
    operation_result: Result<T, String>,
    rollback_result: Result<(), String>,
) -> Result<T, String> {
    match (operation_result, rollback_result) {
        (Ok(result), Ok(())) => Ok(result),
        (Err(operation_error), Ok(())) => Err(operation_error),
        (Ok(_), Err(rollback_error)) => Err(postgres_read_only_transaction_cleanup_error(rollback_error)),
        (Err(operation_error), Err(rollback_error)) => {
            Err(format!("{operation_error}; {}", postgres_read_only_transaction_cleanup_error(rollback_error)))
        }
    }
}

async fn run_postgres_operation_with_rollback<T, Operation, OperationFuture, Rollback, RollbackFuture>(
    operation: Operation,
    rollback: Rollback,
) -> Result<T, String>
where
    Operation: FnOnce() -> OperationFuture,
    OperationFuture: Future<Output = Result<T, String>>,
    Rollback: FnOnce() -> RollbackFuture,
    RollbackFuture: Future<Output = Result<(), String>>,
{
    let operation_result = operation().await;
    let rollback_result = rollback().await;
    merge_postgres_operation_and_rollback_result(operation_result, rollback_result)
}

pub async fn execute_query_in_read_only_transaction_with_rollback(
    pool: &Pool,
    schema: Option<&str>,
    sql: &str,
    max_rows: Option<usize>,
    cancel_token: Option<CancellationToken>,
    budget: DbOperationBudget,
    cancel_context: Option<PostgresCancelContext>,
) -> Result<QueryResult, String> {
    let client = checkout_postgres_client(pool, cancel_token.as_ref(), budget.checkout_timeout).await?;
    let setup = postgres_read_only_transaction_setup();

    run_postgres_operation_with_rollback(
        || async {
            for (statement, stage) in setup {
                execute_postgres_infra_statement(&client, &statement, budget.recycle_timeout, stage).await?;
            }
            if let Some(schema) = schema.map(str::trim).filter(|schema| !schema.is_empty()) {
                set_postgres_search_path(
                    &client,
                    schema,
                    PostgresSearchPathContext::LocalQueryTransaction,
                    budget.recycle_timeout,
                )
                .await?;
            }

            execute_postgres_user_query_with_mode(
                &client,
                sql,
                max_rows,
                cancel_token,
                budget.query_timeout,
                budget.cancel_timeout,
                cancel_context,
                false,
                true,
            )
            .await
        },
        || async {
            execute_postgres_infra_statement(&client, "ROLLBACK", budget.cleanup_timeout, "explain_analyze.rollback")
                .await
                .map(|_| ())
        },
    )
    .await
}

pub async fn stream_select_query_with_cancel(
    pool: &Pool,
    schema: Option<&str>,
    setup_sql: &[String],
    sql: &str,
    max_rows: Option<usize>,
    cancel_token: Option<CancellationToken>,
    budget: DbOperationBudget,
    cancel_context: Option<PostgresCancelContext>,
    on_item: impl FnMut(PostgresQueryStreamItem) -> Result<(), String>,
) -> Result<u64, String> {
    let start = Instant::now();
    let client = checkout_postgres_client(pool, cancel_token.as_ref(), budget.checkout_timeout).await?;
    let mut on_item = on_item;
    let row_limit = max_rows.map(|limit| limit.max(1));
    let schema = schema.map(str::trim).filter(|schema| !schema.is_empty());
    let schema_was_set = schema.is_some_and(|_| !is_transaction_recovery_statement(sql));

    if let Some(schema) = schema.filter(|_| schema_was_set) {
        // Match normal query execution: export may reference unqualified names
        // in the active schema, so the streaming path must use the same search_path.
        set_postgres_search_path(&client, schema, PostgresSearchPathContext::Query, budget.recycle_timeout).await?;
    }

    let setup_transaction_started = !setup_sql.is_empty();
    if setup_transaction_started {
        execute_postgres_infra_statement(&client, "BEGIN", budget.recycle_timeout, "export_setup.begin").await?;
    }

    let query_timeout = budget.query_timeout;
    let timeout_error =
        format!("Query timed out after {} seconds", query_timeout.map_or(0, |timeout| timeout.as_secs()));
    let setup_result = async {
        for setup_statement in setup_sql {
            wait_postgres_query(
                client.cancel_token(),
                cancel_context.clone(),
                cancel_token.clone(),
                query_timeout,
                budget.cancel_timeout,
                async {
                    client.batch_execute(setup_statement).await.map_err(pg_error_to_string)?;
                    Ok(())
                },
            )
            .await?;
        }
        Ok(())
    }
    .await;

    let result = match setup_result {
        Ok(()) => {
            let pg_cancel_token = client.cancel_token();
            let progress_clock = Arc::new(StreamProgressClock::new());
            let progress_clock_for_stream = progress_clock.clone();
            let mut on_stream_item = |item| {
                on_item(item)?;
                progress_clock_for_stream.mark();
                Ok(())
            };
            let result = await_stream_with_progress_timeout(
                stream_select_query_inner_with_mode(
                    &client,
                    sql,
                    row_limit,
                    &mut on_stream_item,
                    setup_transaction_started,
                ),
                query_timeout,
                progress_clock,
                cancel_token.as_ref(),
                timeout_error.clone(),
            )
            .await;
            if result.as_ref().is_err_and(|error| error == &timeout_error || error == crate::query::QUERY_CANCELED) {
                cancel_postgres_query(pg_cancel_token, cancel_context.as_ref(), budget.cancel_timeout).await;
            }
            result
        }
        Err(error) => Err(error),
    };

    let result = if setup_transaction_started {
        let rollback_result =
            execute_postgres_infra_statement(&client, "ROLLBACK", budget.cleanup_timeout, "export_setup.rollback")
                .await;
        match (result, rollback_result) {
            (Ok(rows), Ok(_)) => Ok(rows),
            (Err(query_err), Ok(_)) => Err(query_err),
            (Ok(_), Err(rollback_err)) => Err(rollback_err),
            (Err(query_err), Err(rollback_err)) => Err(format!("{query_err}; {rollback_err}")),
        }
    } else {
        result
    };

    if schema_was_set {
        let reset_result = reset_postgres_search_path(&client, budget.cleanup_timeout, start).await;
        match (result, reset_result) {
            (Ok(rows), Ok(())) => Ok(rows),
            (Err(query_err), Ok(())) => Err(query_err),
            (Ok(_), Err(reset_err)) => Err(reset_err),
            (Err(query_err), Err(reset_err)) => Err(format!("{query_err}; {reset_err}")),
        }
    } else {
        result
    }
}

pub async fn execute_query_with_schema(pool: &Pool, schema: &str, sql: &str) -> Result<QueryResult, String> {
    execute_query_with_schema_and_max_rows(pool, schema, sql, None).await
}

pub async fn execute_query_with_schema_and_max_rows(
    pool: &Pool,
    schema: &str,
    sql: &str,
    max_rows: Option<usize>,
) -> Result<QueryResult, String> {
    let start = Instant::now();
    let checkout_start = Instant::now();
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    log::info!(
        "[postgres][execute_with_schema:pool:done] elapsed_ms={} total_ms={} schema={}",
        checkout_start.elapsed().as_millis(),
        start.elapsed().as_millis(),
        schema
    );
    if is_transaction_recovery_statement(sql) {
        log::info!(
            "[postgres][execute_with_schema:skip-search-path] total_ms={} reason=transaction-recovery",
            start.elapsed().as_millis()
        );
        return execute_query_with_max_rows_inner(&client, sql, max_rows, false, None, false).await;
    }

    let set_schema_start = Instant::now();
    set_postgres_search_path(&client, schema, PostgresSearchPathContext::Query, super::connection_timeout()).await?;
    log::info!(
        "[postgres][execute_with_schema:set-search-path:done] elapsed_ms={} total_ms={}",
        set_schema_start.elapsed().as_millis(),
        start.elapsed().as_millis()
    );

    let query_start = Instant::now();
    let result = execute_query_with_max_rows_inner(&client, sql, max_rows, false, None, false).await;
    if result.is_ok() {
        clear_postgres_caches_after_ddl(pool, Some(&client), sql);
    }
    log::info!(
        "[postgres][execute_with_schema:query:done] elapsed_ms={} total_ms={} ok={}",
        query_start.elapsed().as_millis(),
        start.elapsed().as_millis(),
        result.is_ok()
    );

    let reset_result = reset_postgres_search_path(&client, super::connection_timeout(), start).await;
    merge_postgres_query_and_reset_result(result, reset_result)
}

pub async fn execute_query_with_schema_and_max_rows_and_cancel(
    pool: &Pool,
    schema: &str,
    sql: &str,
    max_rows: Option<usize>,
    cancel_token: Option<CancellationToken>,
    budget: DbOperationBudget,
    cancel_context: Option<PostgresCancelContext>,
    prefer_text_protocol: bool,
) -> Result<QueryResult, String> {
    let start = Instant::now();
    let checkout_start = Instant::now();
    let client = checkout_postgres_client(pool, cancel_token.as_ref(), budget.checkout_timeout).await?;
    log::info!(
        "[postgres][execute_with_schema:pool:done] elapsed_ms={} total_ms={} schema={}",
        checkout_start.elapsed().as_millis(),
        start.elapsed().as_millis(),
        schema
    );
    if is_transaction_recovery_statement(sql) {
        log::info!(
            "[postgres][execute_with_schema:skip-search-path] total_ms={} reason=transaction-recovery",
            start.elapsed().as_millis()
        );
        return execute_postgres_user_query(
            &client,
            sql,
            max_rows,
            cancel_token,
            budget.query_timeout,
            budget.cancel_timeout,
            cancel_context,
            prefer_text_protocol,
        )
        .await;
    }

    let set_schema_start = Instant::now();
    set_postgres_search_path(&client, schema, PostgresSearchPathContext::Query, budget.recycle_timeout).await?;
    log::info!(
        "[postgres][execute_with_schema:set-search-path:done] elapsed_ms={} total_ms={}",
        set_schema_start.elapsed().as_millis(),
        start.elapsed().as_millis()
    );

    let query_start = Instant::now();
    let result = execute_postgres_user_query(
        &client,
        sql,
        max_rows,
        cancel_token,
        budget.query_timeout,
        budget.cancel_timeout,
        cancel_context,
        prefer_text_protocol,
    )
    .await;
    if result.is_ok() {
        clear_postgres_caches_after_ddl(pool, Some(&client), sql);
    }
    log::info!(
        "[postgres][execute_with_schema:query:done] elapsed_ms={} total_ms={} ok={}",
        query_start.elapsed().as_millis(),
        start.elapsed().as_millis(),
        result.is_ok()
    );

    let reset_result = reset_postgres_search_path(&client, budget.cleanup_timeout, start).await;
    merge_postgres_query_and_reset_result(result, reset_result)
}

async fn reset_postgres_search_path(
    client: &deadpool_postgres::Client,
    timeout_duration: Duration,
    start: Instant,
) -> Result<(), String> {
    let reset_start = Instant::now();
    match execute_postgres_infra_statement(client, "RESET search_path", timeout_duration, "schema.reset").await {
        Ok(_) => {
            log::info!(
                "[postgres][execute_with_schema:reset-search-path:done] elapsed_ms={} total_ms={}",
                reset_start.elapsed().as_millis(),
                start.elapsed().as_millis()
            );
            Ok(())
        }
        Err(err) => {
            log::warn!(
                "[postgres][execute_with_schema:reset-search-path:error] elapsed_ms={} total_ms={} error={}",
                reset_start.elapsed().as_millis(),
                start.elapsed().as_millis(),
                err
            );
            Err(postgres_schema_reset_cleanup_error(err))
        }
    }
}

fn merge_postgres_query_and_reset_result(
    query_result: Result<QueryResult, String>,
    reset_result: Result<(), String>,
) -> Result<QueryResult, String> {
    match (query_result, reset_result) {
        (Ok(result), Ok(())) => Ok(result),
        (Err(query_err), Ok(())) => Err(query_err),
        (Ok(_), Err(reset_err)) => Err(reset_err),
        (Err(query_err), Err(reset_err)) => Err(format!("{query_err}; {reset_err}")),
    }
}

fn postgres_schema_reset_cleanup_error(err: String) -> String {
    format!("PostgreSQL schema.reset cleanup failed: {err}")
}

pub(crate) async fn execute_postgres_infra_statement(
    client: &deadpool_postgres::Client,
    sql: &str,
    timeout_duration: Duration,
    stage: &str,
) -> Result<u64, String> {
    tokio::time::timeout(timeout_duration, client.execute_typed(sql, &[]))
        .await
        .map_err(|_| format!("PostgreSQL {stage} timed out after {} seconds", timeout_duration.as_secs()))?
        .map_err(pg_error_to_string)
}

pub(crate) async fn wait_postgres_operation<T, F>(
    pg_cancel_token: tokio_postgres::CancelToken,
    cancel_context: Option<PostgresCancelContext>,
    timeout_duration: Option<Duration>,
    cancel_timeout: Duration,
    future: F,
) -> Result<T, String>
where
    F: Future<Output = Result<T, String>>,
{
    wait_postgres_query(pg_cancel_token, cancel_context, None, timeout_duration, cancel_timeout, future).await
}

async fn wait_postgres_query<T, F>(
    pg_cancel_token: tokio_postgres::CancelToken,
    cancel_context: Option<PostgresCancelContext>,
    cancel_token: Option<CancellationToken>,
    timeout_duration: Option<Duration>,
    cancel_timeout: Duration,
    future: F,
) -> Result<T, String>
where
    F: Future<Output = Result<T, String>>,
{
    match (cancel_token, timeout_duration) {
        (Some(token), Some(duration)) => {
            tokio::select! {
                biased;
                _ = token.cancelled() => {
                    cancel_postgres_query(pg_cancel_token, cancel_context.as_ref(), cancel_timeout).await;
                    Err(crate::query::canceled_error())
                }
                result = tokio::time::timeout(duration, future) => match result {
                    Ok(result) => result,
                    Err(_) => {
                        cancel_postgres_query(pg_cancel_token, cancel_context.as_ref(), cancel_timeout).await;
                        Err(format!("Query timed out after {} seconds", duration.as_secs()))
                    }
                },
            }
        }
        (None, Some(duration)) => match tokio::time::timeout(duration, future).await {
            Ok(result) => result,
            Err(_) => {
                cancel_postgres_query(pg_cancel_token, cancel_context.as_ref(), cancel_timeout).await;
                Err(format!("Query timed out after {} seconds", duration.as_secs()))
            }
        },
        (Some(token), None) => {
            tokio::select! {
                biased;
                _ = token.cancelled() => {
                    cancel_postgres_query(pg_cancel_token, cancel_context.as_ref(), cancel_timeout).await;
                    Err(crate::query::canceled_error())
                }
                result = future => result,
            }
        }
        (None, None) => future.await,
    }
}

async fn execute_postgres_user_query(
    client: &deadpool_postgres::Client,
    sql: &str,
    max_rows: Option<usize>,
    cancel_token: Option<CancellationToken>,
    timeout_duration: Option<Duration>,
    cancel_timeout: Duration,
    cancel_context: Option<PostgresCancelContext>,
    prefer_text_protocol: bool,
) -> Result<QueryResult, String> {
    execute_postgres_user_query_with_mode(
        client,
        sql,
        max_rows,
        cancel_token,
        timeout_duration,
        cancel_timeout,
        cancel_context,
        prefer_text_protocol,
        false,
    )
    .await
}

async fn execute_postgres_user_query_with_mode(
    client: &deadpool_postgres::Client,
    sql: &str,
    max_rows: Option<usize>,
    cancel_token: Option<CancellationToken>,
    timeout_duration: Option<Duration>,
    cancel_timeout: Duration,
    cancel_context: Option<PostgresCancelContext>,
    prefer_text_protocol: bool,
    force_unnamed: bool,
) -> Result<QueryResult, String> {
    let pg_cancel_token = client.cancel_token();
    // Commands do not expose incremental results, so keep their timeout as a
    // wall-clock deadline. Row-returning queries may spend longer transferring
    // a bounded result through a slow tunnel; for those, the same setting is an
    // inactivity budget that resets only after real PostgreSQL progress.
    if !postgres_statement_returns_rows(sql) {
        return wait_postgres_query(
            pg_cancel_token,
            cancel_context,
            cancel_token,
            timeout_duration,
            cancel_timeout,
            execute_query_with_max_rows_inner(client, sql, max_rows, prefer_text_protocol, None, force_unnamed),
        )
        .await;
    }

    let timeout_error =
        format!("Query timed out after {} seconds", timeout_duration.map_or(0, |timeout| timeout.as_secs()));
    let progress_clock = Arc::new(StreamProgressClock::new());
    let result = await_stream_with_progress_timeout(
        execute_query_with_max_rows_inner(
            client,
            sql,
            max_rows,
            prefer_text_protocol,
            Some(progress_clock.clone()),
            force_unnamed,
        ),
        timeout_duration,
        progress_clock,
        cancel_token.as_ref(),
        timeout_error.clone(),
    )
    .await;

    if result.as_ref().is_err_and(|error| error == &timeout_error || error == crate::query::QUERY_CANCELED) {
        cancel_postgres_query(pg_cancel_token, cancel_context.as_ref(), cancel_timeout).await;
    }

    result
}

/// PostgreSQL pool checkout with timeout and cancel token support.
/// When the checkout phase is stuck, the cancel token can terminate the wait early.
pub(crate) type PostgresCheckoutStage = super::PoolCheckoutStage;

pub(crate) fn classify_postgres_checkout_stage(status: deadpool_postgres::Status) -> PostgresCheckoutStage {
    if status.waiting > 0 || (status.available == 0 && status.size >= status.max_size) {
        PostgresCheckoutStage::Wait
    } else if status.available > 0 {
        PostgresCheckoutStage::Recycle
    } else if status.size < status.max_size {
        PostgresCheckoutStage::Create
    } else {
        PostgresCheckoutStage::Unknown
    }
}

fn postgres_pool_error_stage(error: &PoolError) -> PostgresCheckoutStage {
    match error {
        PoolError::Timeout(deadpool_postgres::TimeoutType::Wait) => PostgresCheckoutStage::Wait,
        PoolError::Timeout(deadpool_postgres::TimeoutType::Create) => PostgresCheckoutStage::Create,
        PoolError::Timeout(deadpool_postgres::TimeoutType::Recycle) => PostgresCheckoutStage::Recycle,
        PoolError::Backend(_) | PoolError::PostCreateHook(_) => PostgresCheckoutStage::Create,
        PoolError::Closed | PoolError::NoRuntimeSpecified => PostgresCheckoutStage::Unknown,
    }
}

pub(crate) async fn checkout_postgres_client_classified(
    pool: &Pool,
    cancel_token: Option<&CancellationToken>,
    checkout_timeout: Duration,
) -> Result<deadpool_postgres::Object, super::PoolCheckoutError> {
    let start = Instant::now();
    let get_future = async {
        match tokio::time::timeout(checkout_timeout, pool.get()).await {
            Ok(Ok(client)) => Ok(client),
            Ok(Err(error)) => {
                let stage = postgres_pool_error_stage(&error);
                let timed_out = matches!(&error, PoolError::Timeout(_));
                let detail = pg_pool_error_to_string(error);
                log::warn!(
                    "[db:pool.checkout:error] elapsed_ms={} timeout_ms={} stage={} error={}",
                    start.elapsed().as_millis(),
                    checkout_timeout.as_millis(),
                    stage.as_str(),
                    detail
                );
                if timed_out {
                    Err(super::PoolCheckoutError::Timeout { database: "PostgreSQL", stage, timeout: checkout_timeout })
                } else {
                    Err(super::PoolCheckoutError::Failed { database: "PostgreSQL", stage, detail })
                }
            }
            Err(_) => {
                let stage = classify_postgres_checkout_stage(pool.status());
                log::warn!(
                    "[db:pool.checkout:error] elapsed_ms={} timeout_ms={} stage={} error=checkout timed out",
                    start.elapsed().as_millis(),
                    checkout_timeout.as_millis(),
                    stage.as_str()
                );
                Err(super::PoolCheckoutError::Timeout { database: "PostgreSQL", stage, timeout: checkout_timeout })
            }
        }
    };

    match cancel_token {
        Some(token) => tokio::select! {
            biased;
            _ = token.cancelled() => {
                log::info!(
                    "[db:pool.checkout:cancelled] elapsed_ms={} timeout_ms={}",
                    start.elapsed().as_millis(),
                    checkout_timeout.as_millis()
                );
                Err(super::PoolCheckoutError::Canceled)
            }
            result = get_future => result,
        },
        None => get_future.await,
    }
}

pub async fn checkout_postgres_client(
    pool: &Pool,
    cancel_token: Option<&CancellationToken>,
    checkout_timeout: Duration,
) -> Result<deadpool_postgres::Object, String> {
    let checkout_timeout = effective_postgres_checkout_timeout(pool, checkout_timeout);
    let start = Instant::now();
    let result = checkout_postgres_client_classified(pool, cancel_token, checkout_timeout)
        .await
        .map_err(|error| error.to_string());
    if let Ok(client) = &result {
        log::debug!(
            "[db:pool.checkout:done] elapsed_ms={} timeout_ms={}",
            start.elapsed().as_millis(),
            checkout_timeout.as_millis()
        );
        // Resolve the notice-attribution identity here, outside of any
        // transaction: a lazy first lookup from `drain_postgres_notices`
        // could run inside the read-only EXPLAIN transaction, where a
        // failing identity query would abort the user's statement. Cached
        // after the first checkout of each physical connection.
        let _ = resolve_postgres_client_key(client).await;
    }
    result
}

fn effective_postgres_checkout_timeout(pool: &Pool, requested_timeout: Duration) -> Duration {
    let configured = pool.timeouts();
    [configured.wait, configured.create, configured.recycle]
        .into_iter()
        .flatten()
        .fold(requested_timeout, std::cmp::max)
}

async fn cancel_postgres_query(
    pg_cancel_token: tokio_postgres::CancelToken,
    cancel_context: Option<&PostgresCancelContext>,
    cancel_timeout: Duration,
) {
    let cancel_timeout = postgres_cancel_attempt_timeout(cancel_timeout, cancel_context);
    if let Some(ctx) = cancel_context {
        let tls_result = if ctx.legacy_tls {
            match make_openssl_connect_from_context(ctx) {
                Ok(tls) => Some(tokio::time::timeout(cancel_timeout, pg_cancel_token.cancel_query(tls)).await),
                Err(err) => {
                    log::warn!("Failed to build legacy TLS connector for cancel: {err}; falling back to NoTls cancel");
                    None
                }
            }
        } else {
            match make_rustls_connect_from_context(ctx) {
                Ok(tls) => Some(tokio::time::timeout(cancel_timeout, pg_cancel_token.cancel_query(tls)).await),
                Err(err) => {
                    log::warn!("Failed to build TLS connector for cancel: {err}; falling back to NoTls cancel");
                    None
                }
            }
        };
        if let Some(result) = tls_result {
            match result {
                Ok(Ok(())) => return,
                Ok(Err(err)) => {
                    log::warn!("Failed to send PostgreSQL TLS cancel request: {err}");
                    if ctx.ssl_mode != SslMode::Prefer {
                        return;
                    }
                }
                Err(_) => {
                    log::warn!("Timed out sending PostgreSQL TLS cancel request ({}s)", cancel_timeout.as_secs());
                    if ctx.ssl_mode != SslMode::Prefer {
                        return;
                    }
                }
            }
        }
    }
    match tokio::time::timeout(cancel_timeout, pg_cancel_token.cancel_query(NoTls)).await {
        Ok(Ok(())) => {}
        Ok(Err(err)) => log::warn!("Failed to send PostgreSQL cancel request: {err}"),
        Err(_) => log::warn!("Timed out sending PostgreSQL cancel request ({}s)", cancel_timeout.as_secs()),
    }
}

fn postgres_cancel_attempt_timeout(
    cancel_timeout: Duration,
    _cancel_context: Option<&PostgresCancelContext>,
) -> Duration {
    cancel_timeout
}

fn is_transaction_recovery_statement(sql: &str) -> bool {
    starts_with_executable_sql_keyword(sql, &["ROLLBACK", "ABORT", "COMMIT", "END"])
}

async fn execute_query_with_max_rows_inner(
    client: &deadpool_postgres::Client,
    sql: &str,
    max_rows: Option<usize>,
    prefer_text_protocol: bool,
    progress_clock: Option<Arc<StreamProgressClock>>,
    force_unnamed: bool,
) -> Result<QueryResult, String> {
    let start = Instant::now();
    let row_limit = query_result_row_limit(max_rows);

    // Discard stale notices from infrastructure statements (e.g. the timezone
    // SET issued at connect time) so only messages raised by this statement
    // are attached to its result.
    let _ = drain_postgres_notices(client).await;

    let result = if postgres_statement_returns_rows(sql) {
        if prefer_text_protocol {
            execute_select_text(client, sql, start, row_limit, None, progress_clock.as_deref()).await
        } else {
            execute_select_query_with_progress(client, sql, start, row_limit, progress_clock.as_deref(), force_unnamed)
                .await
        }
    } else {
        let affected =
            if force_unnamed { client.execute_typed(sql, &[]).await } else { client.execute(sql, &[]).await };
        affected.map_err(pg_error_to_string).map(|affected| QueryResult {
            columns: vec![],
            column_types: Vec::new(),
            column_sortables: Vec::new(),
            spatial_columns: vec![],
            spatial_values: vec![],
            rows: vec![],
            affected_rows: affected,
            execution_time_ms: start.elapsed().as_millis(),
            truncated: false,
            session_id: None,
            has_more: false,
            elasticsearch_raw_body: None,
            messages: Vec::new(),
        })
    };

    match result {
        Ok(mut result) => {
            result.messages = drain_postgres_notices(client).await;
            Ok(result)
        }
        Err(error) => {
            // Drop notices so an errored statement's messages cannot leak
            // into the next query on this pooled connection.
            let _ = drain_postgres_notices(client).await;
            Err(error)
        }
    }
}

// Sibling of `postgres_indexes_for_relations_sql` (~line 3288), for a single
// (schema, table) instead of a batch of oids — see the note there.
const POSTGRES_INDEXES_SQL: &str = "SELECT i.relname AS index_name, \
             array_agg(COALESCE(a.attname, pg_get_indexdef(ix.indexrelid, k.n::int, false)) ORDER BY k.n) AS columns, \
             array_agg(CASE WHEN oc.opcdefault THEN NULL ELSE quote_ident(opcns.nspname) || '.' || quote_ident(oc.opcname) END ORDER BY k.n) AS column_opclasses, \
             (ix.indisunique AND ix.indisvalid) AS is_unique, \
             ix.indisprimary AS is_primary, \
             pg_get_expr(ix.indpred, ix.indrelid) AS filter_expr, \
             am.amname AS index_type, \
             ix.indnkeyatts AS nkeyatts, \
             ix.indkey AS indkey, \
             obj_description(i.oid, 'pg_class') AS index_comment, \
             array_agg(a.attname IS NULL ORDER BY k.n) AS key_is_expression \
             FROM pg_index ix \
             JOIN pg_class t ON t.oid = ix.indrelid \
             JOIN pg_class i ON i.oid = ix.indexrelid \
             JOIN pg_namespace n ON n.oid = t.relnamespace \
             JOIN pg_am am ON am.oid = i.relam \
             JOIN LATERAL unnest(ix.indkey, ix.indclass) WITH ORDINALITY AS k(attnum, class_oid, n) ON true \
             LEFT JOIN pg_attribute a ON a.attrelid = t.oid AND a.attnum = k.attnum AND k.attnum > 0 \
             LEFT JOIN pg_opclass oc ON oc.oid = k.class_oid \
             LEFT JOIN pg_namespace opcns ON opcns.oid = oc.opcnamespace \
             WHERE t.oid = (CASE WHEN $1 = '' THEN quote_ident($2) ELSE quote_ident($1) || '.' || quote_ident($2) END)::regclass \
             GROUP BY i.relname, i.oid, ix.indisunique, ix.indisvalid, ix.indisprimary, ix.indpred, ix.indrelid, am.amname, ix.indnkeyatts, ix.indkey \
             ORDER BY i.relname";

// Compat-tier sibling of `postgres_indexes_for_relations_compat_sql` (~line
// 3312) — see the note on `POSTGRES_INDEXES_SQL` above.
const POSTGRES_INDEXES_COMPAT_SQL: &str = "SELECT i.relname AS index_name, \
             ARRAY( \
               SELECT COALESCE(a.attname, pg_get_indexdef(ix.indexrelid, pos.n, false)) \
               FROM generate_series(1, array_length(string_to_array(ix.indkey::text, ' '), 1)) AS pos(n) \
               LEFT JOIN pg_attribute a \
                 ON a.attrelid = t.oid \
                AND a.attnum = (string_to_array(ix.indkey::text, ' '))[pos.n]::int2 \
                AND a.attnum > 0 \
               ORDER BY pos.n \
             ) AS columns, \
             ARRAY( \
               SELECT CASE WHEN oc.opcdefault THEN NULL \
                           ELSE oc.opcname \
                      END \
               FROM generate_series(1, array_length(string_to_array(ix.indkey::text, ' '), 1)) AS pos(n) \
               LEFT JOIN pg_attribute a \
                 ON a.attrelid = t.oid \
                AND a.attnum = (string_to_array(ix.indkey::text, ' '))[pos.n]::int2 \
                AND a.attnum > 0 \
               LEFT JOIN pg_opclass oc \
                 ON oc.oid = (string_to_array(ix.indclass::text, ' '))[pos.n]::oid \
               ORDER BY pos.n \
             ) AS column_opclasses, \
             (ix.indisunique AND ix.indisvalid) AS is_unique, \
             ix.indisprimary AS is_primary, \
             pg_get_expr(ix.indpred, ix.indrelid) AS filter_expr, \
             am.amname AS index_type, \
             NULL::smallint AS nkeyatts, \
             ix.indkey AS indkey, \
             obj_description(i.oid, 'pg_class') AS index_comment, \
             ARRAY( \
               SELECT a.attname IS NULL \
               FROM generate_series(1, array_length(string_to_array(ix.indkey::text, ' '), 1)) AS pos(n) \
               LEFT JOIN pg_attribute a \
                 ON a.attrelid = t.oid \
                AND a.attnum = (string_to_array(ix.indkey::text, ' '))[pos.n]::int2 \
                AND a.attnum > 0 \
               ORDER BY pos.n \
             ) AS key_is_expression \
             FROM pg_index ix \
             JOIN pg_class t ON t.oid = ix.indrelid \
             JOIN pg_class i ON i.oid = ix.indexrelid \
             JOIN pg_namespace n ON n.oid = t.relnamespace \
             JOIN pg_am am ON am.oid = i.relam \
             WHERE t.oid = (CASE WHEN $1 = '' THEN quote_ident($2) ELSE quote_ident($1) || '.' || quote_ident($2) END)::regclass \
             ORDER BY i.relname";

const POSTGRES_OWNERS_SQL: &str =
    "SELECT n.nspname, c.relname, c.relkind::text AS relkind, pg_get_userbyid(c.relowner) \
     FROM pg_class c \
     JOIN pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 \
       AND c.relkind IN ('r', 'v', 'm', 'S', 'f', 'p')";

const POSTGRES_TABLE_OWNER_SQL: &str = "SELECT pg_get_userbyid(c.relowner)::text, \
            ARRAY(SELECT default_acl.privilege_type::text \
                  FROM pg_catalog.aclexplode(pg_catalog.acldefault('r', c.relowner)) default_acl \
                  WHERE default_acl.grantee = c.relowner \
                  ORDER BY default_acl.privilege_type) \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r', 'p') \
     ORDER BY c.oid LIMIT 1";

const POSTGRES_TABLE_ACL_PRIVILEGES_SQL: &str =
    "SELECT CASE WHEN acl.grantee = 0 THEN 'PUBLIC' ELSE grantee.rolname END::text, \
            acl.privilege_type::text, acl.is_grantable, pg_get_userbyid(acl.grantor)::text \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     JOIN LATERAL pg_catalog.aclexplode(COALESCE(c.relacl, pg_catalog.acldefault('r', c.relowner))) acl ON true \
     LEFT JOIN pg_catalog.pg_roles grantee ON grantee.oid = acl.grantee \
     WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r', 'p') \
     ORDER BY 4, 1, 2, 3";

const POSTGRES_COLUMN_ACL_PRIVILEGES_SQL: &str =
    "SELECT CASE WHEN acl.grantee = 0 THEN 'PUBLIC' ELSE grantee.rolname END::text, \
            acl.privilege_type::text, acl.is_grantable, a.attname::text, pg_get_userbyid(acl.grantor)::text \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid AND a.attnum > 0 AND NOT a.attisdropped \
     JOIN LATERAL pg_catalog.aclexplode(a.attacl) acl ON true \
     LEFT JOIN pg_catalog.pg_roles grantee ON grantee.oid = acl.grantee \
     WHERE n.nspname = $1 AND c.relname = $2 AND c.relkind IN ('r', 'p') \
     ORDER BY 5, 1, 2, 3, 4";

pub(crate) fn postgres_owner_object_type(relkind: &str) -> &str {
    match relkind {
        "r" => "TABLE",
        "v" => "VIEW",
        "m" => "MATERIALIZED_VIEW",
        "S" => "SEQUENCE",
        "f" => "FOREIGN TABLE",
        "p" => "PARTITIONED TABLE",
        "I" => "PARTITIONED INDEX",
        _ => relkind,
    }
}

/// Looks up a relation's own `relkind` (e.g. `'r'`, `'v'`, `'S'`), regardless
/// of whether it's a kind this driver otherwise treats as a table. Used to
/// give a specific diagnostic ("it's a view, not a table") instead of a bare
/// "not found" when a `(schema, table)` request turns out not to be a
/// table/partition/foreign table.
pub(crate) async fn postgres_relation_relkind(
    pool: &Pool,
    schema: &str,
    table: &str,
) -> Result<Option<String>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let row = client
        .query_opt(
            "SELECT c.relkind::text FROM pg_catalog.pg_class c \
             JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
             WHERE n.nspname = $1 AND c.relname = $2 LIMIT 1",
            &[&schema, &table],
        )
        .await
        .map_err(pg_error_to_string)?;
    row.map(|row| row.try_get::<_, String>(0)).transpose().map_err(pg_error_to_string)
}

/// Compute per-column operator classes from `pg_opclass` joined via
/// `pg_index.indclass`. For each key column position, the schema-qualified
/// opclass (`quote_ident(nspname) || '.' || quote_ident(opcname)`) is returned
/// unless the class is the type's default (`oc.opcdefault`), so DDL regeneration
/// resolves the opclass regardless of `search_path`. This applies to every key
/// position, including expression keys (`a.attname IS NULL`): the per-column
/// `pg_get_indexdef(indexrelid, colno, pretty)` call returns only the bare
/// expression text (PostgreSQL sets `attrsOnly = (colno != 0)`, so the
/// opclass/COLLATE/DESC block is skipped — see `ruleutils.c`), so the opclass
/// must be read from `indclass` rather than parsed out of that text.
async fn list_indexes_with_sql(
    client: &deadpool_postgres::Client,
    sql: &str,
    schema: &str,
    table: &str,
) -> Result<Vec<IndexInfo>, tokio_postgres::Error> {
    let rows = postgres_query_cached(client, sql, &[&schema, &table]).await?;

    Ok(rows
        .iter()
        .map(|row| {
            let all_cols: Vec<String> = row.try_get::<_, Vec<String>>(1).unwrap_or_default();
            let all_opclasses: Vec<Option<String>> = row.try_get::<_, Vec<Option<String>>>(2).unwrap_or_default();
            let nkeyatts = row.try_get::<_, Option<i16>>(7).ok().flatten().unwrap_or(all_cols.len() as i16) as usize;
            let split_at = nkeyatts.min(all_cols.len());
            let key_cols = all_cols[..split_at].to_vec();
            let key_opclasses = if all_opclasses.len() == all_cols.len() {
                all_opclasses[..split_at].to_vec()
            } else {
                vec![None; split_at]
            };
            let included = if split_at < all_cols.len() { all_cols[split_at..].to_vec() } else { vec![] };
            // `a.attname IS NULL` at a given key position means that key part came back from
            // pg_get_indexdef (a functional/expression key part), not from a real column (#6295).
            let all_is_expr: Vec<bool> = row.try_get::<_, Vec<bool>>(10).unwrap_or_default();
            let key_is_expression =
                if all_is_expr.len() == all_cols.len() { all_is_expr[..split_at].to_vec() } else { Vec::new() };
            IndexInfo {
                name: pg_row_try_string(row, 0),
                columns: key_cols,
                is_unique: pg_row_try_bool(row, 3).unwrap_or(false),
                is_primary: pg_row_try_bool(row, 4).unwrap_or(false),
                filter: row.try_get::<_, Option<String>>(5).ok().flatten(),
                index_type: row.try_get::<_, Option<String>>(6).ok().flatten(),
                included_columns: if included.is_empty() { None } else { Some(included) },
                comment: row.try_get::<_, Option<String>>(9).ok().flatten(),
                key_is_expression,
                column_opclasses: key_opclasses,
            }
        })
        .collect())
}

pub async fn list_indexes(pool: &Pool, schema: &str, table: &str) -> Result<Vec<IndexInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let tiers = [POSTGRES_INDEXES_SQL, POSTGRES_INDEXES_COMPAT_SQL];
    query_with_compat_fallback("list_indexes", &tiers, |sql| list_indexes_with_sql(&client, sql, schema, table)).await
}

/// Names of same-table indexes whose `pg_index.indisvalid` is `false`.
///
/// A cancelled `CREATE INDEX CONCURRENTLY` leaves an INVALID index behind with
/// the requested name; until it is dropped, any retry of the same build fails
/// with `relation already exists`. The structure editor consults this before
/// applying a concurrent build so it can surface the leftover explicitly
/// instead of failing silently.
const POSTGRES_INVALID_INDEXES_SQL: &str = "SELECT idx.relname \
     FROM pg_catalog.pg_index ix \
     JOIN pg_catalog.pg_class idx ON idx.oid = ix.indexrelid \
     JOIN pg_catalog.pg_class t ON t.oid = ix.indrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = t.relnamespace \
     WHERE n.nspname = $1 AND t.relname = $2 AND ix.indisvalid = false \
     ORDER BY idx.relname";

pub async fn list_invalid_indexes(pool: &Pool, schema: &str, table: &str) -> Result<Vec<String>, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, POSTGRES_INVALID_INDEXES_SQL, &[&schema, &table])
        .await
        .map_err(|e| e.to_string())?;
    Ok(rows.iter().map(|row| pg_row_try_string(row, 0)).collect())
}

fn postgres_foreign_keys_sql() -> &'static str {
    "SELECT con.conname AS constraint_name, \
     a.attname AS column_name, \
     ref_n.nspname AS ref_schema, \
     ref_c.relname AS ref_table, \
     ref_a.attname AS ref_column, \
     con.confupdtype::text AS on_update_raw, \
     con.confdeltype::text AS on_delete_raw \
     FROM pg_catalog.pg_constraint con \
     JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     JOIN pg_catalog.pg_class ref_c ON ref_c.oid = con.confrelid \
     JOIN pg_catalog.pg_namespace ref_n ON ref_n.oid = ref_c.relnamespace \
     JOIN LATERAL unnest(con.conkey) WITH ORDINALITY AS fk(attnum, ord) ON true \
     JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid AND a.attnum = fk.attnum AND NOT a.attisdropped \
     JOIN LATERAL unnest(con.confkey) WITH ORDINALITY AS pk(attnum, ord) ON pk.ord = fk.ord \
     JOIN pg_catalog.pg_attribute ref_a ON ref_a.attrelid = ref_c.oid AND ref_a.attnum = pk.attnum AND NOT ref_a.attisdropped \
     WHERE con.contype = 'f' AND n.nspname = $1 AND c.relname = $2 \
     ORDER BY con.conname, fk.ord"
}

// Pre-9.4 sibling of `postgres_foreign_keys_sql`: WITH ORDINALITY requires
// PostgreSQL 9.4, so pair conkey/confkey positions with generate_series over
// the array length plus plain subscripts.
fn postgres_foreign_keys_compat_sql() -> &'static str {
    "SELECT con.conname AS constraint_name, \
     a.attname AS column_name, \
     ref_n.nspname AS ref_schema, \
     ref_c.relname AS ref_table, \
     ref_a.attname AS ref_column, \
     con.confupdtype::text AS on_update_raw, \
     con.confdeltype::text AS on_delete_raw \
     FROM pg_catalog.pg_constraint con \
     JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     JOIN pg_catalog.pg_class ref_c ON ref_c.oid = con.confrelid \
     JOIN pg_catalog.pg_namespace ref_n ON ref_n.oid = ref_c.relnamespace \
     CROSS JOIN generate_series(1, array_length(con.conkey, 1)) AS fk(ord) \
     JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid AND a.attnum = (con.conkey)[fk.ord] AND NOT a.attisdropped \
     JOIN pg_catalog.pg_attribute ref_a ON ref_a.attrelid = ref_c.oid AND ref_a.attnum = (con.confkey)[fk.ord] AND NOT ref_a.attisdropped \
     WHERE con.contype = 'f' AND n.nspname = $1 AND c.relname = $2 \
     ORDER BY con.conname, fk.ord"
}

async fn list_foreign_keys_with_sql(
    client: &deadpool_postgres::Client,
    sql: &'static str,
    schema: &str,
    table: &str,
) -> Result<Vec<ForeignKeyInfo>, tokio_postgres::Error> {
    let rows = postgres_query_cached(client, sql, &[&schema, &table]).await?;
    Ok(rows
        .iter()
        .map(|row| ForeignKeyInfo {
            name: pg_row_try_string(row, 0),
            column: pg_row_try_string(row, 1),
            ref_schema: Some(pg_row_try_string(row, 2)),
            ref_table: pg_row_try_string(row, 3),
            ref_column: pg_row_try_string(row, 4),
            on_update: postgres_fk_action_label(pg_row_try_optional_text(row, 5)),
            on_delete: postgres_fk_action_label(pg_row_try_optional_text(row, 6)),
        })
        .collect())
}

pub async fn list_foreign_keys(pool: &Pool, schema: &str, table: &str) -> Result<Vec<ForeignKeyInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let tiers = [postgres_foreign_keys_sql(), postgres_foreign_keys_compat_sql()];
    query_with_compat_fallback("list_foreign_keys", &tiers, |sql| {
        list_foreign_keys_with_sql(&client, sql, schema, table)
    })
    .await
}

/// OpenGauss-safe foreign key metadata. Mirrors `list_opengauss_constraints`:
/// older OpenGauss releases may reject WITH ORDINALITY or decode catalog arrays
/// differently on the wire, so read conkey/confkey as text and resolve the
/// attribute numbers in Rust.
pub async fn list_opengauss_foreign_keys(
    pool: &Pool,
    schema: &str,
    table: &str,
) -> Result<Vec<ForeignKeyInfo>, String> {
    let schema = if schema.is_empty() { "public" } else { schema };
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, opengauss_foreign_keys_sql(), &[&schema, &table])
        .await
        .map_err(|e| e.to_string())?;
    if rows.is_empty() {
        return Ok(Vec::new());
    }

    let local_relation_oid =
        pg_row_try_u32(&rows[0], 7).ok_or("OpenGauss foreign key metadata did not return a local relation OID")?;
    let local_attributes = opengauss_relation_attributes(&client, local_relation_oid).await?;
    let mut referenced_attributes: HashMap<u32, HashMap<i16, String>> = HashMap::new();
    let mut result = Vec::new();

    for row in &rows {
        let name = pg_row_try_string(row, 0);
        let column_numbers = parse_opengauss_attribute_numbers(&pg_row_try_string(row, 3))
            .map_err(|error| format!("failed to parse OpenGauss foreign key {name} columns: {error}"))?;
        let ref_column_numbers = parse_opengauss_attribute_numbers(&pg_row_try_string(row, 4))
            .map_err(|error| format!("failed to parse OpenGauss foreign key {name} referenced columns: {error}"))?;
        let ref_schema = pg_row_try_string(row, 1);
        let ref_table = pg_row_try_string(row, 2);
        let on_update = postgres_fk_action_label(pg_row_try_optional_text(row, 5));
        let on_delete = postgres_fk_action_label(pg_row_try_optional_text(row, 6));
        let Some(referenced_relation_oid) = pg_row_try_u32(row, 8).filter(|oid| *oid != 0) else {
            continue;
        };
        if let std::collections::hash_map::Entry::Vacant(entry) = referenced_attributes.entry(referenced_relation_oid) {
            entry.insert(opengauss_relation_attributes(&client, referenced_relation_oid).await?);
        }
        let ref_attributes = referenced_attributes.get(&referenced_relation_oid).unwrap();
        for (fk_number, pk_number) in column_numbers.iter().zip(ref_column_numbers.iter()) {
            let Some(column) = local_attributes.get(fk_number) else { continue };
            let Some(ref_column) = ref_attributes.get(pk_number) else { continue };
            result.push(ForeignKeyInfo {
                name: name.clone(),
                column: column.clone(),
                ref_schema: Some(ref_schema.clone()),
                ref_table: ref_table.clone(),
                ref_column: ref_column.clone(),
                on_update: on_update.clone(),
                on_delete: on_delete.clone(),
            });
        }
    }
    Ok(result)
}

fn opengauss_foreign_keys_sql() -> &'static str {
    "SELECT con.conname, \
            ref_n.nspname, ref_c.relname, \
            COALESCE(con.conkey::text, ''), COALESCE(con.confkey::text, ''), \
            con.confupdtype::text, con.confdeltype::text, \
            con.conrelid::oid, con.confrelid::oid \
     FROM pg_catalog.pg_constraint con \
     JOIN pg_catalog.pg_class c ON c.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     JOIN pg_catalog.pg_class ref_c ON ref_c.oid = con.confrelid \
     JOIN pg_catalog.pg_namespace ref_n ON ref_n.oid = ref_c.relnamespace \
     WHERE con.contype = 'f' AND n.nspname = $1 AND c.relname = $2 \
     ORDER BY con.conname"
}

fn postgres_table_dependencies_sql() -> &'static str {
    // Foreign keys aren't the only ordering constraint on export/replay: a
    // partition must be created after its parent table exists too, so union
    // in `pg_inherits` partition-of edges alongside the FK edges.
    "SELECT child.relname AS table_name, parent.relname AS ref_table \
     FROM pg_catalog.pg_constraint con \
     JOIN pg_catalog.pg_class child ON child.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace child_schema ON child_schema.oid = child.relnamespace \
     JOIN pg_catalog.pg_class parent ON parent.oid = con.confrelid \
     JOIN pg_catalog.pg_namespace parent_schema ON parent_schema.oid = parent.relnamespace \
     WHERE con.contype = 'f' \
       AND child_schema.nspname = $1 \
       AND parent_schema.nspname = $1 \
     UNION \
     SELECT child.relname AS table_name, parent.relname AS ref_table \
     FROM pg_catalog.pg_inherits i \
     JOIN pg_catalog.pg_class child ON child.oid = i.inhrelid AND child.relispartition \
     JOIN pg_catalog.pg_namespace child_schema ON child_schema.oid = child.relnamespace \
     JOIN pg_catalog.pg_class parent ON parent.oid = i.inhparent \
     JOIN pg_catalog.pg_namespace parent_schema ON parent_schema.oid = parent.relnamespace \
     WHERE child_schema.nspname = $1 \
       AND parent_schema.nspname = $1 \
     ORDER BY table_name, ref_table"
}

/// 9.x 没有 relispartition；INHERITS 子表同样要先建父表，所以保留这条边。
///
/// No relispartition pre-10; INHERITS children still need their parent
/// created first, so the edge is kept without the filter.
fn postgres_table_dependencies_compat_sql() -> &'static str {
    "SELECT child.relname AS table_name, parent.relname AS ref_table \
     FROM pg_catalog.pg_constraint con \
     JOIN pg_catalog.pg_class child ON child.oid = con.conrelid \
     JOIN pg_catalog.pg_namespace child_schema ON child_schema.oid = child.relnamespace \
     JOIN pg_catalog.pg_class parent ON parent.oid = con.confrelid \
     JOIN pg_catalog.pg_namespace parent_schema ON parent_schema.oid = parent.relnamespace \
     WHERE con.contype = 'f' \
       AND child_schema.nspname = $1 \
       AND parent_schema.nspname = $1 \
     UNION \
     SELECT child.relname AS table_name, parent.relname AS ref_table \
     FROM pg_catalog.pg_inherits i \
     JOIN pg_catalog.pg_class child ON child.oid = i.inhrelid \
     JOIN pg_catalog.pg_namespace child_schema ON child_schema.oid = child.relnamespace \
     JOIN pg_catalog.pg_class parent ON parent.oid = i.inhparent \
     JOIN pg_catalog.pg_namespace parent_schema ON parent_schema.oid = parent.relnamespace \
     WHERE child_schema.nspname = $1 \
       AND parent_schema.nspname = $1 \
     ORDER BY table_name, ref_table"
}

/// Fetch all same-schema table dependencies in one round trip. Whole-database
/// exports use this instead of issuing one information_schema query per table.
pub async fn list_table_dependencies(pool: &Pool, schema: &str) -> Result<Vec<(String, String)>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let params: [&(dyn tokio_postgres::types::ToSql + Sync); 1] = [&schema];
    let rows = query_with_compat_fallback(
        "list_table_dependencies",
        &[postgres_table_dependencies_sql(), postgres_table_dependencies_compat_sql()],
        |sql| postgres_query_cached(&client, sql, &params),
    )
    .await?;

    Ok(rows.iter().map(|row| (pg_row_try_string(row, 0), pg_row_try_string(row, 1))).collect())
}

pub async fn list_triggers(pool: &Pool, schema: &str, table: &str) -> Result<Vec<TriggerInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(
        &client,
        "SELECT trigger_name, event_manipulation, action_timing \
         FROM information_schema.triggers \
         WHERE trigger_schema = $1 AND event_object_table = $2 \
         ORDER BY trigger_name",
        &[&schema, &table],
    )
    .await
    .map_err(|e| e.to_string())?;

    Ok(rows
        .iter()
        .map(|row| TriggerInfo {
            name: pg_row_try_string(row, 0),
            event: pg_row_try_string(row, 1),
            timing: pg_row_try_string(row, 2),
            level: None,
            condition: None,
            language: None,
            enabled: None,
            valid: None,
            comment: None,
            created_at: None,
            statement: None,
        })
        .collect())
}

// A trigger declared on a partitioned table is automatically cloned onto each
// partition (tracked via pg_trigger.tgparentid since PostgreSQL 13); such
// clones are not independently creatable statements — attaching/creating the
// partition already recreates them — so they must be excluded here, or the
// partition's own DDL would re-declare (and fail to create, or duplicate) a
// trigger the parent's DDL already installs. PostgreSQL servers older than 13
// lack the tgparentid column (probed via postgres_trigger_has_tgparentid), so
// use the pre-13 query there; those servers never clone triggers onto
// partitions, so tgisinternal alone is sufficient there.
pub async fn list_trigger_definitions(pool: &Pool, schema: &str, table: &str) -> Result<Vec<String>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let sql = if postgres_trigger_has_tgparentid(&client).await? {
        postgres_trigger_definitions_sql()
    } else {
        postgres_trigger_definitions_sql_without_tgparentid()
    };
    let rows = postgres_query_cached(&client, sql, &[&schema, &table]).await.map_err(|e| e.to_string())?;

    Ok(rows.iter().map(|row| pg_row_try_string(row, 0)).filter(|definition| !definition.trim().is_empty()).collect())
}

fn postgres_trigger_definitions_sql() -> &'static str {
    "SELECT pg_catalog.pg_get_triggerdef(t.oid, true) AS trigger_definition \
     FROM pg_catalog.pg_trigger t \
     JOIN pg_catalog.pg_class c ON c.oid = t.tgrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 AND c.relname = $2 AND NOT t.tgisinternal AND t.tgparentid = 0 \
     ORDER BY t.tgname, t.oid"
}

fn postgres_trigger_definitions_sql_without_tgparentid() -> &'static str {
    "SELECT pg_catalog.pg_get_triggerdef(t.oid, true) AS trigger_definition \
     FROM pg_catalog.pg_trigger t \
     JOIN pg_catalog.pg_class c ON c.oid = t.tgrelid \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 AND c.relname = $2 AND NOT t.tgisinternal \
     ORDER BY t.tgname, t.oid"
}

fn postgres_functions_sql(has_proc_prokind: bool) -> &'static str {
    if has_proc_prokind {
        return "SELECT p.proname, \
                    CASE p.prokind WHEN 'f' THEN 'FUNCTION' WHEN 'p' THEN 'PROCEDURE' ELSE 'FUNCTION' END, \
                    COALESCE(pg_get_function_result(p.oid), ''), \
                    pg_get_functiondef(p.oid), \
                    COALESCE(pg_get_function_arguments(p.oid), '') \
             FROM pg_proc p \
             JOIN pg_namespace n ON n.oid = p.pronamespace \
             WHERE n.nspname = $1 AND p.prokind IN ('f', 'p') \
             ORDER BY p.proname";
    }

    // PostgreSQL 10 and older do not have pg_proc.prokind; procedures were
    // introduced with prokind, so the legacy path can only return functions.
    "SELECT p.proname, \
                    'FUNCTION', \
                    COALESCE(pg_get_function_result(p.oid), ''), \
                    pg_get_functiondef(p.oid), \
                    COALESCE(pg_get_function_arguments(p.oid), '') \
             FROM pg_proc p \
             JOIN pg_namespace n ON n.oid = p.pronamespace \
             WHERE n.nspname = $1 AND NOT p.proisagg AND NOT p.proiswindow \
             ORDER BY p.proname"
}

pub async fn list_functions(pool: &Pool, schema: &str) -> Result<Vec<FunctionInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    // Use pg_proc + pg_get_functiondef() instead of information_schema.routines
    // for reliable function definition retrieval (information_schema.routines.routine_definition
    // is NULL for non-SQL functions like plpgsql)
    let has_proc_prokind = postgres_proc_has_prokind(&client).await?;
    let rows = postgres_query_cached(&client, postgres_functions_sql(has_proc_prokind), &[&schema])
        .await
        .map_err(|e| e.to_string())?;

    Ok(rows
        .iter()
        .map(|row| {
            let def: String = pg_row_try_string(row, 3);
            // Remove schema qualification from CREATE FUNCTION statement
            // to avoid false differences when comparing across schemas.
            // Handle both "schema.name" and schema.name formats.
            let normalized_def = def
                .replace(&format!("CREATE OR REPLACE FUNCTION \"{}\".", schema), "CREATE OR REPLACE FUNCTION ")
                .replace(&format!("CREATE OR REPLACE FUNCTION {}.", schema), "CREATE OR REPLACE FUNCTION ");
            FunctionInfo {
                name: pg_row_try_string(row, 0),
                function_type: pg_row_try_string(row, 1),
                data_type: pg_row_try_string(row, 2),
                definition: normalized_def,
                arguments: pg_row_try_string(row, 4),
            }
        })
        .collect())
}

fn postgres_sequences_sql() -> &'static str {
    "SELECT c.relname, \
      COALESCE(format_type(s.seqtypid, NULL), 'bigint'), \
      COALESCE(s.seqstart::text, '1'), \
      COALESCE(s.seqmin::text, '1'), \
      COALESCE(s.seqmax::text, '9223372036854775807'), \
      COALESCE(s.seqincrement::text, '1'), \
      CASE WHEN s.seqcycle THEN 'YES' ELSE 'NO' END \
     FROM pg_class c \
     JOIN pg_namespace n ON n.oid = c.relnamespace \
     LEFT JOIN pg_sequence s ON s.seqrelid = c.oid \
     WHERE c.relkind = 'S' AND n.nspname = $1 \
     ORDER BY c.relname"
}

fn opengauss_sequences_sql() -> &'static str {
    "SELECT s.sequence_name, \
      COALESCE(s.data_type::text, 'bigint'), \
      COALESCE(s.start_value::text, '1'), \
      COALESCE(s.minimum_value::text, '1'), \
      COALESCE(s.maximum_value::text, '9223372036854775807'), \
      COALESCE(s.increment::text, '1'), \
      COALESCE(s.cycle_option::text, 'NO') \
     FROM information_schema.sequences s \
     JOIN pg_namespace n ON n.nspname = s.sequence_schema \
     JOIN pg_class c ON c.relnamespace = n.oid AND c.relname = s.sequence_name \
     WHERE s.sequence_schema = $1 AND c.relkind IN ('S','L','z','Z') \
     ORDER BY s.sequence_name"
}

fn postgres_sequence_last_values_sql() -> &'static str {
    "SELECT c.relname, pg_sequence_last_value(c.oid)::text \
     FROM pg_class c \
     JOIN pg_namespace n ON n.oid = c.relnamespace \
     WHERE c.relkind = 'S' AND n.nspname = $1"
}

fn opengauss_sequence_last_values_sql() -> &'static str {
    "SELECT c.relname, (pg_sequence_last_value(c.oid)).last_value::text \
     FROM pg_class c \
     JOIN pg_namespace n ON n.oid = c.relnamespace \
     WHERE c.relkind IN ('S','L','z','Z') AND n.nspname = $1"
}

async fn list_sequences_with_sql(
    pool: &Pool,
    schema: &str,
    with_last_values: bool,
    metadata_sql: &str,
    last_values_sql: &str,
) -> Result<Vec<SequenceInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, metadata_sql, &[&schema]).await.map_err(|e| e.to_string())?;

    let mut sequences: Vec<SequenceInfo> = rows
        .iter()
        .map(|row| SequenceInfo {
            name: pg_row_try_string(row, 0),
            data_type: pg_row_try_string(row, 1),
            start_value: pg_row_try_string(row, 2),
            min_value: pg_row_try_string(row, 3),
            max_value: pg_row_try_string(row, 4),
            increment: pg_row_try_string(row, 5),
            cycle: pg_row_try_string(row, 6) == "YES",
            last_value: None,
        })
        .collect();

    if with_last_values {
        if let Ok(rows) = postgres_query_cached(&client, last_values_sql, &[&schema]).await {
            for row in rows {
                let name: String = pg_row_try_string(&row, 0);
                if let Ok(Some(value)) = row.try_get::<_, Option<String>>(1) {
                    if let Some(seq) = sequences.iter_mut().find(|s| s.name == name) {
                        seq.last_value = Some(value);
                    }
                }
            }
        }
    }

    Ok(sequences)
}

pub async fn list_sequences(pool: &Pool, schema: &str, with_last_values: bool) -> Result<Vec<SequenceInfo>, String> {
    // PostgreSQL 10+ stores sequence properties in pg_sequence.
    list_sequences_with_sql(
        pool,
        schema,
        with_last_values,
        postgres_sequences_sql(),
        postgres_sequence_last_values_sql(),
    )
    .await
}

pub async fn list_opengauss_sequences(
    pool: &Pool,
    schema: &str,
    with_last_values: bool,
) -> Result<Vec<SequenceInfo>, String> {
    // openGauss does not expose PostgreSQL 10's pg_sequence catalog. Its
    // information_schema view contains the portable sequence properties, while
    // pg_sequence_last_value returns a record rather than a scalar.
    list_sequences_with_sql(
        pool,
        schema,
        with_last_values,
        opengauss_sequences_sql(),
        opengauss_sequence_last_values_sql(),
    )
    .await
}

pub async fn list_rules(pool: &Pool, schema: &str) -> Result<Vec<RuleInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(
        &client,
        "SELECT schemaname, tablename, rulename, definition \
         FROM pg_rules \
         WHERE schemaname = $1 \
         ORDER BY rulename",
        &[&schema],
    )
    .await
    .map_err(|e| e.to_string())?;

    Ok(rows
        .iter()
        .map(|row| RuleInfo {
            name: pg_row_try_string(row, 2),
            table_name: pg_row_try_string(row, 1),
            definition: pg_row_try_string(row, 3),
        })
        .collect())
}

pub async fn list_extensions(pool: &Pool, schema: Option<&str>) -> Result<Vec<ExtensionInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = if let Some(schema) = schema.filter(|value| !value.is_empty()) {
        postgres_query_cached(
            &client,
            "SELECT e.extname, COALESCE(e.extversion, '') AS extversion, d.description, n.nspname \
             FROM pg_catalog.pg_extension e \
             JOIN pg_catalog.pg_namespace n ON n.oid = e.extnamespace \
             LEFT JOIN pg_catalog.pg_description d ON d.objoid = e.oid AND d.classoid = 'pg_extension'::regclass \
             WHERE n.nspname = $1 \
             ORDER BY e.extname",
            &[&schema],
        )
        .await
    } else {
        postgres_query_cached(
            &client,
            "SELECT e.extname, COALESCE(e.extversion, '') AS extversion, d.description, n.nspname \
             FROM pg_catalog.pg_extension e \
             JOIN pg_catalog.pg_namespace n ON n.oid = e.extnamespace \
             LEFT JOIN pg_catalog.pg_description d ON d.objoid = e.oid AND d.classoid = 'pg_extension'::regclass \
             ORDER BY n.nspname, e.extname",
            &[],
        )
        .await
    }
    .map_err(|e| e.to_string())?;

    Ok(rows
        .iter()
        .map(|row| ExtensionInfo {
            name: pg_row_try_string(row, 0),
            version: pg_row_try_string(row, 1),
            comment: row.try_get::<_, Option<String>>(2).ok().flatten().filter(|s| !s.is_empty()),
            schema: row.try_get::<_, Option<String>>(3).ok().flatten().filter(|s| !s.is_empty()),
        })
        .collect())
}

fn list_extension_member_objects_sql() -> &'static str {
    "SELECT 'RELATION'::text AS object_kind, c.relname, ''::text AS signature \
     FROM pg_catalog.pg_class c \
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
     WHERE n.nspname = $1 \
       AND EXISTS ( \
         SELECT 1 FROM pg_catalog.pg_depend d \
         WHERE d.classid = 'pg_catalog.pg_class'::regclass \
           AND d.objid = c.oid \
           AND d.refclassid = 'pg_catalog.pg_extension'::regclass \
           AND d.deptype = 'e' \
       ) \
     UNION ALL \
     SELECT 'FUNCTION'::text, p.proname, pg_get_function_identity_arguments(p.oid) \
     FROM pg_catalog.pg_proc p \
     JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace \
     WHERE n.nspname = $1 \
       AND EXISTS ( \
         SELECT 1 FROM pg_catalog.pg_depend d \
         WHERE d.classid = 'pg_catalog.pg_proc'::regclass \
           AND d.objid = p.oid \
           AND d.refclassid = 'pg_catalog.pg_extension'::regclass \
           AND d.deptype = 'e' \
       )"
}

pub async fn list_extension_member_objects(pool: &Pool, schema: &str) -> Result<Vec<(String, String, String)>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = match postgres_query_cached(&client, list_extension_member_objects_sql(), &[&schema]).await {
        Ok(rows) => rows,
        Err(primary_error) => {
            // PostgreSQL-compatible servers before the identity-argument
            // formatter can still be filtered using their legacy formatter.
            let fallback_sql = list_extension_member_objects_sql()
                .replace("pg_get_function_identity_arguments(p.oid)", "pg_get_function_arguments(p.oid)");
            postgres_query_cached(&client, &fallback_sql, &[&schema])
                .await
                .map_err(|fallback_error| format!("{primary_error}; legacy fallback failed: {fallback_error}"))?
        }
    };

    Ok(rows
        .iter()
        .map(|row| (pg_row_try_string(row, 0), pg_row_try_string(row, 1), pg_row_try_string(row, 2)))
        .collect())
}

pub async fn list_available_extensions(pool: &Pool) -> Result<Vec<ExtensionInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(
        &client,
        "SELECT name, default_version, comment \
         FROM pg_catalog.pg_available_extensions \
         WHERE installed_version IS NULL \
         ORDER BY name",
        &[],
    )
    .await
    .map_err(|e| e.to_string())?;

    Ok(rows
        .iter()
        .map(|row| ExtensionInfo {
            name: pg_row_try_string(row, 0),
            version: pg_row_try_string(row, 1),
            comment: row.try_get::<_, Option<String>>(2).ok().flatten().filter(|s| !s.is_empty()),
            schema: None,
        })
        .collect())
}

pub async fn list_owners(pool: &Pool, schema: &str) -> Result<Vec<OwnerInfo>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let rows = postgres_query_cached(&client, POSTGRES_OWNERS_SQL, &[&schema]).await.map_err(|e| e.to_string())?;

    Ok(rows
        .iter()
        .map(|row| {
            let relkind: String = pg_row_try_string(row, 2);
            OwnerInfo {
                object_name: pg_row_try_string(row, 1),
                object_type: postgres_owner_object_type(&relkind).to_string(),
                owner: pg_row_try_string(row, 3),
            }
        })
        .collect())
}

pub async fn get_table_owner(pool: &Pool, schema: &str, table: &str) -> Result<Option<String>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let params: [&(dyn tokio_postgres::types::ToSql + Sync); 2] = [&schema, &table];
    let rows = postgres_query_cached(&client, POSTGRES_TABLE_OWNER_SQL, &params).await.map_err(pg_error_to_string)?;

    Ok(rows.first().map(|row| pg_row_try_string(row, 0)).filter(|owner| !owner.is_empty()))
}

pub async fn get_table_access(pool: &Pool, schema: &str, table: &str) -> Result<PostgresTableAccessInfo, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let params: [&(dyn tokio_postgres::types::ToSql + Sync); 2] = [&schema, &table];
    let owner_rows =
        postgres_query_cached(&client, POSTGRES_TABLE_OWNER_SQL, &params).await.map_err(pg_error_to_string)?;
    let owner_row = owner_rows.first().ok_or_else(|| "Table owner not found".to_string())?;
    let owner = pg_row_try_string(owner_row, 0);
    if owner.is_empty() {
        return Err("Table owner not found".to_string());
    }
    let owner_default_privileges = owner_row.try_get::<_, Vec<String>>(1).unwrap_or_default();
    if owner_default_privileges.is_empty() {
        return Err("Table owner default privileges are unavailable".to_string());
    }

    let (table_privileges, column_privileges) = tokio::try_join!(
        postgres_query_cached(&client, POSTGRES_TABLE_ACL_PRIVILEGES_SQL, &params),
        postgres_query_cached(&client, POSTGRES_COLUMN_ACL_PRIVILEGES_SQL, &params),
    )
    .map_err(pg_error_to_string)?;

    let privileges = table_privileges
        .iter()
        .map(|row| PostgresTablePrivilegeInfo {
            grantor: pg_row_try_string(row, 3),
            grantee: pg_row_try_string(row, 0),
            privilege_type: pg_row_try_string(row, 1),
            is_grantable: pg_row_try_bool(row, 2).unwrap_or(false),
            column_name: None,
        })
        .chain(column_privileges.iter().map(|row| PostgresTablePrivilegeInfo {
            grantor: pg_row_try_string(row, 4),
            grantee: pg_row_try_string(row, 0),
            privilege_type: pg_row_try_string(row, 1),
            is_grantable: pg_row_try_bool(row, 2).unwrap_or(false),
            column_name: Some(pg_row_try_string(row, 3)),
        }))
        .collect::<Vec<_>>();
    if privileges.iter().any(|privilege| {
        privilege.grantor.is_empty() || privilege.grantee.is_empty() || privilege.privilege_type.is_empty()
    }) {
        return Err("Table ACL metadata is incomplete".to_string());
    }

    Ok(PostgresTableAccessInfo { owner, owner_default_privileges, privileges })
}

/// Execute multiple SQL statements in a single round-trip using batch_execute.
/// Best for DDL scripts where per-statement affected-row counts are not needed.
pub async fn execute_batch(pool: &Pool, statements: &[String]) -> Result<(), String> {
    let combined = statements.iter().map(|s| s.trim()).filter(|s| !s.is_empty()).collect::<Vec<_>>().join(";\n");
    if combined.is_empty() {
        return Ok(());
    }
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    client.batch_execute(&combined).await.map_err(pg_error_to_string)?;
    clear_postgres_caches_after_ddl(pool, Some(&client), &combined);
    Ok(())
}

pub async fn terminate_current_user_database_backends(pool: &Pool, database: &str) -> Result<u64, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    client
        .execute(
            "SELECT pg_terminate_backend(pid) \
             FROM pg_stat_activity \
             WHERE datname = $1 \
               AND pid <> pg_backend_pid() \
               AND usename = current_user",
            &[&database],
        )
        .await
        .map_err(pg_error_to_string)
}

fn clear_postgres_caches_after_ddl(pool: &Pool, client: Option<&deadpool_postgres::Client>, sql: &str) {
    if !invalidates_postgres_statement_cache(sql) {
        return;
    }
    pool.manager().statement_caches.clear();
    if let Some(client) = client {
        client.clear_type_cache();
    }
}

fn invalidates_postgres_statement_cache(sql: &str) -> bool {
    let trimmed = sql.trim_start();
    starts_with_executable_sql_keyword(
        trimmed,
        &["ALTER", "CREATE", "DROP", "TRUNCATE", "COMMENT", "REINDEX", "VACUUM"],
    )
}

/// Export data via COPY TO STDOUT. `sql` must be a complete COPY statement, e.g.
/// `COPY table (col1, col2) TO STDOUT (FORMAT CSV, HEADER)`.
/// Returns the raw COPY output bytes.
pub async fn copy_out(pool: &Pool, sql: &str) -> Result<Vec<u8>, String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let stream = client.copy_out(sql).await.map_err(pg_error_to_string)?;
    tokio::pin!(stream);
    let mut result = Vec::new();
    while let Some(chunk) = stream.next().await {
        result.extend_from_slice(&chunk.map_err(pg_error_to_string)?);
    }
    Ok(result)
}

/// Import data via COPY FROM STDIN. `sql` must be a complete COPY statement, e.g.
/// `COPY table (col1, col2) FROM STDIN (FORMAT CSV)`.
/// `data` is the raw input in the format specified by the COPY command.
pub async fn copy_in(pool: &Pool, sql: &str, data: &[u8]) -> Result<(), String> {
    let client = checkout_postgres_client(pool, None, super::connection_timeout()).await?;
    let sink = client.copy_in::<str, bytes::Bytes>(sql).await.map_err(pg_error_to_string)?;
    let mut sink = Box::pin(sink);
    sink.as_mut().send(bytes::Bytes::copy_from_slice(data)).await.map_err(pg_error_to_string)?;
    sink.as_mut().close().await.map_err(pg_error_to_string)
}

#[cfg(test)]
mod tests {
    use super::*;
    use openssl::asn1::Asn1Time;
    use openssl::bn::{BigNum, MsbOption};
    use openssl::hash::MessageDigest;
    use openssl::pkey::PKey;
    use openssl::rsa::Rsa;
    use openssl::ssl::{Ssl, SslAcceptor, SslMethod, SslVersion};
    use openssl::x509::extension::{BasicConstraints, KeyUsage, SubjectAlternativeName};
    use openssl::x509::{X509NameBuilder, X509};
    use std::cell::Cell;
    use std::pin::Pin;
    use std::process::Command;
    use std::time::Instant;
    use tokio::io::{AsyncReadExt, AsyncWriteExt};
    use tokio::net::TcpListener;
    use tokio_postgres::types::FromSql;

    fn postgres_numeric_binary(weight: i16, sign: u16, scale: u16, digits: &[u16]) -> Vec<u8> {
        let mut raw = Vec::with_capacity(8 + digits.len() * 2);
        raw.extend_from_slice(&u16::try_from(digits.len()).unwrap().to_be_bytes());
        raw.extend_from_slice(&weight.to_be_bytes());
        raw.extend_from_slice(&sign.to_be_bytes());
        raw.extend_from_slice(&scale.to_be_bytes());
        for digit in digits {
            raw.extend_from_slice(&digit.to_be_bytes());
        }
        raw
    }

    fn postgres_numeric_array_binary(values: &[Option<Vec<u8>>]) -> Vec<u8> {
        let mut raw = Vec::new();
        raw.extend_from_slice(&1_i32.to_be_bytes());
        raw.extend_from_slice(&i32::from(values.iter().any(Option::is_none)).to_be_bytes());
        raw.extend_from_slice(&Type::NUMERIC.oid().to_be_bytes());
        raw.extend_from_slice(&i32::try_from(values.len()).unwrap().to_be_bytes());
        raw.extend_from_slice(&1_i32.to_be_bytes());
        for value in values {
            if let Some(value) = value {
                raw.extend_from_slice(&i32::try_from(value.len()).unwrap().to_be_bytes());
                raw.extend_from_slice(value);
            } else {
                raw.extend_from_slice(&(-1_i32).to_be_bytes());
            }
        }
        raw
    }

    #[test]
    fn postgres_numeric_binary_values_preserve_arbitrary_precision() {
        assert_eq!(decode_pg_numeric_bytes(&postgres_numeric_binary(0, 0x0000, 0, &[])).as_deref(), Some("0"));
        assert_eq!(decode_pg_numeric_bytes(&postgres_numeric_binary(0, 0x0000, 2, &[])).as_deref(), Some("0.00"));
        assert_eq!(
            decode_pg_numeric_bytes(&postgres_numeric_binary(1, 0x0000, 4, &[1, 2345, 6789])).as_deref(),
            Some("12345.6789")
        );
        assert_eq!(
            decode_pg_numeric_bytes(&postgres_numeric_binary(-1, 0x4000, 7, &[12, 3000])).as_deref(),
            Some("-0.0012300")
        );

        let tiny = decode_pg_numeric_bytes(&postgres_numeric_binary(-77, 0x0000, 307, &[10])).unwrap();
        assert_eq!(tiny, format!("0.{}1", "0".repeat(306)));
        assert_eq!(tiny.len(), 309);

        let mut huge_digits = vec![9];
        huge_digits.extend(std::iter::repeat_n(9999, 77));
        let huge = "9".repeat(309);
        assert_eq!(
            decode_pg_numeric_bytes(&postgres_numeric_binary(77, 0x0000, 0, &huge_digits)).as_deref(),
            Some(huge.as_str())
        );

        let decoded = PgNumeric::from_sql(&Type::NUMERIC, &postgres_numeric_binary(-77, 0x0000, 307, &[10])).unwrap();
        assert_eq!(decoded.0, tiny);
        assert!(PgNumeric::accepts(&Type::NUMERIC));
        assert!(!PgNumeric::accepts(&Type::INT8));

        let array_raw = postgres_numeric_array_binary(&[
            Some(postgres_numeric_binary(-77, 0x0000, 307, &[10])),
            None,
            Some(postgres_numeric_binary(77, 0x0000, 0, &huge_digits)),
        ]);
        let array = Vec::<Option<PgNumeric>>::from_sql(&Type::NUMERIC_ARRAY, &array_raw).unwrap();
        assert_eq!(
            array.into_iter().map(|value| value.map(|value| value.0)).collect::<Vec<_>>(),
            vec![Some(tiny), None, Some(huge)]
        );
    }

    #[test]
    fn postgres_numeric_binary_values_preserve_special_values_and_reject_malformed_payloads() {
        assert_eq!(decode_pg_numeric_bytes(&postgres_numeric_binary(0, 0xC000, 0, &[])).as_deref(), Some("NaN"));
        assert_eq!(decode_pg_numeric_bytes(&postgres_numeric_binary(0, 0xD000, 0, &[])).as_deref(), Some("Infinity"));
        assert_eq!(decode_pg_numeric_bytes(&postgres_numeric_binary(0, 0xF000, 0, &[])).as_deref(), Some("-Infinity"));
        assert!(decode_pg_numeric_bytes(&[]).is_none());
        assert!(decode_pg_numeric_bytes(&postgres_numeric_binary(0, 0x8000, 0, &[])).is_none());
        assert!(decode_pg_numeric_bytes(&postgres_numeric_binary(0, 0x0000, 0, &[10_000])).is_none());

        let mut trailing_bytes = postgres_numeric_binary(0, 0x0000, 0, &[1]);
        trailing_bytes.push(0);
        assert!(decode_pg_numeric_bytes(&trailing_bytes).is_none());
    }

    #[test]
    fn postgres_money_binary_values_are_decoded_with_two_decimal_places() {
        assert_eq!(format_pg_money(12345), "123.45");
        assert_eq!(format_pg_money(-5), "-0.05");
        assert_eq!(format_pg_money(0), "0.00");

        let decoded = PgMoney::from_sql(&Type::MONEY, &(-12345_i64).to_be_bytes()).unwrap();
        assert_eq!(format_pg_money(decoded.0), "-123.45");
    }

    fn postgres_error_response(message: &str) -> Vec<u8> {
        let mut payload = Vec::new();
        payload.extend_from_slice(b"SERROR\0");
        payload.extend_from_slice(b"C0A000\0");
        payload.push(b'M');
        payload.extend_from_slice(message.as_bytes());
        payload.extend_from_slice(b"\0\0");

        let mut response = vec![b'E'];
        response.extend_from_slice(&u32::try_from(payload.len() + 4).unwrap().to_be_bytes());
        response.extend_from_slice(&payload);
        response.extend_from_slice(&[b'Z', 0, 0, 0, 5, b'I']);
        response
    }

    async fn serve_tls_handshake_failure_then_plaintext(listener: TcpListener) {
        let (mut tls_socket, _) = listener.accept().await.unwrap();
        let mut ssl_request = [0_u8; 8];
        tls_socket.read_exact(&mut ssl_request).await.unwrap();
        assert_eq!(ssl_request, [0, 0, 0, 8, 4, 210, 22, 47]);
        tls_socket.write_all(b"S").await.unwrap();
        tls_socket.write_all(&[0x15, 0x03, 0x03, 0, 2, 2, 40]).await.unwrap();
        drop(tls_socket);

        let (mut plain_socket, _) = listener.accept().await.unwrap();
        let startup_len = plain_socket.read_u32().await.unwrap();
        assert!(startup_len >= 8);
        let mut startup = vec![0_u8; startup_len as usize - 4];
        plain_socket.read_exact(&mut startup).await.unwrap();
        assert_eq!(&startup[..4], &[0, 3, 0, 0]);
        plain_socket
            .write_all(&[
                b'R', 0, 0, 0, 8, 0, 0, 0, 0, // AuthenticationOk
                b'K', 0, 0, 0, 12, 0, 0, 0, 1, 0, 0, 0, 2, // BackendKeyData
                b'Z', 0, 0, 0, 5, b'I', // ReadyForQuery
            ])
            .await
            .unwrap();

        let mut request = [0_u8; 1024];
        let read = plain_socket.read(&mut request).await.unwrap();
        assert!(read > 0, "client should issue the best-effort identity query");
        plain_socket.write_all(&postgres_error_response("identity probe unavailable")).await.unwrap();
    }

    fn tls12_rsa_certificate_acceptor(cipher_list: &str) -> (SslAcceptor, Vec<u8>) {
        let key = PKey::from_rsa(Rsa::generate(2048).unwrap()).unwrap();
        let mut name = X509NameBuilder::new().unwrap();
        name.append_entry_by_text("CN", "localhost").unwrap();
        let name = name.build();

        let mut serial = BigNum::new().unwrap();
        serial.rand(64, MsbOption::MAYBE_ZERO, false).unwrap();
        let serial = serial.to_asn1_integer().unwrap();
        let mut certificate = X509::builder().unwrap();
        certificate.set_version(2).unwrap();
        certificate.set_serial_number(&serial).unwrap();
        certificate.set_subject_name(&name).unwrap();
        certificate.set_issuer_name(&name).unwrap();
        certificate.set_pubkey(&key).unwrap();
        certificate.set_not_before(Asn1Time::days_from_now(0).unwrap().as_ref()).unwrap();
        certificate.set_not_after(Asn1Time::days_from_now(1).unwrap().as_ref()).unwrap();
        certificate.append_extension(BasicConstraints::new().critical().ca().build().unwrap()).unwrap();
        certificate
            .append_extension(KeyUsage::new().digital_signature().key_encipherment().key_cert_sign().build().unwrap())
            .unwrap();
        let subject_alt_name =
            SubjectAlternativeName::new().dns("localhost").build(&certificate.x509v3_context(None, None)).unwrap();
        certificate.append_extension(subject_alt_name).unwrap();
        certificate.sign(&key, MessageDigest::sha256()).unwrap();
        let certificate = certificate.build();
        let certificate_pem = certificate.to_pem().unwrap();

        let mut acceptor = SslAcceptor::mozilla_intermediate(SslMethod::tls_server()).unwrap();
        acceptor.set_min_proto_version(Some(SslVersion::TLS1_2)).unwrap();
        acceptor.set_max_proto_version(Some(SslVersion::TLS1_2)).unwrap();
        acceptor.set_cipher_list(cipher_list).unwrap();
        acceptor.set_private_key(&key).unwrap();
        acceptor.set_certificate(&certificate).unwrap();
        acceptor.check_private_key().unwrap();
        (acceptor.build(), certificate_pem)
    }

    async fn accept_tls12_with_acceptor(
        mut socket: tokio::net::TcpStream,
        acceptor: &SslAcceptor,
    ) -> Result<tokio_openssl::SslStream<tokio::net::TcpStream>, openssl::ssl::Error> {
        let mut ssl_request = [0_u8; 8];
        socket.read_exact(&mut ssl_request).await.unwrap();
        assert_eq!(ssl_request, [0, 0, 0, 8, 4, 210, 22, 47]);
        socket.write_all(b"S").await.unwrap();

        let ssl = Ssl::new(acceptor.context()).unwrap();
        let mut tls_socket = tokio_openssl::SslStream::new(ssl, socket).unwrap();
        Pin::new(&mut tls_socket).accept().await?;
        Ok(tls_socket)
    }

    async fn accept_tls12(
        socket: tokio::net::TcpStream,
        cipher_list: &str,
    ) -> Result<tokio_openssl::SslStream<tokio::net::TcpStream>, openssl::ssl::Error> {
        let (acceptor, _) = tls12_rsa_certificate_acceptor(cipher_list);
        accept_tls12_with_acceptor(socket, &acceptor).await
    }

    async fn authenticate_tls12_postgres(tls_socket: &mut tokio_openssl::SslStream<tokio::net::TcpStream>) {
        let startup_len = tls_socket.read_u32().await.unwrap();
        assert!(startup_len >= 8);
        let mut startup = vec![0_u8; startup_len as usize - 4];
        tls_socket.read_exact(&mut startup).await.unwrap();
        assert_eq!(&startup[..4], &[0, 3, 0, 0]);
        tls_socket
            .write_all(&[
                b'R', 0, 0, 0, 8, 0, 0, 0, 0, // AuthenticationOk
                b'K', 0, 0, 0, 12, 0, 0, 0, 1, 0, 0, 0, 2, // BackendKeyData
                b'Z', 0, 0, 0, 5, b'I', // ReadyForQuery
            ])
            .await
            .unwrap();

        let mut request = [0_u8; 1024];
        let read = tls_socket.read(&mut request).await.unwrap();
        assert!(read > 0, "client should issue the best-effort identity query");
        tls_socket.write_all(&postgres_error_response("identity probe unavailable")).await.unwrap();
    }

    async fn serve_tls12_postgres(listener: TcpListener, cipher_list: &'static str, expect_handshake: bool) {
        let (socket, _) = listener.accept().await.unwrap();
        let handshake = accept_tls12(socket, cipher_list).await;
        if !expect_handshake {
            assert!(handshake.is_err(), "rustls unexpectedly negotiated a static RSA cipher suite");
            return;
        }
        let mut tls_socket = handshake.unwrap();
        authenticate_tls12_postgres(&mut tls_socket).await;
    }

    async fn serve_tls12_postgres_with_acceptor(listener: TcpListener, acceptor: SslAcceptor, expect_handshake: bool) {
        let (socket, _) = listener.accept().await.unwrap();
        let handshake = accept_tls12_with_acceptor(socket, &acceptor).await;
        if !expect_handshake {
            assert!(handshake.is_err(), "TLS handshake unexpectedly succeeded");
            return;
        }
        let mut tls_socket = handshake.unwrap();
        authenticate_tls12_postgres(&mut tls_socket).await;
    }

    async fn serve_static_rsa_postgres_with_cancel(listener: TcpListener) {
        let (main_socket, _) = listener.accept().await.unwrap();
        let mut main_tls = accept_tls12(main_socket, "AES128-GCM-SHA256").await.unwrap();
        authenticate_tls12_postgres(&mut main_tls).await;

        let (cancel_socket, _) = listener.accept().await.unwrap();
        let mut cancel_tls = accept_tls12(cancel_socket, "AES128-GCM-SHA256").await.unwrap();
        let mut cancel_request = [0_u8; 16];
        cancel_tls.read_exact(&mut cancel_request).await.unwrap();
        assert_eq!(u32::from_be_bytes(cancel_request[0..4].try_into().unwrap()), 16);
        assert_eq!(u32::from_be_bytes(cancel_request[4..8].try_into().unwrap()), 80_877_102);
        assert_eq!(u32::from_be_bytes(cancel_request[8..12].try_into().unwrap()), 1);
        assert_eq!(u32::from_be_bytes(cancel_request[12..16].try_into().unwrap()), 2);
    }

    #[tokio::test]
    async fn postgres_prefer_retries_plaintext_after_tls_handshake_failure() {
        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
        let port = listener.local_addr().unwrap().port();
        let server = tokio::spawn(serve_tls_handshake_failure_then_plaintext(listener));
        let url = format!("postgres://postgres@127.0.0.1:{port}/postgres?sslmode=prefer");

        let result = connect_with_optional_local_timezone(&url, Duration::from_secs(2), None).await;
        assert!(result.is_ok(), "prefer mode should retry without TLS: {result:?}");
        server.await.unwrap();
    }

    #[tokio::test]
    async fn postgres_default_tls_rejects_static_rsa_key_exchange() {
        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
        let port = listener.local_addr().unwrap().port();
        let server = tokio::spawn(serve_tls12_postgres(listener, "AES128-GCM-SHA256", false));
        let url = format!("postgres://postgres@127.0.0.1:{port}/postgres?sslmode=require");

        let error = connect_with_optional_local_timezone(&url, Duration::from_secs(2), None)
            .await
            .expect_err("rustls must not negotiate static RSA key exchange");
        assert!(error.to_ascii_lowercase().contains("tls"), "{error}");
        server.await.unwrap();
    }

    #[tokio::test]
    async fn postgres_legacy_tls_connects_with_static_rsa_key_exchange() {
        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
        let port = listener.local_addr().unwrap().port();
        let server = tokio::spawn(serve_tls12_postgres(listener, "AES128-GCM-SHA256", true));
        let url = format!("postgres://postgres@127.0.0.1:{port}/postgres?sslmode=require&legacy_tls=true");

        let result = connect_with_optional_local_timezone(&url, Duration::from_secs(2), None).await;
        assert!(result.is_ok(), "legacy TLS should negotiate static RSA: {result:?}");
        server.await.unwrap();
    }

    #[tokio::test]
    async fn postgres_legacy_tls_verify_ca_uses_configured_root_without_hostname_check() {
        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
        let port = listener.local_addr().unwrap().port();
        let (acceptor, certificate_pem) = tls12_rsa_certificate_acceptor("AES128-GCM-SHA256");
        let root_dir = tempfile::tempdir().unwrap();
        let root_path = root_dir.path().join("root.pem");
        std::fs::write(&root_path, certificate_pem).unwrap();
        let root_path_text = root_path.to_string_lossy();
        let encoded_root =
            percent_encoding::utf8_percent_encode(root_path_text.as_ref(), percent_encoding::NON_ALPHANUMERIC);
        let server = tokio::spawn(serve_tls12_postgres_with_acceptor(listener, acceptor, true));
        let url = format!(
            "postgres://postgres@127.0.0.1:{port}/postgres?sslmode=verify-ca&legacy_tls=true&sslrootcert={encoded_root}"
        );

        let result = connect_with_optional_local_timezone(&url, Duration::from_secs(2), None).await;
        assert!(result.is_ok(), "verify-ca should trust the configured root without checking the host: {result:?}");
        server.await.unwrap();
    }

    #[tokio::test]
    async fn postgres_legacy_tls_verify_full_rejects_hostname_mismatch() {
        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
        let port = listener.local_addr().unwrap().port();
        let (acceptor, certificate_pem) = tls12_rsa_certificate_acceptor("AES128-GCM-SHA256");
        let root_dir = tempfile::tempdir().unwrap();
        let root_path = root_dir.path().join("root.pem");
        std::fs::write(&root_path, certificate_pem).unwrap();
        let root_path_text = root_path.to_string_lossy();
        let encoded_root =
            percent_encoding::utf8_percent_encode(root_path_text.as_ref(), percent_encoding::NON_ALPHANUMERIC);
        let server = tokio::spawn(serve_tls12_postgres_with_acceptor(listener, acceptor, false));
        let url = format!(
            "postgres://postgres@127.0.0.1:{port}/postgres?sslmode=verify-full&legacy_tls=true&sslrootcert={encoded_root}"
        );

        let error = connect_with_optional_local_timezone(&url, Duration::from_secs(2), None)
            .await
            .expect_err("verify-full must reject a certificate for another host");
        assert!(error.to_ascii_lowercase().contains("certificate"), "{error}");
        server.await.unwrap();
    }

    #[tokio::test]
    async fn postgres_default_tls_still_connects_with_ecdhe_rsa() {
        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
        let port = listener.local_addr().unwrap().port();
        let server = tokio::spawn(serve_tls12_postgres(listener, "ECDHE-RSA-AES128-GCM-SHA256", true));
        let url = format!("postgres://postgres@127.0.0.1:{port}/postgres?sslmode=require");

        let result = connect_with_optional_local_timezone(&url, Duration::from_secs(2), None).await;
        assert!(result.is_ok(), "default TLS should keep negotiating ECDHE-RSA: {result:?}");
        server.await.unwrap();
    }

    #[tokio::test]
    async fn postgres_legacy_tls_cancel_uses_static_rsa_connector() {
        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
        let port = listener.local_addr().unwrap().port();
        let server = tokio::spawn(serve_static_rsa_postgres_with_cancel(listener));
        let url = format!("postgres://postgres@127.0.0.1:{port}/postgres?sslmode=require&legacy_tls=true");

        let pool = connect_with_optional_local_timezone(&url, Duration::from_secs(2), None).await.unwrap();
        let client = pool.get().await.unwrap();
        let context = build_postgres_cancel_context(&url).unwrap();
        assert!(context.legacy_tls);
        cancel_postgres_query(client.cancel_token(), Some(&context), Duration::from_secs(2)).await;

        server.await.unwrap();
    }

    fn pg_array_binary(element_oid: u32, elements: &[Option<Vec<u8>>]) -> Vec<u8> {
        let mut raw = Vec::new();
        raw.extend_from_slice(&1_i32.to_be_bytes());
        raw.extend_from_slice(&i32::from(elements.iter().any(Option::is_none)).to_be_bytes());
        raw.extend_from_slice(&element_oid.to_be_bytes());
        raw.extend_from_slice(&(elements.len() as i32).to_be_bytes());
        raw.extend_from_slice(&1_i32.to_be_bytes());
        for element in elements {
            match element {
                Some(bytes) => {
                    raw.extend_from_slice(&(bytes.len() as i32).to_be_bytes());
                    raw.extend_from_slice(bytes);
                }
                None => raw.extend_from_slice(&(-1_i32).to_be_bytes()),
            }
        }
        raw
    }

    fn pg_jsonb_binary(value: &[u8]) -> Vec<u8> {
        let mut raw = Vec::with_capacity(value.len() + 1);
        raw.push(1);
        raw.extend_from_slice(value);
        raw
    }

    #[test]
    fn gaussdb_compatibility_mode_selects_identifier_quote() {
        for mode in ["M", "B", "mysql", " MYSQL "] {
            assert_eq!(gaussdb_identifier_quote_for_compatibility_mode(mode), Some("`"));
        }
        for mode in ["A", "PG", "ora", " PostgreSQL "] {
            assert_eq!(gaussdb_identifier_quote_for_compatibility_mode(mode), Some("\""));
        }
        assert_eq!(gaussdb_identifier_quote_for_compatibility_mode("C"), None);
        assert_eq!(gaussdb_identifier_quote_for_compatibility_mode(""), None);
    }

    fn test_query_message(message: &str) -> QueryMessage {
        QueryMessage {
            severity: "NOTICE".to_string(),
            message: message.to_string(),
            code: Some("00000".to_string()),
            detail: None,
            hint: None,
        }
    }

    #[test]
    fn postgres_connection_identity_normalizes_vendor_numeric_types_to_text() {
        assert!(POSTGRES_CONNECTION_IDENTITY_SQL.contains("pg_backend_pid()::text"));
        assert!(POSTGRES_CONNECTION_IDENTITY_SQL.contains("inet_server_port()::text"));
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a PostgreSQL-compatible database"]
    async fn postgres_connection_identity_supports_compatible_servers() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect_with_local_timezone(&url, Duration::from_secs(10), "UTC")
            .await
            .expect("connect PostgreSQL-compatible database");
        let client = pool.get().await.expect("checkout PostgreSQL-compatible database");
        let key = postgres_client_key(&client).await.expect("resolve text connection identity");

        assert!(!key.0.is_empty());
        assert!(!key.1.is_empty());
        assert!(!key.2.is_empty());
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a PostgreSQL database"]
    async fn postgres_connection_identity_preserves_notice_capture() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect_with_local_timezone(&url, Duration::from_secs(10), "UTC")
            .await
            .expect("connect PostgreSQL database");
        let client = pool.get().await.expect("checkout PostgreSQL database");

        let result = execute_query_with_max_rows_inner(
            &client,
            "DO $$ BEGIN RAISE NOTICE 'dbx notice identity regression'; END $$",
            None,
            false,
            None,
            false,
        )
        .await
        .expect("execute statement with notice");

        assert!(result.messages.iter().any(|message| message.message == "dbx notice identity regression"));
    }

    #[test]
    fn take_notices_for_key_returns_buffered_notices_and_empties_buffer() {
        let key = ("test-host".to_string(), "9000001".to_string(), "9000001".to_string());
        let buffer = Arc::new(Mutex::new(vec![test_query_message("first"), test_query_message("second")]));
        postgres_notice_buffers()
            .lock()
            .unwrap_or_else(|poisoned| poisoned.into_inner())
            .insert(key.clone(), Arc::downgrade(&buffer));

        let notices = take_notices_for_key(&key);
        assert_eq!(notices.len(), 2);
        assert_eq!(notices[0].message, "first");
        assert_eq!(notices[1].message, "second");
        assert_eq!(notices[0].severity, "NOTICE");
        assert_eq!(notices[0].code.as_deref(), Some("00000"));

        // The buffer was drained but stays registered while the connection lives.
        assert!(take_notices_for_key(&key).is_empty());
        buffer.lock().unwrap_or_else(|poisoned| poisoned.into_inner()).push(test_query_message("third"));
        let notices = take_notices_for_key(&key);
        assert_eq!(notices.len(), 1);
        assert_eq!(notices[0].message, "third");
    }

    #[test]
    fn take_notices_for_key_prunes_dead_buffers_and_misses_return_empty() {
        let live_key = ("test-host".to_string(), "9000002".to_string(), "9000002".to_string());
        let dead_key = ("test-host".to_string(), "9000003".to_string(), "9000003".to_string());
        let live = Arc::new(Mutex::new(vec![test_query_message("live")]));
        let dead = Arc::new(Mutex::new(vec![test_query_message("dead")]));
        {
            let mut buffers = postgres_notice_buffers().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
            buffers.insert(live_key.clone(), Arc::downgrade(&live));
            buffers.insert(dead_key.clone(), Arc::downgrade(&dead));
        }
        drop(dead);

        assert!(
            take_notices_for_key(&("test-host".to_string(), "9000004".to_string(), "9000004".to_string())).is_empty()
        );
        assert!(take_notices_for_key(&dead_key).is_empty());
        let buffers = postgres_notice_buffers().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
        assert!(!buffers.contains_key(&dead_key));
        assert!(buffers.contains_key(&live_key));
        drop(buffers);

        let notices = take_notices_for_key(&live_key);
        assert_eq!(notices.len(), 1);
        assert_eq!(notices[0].message, "live");
    }

    #[test]
    fn take_notices_for_key_distinguishes_same_pid_on_different_servers() {
        // Backend PIDs collide across servers; the (address, port, pid) key
        // keeps notice attribution separate.
        let key_a = ("server-a".to_string(), "5432".to_string(), "42".to_string());
        let key_b = ("server-b".to_string(), "5432".to_string(), "42".to_string());
        let buffer_a = Arc::new(Mutex::new(vec![test_query_message("from-a")]));
        let buffer_b = Arc::new(Mutex::new(vec![test_query_message("from-b")]));
        {
            let mut buffers = postgres_notice_buffers().lock().unwrap_or_else(|poisoned| poisoned.into_inner());
            buffers.insert(key_a.clone(), Arc::downgrade(&buffer_a));
            buffers.insert(key_b.clone(), Arc::downgrade(&buffer_b));
        }

        let notices_a = take_notices_for_key(&key_a);
        let notices_b = take_notices_for_key(&key_b);
        assert_eq!(notices_a.len(), 1);
        assert_eq!(notices_a[0].message, "from-a");
        assert_eq!(notices_b.len(), 1);
        assert_eq!(notices_b[0].message, "from-b");
    }

    #[test]
    fn postgres_json_arrays_decode_elements_without_jsonb_version_bytes() {
        let json_raw = pg_array_binary(
            Type::JSON.oid(),
            &[
                Some(br#"{"kind":"json"}"#.to_vec()),
                Some(br#""text""#.to_vec()),
                Some(br#"[1,true,null]"#.to_vec()),
                None,
            ],
        );
        let jsonb_raw = pg_array_binary(
            Type::JSONB.oid(),
            &[
                Some(pg_jsonb_binary(br#"{"port":10031,"type":"admin_web"}"#)),
                Some(pg_jsonb_binary(br#""quoted""#)),
                Some(pg_jsonb_binary(br#"[2,false,{"nested":true}]"#)),
                None,
            ],
        );

        let json_values = Vec::<Option<serde_json::Value>>::from_sql(&Type::JSON_ARRAY, &json_raw).unwrap();
        let jsonb_values = Vec::<Option<serde_json::Value>>::from_sql(&Type::JSONB_ARRAY, &jsonb_raw).unwrap();

        assert_eq!(
            pg_json_array_values_to_json(json_values),
            serde_json::json!([r#"{"kind":"json"}"#, r#""text""#, "[1,true,null]", null])
        );
        let decoded = pg_json_array_values_to_json(jsonb_values);
        assert_eq!(
            decoded,
            serde_json::json!([
                r#"{"port":10031,"type":"admin_web"}"#,
                r#""quoted""#,
                r#"[2,false,{"nested":true}]"#,
                null
            ])
        );
        assert!(!decoded.to_string().contains('\u{1}'));
    }

    #[test]
    fn postgres_json_array_decoder_is_limited_to_json_element_types() {
        assert!(Vec::<Option<serde_json::Value>>::accepts(&Type::JSON_ARRAY));
        assert!(Vec::<Option<serde_json::Value>>::accepts(&Type::JSONB_ARRAY));
        assert!(!Vec::<Option<serde_json::Value>>::accepts(&Type::TEXT_ARRAY));
        assert!(!Vec::<Option<serde_json::Value>>::accepts(&Type::INT4_ARRAY));
    }

    #[test]
    fn postgres_explain_analyze_uses_read_only_transaction_local_schema() {
        assert_eq!(
            postgres_read_only_transaction_setup(),
            vec![("BEGIN READ ONLY".to_string(), "explain_analyze.begin")]
        );
    }

    #[tokio::test]
    async fn postgres_explain_analyze_rolls_back_after_success_and_query_failures() {
        let rollback_calls = Cell::new(0);
        let result = run_postgres_operation_with_rollback(
            || async { Ok::<_, String>(7) },
            || async {
                rollback_calls.set(rollback_calls.get() + 1);
                Ok(())
            },
        )
        .await;
        assert_eq!(result, Ok(7));
        assert_eq!(rollback_calls.get(), 1);

        for operation_error in ["query failed", crate::query::QUERY_CANCELED, "Query timed out after 30 seconds"] {
            let rollback_calls = Cell::new(0);
            let result = run_postgres_operation_with_rollback(
                || async { Err::<(), _>(operation_error.to_string()) },
                || async {
                    rollback_calls.set(rollback_calls.get() + 1);
                    Ok(())
                },
            )
            .await;

            assert_eq!(result, Err(operation_error.to_string()));
            assert_eq!(rollback_calls.get(), 1);
        }
    }

    #[tokio::test]
    async fn postgres_explain_analyze_marks_rollback_failure_as_pool_pollution() {
        let result = run_postgres_operation_with_rollback(
            || async { Err::<(), _>("query failed".to_string()) },
            || async { Err("PostgreSQL explain_analyze.rollback timed out after 3 seconds".to_string()) },
        )
        .await;

        assert_eq!(
            result,
            Err("query failed; PostgreSQL read-only transaction cleanup failed: PostgreSQL explain_analyze.rollback timed out after 3 seconds".to_string())
        );
    }

    fn pg_interval_bytes(microseconds: i64, days: i32, months: i32) -> [u8; 16] {
        let mut raw = [0_u8; 16];
        raw[0..8].copy_from_slice(&microseconds.to_be_bytes());
        raw[8..12].copy_from_slice(&days.to_be_bytes());
        raw[12..16].copy_from_slice(&months.to_be_bytes());
        raw
    }

    #[test]
    fn postgres_interval_binary_decodes_and_formats_components() {
        let microseconds = 4 * 3_600_000_000 + 5 * 60_000_000 + 6 * 1_000_000 + 123_456;
        let interval = PgInterval::from_sql(&Type::INTERVAL, &pg_interval_bytes(microseconds, 3, 14)).unwrap();

        assert_eq!(interval, PgInterval { microseconds, days: 3, months: 14 });
        assert_eq!(format_pg_interval(interval), "1 year 2 mons 3 days 04:05:06.123456");
    }

    #[test]
    fn postgres_interval_formats_negative_mixed_and_zero_values() {
        assert_eq!(
            format_pg_interval(PgInterval { microseconds: -3_723_450_000, days: -2, months: -13 }),
            "-1 year -1 mon -2 days -01:02:03.45"
        );
        assert_eq!(
            format_pg_interval(PgInterval { microseconds: -1, days: 2, months: -1 }),
            "-1 mon 2 days -00:00:00.000001"
        );
        assert_eq!(format_pg_interval(PgInterval { microseconds: 0, days: 0, months: 0 }), "00:00:00");
    }

    #[test]
    fn postgres_interval_formats_now_minus_xact_start_shape() {
        let elapsed = PgInterval { microseconds: 123_450_000, days: 0, months: 0 };
        assert_eq!(format_pg_interval(elapsed), "00:02:03.45");
    }

    #[test]
    fn postgres_interval_rejects_invalid_binary_and_keeps_binary_protocol() {
        assert!(PgInterval::from_sql(&Type::INTERVAL, &[0; 15]).is_err());
        assert_eq!(classify_pg_type("interval"), PgColType::Interval);
        assert_eq!(classify_pg_type("_interval"), PgColType::Temporal { fallback: PgTemporalFallback::GenericArray });
        assert!(!pg_type_requires_text_protocol(&Type::INTERVAL, PgColType::Interval));
    }

    fn pg_date_range_bytes(flags: u8, lower: Option<i32>, upper: Option<i32>) -> Vec<u8> {
        let mut raw = vec![flags];
        for days in [lower, upper].into_iter().flatten() {
            raw.extend_from_slice(&4_i32.to_be_bytes());
            raw.extend_from_slice(&days.to_be_bytes());
        }
        raw
    }

    #[test]
    fn postgres_daterange_binary_decodes_reported_value() {
        let raw = pg_date_range_bytes(PG_RANGE_LOWER_INCLUSIVE, Some(9_163), Some(9_168));
        let range = PgDateRange::from_sql(&Type::DATE_RANGE, &raw).unwrap();

        assert_eq!(range.0, "[2025-02-01,2025-02-06)");
    }

    #[test]
    fn postgres_daterange_binary_handles_empty_unbounded_and_infinite_bounds() {
        assert_eq!(PgDateRange::from_sql(&Type::DATE_RANGE, &[PG_RANGE_EMPTY]).unwrap().0, "empty");
        assert_eq!(
            PgDateRange::from_sql(
                &Type::DATE_RANGE,
                &pg_date_range_bytes(PG_RANGE_UPPER_UNBOUNDED | PG_RANGE_LOWER_INCLUSIVE, Some(9_163), None),
            )
            .unwrap()
            .0,
            "[2025-02-01,)"
        );
        assert_eq!(
            PgDateRange::from_sql(
                &Type::DATE_RANGE,
                &pg_date_range_bytes(PG_RANGE_LOWER_UNBOUNDED, None, Some(9_168)),
            )
            .unwrap()
            .0,
            "(,2025-02-06)"
        );
        assert_eq!(
            PgDateRange::from_sql(
                &Type::DATE_RANGE,
                &pg_date_range_bytes(PG_RANGE_LOWER_INCLUSIVE, Some(i32::MIN), Some(i32::MAX)),
            )
            .unwrap()
            .0,
            "[-infinity,infinity)"
        );
    }

    #[test]
    fn postgres_daterange_rejects_malformed_binary_and_keeps_binary_protocol() {
        assert!(PgDateRange::from_sql(&Type::DATE_RANGE, &[]).is_err());
        assert!(PgDateRange::from_sql(&Type::DATE_RANGE, &[PG_RANGE_EMPTY, 0]).is_err());
        assert!(PgDateRange::from_sql(
            &Type::DATE_RANGE,
            &pg_date_range_bytes(PG_RANGE_LOWER_UNBOUNDED | PG_RANGE_LOWER_INCLUSIVE, None, Some(9_168)),
        )
        .is_err());
        assert!(PgDateRange::from_sql(&Type::DATE_RANGE, &[PG_RANGE_LOWER_INCLUSIVE, 0, 0, 0, 3, 0, 0, 0]).is_err());
        assert_eq!(classify_pg_type("daterange"), PgColType::DateRange);
        assert_eq!(classify_pg_type("_daterange"), PgColType::GenericArray);
        assert!(!pg_type_requires_text_protocol(&Type::DATE_RANGE, PgColType::DateRange));
    }

    #[test]
    fn postgres_custom_other_type_requires_text_protocol() {
        assert!(pg_scalar_type_requires_text_protocol(8_880, PgColType::Other));
        assert!(pg_scalar_type_requires_text_protocol(98_765, PgColType::Other));
        assert!(pg_scalar_type_requires_text_protocol(98_765, PgColType::GenericArray));
    }

    #[test]
    fn postgres_record_types_require_text_protocol() {
        assert!(pg_type_requires_text_protocol(&Type::RECORD, PgColType::Other));
        assert!(pg_type_requires_text_protocol(&Type::RECORD_ARRAY, PgColType::GenericArray));

        let dynamic_record =
            Type::new("record".to_string(), Type::RECORD.oid(), Kind::Simple, "pg_catalog".to_string());
        let dynamic_record_array =
            Type::new("_record".to_string(), Type::RECORD_ARRAY.oid(), Kind::Simple, "pg_catalog".to_string());
        assert!(pg_type_requires_text_protocol(&dynamic_record, PgColType::Other));
        assert!(pg_type_requires_text_protocol(&dynamic_record_array, PgColType::GenericArray));
    }

    #[test]
    fn postgres_reg_types_use_text_protocol_for_catalog_names() {
        // Binary reg* values are OIDs, while PostgreSQL's text output is the
        // human-readable object/type name users expect to see in the grid.
        for pg_type in [
            Type::REGPROC,
            Type::REGPROCEDURE,
            Type::REGOPER,
            Type::REGOPERATOR,
            Type::REGCLASS,
            Type::REGTYPE,
            Type::REGNAMESPACE,
            Type::REGROLE,
            Type::REGCOLLATION,
            Type::REGCONFIG,
            Type::REGDICTIONARY,
            Type::REGPROC_ARRAY,
            Type::REGPROCEDURE_ARRAY,
            Type::REGOPER_ARRAY,
            Type::REGOPERATOR_ARRAY,
            Type::REGCLASS_ARRAY,
            Type::REGTYPE_ARRAY,
            Type::REGNAMESPACE_ARRAY,
            Type::REGROLE_ARRAY,
            Type::REGCOLLATION_ARRAY,
            Type::REGCONFIG_ARRAY,
            Type::REGDICTIONARY_ARRAY,
        ] {
            assert!(pg_type_is_reg_type(&pg_type));
            assert!(pg_type_requires_text_protocol(&pg_type, PgColType::Other));
        }
    }

    #[test]
    fn postgres_enum_keeps_binary_protocol() {
        let enum_type = Type::new(
            "withdraw_btc_status".to_string(),
            98_765,
            Kind::Enum(vec!["pending".to_string(), "completed".to_string()]),
            "risk".to_string(),
        );
        let enum_array =
            Type::new("_withdraw_btc_status".to_string(), 98_766, Kind::Array(enum_type.clone()), "risk".to_string());

        assert!(!pg_type_requires_text_protocol(&enum_type, PgColType::Other));
        assert!(pg_type_requires_text_protocol(&enum_array, PgColType::GenericArray));
    }

    #[test]
    fn postgres_builtin_or_supported_type_keeps_binary_protocol() {
        assert!(!pg_type_requires_text_protocol(&Type::INT4, PgColType::Other));
        assert!(!pg_type_requires_text_protocol(&Type::VARCHAR, PgColType::Other));
        assert!(!pg_type_requires_text_protocol(&Type::INT4_ARRAY, PgColType::GenericArray));
        assert!(!pg_scalar_type_requires_text_protocol(98_765, PgColType::Vector));
        assert!(!pg_scalar_type_requires_text_protocol(98_765, PgColType::Geometry));
    }

    #[test]
    fn postgres_compatible_builtin_names_with_unknown_low_oids_require_text_protocol() {
        let compatible_date = Type::new("date".to_string(), 8_881, Kind::Simple, "pg_catalog".to_string());
        let compatible_tinyint = Type::new("tinyint".to_string(), 8_882, Kind::Simple, "pg_catalog".to_string());

        assert!(Type::from_oid(compatible_date.oid()).is_none());
        assert!(Type::from_oid(compatible_tinyint.oid()).is_none());
        assert!(pg_type_requires_text_protocol(
            &compatible_date,
            PgColType::Temporal { fallback: PgTemporalFallback::Probe }
        ));
        assert!(pg_type_requires_text_protocol(&compatible_tinyint, PgColType::Other));
    }

    #[test]
    fn postgres_query_uses_text_when_any_output_type_is_unsupported() {
        let columns =
            [(Type::INT4.oid(), PgColType::Other), (98_765, PgColType::Other), (Type::TEXT.oid(), PgColType::Other)];
        assert!(columns.into_iter().any(|(oid, col_type)| pg_scalar_type_requires_text_protocol(oid, col_type)));
    }

    #[test]
    fn postgres_text_fallback_keeps_matching_prepared_column_types() {
        let columns = vec!["payload".to_string(), "id".to_string()];
        let types = vec!["payload_type".to_string(), "int4".to_string()];
        assert_eq!(matching_pg_text_column_types(&columns, Some(types.clone())), types);
    }

    #[test]
    fn postgres_text_fallback_discards_misaligned_column_types() {
        let columns = vec!["payload".to_string(), "id".to_string()];
        let types = vec!["payload_type".to_string()];
        assert!(matching_pg_text_column_types(&columns, Some(types)).is_empty());
        assert!(matching_pg_text_column_types(&columns, None).is_empty());
    }

    #[test]
    fn postgres_query_search_path_preserves_public_after_catalog() {
        assert_eq!(
            postgres_set_search_path_sql("application", PostgresSearchPathContext::Query),
            "SET search_path TO \"application\", pg_catalog, public"
        );
    }

    #[test]
    fn postgres_transaction_search_paths_prioritize_selected_schema() {
        assert_eq!(
            postgres_set_search_path_sql("application", PostgresSearchPathContext::Transaction),
            "SET search_path TO \"application\", pg_catalog"
        );
        assert_eq!(
            postgres_set_search_path_sql("application", PostgresSearchPathContext::LocalTransaction),
            "SET LOCAL search_path TO \"application\", pg_catalog"
        );
        assert_eq!(
            postgres_set_search_path_sql("application", PostgresSearchPathContext::LocalQueryTransaction),
            "SET LOCAL search_path TO \"application\", pg_catalog, public"
        );
    }

    #[test]
    fn postgres_search_path_safely_quotes_selected_schema() {
        assert_eq!(
            postgres_set_search_path_sql("tenant\"; RESET search_path; --", PostgresSearchPathContext::Query,),
            "SET search_path TO \"tenant\"\"; RESET search_path; --\", pg_catalog, public"
        );
    }

    #[test]
    fn postgres_single_schema_search_path_preserves_scope_and_quoting() {
        assert_eq!(
            postgres_set_single_schema_search_path_sql("application", PostgresSearchPathContext::Query),
            "SET search_path TO \"application\""
        );
        assert_eq!(
            postgres_set_single_schema_search_path_sql("application", PostgresSearchPathContext::Transaction),
            "SET search_path TO \"application\""
        );
        assert_eq!(
            postgres_set_single_schema_search_path_sql(
                "tenant\"; RESET search_path; --",
                PostgresSearchPathContext::LocalTransaction,
            ),
            "SET LOCAL search_path TO \"tenant\"\"; RESET search_path; --\""
        );
        assert_eq!(
            postgres_set_single_schema_search_path_sql("application", PostgresSearchPathContext::LocalQueryTransaction),
            "SET LOCAL search_path TO \"application\""
        );
    }

    #[test]
    fn postgres_search_path_keeps_the_configured_path_when_selected_schema_is_first() {
        let baseline = PostgresSearchPathBaseline {
            configured: "application, extensions, public".to_string(),
            first_resolved_schema: Some("application".to_string()),
            has_explicit_pg_catalog: false,
        };
        assert_eq!(
            postgres_set_preserved_search_path_sql("application", PostgresSearchPathContext::Query, &baseline),
            "SET search_path TO application, extensions, public, pg_catalog"
        );
    }

    #[test]
    fn postgres_search_path_prepends_selected_schema_without_dropping_configured_items() {
        let baseline = PostgresSearchPathBaseline {
            configured: "\"$user\", extensions, public".to_string(),
            first_resolved_schema: Some("public".to_string()),
            has_explicit_pg_catalog: false,
        };
        assert_eq!(
            postgres_set_preserved_search_path_sql("application", PostgresSearchPathContext::Query, &baseline),
            "SET search_path TO \"application\", \"$user\", extensions, public, pg_catalog"
        );
        assert_eq!(
            postgres_set_preserved_search_path_sql(
                "application",
                PostgresSearchPathContext::LocalQueryTransaction,
                &baseline,
            ),
            "SET LOCAL search_path TO \"application\", \"$user\", extensions, public, pg_catalog"
        );
    }

    #[test]
    fn postgres_search_path_keeps_explicit_pg_catalog_position() {
        let baseline = PostgresSearchPathBaseline {
            configured: "extensions, pg_catalog, public".to_string(),
            first_resolved_schema: Some("extensions".to_string()),
            has_explicit_pg_catalog: true,
        };
        assert_eq!(
            postgres_set_preserved_search_path_sql("application", PostgresSearchPathContext::Query, &baseline),
            "SET search_path TO \"application\", extensions, pg_catalog, public"
        );
    }

    #[test]
    fn postgres_single_schema_fallback_only_matches_compatible_server_error() {
        assert!(postgres_requires_single_schema_search_path(
            "ERROR: Hologres does not support search_path with multiple names: admaterial."
        ));
        assert!(!postgres_requires_single_schema_search_path("ERROR: permission denied for schema admaterial"));
    }

    #[test]
    fn postgres_statement_returns_rows_for_returning_dml_only() {
        for sql in [
            "INSERT INTO users (id) VALUES (1) RETURNING id",
            "UPDATE users SET name = 'Ada' RETURNING id, name",
            "DELETE FROM users WHERE id = 1 RETURNING id",
            "MERGE INTO users AS target USING updates AS source ON target.id = source.id WHEN MATCHED THEN UPDATE SET name = source.name RETURNING target.id",
            "WITH removed AS (DELETE FROM users WHERE id = 1 RETURNING id) SELECT * FROM removed",
        ] {
            assert!(postgres_statement_returns_rows(sql), "expected result rows for: {sql}");
        }

        for sql in [
            "INSERT INTO users (id) VALUES (1)",
            "UPDATE users SET name = 'Ada'",
            "DELETE FROM users WHERE id = 1",
            "MERGE INTO users AS target USING updates AS source ON target.id = source.id WHEN MATCHED THEN UPDATE SET name = source.name",
            "INSERT INTO users (note) VALUES ('RETURNING is text')",
        ] {
            assert!(!postgres_statement_returns_rows(sql), "expected command result for: {sql}");
        }
    }

    #[test]
    fn cte_wrapped_dml_parses_as_query_body() {
        let statements = Parser::parse_sql(
            &PostgreSqlDialect {},
            "WITH cte AS (SELECT id FROM t) UPDATE t SET x = 1 WHERE id IN (SELECT id FROM cte)",
        )
        .expect("CTE-wrapped UPDATE should parse");
        let [Statement::Query(query)] = statements.as_slice() else {
            panic!("expected a single Statement::Query, got: {statements:?}");
        };
        assert!(query.with.is_some(), "expected the CTE to be attached to the query");
        assert!(
            matches!(postgres_query_body_dml(&query.body), Some(Statement::Update(_))),
            "expected an UPDATE body, got: {:?}",
            query.body
        );
    }

    #[test]
    fn postgres_statement_returns_rows_for_cte_wrapped_dml() {
        for sql in [
            "WITH cte AS (SELECT id FROM t) SELECT * FROM cte",
            "WITH cte AS (SELECT id FROM t) UPDATE t SET x = 1 WHERE id IN (SELECT id FROM cte) RETURNING id",
            "WITH cte AS (SELECT id FROM t) DELETE FROM t WHERE id IN (SELECT id FROM cte) RETURNING id",
            "WITH cte AS (SELECT id FROM t) INSERT INTO u (id) SELECT id FROM cte RETURNING id",
            // Not parseable by sqlparser: keep assuming a CTE query returns rows.
            "WITH RECURSIVE cte AS MATERIALIZED (SELECT 1) SELECT * FROM cte",
        ] {
            assert!(postgres_statement_returns_rows(sql), "expected result rows for: {sql}");
        }

        for sql in [
            "WITH cte AS (SELECT id FROM t) UPDATE t SET x = 1 WHERE id IN (SELECT id FROM cte)",
            "WITH cte AS (SELECT id FROM t) DELETE FROM t WHERE id IN (SELECT id FROM cte)",
            "WITH cte AS (SELECT id FROM t) INSERT INTO u (id) SELECT id FROM cte",
            "  with cte as (select id from t)\n  update t set x = 1 where id in (select id from cte)  ",
        ] {
            assert!(!postgres_statement_returns_rows(sql), "expected command result for: {sql}");
        }
    }

    #[test]
    fn database_list_does_not_collect_storage_usage() {
        assert!(list_databases_sql().contains("pg_database"));
        assert!(!list_databases_sql().contains("pg_database_size"));
    }

    #[test]
    fn database_storage_is_scoped_and_permission_guarded() {
        let sql = database_storage_sql();
        assert!(sql.contains("d.datname = ANY($1::text[])"));
        assert!(sql.contains("has_database_privilege"));
        assert!(sql.contains("pg_read_all_stats"));
        assert!(sql.contains("pg_database_size"));
        assert!(sql.contains("ELSE NULL"));
    }

    #[test]
    fn classify_pg_type_covers_all_dispatch_branches() {
        assert_eq!(classify_pg_type("bytea"), PgColType::Bytea);
        assert_eq!(classify_pg_type("json"), PgColType::Json);
        assert_eq!(classify_pg_type("JSONB"), PgColType::Json);
        assert_eq!(classify_pg_type("bool"), PgColType::Bool);
        assert_eq!(classify_pg_type("point"), PgColType::Point);
        assert_eq!(classify_pg_type("timestamp"), PgColType::Temporal { fallback: PgTemporalFallback::Probe });
        assert_eq!(classify_pg_type("timestamptz"), PgColType::Temporal { fallback: PgTemporalFallback::Probe });
        assert_eq!(classify_pg_type("date"), PgColType::Temporal { fallback: PgTemporalFallback::Probe });
        assert_eq!(classify_pg_type("time"), PgColType::Temporal { fallback: PgTemporalFallback::Probe });
        assert_eq!(classify_pg_type("timetz"), PgColType::Temporal { fallback: PgTemporalFallback::Probe });
        assert_eq!(classify_pg_type("interval"), PgColType::Interval);
        // 时间数组类型名在原实现中先进时间分支、解码失败后落到通用数组分支
        assert_eq!(classify_pg_type("_timestamp"), PgColType::Temporal { fallback: PgTemporalFallback::GenericArray });
        assert_eq!(classify_pg_type("_interval"), PgColType::Temporal { fallback: PgTemporalFallback::GenericArray });
        // 同时命中时间关键字与 VECTOR( 前缀的类型名，原实现时间解码失败后走 vector 分支
        assert_eq!(classify_pg_type("vector(timestamp)"), PgColType::Temporal { fallback: PgTemporalFallback::Vector });
        assert_eq!(classify_pg_type("numeric"), PgColType::Numeric);
        assert_eq!(classify_pg_type("money"), PgColType::Money);
        assert_eq!(classify_pg_type("uuid"), PgColType::Uuid);
        assert_eq!(classify_pg_type("inet"), PgColType::Inet { cidr: false });
        assert_eq!(classify_pg_type("cidr"), PgColType::Inet { cidr: true });
        assert_eq!(classify_pg_type("macaddr"), PgColType::MacAddr);
        assert_eq!(classify_pg_type("macaddr8"), PgColType::MacAddr);
        assert_eq!(classify_pg_type("bit"), PgColType::BitString);
        assert_eq!(classify_pg_type("varbit"), PgColType::BitString);
        assert_eq!(classify_pg_type("tsvector"), PgColType::TsVector);
        assert_eq!(classify_pg_type("oid"), PgColType::SystemU32);
        assert_eq!(classify_pg_type("xid"), PgColType::SystemU32);
        assert_eq!(classify_pg_type("_inet"), PgColType::InetArray { cidr: false });
        assert_eq!(classify_pg_type("_cidr"), PgColType::InetArray { cidr: true });
        assert_eq!(classify_pg_type("_macaddr"), PgColType::MacAddrArray);
        assert_eq!(classify_pg_type("_bit"), PgColType::BitStringArray);
        assert_eq!(classify_pg_type("_varbit"), PgColType::BitStringArray);
        assert_eq!(classify_pg_type("_int4"), PgColType::GenericArray);
        assert_eq!(classify_pg_type("_time"), PgColType::GenericArray);
        assert_eq!(classify_pg_type("vector"), PgColType::Vector);
        assert_eq!(classify_pg_type("vector(3)"), PgColType::Vector);
        assert_eq!(classify_pg_type("geometry"), PgColType::Geometry);
        assert_eq!(classify_pg_type("geography"), PgColType::Geometry);
        assert_eq!(classify_pg_type("int4"), PgColType::Other);
        assert_eq!(classify_pg_type("varchar"), PgColType::Other);
        assert_eq!(classify_pg_type(""), PgColType::Other);
    }

    #[test]
    fn postgres_text_spatial_value_separates_srid_from_wkt() {
        assert_eq!(
            pg_text_fallback_value("SRID=4326;POINT(1 2)", Some(PgColType::Geometry)),
            (serde_json::json!("POINT(1 2)"), Some(4326))
        );
        assert_eq!(
            pg_text_fallback_value("SRID=0;POINT(1 2)", Some(PgColType::Geometry)),
            (serde_json::json!("POINT(1 2)"), None)
        );
        assert_eq!(
            pg_text_fallback_value("POINT(1 2)", Some(PgColType::Geometry)),
            (serde_json::json!("POINT(1 2)"), None)
        );
    }

    #[test]
    fn postgres_text_spatial_value_decodes_hex_ewkb() {
        let ewkb = "0101000020E6100000000000000000F03F0000000000000040";
        for value in [ewkb.to_string(), format!("0x{ewkb}"), format!("\\x{ewkb}")] {
            assert_eq!(
                pg_text_fallback_value(&value, Some(PgColType::Geometry)),
                (serde_json::json!("POINT(1 2)"), Some(4326))
            );
            assert_eq!(pg_text_fallback_value(&value, None), (serde_json::json!("POINT(1 2)"), Some(4326)));
        }

        let srid_zero = "010100002000000000000000000000F03F0000000000000040";
        assert_eq!(pg_text_fallback_value(srid_zero, None), (serde_json::json!("POINT(1 2)"), None));
    }

    #[test]
    fn postgres_text_fallback_does_not_reinterpret_ordinary_text() {
        for value in ["SRID=abc;POINT(1 2)", "SRID=4326;not geometry", "0101-not-hex", "POINTLESS"] {
            assert_eq!(pg_text_fallback_value(value, None), (serde_json::json!(value), None));
        }
        assert_eq!(pg_text_fallback_value("SRID=4326;point(1 2)", None), (serde_json::json!("point(1 2)"), Some(4326)));
    }

    struct DockerPostgres {
        name: String,
        port: u16,
    }

    impl DockerPostgres {
        fn url(&self) -> String {
            format!("postgres://postgres:postgres@127.0.0.1:{}/postgres?sslmode=disable", self.port)
        }
    }

    impl Drop for DockerPostgres {
        fn drop(&mut self) {
            let _ = Command::new("docker").args(["rm", "-f", &self.name]).status();
        }
    }

    fn docker_ready() -> bool {
        Command::new("docker")
            .args(["version", "--format", "{{.Server.Version}}"])
            .output()
            .map(|output| output.status.success())
            .unwrap_or(false)
    }

    async fn start_docker_postgres() -> Option<DockerPostgres> {
        if !docker_ready() {
            eprintln!("skipping docker-backed postgres test because Docker is unavailable");
            return None;
        }

        let port = portpicker::pick_unused_port().expect("pick unused postgres port");
        let container = DockerPostgres { name: format!("dbx-postgres-enum-{}", uuid::Uuid::new_v4()), port };

        let status = Command::new("docker")
            .args([
                "run",
                "-d",
                "--rm",
                "--name",
                &container.name,
                "-e",
                "POSTGRES_PASSWORD=postgres",
                "-e",
                "POSTGRES_USER=postgres",
                "-e",
                "POSTGRES_DB=postgres",
                "-p",
                &format!("{port}:5432"),
                "postgres:16-alpine",
            ])
            .status()
            .expect("start docker postgres");
        assert!(status.success(), "docker run postgres container should succeed");

        let deadline = Instant::now() + Duration::from_secs(60);
        loop {
            match connect(&container.url(), Duration::from_secs(2)).await {
                Ok(pool) => {
                    drop(pool);
                    return Some(container);
                }
                Err(_) if Instant::now() < deadline => tokio::time::sleep(Duration::from_millis(500)).await,
                Err(error) => panic!("docker postgres did not become ready: {error}"),
            }
        }
    }

    #[tokio::test]
    async fn postgres_dml_returning_preserves_result_rows() {
        let Some(container) = start_docker_postgres().await else {
            return;
        };
        let pool = connect(&container.url(), Duration::from_secs(5)).await.expect("connect postgres");

        execute_query(&pool, "CREATE TABLE dml_returning (id integer PRIMARY KEY, name text NOT NULL)")
            .await
            .expect("create table");

        let inserted = execute_query(&pool, "INSERT INTO dml_returning VALUES (1, 'alice'), (2, 'bob')")
            .await
            .expect("insert rows");
        let updated = execute_query(&pool, "UPDATE dml_returning SET name = 'bob-updated' WHERE id = 2")
            .await
            .expect("update rows");
        let deleted = execute_query(&pool, "DELETE FROM dml_returning WHERE id = 1").await.expect("delete row");
        let unmatched =
            execute_query(&pool, "UPDATE dml_returning SET name = name WHERE id = 999").await.expect("update no rows");

        assert_eq!(inserted.affected_rows, 2);
        assert_eq!(updated.affected_rows, 1);
        assert_eq!(deleted.affected_rows, 1);
        assert_eq!(unmatched.affected_rows, 0);

        let insert_returning = execute_query(&pool, "INSERT INTO dml_returning VALUES (3, 'carol') RETURNING id, name")
            .await
            .expect("insert returning");
        let update_returning =
            execute_query(&pool, "UPDATE dml_returning SET name = 'carol-updated' WHERE id = 3 RETURNING id, name")
                .await
                .expect("update returning");
        let delete_returning = execute_query(&pool, "DELETE FROM dml_returning WHERE id = 3 RETURNING id, name")
            .await
            .expect("delete returning");
        let empty_returning =
            execute_query(&pool, "UPDATE dml_returning SET name = name WHERE id = 999 RETURNING id, name")
                .await
                .expect("empty returning");

        for result in [&insert_returning, &update_returning, &delete_returning] {
            assert_eq!(result.columns, vec!["id", "name"]);
            assert_eq!(result.rows.len(), 1);
        }
        assert_eq!(insert_returning.rows[0], vec![serde_json::json!(3), serde_json::json!("carol")]);
        assert_eq!(update_returning.rows[0], vec![serde_json::json!(3), serde_json::json!("carol-updated")]);
        assert_eq!(delete_returning.rows[0], vec![serde_json::json!(3), serde_json::json!("carol-updated")]);
        assert_eq!(empty_returning.columns, vec!["id", "name"]);
        assert!(empty_returning.rows.is_empty());
    }

    async fn assert_postgres_18(pool: &Pool) {
        let version = execute_query(pool, "SHOW server_version_num").await.expect("query PostgreSQL version");
        let version_num = version.rows[0][0]
            .as_str()
            .expect("server_version_num should be text")
            .parse::<u32>()
            .expect("server_version_num should be numeric");
        assert!((180_000..190_000).contains(&version_num), "expected PostgreSQL 18, got {version_num}");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL 18 database"]
    async fn postgres_custom_composite_result_uses_server_text_output() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        assert_postgres_18(&pool).await;
        let schema = format!("dbx_custom_text_{}", uuid::Uuid::new_v4().simple());
        let schema_ident = pg_quote_ident(&schema);
        let payload_type = format!("{schema_ident}.payload");
        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");
        let exercise = async {
            execute_query(&pool, &format!("CREATE TYPE {payload_type} AS (id integer, label text)")).await?;
            let custom =
                execute_query(&pool, &format!("SELECT ROW(7, 'alpha')::{payload_type} AS payload, 42::int4 AS id"))
                    .await?;
            let builtin = execute_query(&pool, "SELECT 42::int4 AS id").await?;
            Ok::<_, String>((custom, builtin))
        }
        .await;

        let cleanup = execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE")).await;
        cleanup.expect("drop schema");
        let (custom, builtin) = exercise.expect("exercise custom composite fallback");

        assert_eq!(custom.columns, vec!["payload", "id"]);
        assert_eq!(custom.column_types, vec!["payload", "int4"]);
        assert_eq!(custom.rows[0][0], serde_json::Value::String("(7,alpha)".to_string()));
        assert_eq!(custom.rows[0][1], serde_json::Value::String("42".to_string()));
        assert!(!custom.rows[0][0].as_str().unwrap().chars().any(char::is_control));
        assert_eq!(builtin.column_types, vec!["int4"]);
        assert_eq!(builtin.rows[0][0], serde_json::Value::Number(42.into()));
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL 18 database"]
    async fn postgres_custom_type_arrays_and_exports_use_server_text_output() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        assert_postgres_18(&pool).await;
        let schema = format!("dbx_custom_array_{}", uuid::Uuid::new_v4().simple());
        let schema_ident = pg_quote_ident(&schema);
        let payload_type = format!("{schema_ident}.payload");
        let mood_type = format!("{schema_ident}.mood");
        let score_type = format!("{schema_ident}.positive_int");
        let underscore_scalar_type = format!("{schema_ident}._hidden");
        let vector_named_enum_type = format!("{schema_ident}.vector");
        let table = format!("{schema_ident}.custom_arrays");
        let select_sql = format!("SELECT payloads, moods, scores FROM {table}");
        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");

        let exercise = async {
            execute_query(&pool, &format!("CREATE TYPE {payload_type} AS (id integer, label text)")).await?;
            execute_query(&pool, &format!("CREATE TYPE {mood_type} AS ENUM ('ready', 'done')")).await?;
            execute_query(&pool, &format!("CREATE DOMAIN {score_type} AS integer CHECK (VALUE > 0)")).await?;
            execute_query(&pool, &format!("CREATE TYPE {underscore_scalar_type} AS ENUM ('secret')")).await?;
            execute_query(&pool, &format!("CREATE TYPE {vector_named_enum_type} AS ENUM ('label')")).await?;
            execute_query(
                &pool,
                &format!(
                    "CREATE TABLE {table} (payloads {payload_type}[], moods {mood_type}[], scores {score_type}[])"
                ),
            )
            .await?;
            execute_query(
                &pool,
                &format!(
                    "INSERT INTO {table} VALUES \
                     (ARRAY[ROW(7, 'alpha')::{payload_type}], ARRAY['ready'::{mood_type}], ARRAY[7::{score_type}])"
                ),
            )
            .await?;

            let query = execute_query(&pool, &select_sql).await?;
            let underscore_scalar =
                execute_query(&pool, &format!("SELECT 'secret'::{underscore_scalar_type} AS hidden")).await?;
            let vector_named_enum =
                execute_query(&pool, &format!("SELECT 'label'::{vector_named_enum_type} AS label")).await?;
            let client = checkout_postgres_client(&pool, None, Duration::from_secs(5)).await?;

            let mut query_export_rows = Vec::new();
            stream_select_query_inner_with_mode(
                &client,
                &select_sql,
                None,
                &mut |item| {
                    if let PostgresQueryStreamItem::Row(row) = item {
                        query_export_rows.push(row);
                    }
                    Ok(())
                },
                false,
            )
            .await?;

            let cancelled = AtomicBool::new(false);
            let mut table_export_rows = Vec::new();
            stream_query_rows_on_client(&client, &select_sql, None, &cancelled, &mut |row| {
                table_export_rows.push(row.to_vec());
                Ok(())
            })
            .await?;
            drop(client);

            Ok::<_, String>((query, underscore_scalar, vector_named_enum, query_export_rows, table_export_rows))
        }
        .await;

        let cleanup = execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE")).await;
        cleanup.expect("drop schema");
        let (query, underscore_scalar, vector_named_enum, query_export_rows, table_export_rows) =
            exercise.expect("exercise custom array fallbacks");
        let expected = vec![
            serde_json::Value::String(r#"{"(7,alpha)"}"#.to_string()),
            serde_json::Value::String("{ready}".to_string()),
            serde_json::Value::String("{7}".to_string()),
        ];

        assert_eq!(query.rows, vec![expected.clone()]);
        assert_eq!(underscore_scalar.rows, vec![vec![serde_json::Value::String("secret".to_string())]]);
        assert_eq!(vector_named_enum.rows, vec![vec![serde_json::Value::String("label".to_string())]]);
        assert_eq!(query_export_rows, vec![expected.clone()]);
        assert_eq!(table_export_rows, vec![expected]);
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_GAUSSDB_URL pointing at a writable GaussDB database"]
    async fn gaussdb_list_custom_types_excludes_relation_row_types_and_arrays() {
        let url = std::env::var("DBX_TEST_GAUSSDB_URL").expect("DBX_TEST_GAUSSDB_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect gaussdb");
        let schema = format!("dbx_types_{}", uuid::Uuid::new_v4().simple());
        let schema_ident = pg_quote_ident(&schema);
        let status_type = format!("{schema_ident}.status");
        let address_type = format!("{schema_ident}.address");
        let orders_table = format!("{schema_ident}.orders");
        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");

        let exercise = async {
            execute_query(&pool, &format!("CREATE TYPE {status_type} AS ENUM ('draft', 'published')")).await?;
            execute_query(&pool, &format!("CREATE TYPE {address_type} AS (city text, zip text)")).await?;
            execute_query(&pool, &format!("COMMENT ON TYPE {status_type} IS '订单状态'")).await?;
            execute_query(
                &pool,
                &format!("CREATE TABLE {orders_table} (id bigint, state {status_type}, ship_to {address_type})"),
            )
            .await?;
            let custom = list_objects(&pool, &schema, false, false, true).await?;
            let all = list_objects(&pool, &schema, true, true, true).await?;
            Ok::<_, String>((custom, all))
        }
        .await;

        let cleanup = execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE")).await;
        cleanup.expect("drop schema");
        let (custom, all) = exercise.expect("exercise gaussdb custom type listing");

        // GaussDB supports enum and composite user types but not domains.
        let mut type_names: Vec<&str> = custom.iter().map(|o| o.name.as_str()).collect();
        type_names.sort_unstable();
        assert_eq!(type_names, vec!["address", "status"], "custom types = {custom:?}");
        for object in &custom {
            assert_eq!(object.object_type, "TYPE");
            assert_eq!(object.schema.as_deref(), Some(schema.as_str()));
        }
        let status = custom.iter().find(|o| o.name == "status").expect("status type");
        assert_eq!(status.comment.as_deref(), Some("订单状态"), "type comment was lost: {custom:?}");

        let all_names: Vec<&str> = all.iter().map(|o| o.name.as_str()).collect();
        assert!(all_names.contains(&"orders"), "table missing from full listing: {all:?}");
        assert!(
            all_names.iter().all(|name| !name.starts_with('_')),
            "auto-generated array companions leaked into the listing: {all:?}"
        );
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_list_custom_types_excludes_relation_row_types_and_arrays() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let schema = format!("dbx_types_{}", uuid::Uuid::new_v4().simple());
        let schema_ident = pg_quote_ident(&schema);
        let status_type = format!("{schema_ident}.status");
        let email_domain = format!("{schema_ident}.email");
        let address_type = format!("{schema_ident}.address");
        let orders_table = format!("{schema_ident}.orders");
        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");

        let exercise = async {
            execute_query(&pool, &format!("CREATE TYPE {status_type} AS ENUM ('draft', 'published')")).await?;
            execute_query(&pool, &format!("CREATE DOMAIN {email_domain} AS text CHECK (VALUE ~ '.+@.+')")).await?;
            execute_query(&pool, &format!("CREATE TYPE {address_type} AS (city text, zip text)")).await?;
            execute_query(
                &pool,
                &format!("CREATE TABLE {orders_table} (id bigint, state {status_type}, ship_to {address_type})"),
            )
            .await?;
            let custom = list_objects(&pool, &schema, false, false, true).await?;
            let all = list_objects(&pool, &schema, true, true, true).await?;
            Ok::<_, String>((custom, all))
        }
        .await;

        let cleanup = execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE")).await;
        cleanup.expect("drop schema");
        let (custom, all) = exercise.expect("exercise custom type listing");

        // The type-only request returns exactly the user-created enum, domain
        // and composite type, sorted by name. The table's auto-generated row
        // type (orders) and the array companions (_status, _email, _address)
        // must stay out.
        let mut type_names: Vec<&str> = custom.iter().map(|o| o.name.as_str()).collect();
        type_names.sort_unstable();
        assert_eq!(type_names, vec!["address", "email", "status"], "custom types = {custom:?}");
        for object in &custom {
            assert_eq!(object.object_type, "TYPE");
            assert_eq!(object.schema.as_deref(), Some(schema.as_str()));
        }

        let all_names: Vec<&str> = all.iter().map(|o| o.name.as_str()).collect();
        assert!(all_names.contains(&"orders"), "table missing from full listing: {all:?}");
        assert!(
            all_names.iter().all(|name| !name.starts_with('_')),
            "auto-generated array companions leaked into the listing: {all:?}"
        );
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_custom_type_details_reads_members_and_ddl() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let schema = format!("dbx_details_{}", uuid::Uuid::new_v4().simple());
        let schema_ident = pg_quote_ident(&schema);
        let status_type = format!("{schema_ident}.status");
        let email_domain = format!("{schema_ident}.email");
        let address_type = format!("{schema_ident}.address");
        let price_range_type = format!("{schema_ident}.price_range");
        let orders_table = format!("{schema_ident}.orders");
        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");

        let exercise = async {
            execute_query(&pool, &format!("CREATE TYPE {status_type} AS ENUM ('draft', 'published', '已归档')"))
                .await?;
            execute_query(&pool, &format!("CREATE DOMAIN {email_domain} AS text DEFAULT '' CHECK (VALUE <> '')"))
                .await?;
            execute_query(&pool, &format!("CREATE TYPE {address_type} AS (city text, zip numeric(6))")).await?;
            execute_query(&pool, &format!("COMMENT ON TYPE {address_type} IS 'shipping address'")).await?;
            execute_query(&pool, &format!("COMMENT ON COLUMN {address_type}.city IS 'city name'")).await?;
            execute_query(&pool, &format!("CREATE TYPE {price_range_type} AS RANGE (subtype = numeric)")).await?;
            execute_query(
                &pool,
                &format!(
                    "CREATE TABLE {orders_table} (state {status_type}, address {address_type}, email {email_domain})"
                ),
            )
            .await?;
            let status = get_custom_type_details(&pool, &schema, "status").await?;
            let email = get_custom_type_details(&pool, &schema, "email").await?;
            let address = get_custom_type_details(&pool, &schema, "address").await?;
            let price_range = get_custom_type_details(&pool, &schema, "price_range").await?;
            let row_type_error = get_custom_type_details(&pool, &schema, "orders").await.err();
            let array_type_error = get_custom_type_details(&pool, &schema, "_status").await.err();
            Ok::<_, String>((status, email, address, price_range, row_type_error, array_type_error))
        }
        .await;

        let cleanup = execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE")).await;
        cleanup.expect("drop schema");
        let (status, email, address, price_range, row_type_error, array_type_error) =
            exercise.expect("exercise custom type details");

        assert_eq!(status.kind, CustomTypeKind::Enum);
        let enum_values: Vec<&str> = status.members.iter().map(|m| m.enum_value.as_deref().unwrap()).collect();
        assert_eq!(enum_values, vec!["draft", "published", "已归档"]);
        let status_ddl = status.ddl.expect("enum ddl");
        assert!(status_ddl.complete);
        assert!(status_ddl.sql.contains("AS ENUM ('draft', 'published', '已归档')"), "{}", status_ddl.sql);

        assert_eq!(email.kind, CustomTypeKind::Domain);
        assert_eq!(email.properties.base_type.as_deref(), Some("text"));
        assert!(email.properties.default.is_some(), "domain default was lost");
        assert!(
            email.properties.domain_constraints.iter().any(|c| c.definition.contains("VALUE")),
            "domain constraint was lost: {:?}",
            email.properties.domain_constraints
        );
        let email_ddl = email.ddl.expect("domain ddl");
        assert!(email_ddl.complete);
        assert!(email_ddl.sql.contains("CREATE DOMAIN"), "{}", email_ddl.sql);

        assert_eq!(address.kind, CustomTypeKind::Composite);
        assert_eq!(address.comment.as_deref(), Some("shipping address"));
        assert_eq!(address.members.len(), 2);
        assert_eq!(address.members[0].name, "city");
        assert_eq!(address.members[0].data_type, "text");
        assert_eq!(address.members[0].comment.as_deref(), Some("city name"));
        assert_eq!(address.members[1].name, "zip");
        // format_type normalizes numeric(6) to numeric(6,0) on real servers.
        assert_eq!(address.members[1].data_type, "numeric(6,0)");
        let address_ddl = address.ddl.expect("composite ddl");
        assert!(address_ddl.complete);
        assert!(address_ddl.sql.contains("\"city\" text"), "{}", address_ddl.sql);
        assert!(
            address_ddl.sql.contains(&format!("COMMENT ON COLUMN \"{schema}\".\"address\".\"city\" IS 'city name'")),
            "{}",
            address_ddl.sql
        );

        assert_eq!(price_range.kind, CustomTypeKind::Range);
        assert_eq!(price_range.properties.range_subtype.as_deref(), Some("numeric"));
        let range_ddl = price_range.ddl.expect("range ddl");
        assert!(range_ddl.complete);
        assert!(range_ddl.sql.contains("subtype = numeric"), "{}", range_ddl.sql);

        // Relation row types and array companions must be rejected, never
        // presented as independent composite types.
        assert!(row_type_error.is_some(), "relation row type must be rejected");
        assert!(array_type_error.is_some(), "array companion must be rejected");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_GAUSSDB_URL pointing at a writable GaussDB database"]
    async fn gaussdb_custom_type_details_reads_members_and_ddl() {
        let url = std::env::var("DBX_TEST_GAUSSDB_URL").expect("DBX_TEST_GAUSSDB_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect gaussdb");
        let schema = format!("dbx_gdetails_{}", uuid::Uuid::new_v4().simple());
        let schema_ident = pg_quote_ident(&schema);
        let status_type = format!("{schema_ident}.status");
        let address_type = format!("{schema_ident}.address");
        let price_range_type = format!("{schema_ident}.price_range");
        let orders_table = format!("{schema_ident}.orders");
        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");

        let exercise = async {
            execute_query(&pool, &format!("CREATE TYPE {status_type} AS ENUM ('draft', 'published')")).await?;
            execute_query(&pool, &format!("CREATE TYPE {address_type} AS (city text, zip numeric(6))")).await?;
            execute_query(&pool, &format!("COMMENT ON COLUMN {address_type}.city IS 'city name'")).await?;
            execute_query(&pool, &format!("CREATE TYPE {price_range_type} AS RANGE (subtype = numeric)")).await?;
            execute_query(&pool, &format!("CREATE TABLE {orders_table} (state {status_type}, address {address_type})"))
                .await?;
            let status = get_custom_type_details(&pool, &schema, "status").await?;
            let address = get_custom_type_details(&pool, &schema, "address").await?;
            let price_range = get_custom_type_details(&pool, &schema, "price_range").await?;
            let row_type_error = get_custom_type_details(&pool, &schema, "orders").await.err();
            let array_type_error = get_custom_type_details(&pool, &schema, "_status").await.err();
            Ok::<_, String>((status, address, price_range, row_type_error, array_type_error))
        }
        .await;

        let cleanup = execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE")).await;
        if let Err(error) = cleanup {
            // GaussDB range types own system canonical functions, so CASCADE
            // cleanup is subject to instance privileges; that is a server
            // limitation, not a details-query failure.
            eprintln!("[gaussdb][custom-type-details][cleanup] {error}");
        }
        let (status, address, price_range, row_type_error, array_type_error) =
            exercise.expect("exercise gaussdb custom type details");

        assert_eq!(status.kind, CustomTypeKind::Enum);
        let enum_values: Vec<&str> = status.members.iter().map(|m| m.enum_value.as_deref().unwrap()).collect();
        assert_eq!(enum_values, vec!["draft", "published"]);
        let status_ddl = status.ddl.expect("enum ddl");
        assert!(status_ddl.complete);
        assert!(status_ddl.sql.contains("AS ENUM ('draft', 'published')"), "{}", status_ddl.sql);

        assert_eq!(address.kind, CustomTypeKind::Composite);
        assert_eq!(address.members.len(), 2);
        assert_eq!(address.members[0].name, "city");
        assert_eq!(address.members[0].comment.as_deref(), Some("city name"));
        let address_ddl = address.ddl.expect("composite ddl");
        assert!(address_ddl.complete);
        assert!(address_ddl.sql.contains("\"city\" text"), "{}", address_ddl.sql);

        assert_eq!(price_range.kind, CustomTypeKind::Range);
        assert_eq!(price_range.properties.range_subtype.as_deref(), Some("numeric"));
        let range_ddl = price_range.ddl.expect("range ddl");
        assert!(range_ddl.complete);
        assert!(range_ddl.sql.contains("subtype = numeric"), "{}", range_ddl.sql);

        assert!(row_type_error.is_some(), "relation row type must be rejected");
        assert!(array_type_error.is_some(), "array companion must be rejected");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL 18 database"]
    async fn postgres_custom_type_fallback_refreshes_stale_cached_metadata() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool_a = connect(&url, Duration::from_secs(5)).await.expect("connect postgres pool A");
        let pool_b = connect(&url, Duration::from_secs(5)).await.expect("connect postgres pool B");
        assert_postgres_18(&pool_a).await;
        let schema = format!("dbx_custom_stale_{}", uuid::Uuid::new_v4().simple());
        let schema_ident = pg_quote_ident(&schema);
        let payload_type = format!("{schema_ident}.payload");
        let view = format!("{schema_ident}.cached_payload");
        let view_sql = format!("SELECT payload FROM {view}");
        execute_query(&pool_a, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");

        let exercise = async {
            execute_query(&pool_a, &format!("CREATE TYPE {payload_type} AS (id integer, label text)")).await?;
            execute_query(&pool_a, &format!("CREATE VIEW {view} AS SELECT ROW(7, 'alpha')::{payload_type} AS payload"))
                .await?;
            let custom = execute_query(&pool_a, &view_sql).await?;

            execute_query(&pool_b, &format!("DROP VIEW {view}")).await?;
            execute_query(&pool_b, &format!("CREATE VIEW {view} AS SELECT 42::int4 AS payload")).await?;
            let builtin = execute_query(&pool_a, &view_sql).await?;
            Ok::<_, String>((custom, builtin))
        }
        .await;

        let cleanup = execute_query(&pool_a, &format!("DROP SCHEMA {schema_ident} CASCADE")).await;
        cleanup.expect("drop schema");
        let (custom, builtin) = exercise.expect("exercise stale cached custom metadata");
        assert_eq!(custom.column_types, vec!["payload"]);
        assert_eq!(custom.rows[0][0], serde_json::Value::String("(7,alpha)".to_string()));
        assert_eq!(builtin.column_types, vec!["int4"]);
        assert_eq!(builtin.rows[0][0], serde_json::Value::Number(42.into()));
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL 18 database"]
    async fn postgres_text_fallback_stops_before_late_row_error_at_limit() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        assert_postgres_18(&pool).await;
        let schema = format!("dbx_custom_limit_{}", uuid::Uuid::new_v4().simple());
        let schema_ident = pg_quote_ident(&schema);
        let payload_type = format!("{schema_ident}.payload");
        let fail_after_two = format!("{schema_ident}.fail_after_two");
        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");

        let exercise = async {
            execute_query(&pool, &format!("CREATE TYPE {payload_type} AS (id integer)")).await?;
            execute_query(
                &pool,
                &format!(
                    "CREATE FUNCTION {fail_after_two}(i integer) RETURNS integer LANGUAGE plpgsql AS $$ \
                     BEGIN IF i >= 2 THEN RAISE EXCEPTION 'late row failure'; END IF; RETURN i; END $$"
                ),
            )
            .await?;
            let client = checkout_postgres_client(&pool, None, Duration::from_secs(5)).await?;
            let custom_sql = format!(
                "SELECT ROW({fail_after_two}(i))::{payload_type} AS payload \
                 FROM generate_series(1, 2) AS series(i)"
            );
            let limited = execute_select_query(&client, &custom_sql, Instant::now(), 1).await;
            let cancelled = AtomicBool::new(false);
            let mut exported_rows = Vec::new();
            let exported = stream_query_rows_on_client(&client, &custom_sql, Some(1), &cancelled, &mut |row| {
                exported_rows.push(row.to_vec());
                Ok(())
            })
            .await;
            let recovery = execute_select_query(&client, "SELECT 1::int4 AS value", Instant::now(), 1).await;
            drop(client);
            Ok::<_, String>((limited, exported, exported_rows, recovery))
        }
        .await;

        let cleanup = execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE")).await;
        cleanup.expect("drop schema");
        let (limited, exported, exported_rows, recovery) = exercise.expect("set up late row error query");
        let limited = limited.expect("query should stop before late row error");
        let exported = exported.expect("streamed export should stop before late row error");
        let recovery = recovery.expect("connection should remain reusable");
        assert_eq!(limited.column_types, vec!["payload"]);
        assert_eq!(limited.rows, vec![vec![serde_json::Value::String("(1)".to_string())]]);
        assert!(limited.truncated);
        assert_eq!(exported, 1);
        assert_eq!(exported_rows, vec![vec![serde_json::Value::String("(1)".to_string())]]);
        assert_eq!(recovery.column_types, vec!["int4"]);
        assert_eq!(recovery.rows[0][0], serde_json::Value::Number(1.into()));
    }

    fn state_enum_values(columns: &[ColumnInfo]) -> Option<Vec<String>> {
        columns.iter().find(|column| column.name == "state").and_then(|column| column.enum_values.clone())
    }

    // --- pg_quote_ident ---

    #[test]
    fn pg_system_u32_decodes_catalog_integer_types() {
        let raw = 42_u32.to_be_bytes();

        assert_eq!(u32::from_sql(&Type::OID, &raw).unwrap(), 42);
        assert_eq!(PgSystemU32::from_sql(&Type::XID, &raw).unwrap().0, 42);
        assert_eq!(PgSystemU32::from_sql(&Type::CID, &raw).unwrap().0, 42);
        assert!(u32::accepts(&Type::OID));
        assert!(PgSystemU32::accepts(&Type::XID));
        assert!(PgSystemU32::accepts(&Type::CID));
        assert!(!PgSystemU32::accepts(&Type::OID));
        assert!(!PgSystemU32::accepts(&Type::INT4));
    }

    #[test]
    fn pg_point_decodes_binary_coordinates_as_text() {
        let mut raw = Vec::new();
        raw.extend_from_slice(&(-194.0_f64).to_be_bytes());
        raw.extend_from_slice(&53.0_f64.to_be_bytes());

        let point = PgPoint::from_sql(&Type::POINT, &raw).unwrap();

        assert_eq!(point, PgPoint { x: -194.0, y: 53.0 });
        assert_eq!(format_pg_point(point), "(-194,53)");
        assert_eq!(format_pg_point(PgPoint { x: f64::NEG_INFINITY, y: f64::INFINITY }), "(-Infinity,Infinity)");
        assert!(PgPoint::from_sql(&Type::POINT, &[0; 15]).is_err());
        assert!(PgPoint::accepts(&Type::POINT));
        assert!(!PgPoint::accepts(&Type::BYTEA));
    }

    #[test]
    fn pg_any_string_accepts_all_types_and_decodes_utf8() {
        // Accepts any type — built-in, custom enum OIDs, domains, etc.
        assert!(PgAnyString::accepts(&Type::TEXT));
        assert!(PgAnyString::accepts(&Type::INT4));
        assert!(PgAnyString::accepts(&Type::UNKNOWN));
        assert!(PgAnyString::accepts(&Type::OID));
        assert!(PgAnyString::accepts(&Type::BOOL));

        let label = PgAnyString::from_sql(&Type::UNKNOWN, b"pending").unwrap();
        assert_eq!(label.0, "pending");

        let label = PgAnyString::from_sql(&Type::UNKNOWN, b"hello world").unwrap();
        assert_eq!(label.0, "hello world");

        // Non-UTF-8 bytes should fail gracefully
        assert!(PgAnyString::from_sql(&Type::UNKNOWN, &[0xFF, 0xFE, 0xFD]).is_err());
    }

    #[test]
    fn pg_raw_bytes_accepts_all_types_and_preserves_binary_payloads() {
        assert!(PgRawBytes::accepts(&Type::TEXT));
        assert!(PgRawBytes::accepts(&Type::UNKNOWN));
        assert!(PgRawBytes::accepts(&Type::OID));

        let raw = PgRawBytes::from_sql(&Type::UNKNOWN, &[0x01, 0xAB, 0xFF]).unwrap();
        assert_eq!(raw.0, vec![0x01, 0xAB, 0xFF]);
    }

    #[test]
    fn decode_bool_bytes_handles_standard_and_gaussdb_encodings() {
        // Standard PostgreSQL binary boolean: 0x00 / 0x01
        assert_eq!(decode_bool_bytes(&[0x00]), Some(false));
        assert_eq!(decode_bool_bytes(&[0x01]), Some(true));
        // GaussDB binary boolean: ASCII 't' (0x74) / 'f' (0x66)
        assert_eq!(decode_bool_bytes(&[0x74]), Some(true));
        assert_eq!(decode_bool_bytes(&[0x66]), Some(false));
        assert_eq!(decode_bool_bytes(b"t"), Some(true));
        assert_eq!(decode_bool_bytes(b"f"), Some(false));
        assert_eq!(decode_bool_bytes(b"T"), Some(true));
        assert_eq!(decode_bool_bytes(b"F"), Some(false));
        // Unrecognized encodings return None
        assert_eq!(decode_bool_bytes(&[0x02]), None);
        assert_eq!(decode_bool_bytes(&[0x74, 0x66]), None);
        assert_eq!(decode_bool_bytes(&[]), None);
    }

    #[test]
    fn raw_gaussdb_boolean_takes_precedence_over_standard_decoder() {
        assert_eq!(decode_bool_candidates(Some(b"f"), Some(true)), Some(false));
        assert_eq!(decode_bool_candidates(Some(b"t"), Some(true)), Some(true));
        assert_eq!(decode_bool_candidates(Some(&[0x00]), Some(true)), Some(false));
        assert_eq!(decode_bool_candidates(Some(&[0x01]), Some(false)), Some(true));
        assert_eq!(decode_bool_candidates(Some(&[0x02]), Some(false)), Some(false));
    }

    #[test]
    fn postgres_foreign_keys_sql_selects_referential_actions() {
        let sql = postgres_foreign_keys_sql();

        assert!(sql.contains("pg_catalog.pg_constraint"));
        assert!(sql.contains("con.confupdtype::text AS on_update_raw"));
        assert!(sql.contains("con.confdeltype::text AS on_delete_raw"));
        assert!(sql.contains("confdeltype"));
        assert!(sql.contains("ref_n.nspname"));
        assert!(sql.contains("unnest(con.conkey) WITH ORDINALITY"));
        assert!(sql.contains("n.nspname = $1 AND c.relname = $2"));
        assert!(sql.contains("con.contype = 'f'"));
        assert!(sql.contains("NOT a.attisdropped"));
        assert!(sql.contains("JOIN LATERAL"));
        assert!(!sql.contains("information_schema"));
    }

    #[test]
    fn postgres_foreign_key_metadata_has_legacy_catalog_fallback() {
        // The compat tiers exist for pre-9.4 servers, so they must avoid WITH
        // ORDINALITY (a 9.4 feature) and pair conkey/confkey positions through
        // generate_series + plain array subscripts instead, mirroring the index
        // compat invariant.
        for compat_sql in [postgres_foreign_keys_compat_sql(), postgres_foreign_keys_for_relations_compat_sql()] {
            assert!(!compat_sql.contains("WITH ORDINALITY"));
            assert!(compat_sql.contains("generate_series"));
            assert!(compat_sql.contains("array_length(con.conkey, 1)"));
            assert!(compat_sql.contains("con.contype = 'f'"));
            assert!(compat_sql.contains("NOT a.attisdropped"));
            assert!(!compat_sql.contains("information_schema"));
        }
        // OpenGauss resolves attribute numbers in Rust, so its SQL must not
        // expand catalog arrays at all.
        let opengauss_sql = opengauss_foreign_keys_sql();
        assert!(!opengauss_sql.contains("WITH ORDINALITY"));
        assert!(!opengauss_sql.contains("unnest"));
        assert!(opengauss_sql.contains("con.conkey::text"));
        assert!(opengauss_sql.contains("con.confkey::text"));
    }

    #[test]
    fn postgres_table_dependencies_sql_batches_schema_foreign_keys() {
        let sql = postgres_table_dependencies_sql();
        let compat_sql = postgres_table_dependencies_compat_sql();

        assert!(sql.contains("pg_catalog.pg_constraint"));
        assert!(sql.contains("con.contype = 'f'"));
        assert!(sql.contains("child_schema.nspname = $1"));
        assert!(sql.contains("parent_schema.nspname = $1"));
        assert!(!sql.contains("information_schema"));
        assert!(sql.contains("pg_catalog.pg_inherits"));
        assert!(sql.contains("child.relispartition"));
        // 兼容版面向 9.x：不能引用 relispartition，但 INHERITS 边要保留
        // （旧式子表同样要先建父表）。
        assert!(!compat_sql.contains("relispartition"));
        assert!(compat_sql.contains("pg_catalog.pg_inherits"));
        assert!(compat_sql.contains("con.contype = 'f'"));
        assert!(compat_sql.contains("ORDER BY table_name, ref_table"));
    }

    #[test]
    fn decodes_tsvector_binary_output() {
        let raw = [
            0, 0, 0, 2, b'b', b'a', b'c', b'k', b'\\', b's', b'l', b'a', b's', b'h', 0, 0, 1, 0x80, 0x03, b'o', b'\'',
            b'c', b'l', b'o', b'c', b'k', 0, 0, 2, 0, 1, 0xc0, 0x02,
        ];

        assert_eq!(decode_tsvector_bytes(&raw).as_deref(), Some("'back\\\\slash':3B 'o''clock':1,2A"));
    }

    fn encode_pgvector_bytes(values: &[f32]) -> Vec<u8> {
        let dims = u16::try_from(values.len()).expect("dim fits u16");
        let mut raw = Vec::with_capacity(4 + values.len() * 4);
        raw.extend_from_slice(&dims.to_be_bytes());
        raw.extend_from_slice(&0u16.to_be_bytes());
        for value in values {
            raw.extend_from_slice(&value.to_be_bytes());
        }
        raw
    }

    #[test]
    fn decodes_pgvector_binary_output() {
        let values = [0.1f32, -2.5f32, 1.2345679e-5f32];
        let decoded = decode_pgvector_bytes(&encode_pgvector_bytes(&values)).expect("decode vector");
        assert_eq!(decoded, values);
    }

    #[test]
    fn pgvector_element_number_round_trips_full_f32_precision() {
        let values = [0.1f32, 0.12345679f32, 1.2345679e-5f32, -0.00012345679f32, 1.2345678f32, 1e20f32];

        for value in values {
            let json = pg_vector_element_number(value);
            let text = json.to_string();
            let restored: f32 = text.parse().expect("json number parses as f32");
            let rounded_six = ((value as f64 * 1_000_000.0).round() / 1_000_000.0) as f32;

            // Display text must recover the exact stored float4 bits.
            assert_eq!(restored, value, "lost f32 precision for {value} -> {text}");
            // Fixed 6-decimal rounding is what caused #3931; reject that path when it differs.
            if rounded_six != value {
                assert_ne!(restored, rounded_six, "still clamped to 6 decimals for {value}");
            }
        }
    }

    #[test]
    fn pgvector_binary_to_json_preserves_component_precision() {
        let values = [0.12345679f32, 1.2345679e-5f32, -2.5f32];
        let decoded = decode_pgvector_bytes(&encode_pgvector_bytes(&values)).expect("decode vector");
        let json = serde_json::Value::Array(decoded.into_iter().map(pg_vector_element_number).collect());
        let arr = json.as_array().expect("vector json array");

        assert_eq!(arr.len(), values.len());
        for (component, expected) in arr.iter().zip(values) {
            let restored: f32 = component.to_string().parse().expect("component parses as f32");
            assert_eq!(restored, expected);
        }
    }

    fn decode_hex(hex: &str) -> Vec<u8> {
        assert_eq!(hex.len() % 2, 0, "hex input must have an even number of chars");
        (0..hex.len()).step_by(2).map(|idx| u8::from_str_radix(&hex[idx..idx + 2], 16).unwrap()).collect()
    }

    #[test]
    fn decodes_postgres_inet_binary_output() {
        assert_eq!(
            decode_pg_network_address_bytes(&decode_hex("02200004c0a8010a"), false).as_deref(),
            Some("192.168.1.10")
        );
        assert_eq!(
            decode_pg_network_address_bytes(&decode_hex("0310001020010db8abcd00120000000000000001"), false).as_deref(),
            Some("2001:db8:abcd:12::1/16")
        );
        assert_eq!(
            decode_pg_network_address_bytes(&decode_hex("0340001020010db8abcd00120000000000000001"), false).as_deref(),
            Some("2001:db8:abcd:12::1/64")
        );
    }

    #[test]
    fn decodes_postgres_cidr_binary_output() {
        assert_eq!(
            decode_pg_network_address_bytes(&decode_hex("02180104c0a80100"), true).as_deref(),
            Some("192.168.1.0/24")
        );
        assert_eq!(
            decode_pg_network_address_bytes(&decode_hex("02200104c0a8010a"), true).as_deref(),
            Some("192.168.1.10/32")
        );
        assert_eq!(
            decode_pg_network_address_bytes(&decode_hex("0380011000000000000000000000000000000001"), true).as_deref(),
            Some("::1/128")
        );
    }

    #[test]
    fn rejects_invalid_postgres_network_binary_output() {
        assert_eq!(decode_pg_network_address_bytes(&[], false), None);
        assert_eq!(decode_pg_network_address_bytes(&decode_hex("04200004c0a8010a"), false), None);
        assert_eq!(decode_pg_network_address_bytes(&decode_hex("02210004c0a8010a"), false), None);
        assert_eq!(decode_pg_network_address_bytes(&decode_hex("02200004c0a801"), false), None);
    }

    #[test]
    fn decodes_postgres_macaddr_binary_output() {
        assert_eq!(decode_pg_macaddr_bytes(&decode_hex("08002b010203")).as_deref(), Some("08:00:2b:01:02:03"));
        assert_eq!(
            decode_pg_macaddr_bytes(&decode_hex("08002bfffe010203")).as_deref(),
            Some("08:00:2b:ff:fe:01:02:03")
        );
        assert_eq!(decode_pg_macaddr_bytes(&decode_hex("08002b")), None);
    }

    #[test]
    fn decodes_postgres_bit_string_binary_output() {
        assert_eq!(decode_pg_bit_string_bytes(&decode_hex("00000005a8")).as_deref(), Some("10101"));
        assert_eq!(decode_pg_bit_string_bytes(&decode_hex("00000009a880")).as_deref(), Some("101010001"));
        assert_eq!(decode_pg_bit_string_bytes(&decode_hex("00000000")).as_deref(), Some(""));
        assert_eq!(decode_pg_bit_string_bytes(&decode_hex("00000005a8ff")), None);
        assert_eq!(decode_pg_bit_string_bytes(&decode_hex("ffffffff")), None);
    }

    #[test]
    fn ewkb_point_with_srid_formats_as_wkt() {
        let raw = decode_hex("0101000020E6100000C520B07268195D404E62105839F44340");
        assert_eq!(super::super::wkb::wkb_to_wkt(&raw), Some("POINT(116.397 39.908)".to_string()));
    }

    #[test]
    fn ewkb_multi_polygon_formats_as_wkt() {
        let raw = decode_hex(
            "0106000020E610000002000000010300000001000000050000000000000000005D4000000000000044400000000000405D4000000000000044400000000000405D4000000000008044400000000000005D4000000000008044400000000000005D400000000000004440010300000001000000050000000000000000805D4000000000008043400000000000C05D4000000000008043400000000000C05D4000000000000044400000000000805D4000000000000044400000000000805D400000000000804340",
        );
        assert_eq!(
            super::super::wkb::wkb_to_wkt(&raw),
            Some(
                "MULTIPOLYGON(((116 40,117 40,117 41,116 41,116 40)),((118 39,119 39,119 40,118 40,118 39)))"
                    .to_string()
            )
        );
    }

    #[test]
    fn ewkb_geometry_collection_formats_as_wkt() {
        let raw = decode_hex(
            "0107000020E61000000200000001010000000000000000005D4000000000000044400102000000020000000000000000405D4000000000008044400000000000805D400000000000004540",
        );
        assert_eq!(
            super::super::wkb::wkb_to_wkt(&raw),
            Some("GEOMETRYCOLLECTION(POINT(116 40),LINESTRING(117 41,118 42))".to_string())
        );
    }

    #[test]
    fn pg_optional_array_to_json_preserves_text_values_and_nulls() {
        let value = pg_optional_array_to_json(
            vec![Some("productManager".to_string()), None, Some("projectOwner".to_string())],
            serde_json::Value::String,
        );

        assert_eq!(value, serde_json::json!(["productManager", null, "projectOwner"]));
    }

    #[test]
    fn pg_quote_ident_plain_identifier() {
        assert_eq!(pg_quote_ident("public"), "\"public\"");
    }

    #[test]
    fn pg_quote_ident_escapes_double_quotes() {
        assert_eq!(pg_quote_ident("my\"schema"), "\"my\"\"schema\"");
    }

    #[test]
    fn pg_quote_ident_empty_string() {
        assert_eq!(pg_quote_ident(""), "\"\"");
    }

    #[test]
    fn pg_quote_ident_special_chars() {
        // PostgreSQL allows many special chars in quoted identifiers
        let ident = "my schema with spaces";
        assert_eq!(pg_quote_ident(ident), "\"my schema with spaces\"");
    }

    #[test]
    fn pg_quote_ident_injection_attempt() {
        // A malicious schema name that tries to break out of quotes
        let malicious = r#"public"; DROP TABLE users; --"#;
        let escaped = pg_quote_ident(malicious);
        // Double quotes should be doubled, not breaking out
        assert_eq!(escaped, r#""public""; DROP TABLE users; --""#);
        assert!(escaped.matches('"').count().is_multiple_of(2), "quote count should be even");
    }

    #[test]
    fn postgres_table_access_reads_complete_catalog_acls() {
        assert!(POSTGRES_TABLE_OWNER_SQL.contains("acldefault('r', c.relowner)"));
        assert!(
            POSTGRES_TABLE_ACL_PRIVILEGES_SQL.contains("COALESCE(c.relacl, pg_catalog.acldefault('r', c.relowner))")
        );
        assert!(POSTGRES_COLUMN_ACL_PRIVILEGES_SQL.contains("aclexplode(a.attacl)"));
        assert!(POSTGRES_TABLE_ACL_PRIVILEGES_SQL.contains("acl.grantee = 0 THEN 'PUBLIC'"));
        assert!(POSTGRES_COLUMN_ACL_PRIVILEGES_SQL.contains("acl.grantee = 0 THEN 'PUBLIC'"));
        assert!(POSTGRES_TABLE_ACL_PRIVILEGES_SQL.contains("pg_get_userbyid(acl.grantor)"));
        assert!(POSTGRES_COLUMN_ACL_PRIVILEGES_SQL.contains("pg_get_userbyid(acl.grantor)"));
    }

    // --- query_result_row_limit ---

    #[test]
    fn row_limit_uses_max_rows_when_present() {
        assert_eq!(query_result_row_limit(Some(50)), 50);
    }

    #[test]
    fn row_limit_falls_back_to_default() {
        let default = crate::query::MAX_ROWS;
        assert_eq!(query_result_row_limit(None), default);
    }

    #[test]
    fn row_limit_clamps_zero_to_one() {
        assert_eq!(query_result_row_limit(Some(0)), 1);
    }

    #[test]
    fn row_limit_allows_max_rows_override() {
        assert_eq!(query_result_row_limit(Some(5)), 5);
    }

    #[test]
    fn timestamptz_display_preserves_local_offset() {
        let text = format_pg_timestamptz(Local::now());
        assert!(!text.ends_with("+00:00") || Local::now().offset().local_minus_utc() == 0);
    }

    // --- validate_postgres_ssl_paths ---

    #[test]
    fn ssl_validation_passes_for_clean_url() {
        assert!(validate_postgres_ssl_paths("postgres://localhost/db").is_ok());
    }

    #[test]
    fn ssl_validation_passes_for_url_without_query() {
        assert!(validate_postgres_ssl_paths("host=localhost dbname=test").is_ok());
    }

    #[test]
    fn ssl_validation_passes_for_irrelevant_params() {
        assert!(validate_postgres_ssl_paths("postgres://localhost/db?sslmode=require&connect_timeout=10").is_ok());
    }

    #[test]
    fn ssl_validation_rejects_nonexistent_sslcert_path() {
        let result = validate_postgres_ssl_paths("postgres://localhost/db?sslcert=/nonexistent/path/cert.pem");
        assert!(result.is_err());
        assert!(result.unwrap_err().contains("sslcert"), "error should mention sslcert");
    }

    #[test]
    fn ssl_validation_rejects_nonexistent_sslkey_path() {
        let result = validate_postgres_ssl_paths("postgres://localhost/db?sslkey=/nonexistent/path/key.pem");
        assert!(result.is_err());
        assert!(result.unwrap_err().contains("sslkey"), "error should mention sslkey");
    }

    #[test]
    fn ssl_validation_rejects_nonexistent_sslrootcert_path() {
        let result = validate_postgres_ssl_paths("postgres://localhost/db?sslrootcert=/nonexistent/path/root.crt");
        assert!(result.is_err());
        assert!(result.unwrap_err().contains("sslrootcert"), "error should mention sslrootcert");
    }

    #[test]
    fn ssl_validation_rejects_path_traversal_in_sslcert() {
        let result = validate_postgres_ssl_paths("postgres://localhost/db?sslcert=../../../etc/passwd");
        assert!(result.is_err());
    }

    #[test]
    fn ssl_validation_handles_url_encoded_ssl_param() {
        // %2F = '/', so sslcert=%2Ftmp%2Fcert.pem means sslcert=/tmp/cert.pem
        let result = validate_postgres_ssl_paths("postgres://localhost/db?sslcert=%2Fnonexistent%2Fcert.pem");
        assert!(result.is_err());
    }

    #[test]
    fn ssl_validation_handles_multiple_params() {
        let result =
            validate_postgres_ssl_paths("postgres://localhost/db?sslmode=require&sslcert=/nonexistent/cert.pem");
        assert!(result.is_err());
    }

    #[test]
    fn postgres_connection_url_strips_ssl_file_params_before_driver_parse() {
        let dir = std::env::temp_dir();
        let cert = dir.join(format!("dbx-postgres-cert-{}.pem", std::process::id()));
        let key = dir.join(format!("dbx-postgres-key-{}.pem", std::process::id()));
        let root = dir.join(format!("dbx-postgres-root-{}.pem", std::process::id()));
        std::fs::write(&cert, "not a real cert").unwrap();
        std::fs::write(&key, "not a real key").unwrap();
        std::fs::write(&root, "not a real root").unwrap();

        let url = format!(
            "postgres://localhost/db?sslmode=verify-full&sslcert={}&sslkey={}&sslrootcert={}&application_name=dbx",
            cert.display(),
            key.display(),
            root.display()
        );
        let parsed = postgres_connection_url(&url).unwrap();

        assert_eq!(parsed.url, "postgres://localhost/db?sslmode=require&application_name=dbx");
        assert_eq!(parsed.ssl_files.sslcert.as_deref(), Some(cert.to_str().unwrap()));
        assert_eq!(parsed.ssl_files.sslkey.as_deref(), Some(key.to_str().unwrap()));
        assert_eq!(parsed.ssl_files.sslrootcert.as_deref(), Some(root.to_str().unwrap()));
        assert!(!parsed.accepts_invalid_certs);
        assert!(parsed.verifies_hostname);
        tokio_postgres::Config::from_str(&parsed.url).unwrap();

        let _ = std::fs::remove_file(cert);
        let _ = std::fs::remove_file(key);
        let _ = std::fs::remove_file(root);
    }

    #[test]
    fn postgres_connection_url_keeps_verify_ca_ca_only_semantics() {
        let parsed = postgres_connection_url("postgres://localhost/db?sslmode=verify-ca").unwrap();

        assert_eq!(parsed.url, "postgres://localhost/db?sslmode=require");
        assert!(!parsed.accepts_invalid_certs);
        assert!(!parsed.verifies_hostname);
    }

    #[test]
    fn postgres_connection_url_extracts_legacy_tls_before_driver_parse() {
        let parsed =
            postgres_connection_url("postgres://localhost/db?sslmode=require&legacy_tls=true&application_name=dbx")
                .unwrap();

        assert_eq!(parsed.url, "postgres://localhost/db?sslmode=require&application_name=dbx");
        assert!(parsed.legacy_tls);
        tokio_postgres::Config::from_str(&parsed.url).unwrap();

        let parsed = postgres_connection_url("postgres://localhost/db?legacy_tls=false").unwrap();
        assert_eq!(parsed.url, "postgres://localhost/db");
        assert!(!parsed.legacy_tls);
    }

    #[test]
    fn postgres_connection_url_normalizes_channel_binding_require_to_prefer() {
        let parsed =
            postgres_connection_url("postgres://localhost/db?sslmode=require&channel_binding=require").unwrap();

        assert_eq!(parsed.url, "postgres://localhost/db?sslmode=require&channel_binding=prefer");
        // The sanitized URL must be parseable by the driver
        tokio_postgres::Config::from_str(&parsed.url).unwrap();
    }

    #[test]
    fn postgres_connection_url_keeps_channel_binding_prefer() {
        let parsed = postgres_connection_url("postgres://localhost/db?channel_binding=prefer").unwrap();

        assert_eq!(parsed.url, "postgres://localhost/db?channel_binding=prefer");
        tokio_postgres::Config::from_str(&parsed.url).unwrap();
    }

    #[test]
    fn postgres_tls_rejects_unpaired_client_cert_and_key() {
        let _ = rustls::crypto::aws_lc_rs::default_provider().install_default();
        let pg_config = tokio_postgres::Config::from_str("postgres://localhost/db?sslmode=require").unwrap();
        let ssl_files =
            PostgresSslFiles { sslcert: Some("/tmp/client.crt".to_string()), sslkey: None, sslrootcert: None };

        let error = match postgres_tls_config(&pg_config, &ssl_files, true, false) {
            Ok(_) => panic!("expected missing sslkey to fail"),
            Err(error) => error,
        };
        assert!(error.contains("sslkey"));
    }

    #[test]
    fn postgres_tls_rejects_empty_client_certificate() {
        let _ = rustls::crypto::aws_lc_rs::default_provider().install_default();
        let dir = std::env::temp_dir();
        let suffix = uuid::Uuid::new_v4().simple();
        let cert = dir.join(format!("dbx-postgres-empty-client-{suffix}.crt"));
        let key = dir.join(format!("dbx-postgres-empty-client-{suffix}.key"));
        std::fs::write(&cert, []).unwrap();
        std::fs::write(&key, []).unwrap();
        let pg_config = tokio_postgres::Config::from_str("postgres://localhost/db?sslmode=require").unwrap();
        let ssl_files = PostgresSslFiles {
            sslcert: Some(cert.to_string_lossy().into_owned()),
            sslkey: Some(key.to_string_lossy().into_owned()),
            sslrootcert: None,
        };

        let error = postgres_tls_config(&pg_config, &ssl_files, true, false)
            .expect_err("empty client certificate should fail before connecting");
        assert!(error.contains("no certificates"), "{error}");

        let _ = std::fs::remove_file(cert);
        let _ = std::fs::remove_file(key);
    }

    #[test]
    fn postgres_tls_rejects_malformed_private_key() {
        let _ = rustls::crypto::aws_lc_rs::default_provider().install_default();
        let dir = std::env::temp_dir();
        let suffix = uuid::Uuid::new_v4().simple();
        let cert = dir.join(format!("dbx-postgres-client-{suffix}.crt"));
        let key = dir.join(format!("dbx-postgres-malformed-client-{suffix}.key"));
        std::fs::write(&cert, "-----BEGIN CERTIFICATE-----\nMAA=\n-----END CERTIFICATE-----\n").unwrap();
        std::fs::write(&key, "-----BEGIN PRIVATE KEY-----\nMAA=\n-----END PRIVATE KEY-----\n").unwrap();
        let pg_config = tokio_postgres::Config::from_str("postgres://localhost/db?sslmode=require").unwrap();
        let ssl_files = PostgresSslFiles {
            sslcert: Some(cert.to_string_lossy().into_owned()),
            sslkey: Some(key.to_string_lossy().into_owned()),
            sslrootcert: None,
        };

        let error = postgres_tls_config(&pg_config, &ssl_files, true, false)
            .expect_err("malformed private key should fail before connecting");
        assert!(error.contains("client private key is invalid"), "{error}");

        let _ = std::fs::remove_file(cert);
        let _ = std::fs::remove_file(key);
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_MTLS_URL pointing at PostgreSQL 14 with required client certificates"]
    async fn postgres_mtls_accepts_configured_client_identity() {
        let url = std::env::var("DBX_TEST_POSTGRES_MTLS_URL").expect("DBX_TEST_POSTGRES_MTLS_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect with client certificate");
        let client = pool.get().await.expect("get PostgreSQL mTLS client");
        let row = client
            .query_one(
                "SELECT current_user, ssl, current_setting('server_version_num')::int \
                 FROM pg_stat_ssl WHERE pid = pg_backend_pid()",
                &[],
            )
            .await
            .expect("query PostgreSQL TLS session");

        assert_eq!(row.get::<_, String>(0), "db");
        assert!(row.get::<_, bool>(1));
        assert!((140_000..150_000).contains(&row.get::<_, i32>(2)));
    }

    #[test]
    #[ignore = "requires DBX_TEST_POSTGRES_MTLS_URL with a valid client certificate"]
    fn postgres_mtls_cancel_connector_reuses_client_identity() {
        let url = std::env::var("DBX_TEST_POSTGRES_MTLS_URL").expect("DBX_TEST_POSTGRES_MTLS_URL");
        let _ = rustls::crypto::aws_lc_rs::default_provider().install_default();
        let context = build_postgres_cancel_context(&url).expect("build PostgreSQL TLS cancel context");

        make_rustls_connect_from_context(&context).expect("rebuild TLS connector with client certificate");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_MTLS_REJECT_URL that the TLS server must reject"]
    async fn postgres_mtls_rejects_invalid_tls_identity() {
        let url = std::env::var("DBX_TEST_POSTGRES_MTLS_REJECT_URL").expect("DBX_TEST_POSTGRES_MTLS_REJECT_URL");
        let error =
            connect(&url, Duration::from_secs(5)).await.expect_err("invalid TLS identity must not authenticate");

        assert!(error.contains("PostgreSQL connection failed"), "{error}");
    }

    #[test]
    fn postgres_accept_all_tls_signature_does_not_parse_unverified_cert() {
        let verifier = NoPostgresCertVerification { provider: Arc::new(rustls::crypto::aws_lc_rs::default_provider()) };
        let malformed_cert = CertificateDer::from(vec![0x30, 0x03, 0x02, 0x01, 0x00]);

        assert!(verifier.accept_tls_signature_for_unverified_cert(&malformed_cert).is_ok());
    }

    #[test]
    fn inject_postgres_keepalive_params_preserves_url_fragment() {
        let url = "postgres://localhost/app?sslmode=require#read-only";

        assert_eq!(
            inject_postgres_keepalive_params(url),
            "postgres://localhost/app?sslmode=require&keepalives=1&keepalives_idle=30&keepalives_interval=10&keepalives_retries=3#read-only"
        );
    }

    #[test]
    fn postgres_cancel_attempt_timeout_is_single_budget() {
        assert_eq!(postgres_cancel_attempt_timeout(Duration::from_secs(5), None), Duration::from_secs(5));
        assert_eq!(
            postgres_cancel_attempt_timeout(
                Duration::from_secs(5),
                Some(&PostgresCancelContext {
                    ssl_files: PostgresSslFiles::default(),
                    accepts_invalid_certs: true,
                    verifies_hostname: false,
                    ssl_mode: SslMode::Require,
                    legacy_tls: false,
                })
            ),
            Duration::from_secs(5)
        );
    }

    #[test]
    fn postgres_checkout_timeout_respects_pool_configuration() {
        let manager = deadpool_postgres::Manager::new(tokio_postgres::Config::new(), NoTls);
        let pool = Pool::builder(manager)
            .runtime(Runtime::Tokio1)
            .wait_timeout(Some(Duration::from_secs(10)))
            .create_timeout(Some(Duration::from_secs(10)))
            .recycle_timeout(Some(Duration::from_secs(10)))
            .build()
            .expect("build postgres pool");

        assert_eq!(effective_postgres_checkout_timeout(&pool, Duration::from_secs(5)), Duration::from_secs(10));
        assert_eq!(effective_postgres_checkout_timeout(&pool, Duration::from_secs(15)), Duration::from_secs(15));
    }

    #[tokio::test]
    async fn postgres_checkout_fault_injection_classifies_full_pool_as_wait() {
        assert!(tokio::time::timeout(Duration::from_millis(1), std::future::pending::<()>()).await.is_err());
        assert_eq!(
            classify_postgres_checkout_stage(deadpool_postgres::Status {
                max_size: 1,
                size: 1,
                available: 0,
                waiting: 1
            }),
            PostgresCheckoutStage::Wait
        );
    }

    #[tokio::test]
    async fn postgres_checkout_fault_injection_preserves_create_and_recycle_stages() {
        assert!(tokio::time::timeout(Duration::from_millis(1), std::future::pending::<()>()).await.is_err());
        assert_eq!(
            classify_postgres_checkout_stage(deadpool_postgres::Status {
                max_size: 2,
                size: 1,
                available: 0,
                waiting: 0
            }),
            PostgresCheckoutStage::Create
        );
        assert_eq!(
            classify_postgres_checkout_stage(deadpool_postgres::Status {
                max_size: 1,
                size: 1,
                available: 1,
                waiting: 0
            }),
            PostgresCheckoutStage::Recycle
        );
    }

    #[tokio::test]
    async fn postgres_session_setup_reports_its_own_timeout_stage() {
        let error =
            postgres_session_setup_with_timeout(Duration::from_millis(1), std::future::pending::<Result<(), String>>())
                .await
                .expect_err("pending session setup should time out");

        assert!(error.starts_with("PostgreSQL session setup connection timed out"), "{error}");
    }

    #[tokio::test]
    async fn postgres_row_query_timeout_tracks_inactivity_instead_of_total_duration() {
        let progress_clock = Arc::new(StreamProgressClock::new());
        let progress_clock_for_query = progress_clock.clone();
        let future = async {
            for _ in 0..4 {
                tokio::time::sleep(Duration::from_millis(40)).await;
                progress_clock_for_query.mark();
            }
            Ok::<_, String>(())
        };

        let result = await_stream_with_progress_timeout(
            future,
            Some(Duration::from_millis(100)),
            progress_clock,
            None,
            "query inactivity timeout".to_string(),
        )
        .await;

        assert_eq!(result, Ok(()));
    }

    #[tokio::test]
    async fn postgres_row_query_timeout_still_fires_after_no_progress() {
        let progress_clock = Arc::new(StreamProgressClock::new());
        let error = await_stream_with_progress_timeout(
            std::future::pending::<Result<(), String>>(),
            Some(Duration::from_millis(10)),
            progress_clock,
            None,
            "query inactivity timeout".to_string(),
        )
        .await
        .expect_err("a stalled query should time out");

        assert_eq!(error, "query inactivity timeout");
    }

    #[tokio::test]
    async fn postgres_row_query_timeout_covers_stall_after_last_row() {
        let progress_clock = Arc::new(StreamProgressClock::new());
        let progress_clock_for_query = progress_clock.clone();
        let error = await_stream_with_progress_timeout(
            async move {
                progress_clock_for_query.mark();
                std::future::pending::<Result<(), String>>().await
            },
            Some(Duration::from_millis(10)),
            progress_clock,
            None,
            "query completion inactivity timeout".to_string(),
        )
        .await
        .expect_err("a stream stalled after its last row should time out");

        assert_eq!(error, "query completion inactivity timeout");
    }

    #[tokio::test]
    async fn postgres_row_query_without_timeout_still_honors_cancellation() {
        let progress_clock = Arc::new(StreamProgressClock::new());
        let cancel_token = CancellationToken::new();
        cancel_token.cancel();
        let error = await_stream_with_progress_timeout(
            std::future::pending::<Result<(), String>>(),
            None,
            progress_clock,
            Some(&cancel_token),
            "disabled query timeout".to_string(),
        )
        .await
        .expect_err("cancellation must remain active when query timeout is disabled");

        assert_eq!(error, crate::query::QUERY_CANCELED);
    }

    #[test]
    fn postgres_cancel_context_omits_disabled_ssl_mode() {
        assert!(build_postgres_cancel_context("postgres://localhost/app?sslmode=disable").is_none());
    }

    #[test]
    fn postgres_tls_accepts_invalid_certs_for_require_sslmode() {
        let pg_config = tokio_postgres::Config::from_str("postgres://localhost/db?sslmode=require").unwrap();

        assert!(postgres_sslmode_accepts_invalid_certs(pg_config.get_ssl_mode()));
    }

    #[test]
    fn postgres_tls_accepts_invalid_certs_for_default_prefer_sslmode() {
        let pg_config = tokio_postgres::Config::from_str("postgres://localhost/db").unwrap();

        assert!(postgres_sslmode_accepts_invalid_certs(pg_config.get_ssl_mode()));
    }

    #[test]
    fn postgres_tls_keeps_verification_off_only_when_ssl_is_disabled() {
        let pg_config = tokio_postgres::Config::from_str("postgres://localhost/db?sslmode=disable").unwrap();

        assert!(!postgres_sslmode_accepts_invalid_certs(pg_config.get_ssl_mode()));
    }

    #[test]
    fn postgres_prefer_fallback_url_preserves_other_options() {
        assert_eq!(
            postgres_ssl_fallback_url("postgres://localhost/db?application_name=dbx&sslmode=prefer&connect_timeout=5"),
            Some("postgres://localhost/db?application_name=dbx&sslmode=disable&connect_timeout=5".to_string())
        );
        assert_eq!(
            postgres_ssl_fallback_url("postgres://localhost/db?application_name=dbx"),
            Some("postgres://localhost/db?sslmode=disable&application_name=dbx".to_string())
        );
    }

    #[test]
    fn postgres_prefer_fallback_never_downgrades_strict_tls_modes() {
        for sslmode in ["require", "verify-ca", "verify-full", "disable"] {
            let url = format!("postgres://localhost/db?sslmode={sslmode}");
            assert_eq!(postgres_ssl_fallback_url(&url), None, "unexpected fallback for {sslmode}");
        }
    }

    #[test]
    fn postgres_prefer_fallback_only_retries_tls_handshake_errors() {
        assert!(postgres_error_should_retry_without_tls(
            "error performing TLS handshake: received fatal alert: HandshakeFailure"
        ));
        assert!(!postgres_error_should_retry_without_tls("password authentication failed for user postgres"));
        assert!(!postgres_error_should_retry_without_tls("connection timed out"));
        assert!(!postgres_error_should_retry_without_tls("server does not support TLS"));
    }

    // --- SQL generation ---

    #[test]
    fn postgres_tables_sql_contains_expected_columns() {
        let sql = postgres_tables_sql(Some(500), 0);
        assert!(sql.contains("table_name"));
        assert!(sql.contains("table_type"));
        assert!(sql.contains("table_comment"));
        assert!(sql.contains("pg_catalog.pg_inherits"));
        assert!(sql.contains("parent_schema"));
        assert!(sql.contains("parent_name"));
        assert!(sql.contains("pc.relkind = 'p'"));
        assert!(sql.contains("$1"));
        assert!(sql.contains("BASE TABLE"));
        assert!(sql.contains("VIEW"));
        assert!(sql.contains("MATERIALIZED_VIEW"));
        assert!(sql.contains("FOREIGN TABLE"));
    }

    #[test]
    fn postgres_table_objects_sql_excludes_views_before_pagination() {
        let sql = postgres_table_objects_sql(Some(101), 100);

        assert!(sql.contains("c.relkind IN ('r','f','p')"));
        assert!(sql.contains("LIMIT 101 OFFSET 100"));
    }

    #[test]
    fn postgres_table_comment_sql_targets_single_table() {
        let sql = postgres_table_comment_sql();

        assert!(sql.contains("obj_description(c.oid)"));
        assert!(sql.contains("n.nspname = $1"));
        assert!(sql.contains("c.relname = $2"));
        assert!(sql.contains("LIMIT 1"));
        assert!(!sql.contains("ORDER BY"));
    }

    #[test]
    fn postgres_table_partition_sql_tracks_parents_bounds_and_local_objects() {
        let relation_sql = postgres_table_partition_relation_sql();
        let info_sql = postgres_table_partition_info_sql();
        let info_compat_sql = postgres_table_partition_info_compat_sql();
        let local_objects_sql = postgres_table_partition_local_objects_sql();

        assert!(!relation_sql.contains("row_to_json"));
        assert!(!relation_sql.contains("relispartition"));
        assert!(!relation_sql.contains("relpartbound"));
        assert!(relation_sql.contains("pg_catalog.pg_inherits"));
        assert!(relation_sql.contains("parent.oid = i.inhparent"));
        assert!(relation_sql.contains(") = 'p'"));
        // Foreign tables (relkind 'f') must be reachable here too, or a
        // foreign partition looked up directly (not via recursion from its
        // parent) would never be classified as a partition at all.
        assert!(relation_sql.contains("c.relkind IN ('r','p','f')"));
        assert!(info_sql.contains("pg_catalog.pg_get_expr(c.relpartbound, c.oid, true)"));
        assert!(info_sql.contains("pg_catalog.pg_get_partkeydef(c.oid)"));
        assert!(info_sql.contains("pg_catalog.pg_inherits"));
        assert!(info_sql.contains("parent_schema"));
        assert!(info_sql.contains("parent_table"));
        assert!(info_sql.contains("pg_catalog.pg_foreign_table"));
        assert!(info_sql.contains("pg_catalog.pg_foreign_server"));
        assert!(info_sql.contains("fs.srvname"));
        assert!(info_sql.contains("ft.ftoptions"));
        assert!(info_sql.contains("c.relkind IN ('r','p','f')"));
        // 兼容版面向 9.x：没有 relispartition/relpartbound/pg_get_partkeydef，
        // 但保留了与主查询一致的列序和 LIMIT 形状。
        assert!(!info_compat_sql.contains("relispartition"));
        assert!(!info_compat_sql.contains("relpartbound"));
        assert!(!info_compat_sql.contains("pg_get_partkeydef"));
        assert!(!info_compat_sql.contains("pg_inherits"));
        assert!(info_compat_sql.contains("NULL::text AS parent_schema"));
        assert!(info_compat_sql.contains("NULL::text AS parent_table"));
        assert!(info_compat_sql.contains("NULL::text AS partition_bound"));
        assert!(info_compat_sql.contains("NULL::text AS partition_key"));
        assert!(info_compat_sql.contains("fs.srvname"));
        assert!(info_compat_sql.contains("ft.ftoptions"));
        assert!(info_compat_sql.contains("c.relkind IN ('r','p','f')"));
        assert!(info_compat_sql.contains("LIMIT 1"));
        assert!(local_objects_sql.contains("row_to_json(con)->>'conparentid'"));
        assert!(local_objects_sql.contains("con.contype IN ('p','f')"));
        assert!(local_objects_sql.contains("i.inhrelid = idx.oid"));
        assert!(local_objects_sql.contains("con.contype = 'c' AND con.conislocal"));
        assert!(!local_objects_sql.contains("con.coninhcount = 0"));
        assert!(local_objects_sql.contains("pg_catalog.pg_attrdef"));
    }

    #[test]
    fn postgres_partition_tree_compat_sql_collapses_to_single_relation() {
        let sql = postgres_partition_tree_sql();
        let compat_sql = postgres_partition_tree_compat_sql();

        // 主查询只支持 PostgreSQL 10+（声明式分区）；兼容版不能引用任何
        // 10+ 的目录列/函数。
        assert!(sql.contains("c.relispartition"));
        assert!(sql.contains("pg_catalog.pg_get_expr(c.relpartbound"));
        assert!(sql.contains("pg_catalog.pg_get_partkeydef"));

        assert!(!compat_sql.contains("relispartition"));
        assert!(!compat_sql.contains("relpartbound"));
        assert!(!compat_sql.contains("pg_get_partkeydef"));
        assert!(!compat_sql.contains("pg_inherits"));
        assert!(!compat_sql.contains("WITH RECURSIVE"));
        assert!(compat_sql.contains("NULL::bigint AS parent_oid"));
        assert!(compat_sql.contains("NULL::text AS parent_schema"));
        assert!(compat_sql.contains("NULL::text AS parent_relname"));
        assert!(compat_sql.contains("NULL::text AS partition_bound"));
        assert!(compat_sql.contains("NULL::text AS partition_key"));
        assert!(compat_sql.contains("c.relkind::text AS relkind"));
        assert!(compat_sql.contains("fs.srvname AS foreign_server"));
        assert!(compat_sql.contains("ft.ftoptions AS foreign_options"));
        assert!(compat_sql.contains("n.nspname = $1 AND c.relname = $2"));
        assert!(compat_sql.contains("c.relkind IN ('r','p','f')"));
    }

    #[test]
    fn postgres_check_constraints_sql_selects_definitions_for_relation() {
        let sql = postgres_check_constraints_sql();
        assert!(sql.contains("con.contype = 'c'"));
        assert!(sql.contains("pg_catalog.pg_get_constraintdef(con.oid, true)"));
        assert!(sql.contains("n.nspname = $1 AND c.relname = $2"));
        assert!(sql.contains("ORDER BY con.conname"));
    }

    #[test]
    fn postgres_constraints_sql_covers_all_contypes_and_referential_fields() {
        let sql = postgres_constraints_sql();
        assert!(sql.contains("con.contype::text"));
        assert!(sql.contains("pg_catalog.pg_get_constraintdef(con.oid, true)"));
        // FK-only referential columns are conditionally selected.
        assert!(sql.contains("CASE WHEN con.contype = 'f' THEN con.confmatchtype::text END"));
        assert!(sql.contains("CASE WHEN con.contype = 'f' THEN con.confupdtype::text END"));
        assert!(sql.contains("CASE WHEN con.contype = 'f' THEN con.confdeltype::text END"));
        // conkey/confkey attribute numbers are resolved to names via laterals.
        assert!(sql.contains("unnest(con.conkey) WITH ORDINALITY"));
        assert!(sql.contains("unnest(con.confkey) WITH ORDINALITY"));
        // attname (pg_attribute type `name`) is explicitly cast to text so the
        // array decodes as text[] (matching the COALESCE fallback and Vec<String>).
        assert!(sql.contains("array_agg(a.attname::text ORDER BY ord.ord)"));
        assert_eq!(sql.matches("attname::text").count(), 2);
        assert!(sql.contains("a.attisdropped"));
        assert!(sql.contains("n.nspname = $1 AND c.relname = $2"));
        assert!(sql.contains("c.relkind IN ('r','p','f')"));
        assert!(sql.contains("ORDER BY con.conname"));
    }

    #[test]
    fn opengauss_constraint_sql_avoids_array_and_ordinality_dependencies() {
        let sql = opengauss_constraints_sql(true);
        assert!(sql.contains("con.conkey::text"));
        assert!(sql.contains("con.confkey::text"));
        assert!(sql.contains("con.conrelid::oid"));
        assert!(sql.contains("con.confrelid::oid"));
        assert!(!sql.contains("unnest("));
        assert!(!sql.contains("WITH ORDINALITY"));
        assert!(!sql.contains("LATERAL"));
    }

    #[test]
    fn opengauss_constraint_sql_falls_back_without_convalidated() {
        let sql = opengauss_constraints_sql(false);
        assert!(sql.contains("TRUE"));
        assert!(!sql.contains("con.convalidated"));
    }

    #[test]
    fn opengauss_constraint_attribute_vectors_are_strict() {
        assert_eq!(parse_opengauss_attribute_numbers("1 2 4").unwrap(), vec![1, 2, 4]);
        assert_eq!(parse_opengauss_attribute_numbers("{3,2}").unwrap(), vec![3, 2]);
        assert_eq!(parse_opengauss_attribute_numbers("[4, 5]").unwrap(), vec![4, 5]);
        assert!(parse_opengauss_attribute_numbers("1 bad 3").is_err());
    }

    #[test]
    fn postgres_constraint_type_label_expands_contype_letters() {
        assert_eq!(postgres_constraint_type_label("p"), "PRIMARY KEY");
        assert_eq!(postgres_constraint_type_label("f"), "FOREIGN KEY");
        assert_eq!(postgres_constraint_type_label("u"), "UNIQUE");
        assert_eq!(postgres_constraint_type_label("c"), "CHECK");
        assert_eq!(postgres_constraint_type_label("x"), "EXCLUDE");
        assert_eq!(postgres_constraint_type_label("n"), "NOT NULL");
        assert_eq!(postgres_constraint_type_label("unknown"), "unknown");
    }

    #[test]
    fn postgres_fk_action_label_and_match_type_normalize_letters() {
        assert_eq!(postgres_fk_action_label(Some("c".to_string())).as_deref(), Some("CASCADE"));
        assert_eq!(postgres_fk_action_label(Some("n".to_string())).as_deref(), Some("SET NULL"));
        assert_eq!(postgres_fk_action_label(Some("d".to_string())).as_deref(), Some("SET DEFAULT"));
        assert_eq!(postgres_fk_action_label(Some("a".to_string())).as_deref(), Some("NO ACTION"));
        assert_eq!(postgres_fk_action_label(Some("r".to_string())).as_deref(), Some("RESTRICT"));
        assert_eq!(postgres_fk_action_label(Some("zz".to_string())), None);
        assert_eq!(postgres_fk_action_label(None), None);
        assert_eq!(postgres_constraint_match_type(Some("f".to_string())).as_deref(), Some("FULL"));
        assert_eq!(postgres_constraint_match_type(Some("s".to_string())).as_deref(), Some("SIMPLE"));
        assert_eq!(postgres_constraint_match_type(Some("u".to_string())).as_deref(), Some("SIMPLE"));
        assert_eq!(postgres_constraint_match_type(Some("p".to_string())).as_deref(), Some("PARTIAL"));
        assert_eq!(postgres_constraint_match_type(Some("zz".to_string())), None);
    }

    #[test]
    fn postgres_column_metadata_reads_identity_extra() {
        assert!(POSTGRES_COLUMNS_SQL.contains("a.attidentity"));
        assert!(POSTGRES_COLUMNS_SQL.contains("pg_sequence"));
        assert!(POSTGRES_COLUMNS_SQL.contains("generated by default as identity"));
        assert!(POSTGRES_COLUMNS_SQL.contains("generated always as identity"));
        assert!(POSTGRES_COLUMNS_SQL.contains("COALESCE(c.is_nullable = 'YES', NOT a.attnotnull)"));
        assert!(POSTGRES_COLUMNS_SQL.contains("LEFT JOIN information_schema.columns"));
        assert!(POSTGRES_COLUMNS_SQL.contains("pg_enum"));
        assert!(POSTGRES_COLUMNS_SQL.contains("AS enum_values"));
    }

    #[test]
    fn postgres_single_relation_metadata_can_resolve_through_search_path() {
        for sql in [POSTGRES_COLUMNS_SQL, POSTGRES_COLUMNS_COMPAT_SQL] {
            assert!(sql.contains("CASE WHEN $1 = '' THEN quote_ident($2)"));
            assert!(sql.contains("c.table_schema = relation_namespace.nspname"));
        }
        for sql in [POSTGRES_INDEXES_SQL, POSTGRES_INDEXES_COMPAT_SQL] {
            assert!(sql.contains("t.oid = (CASE WHEN $1 = '' THEN quote_ident($2)"));
        }
    }

    #[test]
    fn postgres_column_metadata_marks_only_owned_integer_sequence_defaults_as_serial() {
        let modern_sql = [POSTGRES_COLUMNS_SQL, postgres_columns_for_relations_sql()];
        let compat_sql = [POSTGRES_COLUMNS_COMPAT_SQL, postgres_columns_for_relations_compat_sql()];
        for sql in modern_sql.into_iter().chain(compat_sql) {
            assert!(sql.contains("a.atttypid IN (20, 21, 23)"));
            assert!(sql.contains("WHEN 21 THEN 'smallserial'"));
            assert!(sql.contains("WHEN 23 THEN 'serial'"));
            assert!(sql.contains("WHEN 20 THEN 'bigserial'"));
        }
        for sql in modern_sql {
            assert!(sql.contains("LEFT JOIN LATERAL"));
            assert!(sql.contains("a.attidentity <> '' AND sequence_dep.deptype = 'i'"));
            assert!(sql.contains("a.attidentity = ''"));
            assert!(sql.contains("sequence_dep.deptype = 'a' AND EXISTS"));
            assert!(sql.contains("sequence_class.relkind = 'S'"));
            assert!(sql.contains("ORDER BY sequence_dep.objid"));
            assert!(sql.contains("LIMIT 1"));
            assert!(sql.contains("pseq.seqrelid IS NOT NULL"));
            assert!(sql.contains("serial_default_dep.objid = ad.oid"));
            assert!(sql.contains("serial_default_dep.refobjid = sequence_dep.objid"));
            assert!(sql.contains(
                "pg_get_expr(ad.adbin, ad.adrelid) = format('nextval(%L::regclass)', dep.objid::regclass::text)"
            ));
        }
        for sql in compat_sql {
            assert!(!sql.contains("LEFT JOIN LATERAL"));
            assert!(sql.contains("serial_seq.oid = ("));
            assert!(sql.contains("sequence_dep.deptype = 'a' AND EXISTS"));
            assert!(sql.contains("sequence_class.relkind = 'S'"));
            assert!(sql.contains("ORDER BY sequence_dep.objid"));
            assert!(sql.contains("LIMIT 1"));
            assert!(sql.contains("serial_seq.relkind = 'S'"));
            assert!(sql.contains("serial_default_dep.objid = ad.oid"));
            assert!(sql.contains("serial_default_dep.refobjid = sequence_dep.objid"));
            assert!(sql.contains(
                "pg_get_expr(ad.adbin, ad.adrelid) = format('nextval(%L::regclass)', serial_seq.oid::regclass::text)"
            ));
        }

        assert!(!POSTGRES_COLUMNS_INFORMATION_SCHEMA_SQL.contains("serial_dep"));
        assert!(POSTGRES_COLUMNS_INFORMATION_SCHEMA_SQL.contains("NULL::text AS column_extra"));
    }

    #[test]
    fn postgres_partition_local_checks_keep_merged_local_definitions() {
        for sql in
            [postgres_table_partition_local_objects_sql(), postgres_table_partition_local_objects_for_relations_sql()]
        {
            assert!(sql.contains("con.contype = 'c' AND con.conislocal"));
            assert!(!sql.contains("con.coninhcount = 0"));
        }
    }

    #[test]
    fn postgres_partition_batch_metadata_uses_bounded_compat_tiers() {
        let column_tiers = postgres_columns_for_relations_query_tiers();
        assert_eq!(column_tiers.len(), 2);
        assert!(column_tiers.iter().all(|sql| sql.contains("c.oid = ANY($1::bigint[])")));
        assert!(column_tiers[0].contains("a.attgenerated"));
        assert!(!column_tiers[1].contains("a.attgenerated"));
        assert!(!column_tiers[1].contains("pg_sequence"));
        assert!(column_tiers[1].contains("sequence_dep.deptype = 'a'"));
        assert!(!column_tiers[1].contains("LEFT JOIN LATERAL"));

        let index_tiers = postgres_indexes_for_relations_query_tiers();
        assert_eq!(index_tiers.len(), 2);
        assert!(index_tiers.iter().all(|sql| sql.contains("t.oid = ANY($1::bigint[])")));
        assert!(index_tiers[0].contains("ix.indnkeyatts"));
        assert!(!index_tiers[1].contains("ix.indnkeyatts"));
        assert!(index_tiers[1].contains("string_to_array(ix.indkey::text, ' ')"));

        let local_object_tiers = postgres_table_partition_local_objects_for_relations_query_tiers();
        assert_eq!(local_object_tiers.len(), 2);
        assert!(local_object_tiers[0].contains("row_to_json(con)->>'conparentid'"));
        assert!(!local_object_tiers[1].contains("row_to_json"));
        assert!(!local_object_tiers[1].contains("conparentid"));
        assert!(local_object_tiers.iter().all(|sql| sql.contains("con.conrelid = ANY($1::bigint[])")));
    }

    #[test]
    fn postgres_partition_batch_foreign_keys_keep_ordered_paired_compat_tier() {
        let tiers = postgres_foreign_keys_for_relations_query_tiers();
        assert_eq!(tiers.len(), 2);

        let modern_sql = tiers[0];
        assert_eq!(modern_sql, postgres_foreign_keys_for_relations_sql());
        assert!(modern_sql.contains("unnest($1::text[], $2::text[])"));
        assert!(!modern_sql.contains("generate_subscripts"));
        assert!(modern_sql.contains("pg_catalog.pg_constraint"));
        assert!(!modern_sql.contains("information_schema"));
        assert!(modern_sql.contains("con.confupdtype::text"));
        assert!(modern_sql.contains("confdeltype"));
        assert!(modern_sql.contains("con.contype = 'f'"));
        assert!(modern_sql.contains("ORDER BY rel.rel_schema, rel.rel_table, con.conname, fk.ord"));

        let compat_sql = tiers[1];
        assert_eq!(compat_sql, postgres_foreign_keys_for_relations_compat_sql());
        assert!(!compat_sql.contains("unnest($1::text[]"));
        assert!(compat_sql.contains("generate_subscripts($1::text[], 1)"));
        assert!(compat_sql.contains("($1::text[])[rel.i] AS rel_schema"));
        assert!(compat_sql.contains("($2::text[])[rel.i] AS rel_table"));
        assert!(compat_sql.contains("pg_catalog.pg_constraint"));
        assert!(!compat_sql.contains("information_schema"));
        assert!(compat_sql.contains("confdeltype"));
        assert!(compat_sql.contains("con.contype = 'f'"));
        assert!(compat_sql.contains("ORDER BY rel.rel_schema, rel.rel_table, con.conname, fk.ord"));
    }

    #[test]
    fn postgres_column_metadata_has_opengauss_compatible_fallback() {
        assert!(!POSTGRES_COLUMNS_COMPAT_SQL.contains("a.attidentity"));
        assert!(!POSTGRES_COLUMNS_COMPAT_SQL.contains("pg_sequence"));
        assert!(POSTGRES_COLUMNS_COMPAT_SQL.contains("AS column_extra"));
        assert!(POSTGRES_COLUMNS_COMPAT_SQL.contains("col_description"));
        assert!(POSTGRES_COLUMNS_COMPAT_SQL.contains("COALESCE(c.is_nullable = 'YES', NOT a.attnotnull)"));
        assert!(POSTGRES_COLUMNS_COMPAT_SQL.contains("LEFT JOIN information_schema.columns"));
        assert!(POSTGRES_COLUMNS_COMPAT_SQL.contains("NULL::text AS enum_values"));
        assert!(!POSTGRES_COLUMNS_COMPAT_SQL.contains("pg_enum"));
    }

    #[test]
    fn postgres_column_metadata_has_information_schema_fallback() {
        assert!(POSTGRES_COLUMNS_INFORMATION_SCHEMA_SQL.contains("information_schema.columns"));
        assert!(POSTGRES_COLUMNS_INFORMATION_SCHEMA_SQL.contains("information_schema.table_constraints"));
        assert!(POSTGRES_COLUMNS_INFORMATION_SCHEMA_SQL.contains("information_schema.key_column_usage"));
        assert!(POSTGRES_COLUMNS_INFORMATION_SCHEMA_SQL.contains("NULL::text AS enum_values"));
        assert!(!POSTGRES_COLUMNS_INFORMATION_SCHEMA_SQL.contains("pg_attribute"));
        assert!(!POSTGRES_COLUMNS_INFORMATION_SCHEMA_SQL.contains("regclass"));
    }

    #[test]
    fn opengauss_sequence_metadata_uses_compatible_information_schema_view() {
        let sql = opengauss_sequences_sql();

        assert!(sql.contains("information_schema.sequences"));
        assert!(sql.contains("s.sequence_schema = $1"));
        assert!(sql.contains("c.relkind IN ('S','L','z','Z')"));
        assert!(sql.contains("sequence_name"));
        assert!(sql.contains("start_value"));
        assert!(sql.contains("minimum_value"));
        assert!(sql.contains("maximum_value"));
        assert!(sql.contains("increment"));
        assert!(sql.contains("cycle_option"));
        assert!(!sql.contains("pg_sequence s"));
    }

    #[test]
    fn opengauss_sequence_last_values_extract_record_field_as_text() {
        let sql = opengauss_sequence_last_values_sql();

        assert!(sql.contains("(pg_sequence_last_value(c.oid)).last_value::text"));
        assert!(sql.contains("c.relkind IN ('S','L','z','Z')"));
        assert!(sql.contains("n.nspname = $1"));
    }

    #[test]
    fn postgres_sequence_last_values_are_read_as_text() {
        assert!(postgres_sequence_last_values_sql().contains("pg_sequence_last_value(c.oid)::text"));
    }

    #[test]
    fn extension_member_query_filters_only_owned_relations_and_routines() {
        let sql = list_extension_member_objects_sql();

        assert!(sql.contains("d.classid = 'pg_catalog.pg_class'::regclass"));
        assert!(sql.contains("d.classid = 'pg_catalog.pg_proc'::regclass"));
        assert!(sql.contains("d.refclassid = 'pg_catalog.pg_extension'::regclass"));
        assert!(sql.contains("d.deptype = 'e'"));
        assert!(sql.contains("pg_get_function_identity_arguments(p.oid)"));
        assert!(!sql.contains("d.deptype = 'x'"));
    }

    #[tokio::test]
    async fn postgres_column_metadata_query_returns_enum_values_against_real_postgres() {
        let Some(container) = start_docker_postgres().await else {
            return;
        };

        let pool = connect(&container.url(), Duration::from_secs(5)).await.expect("connect postgres");
        let schema = format!("dbx_enum_meta_{}", std::process::id());
        let schema_ident = format!("\"{}\"", schema.replace('\"', "\"\""));
        let table = format!("{schema_ident}.orders");
        let type_ident = format!("{schema_ident}.\"status\"");

        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");
        execute_query(&pool, &format!("CREATE TYPE {type_ident} AS ENUM ('pending', 'active', 'archived')"))
            .await
            .expect("create enum type");
        execute_query(&pool, &format!("CREATE TABLE {table} (id integer PRIMARY KEY, state {type_ident} NOT NULL)"))
            .await
            .expect("create table");

        let client =
            checkout_postgres_client(&pool, None, crate::db::connection_timeout()).await.expect("checkout client");

        let columns =
            get_columns_with_sql(&client, POSTGRES_COLUMNS_SQL, &schema, "orders").await.expect("primary columns");
        assert_eq!(
            state_enum_values(&columns),
            Some(vec!["pending".to_string(), "active".to_string(), "archived".to_string()])
        );
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_unqualified_metadata_follows_search_path() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let client =
            checkout_postgres_client(&pool, None, crate::db::connection_timeout()).await.expect("checkout client");
        let suffix = std::process::id();
        let schema = format!("dbx_search_path_meta_{suffix}");
        let table = format!("comments_{suffix}");
        let schema_ident = format!("\"{}\"", schema.replace('\"', "\"\""));
        let table_ident = format!("\"{}\"", table.replace('\"', "\"\""));

        client
            .batch_execute(&format!(
                "CREATE SCHEMA {schema_ident}; \
                 CREATE TABLE {schema_ident}.{table_ident} (id integer PRIMARY KEY, display_name text); \
                 COMMENT ON COLUMN {schema_ident}.{table_ident}.display_name IS '客户姓名'; \
                 SET search_path TO {schema_ident}, public;"
            ))
            .await
            .expect("create search_path metadata fixtures");

        let columns = get_columns_with_sql(&client, POSTGRES_COLUMNS_SQL, "", &table)
            .await
            .expect("load columns through search_path");
        assert_eq!(
            columns.iter().find(|column| column.name == "display_name").and_then(|column| column.comment.as_deref()),
            Some("客户姓名")
        );

        let indexes = list_indexes_with_sql(&client, POSTGRES_INDEXES_SQL, "", &table)
            .await
            .expect("load indexes through search_path");
        assert!(indexes.iter().any(|index| index.is_primary && index.columns == ["id"]));

        client
            .batch_execute(&format!("RESET search_path; DROP SCHEMA {schema_ident} CASCADE"))
            .await
            .expect("clean search_path metadata fixtures");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_column_metadata_decode_type_mismatch_uses_fallbacks() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, std::time::Duration::from_secs(5)).await.expect("connect postgres");
        let client =
            checkout_postgres_client(&pool, None, std::time::Duration::from_secs(5)).await.expect("checkout postgres");
        let row = client
            .query_one(
                "SELECT \
                   1::int4 AS column_name, \
                   'text'::text AS full_type, \
                   'YES'::text AS is_nullable, \
                   NULL::text AS column_default, \
                   1::int4 AS is_pk, \
                   NULL::text AS column_comment, \
                   NULL::text AS column_extra, \
                   NULL::int4 AS numeric_precision, \
                   NULL::int4 AS numeric_scale, \
                   NULL::int4 AS character_maximum_length",
                &[],
            )
            .await
            .expect("query mismatched metadata row");

        let info = column_info_from_row(&row);
        // int4 column_name should be converted to string "1" instead of panicking
        assert_eq!(info.name, "1");
        // text 'YES' is not a standard bool, pg_row_try_bool falls back to string match
        assert!(info.is_nullable);
        // int4 1 should be interpreted as true for is_primary_key
        assert!(info.is_primary_key);
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_owned_serial_table_ddl_round_trips_without_external_sequences() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let suffix = uuid::Uuid::new_v4().simple();
        let schema = format!("dbx 6405 \"{suffix}");
        let schema_ident = pg_quote_ident(&schema);
        let table_name = "order\"items";
        let table_ident = pg_quote_ident(table_name);
        let table = format!("{schema_ident}.{table_ident}");
        let custom_sequence_name = "custom\"source";
        let custom_sequence = format!("{schema_ident}.{}", pg_quote_ident(custom_sequence_name));
        let custom_table_name = "custom defaults";
        let custom_table = format!("{schema_ident}.{}", pg_quote_ident(custom_table_name));
        let owned_custom_sequence_name = "owned custom source";
        let owned_custom_sequence = format!("{schema_ident}.{}", pg_quote_ident(owned_custom_sequence_name));
        let owned_custom_table_name = "owned custom defaults";
        let owned_custom_table = format!("{schema_ident}.{}", pg_quote_ident(owned_custom_table_name));
        let dropped_default_table_name = "dropped default";
        let dropped_default_table = format!("{schema_ident}.{}", pg_quote_ident(dropped_default_table_name));
        let client = pool.get().await.expect("get postgres client");
        client
            .batch_execute(&format!(
                "CREATE SCHEMA {schema_ident}; \
                 CREATE TABLE {table} (\
                   \"small\"\"id\" smallserial, \
                   \"regular id\" serial, \
                   \"large\"\"id\" bigserial, \
                   identity_id bigint GENERATED BY DEFAULT AS IDENTITY, \
                   base bigint DEFAULT 2, \
                   generated bigint GENERATED ALWAYS AS (base * 2) STORED\
                 ); \
                 CREATE SEQUENCE {custom_sequence}; \
                 CREATE TABLE {custom_table} (id bigint DEFAULT nextval({}::regclass)); \
                 CREATE TABLE {owned_custom_table} (id bigint NOT NULL); \
                 CREATE SEQUENCE {owned_custom_sequence} OWNED BY {owned_custom_table}.id; \
                 ALTER TABLE {owned_custom_table} ALTER COLUMN id \
                   SET DEFAULT nextval({}::regclass) + 7; \
                 CREATE TABLE {dropped_default_table} (id serial); \
                 ALTER TABLE {dropped_default_table} ALTER COLUMN id DROP DEFAULT",
                pg_quote_literal(&custom_sequence),
                pg_quote_literal(&owned_custom_sequence),
            ))
            .await
            .expect("create serial probe objects");

        let ddl = crate::schema::pg_ddl(&pool, &schema, table_name).await.expect("read serial table ddl");
        let custom_ddl =
            crate::schema::pg_ddl(&pool, &schema, custom_table_name).await.expect("read custom-default table ddl");
        let owned_custom_ddl = crate::schema::pg_ddl(&pool, &schema, owned_custom_table_name)
            .await
            .expect("read owned custom-default table ddl");
        let dropped_default_ddl = crate::schema::pg_ddl(&pool, &schema, dropped_default_table_name)
            .await
            .expect("read dropped-default table ddl");

        assert!(ddl.contains("\"small\"\"id\" smallserial NOT NULL"), "ddl: {ddl}");
        assert!(ddl.contains("\"regular id\" serial NOT NULL"), "ddl: {ddl}");
        assert!(ddl.contains("\"large\"\"id\" bigserial NOT NULL"), "ddl: {ddl}");
        assert!(ddl.contains("\"identity_id\" bigint generated by default as identity"), "ddl: {ddl}");
        assert!(ddl.contains("\"generated\" bigint generated always as ((base * 2)) stored"), "ddl: {ddl}");
        assert!(!ddl.contains("nextval("), "ddl: {ddl}");
        assert!(custom_ddl.contains("bigint DEFAULT nextval("), "ddl: {custom_ddl}");
        assert!(!custom_ddl.contains("bigserial"), "ddl: {custom_ddl}");
        assert!(owned_custom_ddl.contains("bigint NOT NULL DEFAULT (nextval("), "ddl: {owned_custom_ddl}");
        assert!(owned_custom_ddl.contains(" + 7)"), "ddl: {owned_custom_ddl}");
        assert!(!owned_custom_ddl.contains("bigserial"), "ddl: {owned_custom_ddl}");
        assert!(dropped_default_ddl.contains("\"id\" integer NOT NULL"), "ddl: {dropped_default_ddl}");
        assert!(!dropped_default_ddl.contains("serial"), "ddl: {dropped_default_ddl}");
        assert!(!dropped_default_ddl.contains("DEFAULT"), "ddl: {dropped_default_ddl}");

        client.batch_execute(&format!("DROP TABLE {table} CASCADE; {ddl}")).await.expect("replay copied table ddl");
        let inserted = client
            .query_one(
                &format!(
                    "INSERT INTO {table} DEFAULT VALUES RETURNING \"small\"\"id\", \"regular id\", \"large\"\"id\", identity_id, generated"
                ),
                &[],
            )
            .await
            .expect("insert with replayed sequence defaults");
        assert_eq!(inserted.get::<_, i16>(0), 1);
        assert_eq!(inserted.get::<_, i32>(1), 1);
        assert_eq!(inserted.get::<_, i64>(2), 1);
        assert_eq!(inserted.get::<_, i64>(3), 1);
        assert_eq!(inserted.get::<_, i64>(4), 4);

        client.batch_execute(&format!("DROP SCHEMA {schema_ident} CASCADE")).await.expect("drop serial probe schema");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_column_metadata_dependency_joins_return_each_column_once() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let suffix = uuid::Uuid::new_v4().simple();
        let schema = format!("dbx 6547 \"{suffix}");
        let schema_ident = pg_quote_ident(&schema);
        let table_name = "issue6547_repro";
        let table_ident = pg_quote_ident(table_name);
        let table = format!("{schema_ident}.{table_ident}");
        let client = pool.get().await.expect("get postgres client");
        client
            .batch_execute(&format!(
                "CREATE SCHEMA {schema_ident}; \
                 CREATE TABLE {table} (\
                   id serial PRIMARY KEY, \
                   value text, \
                   small_id smallserial, \
                   big_id bigserial, \
                   ident_id bigint GENERATED BY DEFAULT AS IDENTITY, \
                   plain_int integer, \
                   vc varchar(32), \
                   num numeric(10, 2), \
                   ts timestamp\
                 ); \
                 CREATE SEQUENCE {schema_ident}.serial_decoy OWNED BY {table}.id; \
                 CREATE SEQUENCE {schema_ident}.identity_decoy OWNED BY {table}.ident_id; \
                 CREATE INDEX idx_issue6547_repro_id ON {table}(id); \
                 CREATE INDEX idx_issue6547_repro_big ON {table}(big_id); \
                 CREATE UNIQUE INDEX uniq_issue6547_repro_vc ON {table}(vc);"
            ))
            .await
            .expect("create repro table");

        let columns = get_columns(&pool, &schema, table_name).await.expect("get columns");
        // One pg_attribute row must produce exactly one ColumnInfo even when
        // the column has multiple sequence dependencies and several indexes.
        // Only the sequence used by the default, or the internal identity
        // sequence, is semantic metadata for the column.
        let mut seen: std::collections::HashSet<&str> = std::collections::HashSet::new();
        for column in &columns {
            assert!(seen.insert(column.name.as_str()), "duplicate column {:?} in {columns:?}", column.name);
        }
        assert_eq!(columns.len(), 9, "expected 9 columns, got {columns:?}");

        for (name, expected_extra) in [("id", "serial"), ("small_id", "smallserial"), ("big_id", "bigserial")] {
            let column = columns.iter().find(|c| c.name == name).unwrap_or_else(|| panic!("missing {name}"));
            assert_eq!(column.extra.as_deref(), Some(expected_extra), "{name} extra mismatch");
        }
        let ident = columns.iter().find(|c| c.name == "ident_id").expect("ident_id column");
        assert!(
            ident.extra.as_deref().is_some_and(|extra| extra.starts_with("generated by default as identity")),
            "ident_id extra: {:?}",
            ident.extra
        );
        // Ordinary columns keep their plain metadata.
        let vc = columns.iter().find(|c| c.name == "vc").expect("vc column");
        assert_eq!(vc.data_type, "character varying(32)");
        let num = columns.iter().find(|c| c.name == "num").expect("num column");
        assert_eq!(num.data_type, "numeric(10,2)");
        assert_eq!(num.numeric_precision, Some(10));
        assert_eq!(num.numeric_scale, Some(2));
        let ts = columns.iter().find(|c| c.name == "ts").expect("ts column");
        assert_eq!(ts.data_type, "timestamp without time zone");

        // The rendered column section of the DDL must contain each column
        // definition exactly once. Before the dependency-join fix these
        // queries could return "id" (serial + PRIMARY KEY + secondary index
        // = several pg_depend rows) any number of times.
        let ddl = crate::schema::pg_ddl(&pool, &schema, table_name).await.expect("read repro table ddl");
        for needle in [r#"  "id" serial NOT NULL"#, r#"  "value" text"#, r#"  "vc" character varying(32)"#] {
            assert_eq!(ddl.matches(needle).count(), 1, "needle {needle:?} not unique in ddl:\n{ddl}");
        }

        drop(client);
        execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE")).await.expect("drop repro schema");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_column_metadata_compat_query_returns_each_column_once() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let suffix = uuid::Uuid::new_v4().simple();
        let schema = format!("dbx 6547 compat \"{suffix}");
        let schema_ident = pg_quote_ident(&schema);
        let table_name = "issue6547_repro";
        let table_ident = pg_quote_ident(table_name);
        let table = format!("{schema_ident}.{table_ident}");
        let client = pool.get().await.expect("get postgres client");
        client
            .batch_execute(&format!(
                "CREATE SCHEMA {schema_ident}; \
                 CREATE TABLE {table} (id serial PRIMARY KEY, value text); \
                 CREATE SEQUENCE {schema_ident}.serial_decoy OWNED BY {table}.id; \
                 CREATE INDEX idx_issue6547_repro_id ON {table}(id)"
            ))
            .await
            .expect("create compat repro table");

        let columns = get_columns_with_sql(&client, POSTGRES_COLUMNS_COMPAT_SQL, &schema, table_name)
            .await
            .expect("compat columns");
        let names: Vec<&str> = columns.iter().map(|c| c.name.as_str()).collect();
        let mut seen: std::collections::HashSet<&str> = std::collections::HashSet::new();
        for name in &names {
            assert!(seen.insert(*name), "duplicate column {name:?} in {names:?}");
        }
        assert_eq!(names, vec!["id", "value"], "unexpected compat columns {names:?}");
        let id = columns.iter().find(|c| c.name == "id").expect("id column");
        assert_eq!(id.extra.as_deref(), Some("serial"), "compat id extra: {:?}", id.extra);

        drop(client);
        execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE")).await.expect("drop compat repro schema");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_batched_column_metadata_returns_each_column_once() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let suffix = uuid::Uuid::new_v4().simple();
        let schema = format!("dbx 6547 batch \"{suffix}");
        let schema_ident = pg_quote_ident(&schema);
        let table_name = "issue6547_repro";
        let table_ident = pg_quote_ident(table_name);
        let table = format!("{schema_ident}.{table_ident}");
        let client = pool.get().await.expect("get postgres client");
        client
            .batch_execute(&format!(
                "CREATE SCHEMA {schema_ident}; \
                 CREATE TABLE {table} (id serial PRIMARY KEY, value text); \
                 CREATE SEQUENCE {schema_ident}.serial_decoy OWNED BY {table}.id; \
                 CREATE INDEX idx_issue6547_repro_id ON {table}(id)"
            ))
            .await
            .expect("create batch repro table");
        let oid = client
            .query_one(
                "SELECT c.oid::bigint FROM pg_catalog.pg_class c \
                 JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
                 WHERE n.nspname = $1 AND c.relname = $2",
                &[&schema, &table_name],
            )
            .await
            .expect("lookup repro table oid")
            .get::<_, i64>(0);
        let relations = vec![(oid, schema.clone(), table_name.to_string())];

        let columns_by_oid = get_columns_for_relations(&pool, &relations).await.expect("batched columns");
        let columns = columns_by_oid.get(&oid).unwrap_or_else(|| panic!("no batched columns for {oid}"));
        let names: Vec<&str> = columns.iter().map(|c| c.name.as_str()).collect();
        let mut seen: std::collections::HashSet<&str> = std::collections::HashSet::new();
        for name in &names {
            assert!(seen.insert(*name), "duplicate column {name:?} in {names:?}");
        }
        assert_eq!(names, vec!["id", "value"], "unexpected batched columns {names:?}");
        let id = columns.iter().find(|c| c.name == "id").expect("id column");
        assert_eq!(id.extra.as_deref(), Some("serial"), "batched id extra: {:?}", id.extra);

        // The batched sibling must stay duplicate-free too: the partition DDL
        // path (pg_ddl_with_partitions) consumes exactly these results.
        let columns_by_oid_compat =
            get_columns_for_relations_with_sql(&client, postgres_columns_for_relations_compat_sql(), &[oid])
                .await
                .expect("batched compat columns");
        let names_compat: Vec<&str> = columns_by_oid_compat
            .get(&oid)
            .expect("no batched compat columns")
            .iter()
            .map(|c| c.name.as_str())
            .collect();
        let mut seen_compat: std::collections::HashSet<&str> = std::collections::HashSet::new();
        for name in &names_compat {
            assert!(seen_compat.insert(*name), "duplicate column {name:?} in {names_compat:?}");
        }
        assert_eq!(names_compat, vec!["id", "value"], "unexpected batched compat columns {names_compat:?}");

        drop(client);
        execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE")).await.expect("drop batch repro schema");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL 9.x database"]
    async fn postgres_legacy_table_ddl_uses_compatible_partition_probe() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let version = execute_query(&pool, "SHOW server_version_num").await.expect("query PostgreSQL version");
        let version_num = version.rows[0][0]
            .as_str()
            .expect("server_version_num should be text")
            .parse::<u32>()
            .expect("server_version_num should be numeric");
        assert!((90000..100000).contains(&version_num), "expected PostgreSQL 9.x, got {version_num}");

        let schema = format!("dbx_legacy_ddl_{}", uuid::Uuid::new_v4().simple());
        let schema_ident = pg_quote_ident(&schema);
        let parent = format!("{schema_ident}.parent");
        let child = format!("{schema_ident}.child");
        let function = format!("{schema_ident}.fill_child_name");
        let client = pool.get().await.expect("get postgres client");
        client
            .batch_execute(&format!(
                "CREATE SCHEMA {schema_ident}; \
                 CREATE TABLE {parent} (id integer PRIMARY KEY); \
                 CREATE TABLE {child} (parent_id integer REFERENCES {parent}(id), name text) INHERITS ({parent}); \
                 ALTER TABLE {child} ADD PRIMARY KEY (id); \
                 CREATE INDEX child_name_idx ON {child}(name); \
                 CREATE FUNCTION {function}() RETURNS trigger LANGUAGE plpgsql AS $$BEGIN NEW.name := COALESCE(NEW.name, chr(120)); RETURN NEW; END$$; \
                 CREATE TRIGGER child_bi BEFORE INSERT ON {child} FOR EACH ROW EXECUTE PROCEDURE {function}()"
            ))
            .await
            .expect("create PostgreSQL 9.x DDL fixtures");
        drop(client);

        let partition_info =
            get_table_partition_info(&pool, &schema, "child").await.expect("classify PostgreSQL 9.x inherited table");
        let ddl = crate::schema::pg_ddl(&pool, &schema, "child").await;
        // 查看表 DDL（DISPLAY 路径）在 9.x 上不能因 relispartition 报错，
        // INHERITS 子表也不能被当成声明式分区渲染。
        // The view-DDL path must not fail on the missing relispartition
        // column pre-10, and INHERITS children must render as plain tables.
        let ddl_with_partitions = crate::schema::pg_ddl_with_partitions(&pool, &schema, "child").await;
        let parent_ddl = crate::schema::pg_ddl_with_partitions(&pool, &schema, "parent").await;
        execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE"))
            .await
            .expect("drop PostgreSQL 9.x DDL fixtures");
        let ddl = ddl.expect("generate PostgreSQL 9.x table DDL");
        let ddl_with_partitions = ddl_with_partitions.expect("generate PostgreSQL 9.x partition-tree DDL");
        let parent_ddl = parent_ddl.expect("generate PostgreSQL 9.x partition-tree DDL for parent");

        assert!(ddl.contains("CREATE TABLE"), "ddl: {ddl}");
        assert!(ddl.contains("PRIMARY KEY"), "ddl: {ddl}");
        assert!(ddl.contains("FOREIGN KEY"), "ddl: {ddl}");
        assert!(ddl.contains("CREATE INDEX \"child_name_idx\""), "ddl: {ddl}");
        assert!(ddl.contains("CREATE TRIGGER child_bi"), "ddl: {ddl}");
        assert_eq!(partition_info, PostgresTablePartitionInfo::default());
        assert!(!ddl.contains("PARTITION OF"), "ddl: {ddl}");
        assert!(ddl_with_partitions.contains("CREATE TABLE"), "ddl_with_partitions: {ddl_with_partitions}");
        assert!(!ddl_with_partitions.contains("PARTITION OF"), "ddl_with_partitions: {ddl_with_partitions}");
        // 9.x 没有声明式分区：父表的分区树只含父表自身（子表按普通表）。
        assert_eq!(parent_ddl.matches("CREATE TABLE").count(), 1, "parent_ddl: {parent_ddl}");
        assert!(!parent_ddl.contains("PARTITION OF"), "parent_ddl: {parent_ddl}");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_legacy_batched_ddl_metadata_preserves_relation_pairs_across_compat_tiers() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let schema = format!("dbx_batch_fkeys_{}", uuid::Uuid::new_v4().simple());
        let schema_ident = pg_quote_ident(&schema);
        let client = pool.get().await.expect("get postgres client");
        client
            .batch_execute(&format!(
                "CREATE SCHEMA {schema_ident}; \
                 CREATE TABLE {schema_ident}.parent_a (id integer PRIMARY KEY); \
                 CREATE TABLE {schema_ident}.parent_b (id integer PRIMARY KEY); \
                 CREATE TABLE {schema_ident}.child_a ( \
                   id integer PRIMARY KEY, parent_id integer, \
                   CONSTRAINT child_a_parent_fk FOREIGN KEY (parent_id) REFERENCES {schema_ident}.parent_a(id) \
                 ); \
                 CREATE TABLE {schema_ident}.child_b ( \
                   id integer PRIMARY KEY, parent_id integer, \
                   CONSTRAINT child_b_parent_fk FOREIGN KEY (parent_id) REFERENCES {schema_ident}.parent_b(id) \
                 ); \
                 CREATE TABLE {schema_ident}.without_fk (id integer PRIMARY KEY)"
            ))
            .await
            .expect("create batched foreign-key fixtures");

        let version_num = client
            .query_one("SHOW server_version_num", &[])
            .await
            .expect("query PostgreSQL version")
            .get::<_, String>(0)
            .parse::<u32>()
            .expect("server_version_num should be numeric");
        let has_conparentid = client
            .query_one(
                "SELECT EXISTS ( \
                   SELECT 1 FROM pg_catalog.pg_attribute \
                   WHERE attrelid = 'pg_catalog.pg_constraint'::pg_catalog.regclass \
                     AND attname = 'conparentid' AND NOT attisdropped \
                 )",
                &[],
            )
            .await
            .expect("probe pg_constraint.conparentid")
            .get::<_, bool>(0);
        if version_num < 110000 {
            assert!(!has_conparentid, "pre-11 PostgreSQL must not have parent-linked constraint clones");
        }

        let empty = list_foreign_keys_for_relations(&pool, &[]).await.expect("empty relation batch");
        assert!(empty.is_empty());

        let single_relations = vec![(schema.clone(), "child_a".to_string())];
        let single = list_foreign_keys_for_relations(&pool, &single_relations).await.expect("single relation batch");
        let single_fk = &single[&(schema.clone(), "child_a".to_string())][0];
        assert_eq!(single_fk.name, "child_a_parent_fk");
        assert_eq!(single_fk.ref_table, "parent_a");

        // Keep the pairs deliberately out of name order. A cross product or
        // independently unnested array would duplicate or misattribute keys.
        let relations = vec![
            (schema.clone(), "child_b".to_string()),
            (schema.clone(), "without_fk".to_string()),
            (schema.clone(), "child_a".to_string()),
        ];
        let batched = list_foreign_keys_for_relations(&pool, &relations).await.expect("multi-relation batch");
        assert_eq!(batched.len(), 2, "batched keys: {batched:?}");
        assert!(!batched.contains_key(&(schema.clone(), "without_fk".to_string())));
        assert_eq!(batched[&(schema.clone(), "child_a".to_string())][0].ref_table, "parent_a");
        assert_eq!(batched[&(schema.clone(), "child_b".to_string())][0].ref_table, "parent_b");

        let schemas: Vec<&str> = relations.iter().map(|(schema, _)| schema.as_str()).collect();
        let tables: Vec<&str> = relations.iter().map(|(_, table)| table.as_str()).collect();
        let compat = list_foreign_keys_for_relations_with_sql(
            &client,
            postgres_foreign_keys_for_relations_compat_sql(),
            &schemas,
            &tables,
        )
        .await
        .expect("subscript-paired compatibility query");
        assert_eq!(compat[&(schema.clone(), "child_a".to_string())][0].ref_table, "parent_a");
        assert_eq!(compat[&(schema.clone(), "child_b".to_string())][0].ref_table, "parent_b");

        let modern = list_foreign_keys_for_relations_with_sql(
            &client,
            postgres_foreign_keys_for_relations_sql(),
            &schemas,
            &tables,
        )
        .await;
        if version_num >= 90400 {
            let modern = modern.expect("multi-array unnest primary query");
            assert_eq!(modern[&(schema.clone(), "child_a".to_string())][0].ref_table, "parent_a");
            assert_eq!(modern[&(schema.clone(), "child_b".to_string())][0].ref_table, "parent_b");
        } else {
            modern.expect_err("pre-9.4 server must reject multi-array unnest");
        }

        let relation_oids: Vec<i64> = client
            .query(
                "SELECT c.oid::bigint \
                 FROM pg_catalog.pg_class c \
                 JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \
                 WHERE n.nspname = $1 ORDER BY c.relname",
                &[&schema],
            )
            .await
            .expect("query fixture relation oids")
            .into_iter()
            .map(|row| row.get(0))
            .collect();
        get_table_partition_local_objects_for_relations_with_sql(
            &client,
            postgres_table_partition_local_objects_for_relations_compat_sql(),
            &relation_oids,
        )
        .await
        .expect("pre-parent-clone local-object query");
        let modern_local_objects = get_table_partition_local_objects_for_relations_with_sql(
            &client,
            postgres_table_partition_local_objects_for_relations_sql(),
            &relation_oids,
        )
        .await;
        if version_num >= 90300 {
            modern_local_objects.expect("JSON-extraction local-object query");
        } else {
            modern_local_objects.expect_err("PostgreSQL 9.2 must reject the JSON ->> operator");
        }
        drop(client);

        let child_ddl = crate::schema::pg_ddl_with_partitions(&pool, &schema, "child_a")
            .await
            .expect("display DDL with foreign key");
        let without_fk_ddl = crate::schema::pg_ddl_with_partitions(&pool, &schema, "without_fk")
            .await
            .expect("display DDL without foreign key");
        execute_query(&pool, &format!("DROP SCHEMA {schema_ident} CASCADE"))
            .await
            .expect("drop batched foreign-key fixtures");

        assert!(child_ddl.contains("FOREIGN KEY"), "child ddl: {child_ddl}");
        assert!(!without_fk_ddl.contains("FOREIGN KEY"), "without-fk ddl: {without_fk_ddl}");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_ddl_emits_not_valid_check_constraints_as_separate_replayable_alter() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let pid = std::process::id();
        let schema = format!("dbx_not_valid_check_{pid}");
        let schema_ident = pg_quote_ident(&schema);
        let table = format!("{schema_ident}.events");

        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");
        let client = pool.get().await.expect("get postgres client");
        client
            .batch_execute(&format!(
                "CREATE TABLE {table} (id integer, amount integer); \
                 ALTER TABLE {table} ADD CONSTRAINT c_pos CHECK (amount > 0) NOT VALID"
            ))
            .await
            .expect("create table with unvalidated check constraint");

        let ddl = crate::schema::pg_ddl(&pool, &schema, "events").await.expect("events ddl");

        // A `NOT VALID` CHECK constraint is illegal inline in a `CREATE
        // TABLE` column list — Postgres only accepts it after `ALTER TABLE
        // ADD CONSTRAINT`. Replaying the generated DDL onto a fresh schema
        // exercises that this is real, executable syntax, not just a string
        // match.
        let replay_schema = format!("{schema}_replay");
        let replay_schema_ident = pg_quote_ident(&replay_schema);
        execute_query(&pool, &format!("CREATE SCHEMA {replay_schema_ident}")).await.expect("create replay schema");
        client
            .batch_execute(&ddl.replace(&schema, &replay_schema))
            .await
            .unwrap_or_else(|error| panic!("replay not-valid-check ddl failed: {error:?}; ddl: {ddl}"));

        client
            .batch_execute(&format!("DROP SCHEMA {schema_ident} CASCADE; DROP SCHEMA {replay_schema_ident} CASCADE"))
            .await
            .expect("drop schemas");

        assert!(!ddl.contains("NOT VALID)"), "NOT VALID must not appear inline in the column list: {ddl}");
        assert!(ddl.contains("CREATE TABLE"), "ddl: {ddl}");
        assert!(!ddl.contains("\"amount\" integer,"), "check constraint must not be inlined into columns: {ddl}");
        assert!(ddl.contains("ALTER TABLE"), "ddl: {ddl}");
        assert!(
            ddl.contains("ADD CONSTRAINT \"c_pos\" CHECK (amount > 0) NOT VALID;"),
            "expected a separate ALTER TABLE ADD CONSTRAINT ... NOT VALID statement: {ddl}"
        );
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_partition_metadata_renders_replayable_children_and_subpartitions() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let pid = std::process::id();
        let schema = format!("dbx_partition_meta_{pid}");
        let schema_ident = pg_quote_ident(&schema);
        let replay_schema = format!("{schema}_replay");
        let replay_schema_ident = pg_quote_ident(&replay_schema);
        let parent = format!("{schema_ident}.parent");
        let child = format!("{schema_ident}.child");
        let default_child = format!("{schema_ident}.child_default");
        let subpartition = format!("{schema_ident}.subpartition");
        let inherited_parent = format!("{schema_ident}.inherited_parent");
        let inherited_child = format!("{schema_ident}.inherited_child");
        // Declared in "public" (not the per-test schema) so the same
        // qualified name keeps resolving after `schema_ident` substrings are
        // rewritten to `replay_schema_ident` for the replay pass below.
        let trigger_fn = format!("public.dbx_partition_meta_trigger_fn_{pid}");

        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");
        let client = pool.get().await.expect("get postgres client");
        client
            .batch_execute(&format!(
                "CREATE OR REPLACE FUNCTION {trigger_fn}() RETURNS trigger LANGUAGE plpgsql AS \
                 $$ BEGIN RETURN NEW; END $$; \
                 CREATE TABLE {parent} (id integer, payload text, status text DEFAULT 'pending') PARTITION BY RANGE (id); \
                 CREATE TABLE {child} PARTITION OF {parent} ( \
                   PRIMARY KEY (id), \
                   CONSTRAINT child_payload_not_blank CHECK (payload <> ''), \
                   status WITH OPTIONS DEFAULT 'child-status' \
                 ) FOR VALUES FROM (1) TO (10); \
                 CREATE INDEX child_payload_idx ON {child} (payload); \
                 CREATE TABLE {default_child} PARTITION OF {parent} DEFAULT; \
                 CREATE TABLE {subpartition} PARTITION OF {parent} FOR VALUES FROM (10) TO (20) PARTITION BY HASH (payload); \
                 ALTER TABLE {parent} ADD CONSTRAINT parent_id_positive CHECK (id > 0); \
                 CREATE TRIGGER parent_biu BEFORE INSERT ON {parent} FOR EACH ROW EXECUTE FUNCTION {trigger_fn}(); \
                 CREATE TABLE {inherited_parent} (id integer, bucket integer, PRIMARY KEY (id, bucket)) PARTITION BY RANGE (bucket); \
                 CREATE TABLE {inherited_child} PARTITION OF {inherited_parent} FOR VALUES FROM (1) TO (10)"
            ))
            .await
            .expect("create partitioned tables");

        let parent_info = get_table_partition_info(&pool, &schema, "parent").await.expect("parent metadata");
        let child_info = get_table_partition_info(&pool, &schema, "child").await.expect("child metadata");
        let default_info = get_table_partition_info(&pool, &schema, "child_default").await.expect("default metadata");
        let subpartition_info =
            get_table_partition_info(&pool, &schema, "subpartition").await.expect("subpartition metadata");
        let child_local_objects =
            get_table_partition_local_objects(&pool, &schema, "child").await.expect("child local objects");
        let inherited_child_local_objects = get_table_partition_local_objects(&pool, &schema, "inherited_child")
            .await
            .expect("inherited child local objects");
        let parent_ddl = crate::schema::pg_ddl_with_partitions(&pool, &schema, "parent").await.expect("parent ddl");
        let child_ddl = crate::schema::pg_ddl(&pool, &schema, "child").await.expect("child ddl");
        let default_ddl = crate::schema::pg_ddl(&pool, &schema, "child_default").await.expect("default ddl");
        let subpartition_ddl = crate::schema::pg_ddl(&pool, &schema, "subpartition").await.expect("subpartition ddl");
        let inherited_parent_ddl = crate::schema::pg_ddl_with_partitions(&pool, &schema, "inherited_parent")
            .await
            .expect("inherited parent ddl");
        let inherited_child_ddl =
            crate::schema::pg_ddl(&pool, &schema, "inherited_child").await.expect("inherited child ddl");
        // The bare (non-recursive) parent DDL, exactly what database export
        // and table transfer produce per-relation — used below to give the
        // single-relation partition ddls (child_ddl, default_ddl,
        // subpartition_ddl, inherited_child_ddl) a real parent shell to
        // replay against, so their syntax is actually exercised by
        // PostgreSQL rather than only checked with string assertions.
        let bare_parent_ddl = crate::schema::pg_ddl(&pool, &schema, "parent").await.expect("bare parent ddl");
        let bare_inherited_parent_ddl =
            crate::schema::pg_ddl(&pool, &schema, "inherited_parent").await.expect("bare inherited parent ddl");

        // `parent_ddl`/`inherited_parent_ddl` already embed their full
        // partition subtree (that's the fix under test), so replaying the
        // per-partition ddl strings on top would recreate the same relations
        // twice. Only the two top-level requests need replaying; the
        // individually-fetched partition ddls above are replayed separately
        // below, on top of a bare (childless) copy of their parent.
        execute_query(&pool, &format!("CREATE SCHEMA {replay_schema_ident}")).await.expect("create replay schema");
        for ddl in [&parent_ddl, &inherited_parent_ddl] {
            client
                .batch_execute(&ddl.replace(&schema, &replay_schema))
                .await
                .unwrap_or_else(|error| panic!("replay partition ddl failed: {error:?}; ddl: {ddl}"));
        }

        // Single-relation partition ddls are now a real production code
        // path (database export/table transfer fetch each partition this
        // way), so replay them for real too: a fresh schema gets just the
        // bare parents, then each single-relation partition ddl on top.
        let bare_schema = format!("{schema}_bare");
        let bare_schema_ident = pg_quote_ident(&bare_schema);
        execute_query(&pool, &format!("CREATE SCHEMA {bare_schema_ident}")).await.expect("create bare schema");
        for ddl in [&bare_parent_ddl, &bare_inherited_parent_ddl] {
            client
                .batch_execute(&ddl.replace(&schema, &bare_schema))
                .await
                .unwrap_or_else(|error| panic!("replay bare parent ddl failed: {error:?}; ddl: {ddl}"));
        }
        for ddl in [&child_ddl, &default_ddl, &subpartition_ddl, &inherited_child_ddl] {
            client
                .batch_execute(&ddl.replace(&schema, &bare_schema))
                .await
                .unwrap_or_else(|error| panic!("replay single-relation partition ddl failed: {error:?}; ddl: {ddl}"));
        }

        client
            .batch_execute(&format!(
                "DROP SCHEMA {schema_ident} CASCADE; DROP SCHEMA {replay_schema_ident} CASCADE; \
                 DROP SCHEMA {bare_schema_ident} CASCADE; DROP FUNCTION IF EXISTS {trigger_fn}()"
            ))
            .await
            .expect("drop schemas and trigger function");

        assert_eq!(parent_info.key.as_deref(), Some("RANGE (id)"));
        assert!(!parent_info.is_partition);
        assert_eq!(child_info.parent_schema.as_deref(), Some(schema.as_str()));
        assert_eq!(child_info.parent_table.as_deref(), Some("parent"));
        assert_eq!(child_info.bound.as_deref(), Some("FOR VALUES FROM (1) TO (10)"));
        assert!(child_local_objects.has_primary_key);
        assert!(child_local_objects.indexes.contains("child_payload_idx"));
        assert!(child_local_objects.check_constraints.contains("child_payload_not_blank"));
        assert!(!child_local_objects.check_constraints.contains("parent_id_positive"));
        assert_eq!(child_local_objects.column_defaults.get("status"), Some(&PostgresColumnDefaultState::Overridden));
        assert!(!inherited_child_local_objects.has_primary_key);
        assert!(inherited_child_local_objects.indexes.is_empty());
        assert_eq!(default_info.bound.as_deref(), Some("DEFAULT"));
        assert_eq!(subpartition_info.key.as_deref(), Some("HASH (payload)"));
        assert!(parent_ddl.contains(") PARTITION BY RANGE (id);"), "ddl: {parent_ddl}");
        assert!(parent_ddl.contains("CONSTRAINT \"parent_id_positive\" CHECK (id > 0)"), "ddl: {parent_ddl}");
        // The parent's trigger is automatically cloned onto every partition
        // by PostgreSQL itself when the partition is created/attached, so it
        // must appear exactly once in the combined DDL, not once per relation.
        assert_eq!(parent_ddl.matches("CREATE TRIGGER").count(), 1, "ddl: {parent_ddl}");
        assert!(child_ddl.contains("CREATE TABLE"), "ddl: {child_ddl}");
        assert!(child_ddl.contains("PARTITION OF"), "ddl: {child_ddl}");
        assert!(child_ddl.contains("PRIMARY KEY (\"id\")"), "ddl: {child_ddl}");
        assert!(child_ddl.contains("FOR VALUES FROM (1) TO (10);"), "ddl: {child_ddl}");
        assert!(child_ddl.contains("CREATE INDEX \"child_payload_idx\""), "ddl: {child_ddl}");
        assert!(child_ddl.contains("CONSTRAINT \"child_payload_not_blank\" CHECK (payload"), "ddl: {child_ddl}");
        assert!(!child_ddl.contains("parent_id_positive"), "ddl: {child_ddl}");
        assert!(child_ddl.contains("\"status\" WITH OPTIONS DEFAULT 'child-status'"), "ddl: {child_ddl}");
        assert!(
            !child_ddl.contains("CREATE TRIGGER"),
            "child must not redeclare the parent's cloned trigger: {child_ddl}"
        );
        assert!(default_ddl.contains(" DEFAULT;"), "ddl: {default_ddl}");
        assert!(
            subpartition_ddl.contains("FOR VALUES FROM (10) TO (20) PARTITION BY HASH (payload);"),
            "ddl: {subpartition_ddl}"
        );
        assert!(!inherited_child_ddl.contains("PRIMARY KEY"), "ddl: {inherited_child_ddl}");
        assert!(!inherited_child_ddl.contains("CREATE INDEX"), "ddl: {inherited_child_ddl}");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database with postgres_fdw available"]
    async fn postgres_partition_ddl_uses_foreign_table_syntax_for_foreign_partitions() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let pid = std::process::id();
        let schema = format!("dbx_partition_fdw_{pid}");
        let schema_ident = pg_quote_ident(&schema);
        let server = format!("dbx_partition_fdw_server_{pid}");
        let server_ident = pg_quote_ident(&server);
        let replay_schema = format!("{schema}_replay");
        let replay_schema_ident = pg_quote_ident(&replay_schema);
        let parent = format!("{schema_ident}.parent");
        let local_child = format!("{schema_ident}.local_child");
        let foreign_child = format!("{schema_ident}.foreign_child");

        execute_query(&pool, &format!("CREATE SCHEMA {schema_ident}")).await.expect("create schema");
        let client = pool.get().await.expect("get postgres client");
        client
            .batch_execute(&format!(
                "CREATE EXTENSION IF NOT EXISTS postgres_fdw; \
                 CREATE SERVER {server_ident} FOREIGN DATA WRAPPER postgres_fdw \
                   OPTIONS (host 'localhost', dbname 'postgres', port '5432'); \
                 CREATE USER MAPPING FOR CURRENT_USER SERVER {server_ident} \
                   OPTIONS (user 'postgres', password 'postgres'); \
                 CREATE TABLE {parent} (id integer, payload text) PARTITION BY RANGE (id); \
                 CREATE TABLE {local_child} PARTITION OF {parent} FOR VALUES FROM (1) TO (10); \
                 CREATE FOREIGN TABLE {foreign_child} PARTITION OF {parent} \
                   FOR VALUES FROM (10) TO (20) \
                   SERVER {server_ident} OPTIONS (schema_name 'public', table_name 'foreign_child_data')"
            ))
            .await
            .expect("create partitioned tables with a foreign partition");

        let foreign_info = get_table_partition_info(&pool, &schema, "foreign_child").await.expect("foreign child info");
        let local_info = get_table_partition_info(&pool, &schema, "local_child").await.expect("local child info");
        let parent_ddl = crate::schema::pg_ddl_with_partitions(&pool, &schema, "parent").await.expect("parent ddl");
        let foreign_ddl = crate::schema::pg_ddl(&pool, &schema, "foreign_child").await.expect("foreign child ddl");

        execute_query(&pool, &format!("CREATE SCHEMA {replay_schema_ident}")).await.expect("create replay schema");
        client
            .batch_execute(&parent_ddl.replace(&schema, &replay_schema))
            .await
            .unwrap_or_else(|error| panic!("replay foreign partition ddl failed: {error:?}; ddl: {parent_ddl}"));

        client
            .batch_execute(&format!(
                "DROP SCHEMA {schema_ident} CASCADE; DROP SCHEMA {replay_schema_ident} CASCADE; \
                 DROP SERVER {server_ident} CASCADE"
            ))
            .await
            .expect("drop schemas and foreign server");

        assert!(!local_info.is_foreign);
        assert!(foreign_info.is_foreign);
        assert_eq!(foreign_info.foreign_server.as_deref(), Some(server.as_str()));
        assert!(
            foreign_info.foreign_options.contains(&("schema_name".to_string(), "public".to_string())),
            "options: {:?}",
            foreign_info.foreign_options
        );
        assert!(parent_ddl.contains("CREATE FOREIGN TABLE"), "ddl: {parent_ddl}");
        assert!(foreign_ddl.starts_with("CREATE FOREIGN TABLE"), "ddl: {foreign_ddl}");
        assert!(foreign_ddl.contains("PARTITION OF"), "ddl: {foreign_ddl}");
        assert!(foreign_ddl.contains(&format!("SERVER {}", pg_quote_ident(&server))), "ddl: {foreign_ddl}");
        assert!(foreign_ddl.contains("\"schema_name\" 'public'"), "ddl: {foreign_ddl}");
        assert!(foreign_ddl.contains("\"table_name\" 'foreign_child_data'"), "ddl: {foreign_ddl}");
        assert!(!foreign_ddl.contains("PRIMARY KEY"), "ddl: {foreign_ddl}");
        assert!(!foreign_ddl.contains("CREATE INDEX"), "ddl: {foreign_ddl}");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn postgres_schema_context_prioritizes_selected_schema_and_cleans_up() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect(&url, Duration::from_secs(5)).await.expect("connect postgres");
        let suffix = format!("{}_{}", std::process::id(), uuid::Uuid::new_v4().simple());
        let schema = format!("dbx_issue_830_\"{suffix}");
        let schema_ident = pg_quote_ident(&schema);
        let helper = format!("dbx_issue_830_public_{suffix}");
        let helper_ident = pg_quote_ident(&helper);
        let initial_path = execute_query(&pool, "SHOW search_path").await.expect("read initial search_path");
        let initial_path_value = initial_path.rows[0][0].as_str().expect("search_path string").to_string();
        let client = pool.get().await.expect("get setup client");
        client
            .batch_execute(&format!(
                "CREATE SCHEMA {schema_ident}; \
                 CREATE TABLE {schema_ident}.pg_settings(marker text); \
                 INSERT INTO {schema_ident}.pg_settings VALUES ('selected-schema'); \
                 CREATE FUNCTION public.{helper_ident}() RETURNS text \
                 LANGUAGE SQL IMMUTABLE AS $$ SELECT 'public-fallback'::text $$"
            ))
            .await
            .expect("create search_path fixtures");
        drop(client);

        let query_sql = format!("SELECT marker, {helper_ident}() AS helper FROM pg_settings");
        let stale_session_recovery = async {
            let client = pool.get().await.map_err(|error| error.to_string())?;
            set_postgres_search_path(&client, &schema, PostgresSearchPathContext::Query, Duration::from_secs(5))
                .await?;
            client.execute("SET search_path TO public", &[]).await.map_err(pg_error_to_string)?;
            set_postgres_search_path(&client, &schema, PostgresSearchPathContext::Query, Duration::from_secs(5))
                .await?;
            let selected: String = client
                .query_one("SELECT marker FROM pg_settings", &[])
                .await
                .map_err(pg_error_to_string)?
                .try_get(0)
                .map_err(pg_error_to_string)?;
            client.execute("RESET search_path", &[]).await.map_err(pg_error_to_string)?;
            Ok::<_, String>(selected)
        }
        .await;
        let ordinary_result = execute_query_with_schema(&pool, &schema, &query_sql).await;
        let path_after_ordinary = execute_query(&pool, "SHOW search_path").await;
        let read_only_result = execute_query_in_read_only_transaction_with_rollback(
            &pool,
            Some(&schema),
            &query_sql,
            None,
            None,
            DbOperationBudget::with_defaults(),
            None,
        )
        .await;
        let path_after_read_only = execute_query(&pool, "SHOW search_path").await;

        let mut streamed_rows = Vec::new();
        let streaming_result = stream_select_query_with_cancel(
            &pool,
            Some(&schema),
            &[],
            &query_sql,
            None,
            None,
            DbOperationBudget::with_defaults(),
            None,
            |item| {
                if let PostgresQueryStreamItem::Row(row) = item {
                    streamed_rows.push(row);
                }
                Ok(())
            },
        )
        .await;
        let path_after_streaming = execute_query(&pool, "SHOW search_path").await;

        let transaction_cleanup = async {
            let client = pool.get().await.map_err(|error| error.to_string())?;
            client
                .execute(&postgres_set_search_path_sql(&schema, PostgresSearchPathContext::Transaction), &[])
                .await
                .map_err(pg_error_to_string)?;
            let selected: String = client
                .query_one("SELECT marker FROM pg_settings", &[])
                .await
                .map_err(pg_error_to_string)?
                .try_get(0)
                .map_err(pg_error_to_string)?;
            client.execute("RESET search_path", &[]).await.map_err(pg_error_to_string)?;
            let after_reset: String = client
                .query_one("SHOW search_path", &[])
                .await
                .map_err(pg_error_to_string)?
                .try_get(0)
                .map_err(pg_error_to_string)?;

            client.execute("BEGIN", &[]).await.map_err(pg_error_to_string)?;
            client
                .execute(&postgres_set_search_path_sql(&schema, PostgresSearchPathContext::LocalTransaction), &[])
                .await
                .map_err(pg_error_to_string)?;
            let local_selected: String = client
                .query_one("SELECT marker FROM pg_settings", &[])
                .await
                .map_err(pg_error_to_string)?
                .try_get(0)
                .map_err(pg_error_to_string)?;
            client.execute("COMMIT", &[]).await.map_err(pg_error_to_string)?;
            let after_commit: String = client
                .query_one("SHOW search_path", &[])
                .await
                .map_err(pg_error_to_string)?
                .try_get(0)
                .map_err(pg_error_to_string)?;
            Ok::<_, String>((selected, after_reset, local_selected, after_commit))
        }
        .await;

        let cleanup_client = pool.get().await.expect("get cleanup client");
        cleanup_client
            .batch_execute(&format!("DROP FUNCTION public.{helper_ident}(); DROP SCHEMA {schema_ident} CASCADE"))
            .await
            .expect("clean search_path fixtures");

        let ordinary = ordinary_result.expect("ordinary schema query");
        assert_eq!(stale_session_recovery.expect("recover stale session search_path"), "selected-schema");
        assert_eq!(
            ordinary.rows,
            vec![vec![serde_json::json!("selected-schema"), serde_json::json!("public-fallback")]]
        );
        assert_eq!(path_after_ordinary.expect("path after ordinary query").rows, initial_path.rows);
        assert_eq!(
            read_only_result.expect("read-only schema query").rows,
            vec![vec![serde_json::json!("selected-schema"), serde_json::json!("public-fallback")]]
        );
        assert_eq!(path_after_read_only.expect("path after read-only query").rows, initial_path.rows);
        assert_eq!(streaming_result.expect("streaming schema query"), 1);
        assert_eq!(
            streamed_rows,
            vec![vec![serde_json::json!("selected-schema"), serde_json::json!("public-fallback")]]
        );
        assert_eq!(path_after_streaming.expect("path after streaming query").rows, initial_path.rows);
        let (selected, after_reset, local_selected, after_commit) = transaction_cleanup.expect("transaction cleanup");
        assert_eq!(selected, "selected-schema");
        assert_eq!(local_selected, "selected-schema");
        assert_eq!(after_reset, initial_path_value);
        assert_eq!(after_commit, initial_path_value);
    }

    #[test]
    fn postgres_index_metadata_has_legacy_catalog_fallback() {
        assert!(POSTGRES_INDEXES_SQL.contains("ix.indnkeyatts"));
        assert!(!POSTGRES_INDEXES_COMPAT_SQL.contains("ix.indnkeyatts"));
        assert!(POSTGRES_INDEXES_COMPAT_SQL.contains("NULL::smallint AS nkeyatts"));
        assert!(!POSTGRES_INDEXES_COMPAT_SQL.contains("LATERAL"));
        assert!(!POSTGRES_INDEXES_COMPAT_SQL.contains("WITH ORDINALITY"));
        assert!(POSTGRES_INDEXES_COMPAT_SQL.contains("generate_series"));
        assert!(POSTGRES_INDEXES_COMPAT_SQL.contains("string_to_array(ix.indkey::text, ' ')"));
        for sql in [
            POSTGRES_INDEXES_SQL,
            POSTGRES_INDEXES_COMPAT_SQL,
            postgres_indexes_for_relations_sql(),
            postgres_indexes_for_relations_compat_sql(),
        ] {
            assert!(sql.contains("ix.indisunique AND ix.indisvalid"));
        }
    }

    #[test]
    fn postgres_index_metadata_tracks_expression_key_provenance() {
        // #6295 fix: each index key part's `a.attname IS NULL` tags whether it came from a real
        // column or from pg_get_indexdef, so DDL generation never has to guess from the text.
        assert!(POSTGRES_INDEXES_SQL.contains("array_agg(a.attname IS NULL ORDER BY k.n) AS key_is_expression"));
        assert!(POSTGRES_INDEXES_COMPAT_SQL.contains("SELECT a.attname IS NULL"));
        assert!(POSTGRES_INDEXES_COMPAT_SQL.contains("AS key_is_expression"));
    }

    #[test]
    fn postgres_index_metadata_schema_qualifies_opclass() {
        // The LATERAL (modern) index-introspection SQL returns each non-default
        // opclass schema-qualified (`quote_ident(nspname) || '.' || quote_ident(opcname)`)
        // and joins `pg_namespace` on `opcnamespace`, so DDL regeneration resolves
        // opclasses (e.g. `gin_trgm_ops` from `pg_trgm`) regardless of `search_path`.
        // The compat (pre-LATERAL) fallback keeps bare `oc.opcname` — no regression,
        // just no schema-qualification for the rare old-PG × non-default-schema case.
        for sql in [POSTGRES_INDEXES_SQL, postgres_indexes_for_relations_sql()] {
            assert!(
                sql.contains("quote_ident(opcns.nspname) || '.' || quote_ident(oc.opcname)"),
                "expected schema-qualified opclass in {sql}"
            );
            assert!(
                sql.contains("LEFT JOIN pg_namespace opcns ON opcns.oid = oc.opcnamespace"),
                "expected opcnamespace join in {sql}"
            );
        }
    }

    #[test]
    fn postgres_owner_metadata_casts_relkind_to_text() {
        assert!(POSTGRES_OWNERS_SQL.contains("c.relkind::text AS relkind"));
        assert!(POSTGRES_OWNERS_SQL.contains("c.relkind IN ('r', 'v', 'm', 'S', 'f', 'p')"));
    }

    #[test]
    fn postgres_owner_object_type_maps_relkind_codes() {
        assert_eq!(postgres_owner_object_type("r"), "TABLE");
        assert_eq!(postgres_owner_object_type("v"), "VIEW");
        assert_eq!(postgres_owner_object_type("m"), "MATERIALIZED_VIEW");
        assert_eq!(postgres_owner_object_type("S"), "SEQUENCE");
        assert_eq!(postgres_owner_object_type("f"), "FOREIGN TABLE");
        assert_eq!(postgres_owner_object_type("p"), "PARTITIONED TABLE");
        assert_eq!(postgres_owner_object_type("?"), "?");
    }

    fn test_custom_type_info(typtype: &str) -> CustomTypeGeneralInfo {
        CustomTypeGeneralInfo {
            oid: 100,
            typtype: typtype.to_string(),
            typisdefined: true,
            typbasetype: 0,
            typnotnull: false,
            typrelid: 0,
            typelem: 0,
            typcollation: 0,
            typdefaultbin: None,
            typdefault: None,
            typlen: -1,
            typbyval: false,
            typalign: "c".to_string(),
            typstorage: "p".to_string(),
            typtypmod: -1,
            input_function: None,
            output_function: None,
            receive_function: None,
            send_function: None,
            analyze_function: None,
            comment: None,
            relkind: None,
            collation: None,
        }
    }

    #[test]
    fn custom_type_ddl_enum_quotes_values_in_order() {
        let info = test_custom_type_info("e");
        let members = vec![
            CustomTypeMember {
                name: String::new(),
                data_type: String::new(),
                ordinal: 1,
                nullable: None,
                default: None,
                comment: None,
                enum_value: Some("draft".to_string()),
            },
            CustomTypeMember {
                name: String::new(),
                data_type: String::new(),
                ordinal: 2,
                nullable: None,
                default: None,
                comment: None,
                enum_value: Some("已归档".to_string()),
            },
        ];
        let ddl = build_custom_type_ddl(
            "app",
            "status",
            CustomTypeKind::Enum,
            &info,
            &members,
            &CustomTypeProperties::default(),
            &[],
        );
        assert_eq!(ddl.sql, "CREATE TYPE \"app\".\"status\" AS ENUM ('draft', '已归档');");
        assert!(ddl.complete);
        assert!(ddl.warnings.is_empty());
    }

    #[test]
    fn custom_type_ddl_composite_lists_fields_and_comments() {
        let info = test_custom_type_info("c");
        let members = vec![
            CustomTypeMember {
                name: "city".to_string(),
                data_type: "text".to_string(),
                ordinal: 1,
                nullable: Some(true),
                default: None,
                comment: Some("city name".to_string()),
                enum_value: None,
            },
            CustomTypeMember {
                name: "zip".to_string(),
                data_type: "numeric(6)".to_string(),
                ordinal: 2,
                nullable: Some(true),
                default: None,
                comment: None,
                enum_value: None,
            },
        ];
        let ddl = build_custom_type_ddl(
            "app",
            "address",
            CustomTypeKind::Composite,
            &info,
            &members,
            &CustomTypeProperties::default(),
            &[],
        );
        assert_eq!(
            ddl.sql,
            "CREATE TYPE \"app\".\"address\" AS (\n  \"city\" text,\n  \"zip\" numeric(6)\n);\nCOMMENT ON COLUMN \"app\".\"address\".\"city\" IS 'city name';"
        );
        assert!(ddl.complete);
    }

    #[test]
    fn custom_type_ddl_domain_combines_base_default_notnull_and_constraints() {
        let info = test_custom_type_info("d");
        let properties = CustomTypeProperties {
            base_type: Some("text".to_string()),
            collation: Some("C".to_string()),
            default: Some("''::text".to_string()),
            not_null: Some(true),
            domain_constraints: vec![CustomTypeDomainConstraint {
                name: "email_valid".to_string(),
                definition: "CHECK ((VALUE <> ''::text))".to_string(),
            }],
            ..Default::default()
        };
        let ddl = build_custom_type_ddl("app", "email", CustomTypeKind::Domain, &info, &[], &properties, &[]);
        assert_eq!(
            ddl.sql,
            "CREATE DOMAIN \"app\".\"email\" AS text\n  COLLATE \"C\"\n  DEFAULT ''::text\n  NOT NULL\n  CONSTRAINT \"email_valid\" CHECK ((VALUE <> ''::text));"
        );
        assert!(ddl.complete);
    }

    #[test]
    fn custom_type_ddl_domain_is_incomplete_when_attributes_failed() {
        let info = test_custom_type_info("d");
        let properties = CustomTypeProperties { base_type: Some("text".to_string()), ..Default::default() };
        let ddl = build_custom_type_ddl(
            "app",
            "email",
            CustomTypeKind::Domain,
            &info,
            &[],
            &properties,
            &["domain constraints could not be read: x".to_string()],
        );
        assert!(!ddl.complete, "DDL must be marked incomplete when constraints failed: {ddl:?}");

        let constraint_decode_failed = build_custom_type_ddl(
            "app",
            "email",
            CustomTypeKind::Domain,
            &info,
            &[],
            &properties,
            &["domain constraints could not be decoded: x".to_string()],
        );
        assert!(
            !constraint_decode_failed.complete,
            "DDL must be marked incomplete when constraints cannot be decoded: {constraint_decode_failed:?}"
        );

        let default_failed = build_custom_type_ddl(
            "app",
            "email",
            CustomTypeKind::Domain,
            &info,
            &[],
            &properties,
            &["default value could not be rendered; the generated DDL is incomplete".to_string()],
        );
        assert!(!default_failed.complete, "DDL must be marked incomplete when the default failed: {default_failed:?}");
        assert!(default_failed.warnings.iter().any(|w| w.contains("default value")));
    }

    #[test]
    fn custom_type_qualified_format_type_expression_qualifies_user_types() {
        let expression = postgres_qualified_format_type_expression("t", "n", "elem", "elem_n", "t.oid", "t.typtypmod");
        assert!(expression.contains("quote_ident(n.nspname) || '.' || quote_ident(t.typname)"));
        assert!(expression.contains("quote_ident(elem_n.nspname) || '.' || quote_ident(elem.typname) || '[]'"));
        assert!(expression.contains("format_type(t.oid, t.typtypmod)"));
    }

    #[test]
    fn custom_type_ddl_range_uses_subtype_and_canonical() {
        let info = test_custom_type_info("r");
        let properties = CustomTypeProperties {
            range_subtype: Some("numeric".to_string()),
            range_canonical_function: Some("numeric_range_canonical".to_string()),
            range_subtype_diff_function: Some("numeric_range_subdiff".to_string()),
            ..Default::default()
        };
        let ddl = build_custom_type_ddl("app", "price_range", CustomTypeKind::Range, &info, &[], &properties, &[]);
        assert_eq!(
            ddl.sql,
            "CREATE TYPE \"app\".\"price_range\" AS RANGE (\n  subtype = numeric,\n  canonical = \"numeric_range_canonical\",\n  subtype_diff = \"numeric_range_subdiff\"\n);"
        );
        assert!(ddl.complete);
    }

    #[test]
    fn custom_type_ddl_range_without_subtype_is_incomplete() {
        let info = test_custom_type_info("r");
        let properties = CustomTypeProperties {
            range_multirange_name: Some("price_multirange".to_string()),
            range_canonical_function: Some("range_canonical".to_string()),
            ..Default::default()
        };
        let ddl = build_custom_type_ddl("app", "price_range", CustomTypeKind::Range, &info, &[], &properties, &[]);

        assert!(!ddl.complete, "a range without subtype cannot be reconstructed: {ddl:?}");
        assert_eq!(ddl.sql, "CREATE TYPE \"app\".\"price_range\" AS RANGE (subtype = unknown);");
        assert!(ddl.warnings.iter().any(|warning| warning.contains("range attributes")));
    }

    #[test]
    fn custom_type_ddl_range_keeps_catalog_qualified_names() {
        let info = test_custom_type_info("r");
        let properties = CustomTypeProperties {
            range_subtype: Some("numeric".to_string()),
            range_canonical_function: Some("\"extensions\".\"range_canonical\"".to_string()),
            range_subtype_diff_function: Some("\"extensions\".\"range_subdiff\"".to_string()),
            range_subtype_opclass: Some("\"extensions\".\"numeric_ops\"".to_string()),
            ..Default::default()
        };
        let ddl = build_custom_type_ddl("app", "price_range", CustomTypeKind::Range, &info, &[], &properties, &[]);

        assert!(ddl.complete, "{ddl:?}");
        assert!(ddl.sql.contains("subtype_opclass = \"extensions\".\"numeric_ops\""));
        assert!(ddl.sql.contains("canonical = \"extensions\".\"range_canonical\""));
        assert!(ddl.sql.contains("subtype_diff = \"extensions\".\"range_subdiff\""));
    }

    #[test]
    fn custom_type_ddl_range_emits_custom_multirange_name() {
        let info = test_custom_type_info("r");
        let properties = CustomTypeProperties {
            range_subtype: Some("numeric".to_string()),
            range_multirange_name: Some("price_multirange".to_string()),
            ..Default::default()
        };
        let ddl = build_custom_type_ddl("app", "price_range", CustomTypeKind::Range, &info, &[], &properties, &[]);
        assert!(ddl.complete, "{ddl:?}");
        assert!(
            ddl.sql.contains("multirange_type_name = \"price_multirange\""),
            "custom multirange name must be emitted: {}",
            ddl.sql
        );
    }

    #[test]
    fn custom_type_ddl_multirange_and_base_are_marked_incomplete() {
        let multirange = build_custom_type_ddl(
            "app",
            "_price_range",
            CustomTypeKind::Multirange,
            &test_custom_type_info("m"),
            &[],
            &CustomTypeProperties::default(),
            &[],
        );
        assert!(!multirange.complete);
        assert!(multirange.sql.is_empty());
        assert!(multirange.warnings.iter().any(|w| w.contains("multirange companion")));

        let base = build_custom_type_ddl(
            "app",
            "point2d",
            CustomTypeKind::Base,
            &test_custom_type_info("b"),
            &[],
            &CustomTypeProperties::default(),
            &[],
        );
        assert!(!base.complete);
        assert!(base.warnings.iter().any(|w| w.contains("base type")));
    }

    #[test]
    fn custom_type_ddl_escapes_identifiers_and_literals() {
        let info = test_custom_type_info("e");
        let members = vec![CustomTypeMember {
            name: String::new(),
            data_type: String::new(),
            ordinal: 1,
            nullable: None,
            default: None,
            comment: None,
            enum_value: Some("it's \"quoted\"".to_string()),
        }];
        let ddl = build_custom_type_ddl(
            "we\"ird",
            "ty\"pe",
            CustomTypeKind::Enum,
            &info,
            &members,
            &CustomTypeProperties::default(),
            &[],
        );
        assert_eq!(ddl.sql, "CREATE TYPE \"we\"\"ird\".\"ty\"\"pe\" AS ENUM ('it''s \"quoted\"');");
    }

    #[test]
    fn custom_type_kind_for_maps_catalog_codes() {
        assert_eq!(custom_type_kind_for("b"), Some(CustomTypeKind::Base));
        assert_eq!(custom_type_kind_for("c"), Some(CustomTypeKind::Composite));
        assert_eq!(custom_type_kind_for("d"), Some(CustomTypeKind::Domain));
        assert_eq!(custom_type_kind_for("e"), Some(CustomTypeKind::Enum));
        assert_eq!(custom_type_kind_for("r"), Some(CustomTypeKind::Range));
        assert_eq!(custom_type_kind_for("m"), Some(CustomTypeKind::Multirange));
        assert_eq!(custom_type_kind_for("p"), None);
    }

    #[test]
    fn custom_type_list_metadata_decodes_kind_and_member_capability() {
        assert_eq!(custom_type_list_metadata(Some("c:1")), (Some("composite".to_string()), Some(true)));
        assert_eq!(custom_type_list_metadata(Some("d:0")), (Some("domain".to_string()), Some(false)));
        assert_eq!(custom_type_list_metadata(None), (None, None));
        assert_eq!(custom_type_list_metadata(Some("invalid")), (None, None));
    }

    #[test]
    fn custom_type_general_info_sql_looks_up_by_schema_and_name() {
        let sql = custom_type_general_info_sql();
        assert!(sql.contains("pg_catalog.pg_type"));
        assert!(sql.contains("pg_catalog.pg_namespace"));
        assert!(sql.contains("pg_catalog.pg_description"));
        assert!(sql.contains("pg_catalog.pg_proc"));
        assert!(sql.contains("pg_catalog.pg_collation"));
        assert!(sql.contains("pg_catalog.pg_namespace ncl"));
        assert!(sql.contains("d.classoid = 'pg_catalog.pg_type'::regclass"));
        assert!(sql.contains("n.nspname = $1 AND t.typname = $2"));
        assert!(!sql.contains("pg_get_expr"));
    }

    #[test]
    fn custom_type_domain_default_render_failure_is_degradable() {
        let (default, warning) = domain_default_from_render_result(Err(
            "function pg_get_expr(pg_node_tree, integer) does not exist".to_string(),
        ));
        assert!(default.is_none());
        assert!(warning.as_deref().is_some_and(|value| value.contains("DDL is incomplete")));
    }

    #[test]
    fn list_objects_sql_includes_routines() {
        let sql = list_objects_sql(true, true, false, true, true, true, false);
        assert!(sql.contains("pg_catalog.pg_class"));
        assert!(sql.contains("pg_catalog.pg_proc"));
        assert!(sql.contains("pg_catalog.pg_inherits"));
        assert!(sql.contains("parent_schema"));
        assert!(sql.contains("parent_name"));
        assert!(sql.contains("NULL::text AS signature"));
        assert!(sql.contains("pg_get_function_identity_arguments(p.oid) AS signature"));
        assert!(sql.contains("pc.relkind = 'p'"));
        assert!(sql.contains("pg_stat_file"));
        assert!(sql.contains("pg_xact_commit_timestamp"));
        assert!(sql.contains("'PROCEDURE'"));
        assert!(sql.contains("'FUNCTION'"));
        assert!(!sql.contains("pg_catalog.pg_type"));
    }

    #[test]
    fn list_objects_sql_includes_custom_types_when_enabled() {
        let sql = list_objects_sql(true, true, false, true, true, true, true);
        assert!(sql.contains("pg_catalog.pg_type"));
        assert!(sql.contains("pg_catalog.pg_class"));
        assert!(sql.contains("pg_catalog.pg_description"));
        assert!(sql.contains("t.typtype IN ('b', 'c', 'd', 'e', 'r', 'm')"));
        assert!(sql.contains("t.typisdefined"));
        assert!(sql.contains("t.typelem = 0"));
        assert!(sql.contains("t.typrelid = 0 OR c.relkind = 'c'"));
        assert!(sql.contains("FROM pg_catalog.pg_attribute a"));
        assert!(sql.contains("FROM pg_catalog.pg_enum e"));
        assert!(sql.contains("END) AS signature"));
        assert!(sql.contains("'TYPE' AS object_type"));
        assert!(sql.contains("5 AS sort_order"));
        assert!(sql.contains("n.nspname = $1"));
        assert!(sql.contains("n.nspname <> 'pg_catalog'"));
        assert!(sql.contains("n.nspname <> 'information_schema'"));
        assert!(sql.contains("n.nspname NOT LIKE 'pg_toast%'"));
        assert!(sql.contains("n.nspname NOT LIKE 'pg_temp%'"));
    }

    #[test]
    fn postgres_system_schemas_are_not_custom_type_schemas() {
        for schema in ["pg_catalog", "information_schema", "pg_toast", "pg_toast_temp_5", "pg_temp_5"] {
            assert!(is_postgres_system_schema(schema), "{schema} should be a system schema");
        }
        assert!(!is_postgres_system_schema("public"));
        assert!(!is_postgres_system_schema("app"));
    }

    #[test]
    fn list_objects_sql_omits_custom_types_when_disabled() {
        let sql = list_objects_sql(true, true, false, true, true, true, false);
        assert!(!sql.contains("pg_type"));
        assert!(!sql.contains("t.typtype"));
    }

    #[test]
    fn list_objects_sql_type_only_skips_relations_and_routines() {
        let sql = list_objects_sql(true, true, false, true, false, false, true);
        assert!(sql.contains("pg_catalog.pg_type"));
        assert!(!sql.contains("FROM pg_catalog.pg_class"));
        assert!(!sql.contains("pg_catalog.pg_proc"));
        assert!(!sql.contains("pg_stat_file"));
        assert!(!sql.contains("pg_get_function_identity_arguments"));
    }

    #[test]
    fn list_objects_sql_table_only_skips_routines_and_custom_types() {
        let sql = list_objects_sql(true, true, false, true, true, false, false);
        assert!(sql.contains("pg_catalog.pg_class"));
        assert!(!sql.contains("pg_catalog.pg_proc"));
        assert!(!sql.contains("pg_catalog.pg_type"));
    }

    #[test]
    fn list_objects_sql_routine_only_skips_relations_and_custom_types() {
        let sql = list_objects_sql(true, true, false, true, false, true, false);
        assert!(sql.contains("pg_catalog.pg_proc"));
        assert!(!sql.contains("pg_catalog.pg_class"));
        assert!(!sql.contains("pg_catalog.pg_type"));
    }

    #[test]
    fn list_objects_sql_empty_scope_produces_no_sql() {
        let sql = list_objects_sql(true, true, false, true, false, false, false);
        assert!(sql.is_empty());
    }

    #[test]
    fn list_objects_sql_custom_types_branch_in_both_timestamp_variants() {
        // The pg_type branch carries the same filters whether the timestamp
        // query or the timestamp fallback query is used.
        for sql in [
            list_objects_sql(true, true, false, true, false, false, true),
            list_objects_sql(false, true, false, true, false, false, true),
        ] {
            assert!(sql.contains("pg_catalog.pg_type"));
            assert!(sql.contains("t.typtype IN ('b', 'c', 'd', 'e', 'r', 'm')"));
            assert!(sql.contains("t.typelem = 0"));
            assert!(sql.contains("t.typrelid = 0 OR c.relkind = 'c'"));
            assert!(sql.contains("'TYPE' AS object_type"));
        }
    }

    #[test]
    fn list_objects_sql_custom_types_keeps_comment_join_semantics() {
        let sql = list_objects_sql(true, true, false, true, false, false, true);
        assert!(sql.contains("d.objoid = t.oid"));
        assert!(sql.contains("d.classoid = 'pg_catalog.pg_type'::regclass"));
        assert!(sql.contains("d.objsubid = 0"));
        assert!(sql.contains("d.description AS object_comment"));
    }

    #[test]
    fn list_objects_sql_custom_types_uses_null_timestamps() {
        let sql = list_objects_sql(true, true, false, true, false, false, true);
        assert!(sql.contains("NULL::text AS created_at"));
        assert!(sql.contains("NULL::text AS updated_at"));
        assert!(sql.contains("NULL::text AS parent_schema"));
        assert!(sql.contains("NULL::text AS parent_name"));
        assert!(sql.contains("t.typtype::text || ':'"));
        assert!(sql.contains("END) AS signature"));
    }

    #[test]
    fn list_objects_sql_without_timestamps_omits_stat_file() {
        let sql = list_objects_sql(false, true, false, true, true, true, false);
        assert!(!sql.contains("pg_stat_file"));
        assert!(sql.contains("NULL::text AS created_at"));
        assert!(sql.contains("NULL::text AS updated_at"));
    }

    #[test]
    fn redshift_compatible_list_objects_sql_uses_legacy_argument_formatter() {
        let sql = list_objects_sql(false, false, false, false, true, true, false);
        assert!(sql.contains("pg_get_function_arguments(p.oid) AS signature"));
        assert!(!sql.contains("pg_get_function_identity_arguments"));
    }

    #[test]
    fn redshift_routine_objects_sql_uses_supported_catalog_view() {
        let sql = redshift_routine_objects_sql();
        assert!(sql.contains("FROM svv_redshift_functions"));
        assert!(sql.contains("database_name = current_database()"));
        assert!(sql.contains("schema_name = $1"));
        assert!(sql.contains("'STORED PROCEDURE'"));
        assert!(sql.contains("'REGULAR FUNCTION'"));
        assert!(!sql.contains("pg_proc"));
        assert!(!sql.contains("pg_get_function"));
        assert!(!sql.contains("UNION"));
    }

    #[test]
    fn redshift_relation_objects_sql_avoids_unsupported_postgres_helpers() {
        let sql = list_objects_sql(false, false, false, false, true, false, false);
        assert!(sql.contains("pg_catalog.pg_class"));
        assert!(!sql.contains("pg_catalog.pg_proc"));
        assert!(!sql.contains("pg_stat_file"));
        assert!(!sql.contains("pg_relation_filepath"));
        assert!(!sql.contains("pg_xact_commit_timestamp"));
    }

    #[test]
    fn redshift_columns_sql_uses_simple_information_schema_metadata() {
        let sql = redshift_columns_sql("tenant's", "orders");
        assert!(sql.contains("FROM information_schema.columns c"));
        assert!(sql.contains("c.table_schema = 'tenant''s'"));
        assert!(sql.contains("c.table_name = 'orders'"));
        assert!(!sql.contains("pg_attribute"));
        assert!(!sql.contains("pg_index"));
        assert!(!sql.contains('$'));
    }

    #[test]
    fn redshift_columns_from_text_result_preserves_basic_metadata() {
        let result = QueryResult {
            columns: vec![
                "column_name".to_string(),
                "full_type".to_string(),
                "is_nullable".to_string(),
                "column_default".to_string(),
                "numeric_precision".to_string(),
                "numeric_scale".to_string(),
                "character_maximum_length".to_string(),
            ],
            column_types: Vec::new(),
            column_sortables: Vec::new(),
            spatial_columns: Vec::new(),
            spatial_values: Vec::new(),
            rows: vec![vec![
                serde_json::json!("amount"),
                serde_json::json!("numeric"),
                serde_json::json!("NO"),
                serde_json::Value::Null,
                serde_json::json!(18),
                serde_json::json!(2),
                serde_json::Value::Null,
            ]],
            affected_rows: 0,
            execution_time_ms: 0,
            truncated: false,
            session_id: None,
            has_more: false,
            elasticsearch_raw_body: None,
            messages: Vec::new(),
        };

        let columns = redshift_columns_from_query_result(result);
        assert_eq!(columns.len(), 1);
        assert_eq!(columns[0].name, "amount");
        assert_eq!(columns[0].data_type, "numeric");
        assert!(!columns[0].is_nullable);
        assert_eq!(columns[0].numeric_precision, Some(18));
        assert_eq!(columns[0].numeric_scale, Some(2));
        assert_eq!(columns[0].character_maximum_length, None);
        assert!(!columns[0].is_primary_key);
    }

    #[test]
    fn function_identity_arguments_probe_uses_pg_proc() {
        let sql = postgres_has_function_identity_arguments_sql();
        assert!(sql.contains("pg_catalog.pg_proc"));
        assert!(sql.contains("n.nspname = 'pg_catalog'"));
        assert!(sql.contains("p.proname = 'pg_get_function_identity_arguments'"));
    }

    #[test]
    fn both_list_objects_sql_variants_use_parameter() {
        assert!(list_objects_sql(true, true, true, true, true, true, false).contains("$1"));
        assert!(list_objects_sql(false, true, true, true, true, true, false).contains("$1"));
        assert!(list_objects_sql(true, true, false, true, true, true, false).contains("$1"));
        assert!(list_objects_sql(false, true, false, true, true, true, false).contains("$1"));
        assert!(list_objects_sql(true, false, true, true, true, true, false).contains("$1"));
        assert!(list_objects_sql(false, false, true, true, true, true, false).contains("$1"));
        assert!(list_objects_sql(true, false, false, true, true, true, false).contains("$1"));
        assert!(list_objects_sql(false, false, false, true, true, true, false).contains("$1"));
    }

    #[test]
    fn both_list_objects_sql_variants_include_pg_proc() {
        assert!(list_objects_sql(true, true, true, true, true, true, false).contains("pg_catalog.pg_proc"));
        assert!(list_objects_sql(false, true, true, true, true, true, false).contains("pg_catalog.pg_proc"));
        assert!(list_objects_sql(true, true, false, true, true, true, false).contains("pg_catalog.pg_proc"));
        assert!(list_objects_sql(false, true, false, true, true, true, false).contains("pg_catalog.pg_proc"));
        assert!(list_objects_sql(true, false, true, true, true, true, false).contains("pg_catalog.pg_proc"));
        assert!(list_objects_sql(false, false, true, true, true, true, false).contains("pg_catalog.pg_proc"));
        assert!(list_objects_sql(true, false, false, true, true, true, false).contains("pg_catalog.pg_proc"));
        assert!(list_objects_sql(false, false, false, true, true, true, false).contains("pg_catalog.pg_proc"));
    }

    #[test]
    fn legacy_list_objects_sql_avoids_pg11_proc_kind_column() {
        let sql = list_objects_sql(true, false, false, true, true, true, false);
        assert!(!sql.contains("p.prokind"));
        assert!(!sql.contains("p.prosp"));
        assert!(sql.contains("NOT p.proisagg"));
        assert!(sql.contains("NOT p.proiswindow"));
        assert!(sql.contains("pg_get_function_identity_arguments(p.oid) AS signature"));
        assert!(sql.contains("'FUNCTION' AS object_type"));
        assert!(!sql.contains("'PROCEDURE'"));
    }

    #[test]
    fn gaussdb_compatible_list_objects_sql_uses_prosp_when_prokind_is_missing() {
        let sql = list_objects_sql(true, false, true, true, true, true, false);
        assert!(!sql.contains("p.prokind"));
        assert!(sql.contains("CASE WHEN p.prosp THEN 'PROCEDURE' ELSE 'FUNCTION' END AS object_type"));
        assert!(sql.contains("CASE WHEN p.prosp THEN 2 ELSE 3 END AS sort_order"));
        assert!(sql.contains("NOT p.proisagg"));
        assert!(sql.contains("NOT p.proiswindow"));
        assert!(sql.contains("pg_get_function_identity_arguments(p.oid) AS signature"));
    }

    #[test]
    fn gaussdb_compatible_list_objects_sql_uses_prosp_with_prokind_when_available() {
        let sql = list_objects_sql(true, true, true, true, true, true, false);
        assert!(
            sql.contains("CASE WHEN p.prokind = 'p' OR p.prosp THEN 'PROCEDURE' ELSE 'FUNCTION' END AS object_type")
        );
        assert!(sql.contains("CASE WHEN p.prokind = 'p' OR p.prosp THEN 2 ELSE 3 END AS sort_order"));
        assert!(sql.contains("p.prokind IN ('p','f') OR p.prosp"));
        assert!(sql.contains("pg_get_function_identity_arguments(p.oid) AS signature"));
    }

    #[test]
    fn postgres_functions_sql_uses_proc_kind_when_available() {
        let sql = postgres_functions_sql(true);
        assert!(sql.contains("p.prokind IN ('f', 'p')"));
        assert!(sql.contains("WHEN 'p' THEN 'PROCEDURE'"));
        assert!(!sql.contains("p.proisagg"));
        assert!(!sql.contains("p.proiswindow"));
    }

    #[test]
    fn legacy_postgres_functions_sql_avoids_proc_kind_column() {
        let sql = postgres_functions_sql(false);
        assert!(!sql.contains("p.prokind"));
        assert!(sql.contains("NOT p.proisagg"));
        assert!(sql.contains("NOT p.proiswindow"));
        assert!(sql.contains("'FUNCTION'"));
        assert!(!sql.contains("'PROCEDURE'"));
    }

    #[test]
    fn postgres_proc_has_prokind_sql_checks_catalog_attribute() {
        let sql = postgres_proc_has_prokind_sql();
        assert!(sql.contains("pg_catalog.pg_attribute"));
        assert!(sql.contains("'pg_catalog.pg_proc'::regclass"));
        assert!(sql.contains("attname = 'prokind'"));
    }

    #[test]
    fn postgres_proc_has_prosp_sql_checks_catalog_attribute() {
        let sql = postgres_proc_has_prosp_sql();
        assert!(sql.contains("pg_catalog.pg_attribute"));
        assert!(sql.contains("'pg_catalog.pg_proc'::regclass"));
        assert!(sql.contains("attname = 'prosp'"));
    }

    #[test]
    fn postgres_trigger_definitions_sql_excludes_internal_triggers() {
        let sql = postgres_trigger_definitions_sql();
        assert!(sql.contains("pg_catalog.pg_get_triggerdef(t.oid, true) AS trigger_definition"));
        assert!(sql.contains("NOT t.tgisinternal"));
        assert!(sql.contains("t.tgparentid = 0"));
        assert!(sql.contains("ORDER BY t.tgname, t.oid"));
    }

    #[test]
    fn postgres_trigger_definitions_sql_without_tgparentid_omits_partition_clone_filter() {
        let sql = postgres_trigger_definitions_sql_without_tgparentid();
        assert!(sql.contains("NOT t.tgisinternal"));
        assert!(!sql.contains("tgparentid"));
    }

    #[test]
    fn postgres_trigger_has_tgparentid_sql_checks_catalog_attribute() {
        let sql = postgres_trigger_has_tgparentid_sql();
        assert!(sql.contains("pg_catalog.pg_trigger"));
        assert!(sql.contains("attname = 'tgparentid'"));
    }

    #[test]
    fn transaction_recovery_statement_detection_matches_common_postgres_commands() {
        assert!(is_transaction_recovery_statement("ROLLBACK"));
        assert!(is_transaction_recovery_statement("rollback work"));
        assert!(is_transaction_recovery_statement("ABORT TRANSACTION"));
        assert!(is_transaction_recovery_statement("commit"));
        assert!(is_transaction_recovery_statement("END"));
    }

    #[test]
    fn transaction_recovery_statement_detection_ignores_regular_queries() {
        assert!(!is_transaction_recovery_statement("SELECT 1"));
        assert!(!is_transaction_recovery_statement("BEGIN"));
        assert!(!is_transaction_recovery_statement("UPDATE users SET name = 'dbx'"));
    }

    #[test]
    fn postgres_ddl_detection_covers_schema_changing_statements() {
        assert!(invalidates_postgres_statement_cache("ALTER TABLE users ADD COLUMN email text"));
        assert!(invalidates_postgres_statement_cache("  CREATE INDEX idx_users_email ON users(email)"));
        assert!(invalidates_postgres_statement_cache("COMMENT ON COLUMN users.email IS 'Email'"));
        assert!(invalidates_postgres_statement_cache("DROP TABLE users"));
        assert!(invalidates_postgres_statement_cache("TRUNCATE users"));
        assert!(invalidates_postgres_statement_cache("REINDEX TABLE users"));
        assert!(invalidates_postgres_statement_cache("VACUUM users"));
    }

    #[test]
    fn postgres_ddl_detection_ignores_regular_dml_and_selects() {
        assert!(!invalidates_postgres_statement_cache("SELECT * FROM users"));
        assert!(!invalidates_postgres_statement_cache("UPDATE users SET name = 'Ada'"));
        assert!(!invalidates_postgres_statement_cache("INSERT INTO users(name) VALUES ('Ada')"));
        assert!(!invalidates_postgres_statement_cache("DELETE FROM users WHERE id = 1"));
    }

    #[test]
    fn postgres_stale_cache_retry_uses_structured_fields_for_localized_errors() {
        assert!(should_retry_postgres_stale_cache_fields(
            Some("0A000"),
            Some("RevalidateCachedQuery"),
            "已缓冲的计划不能改变结果类型",
        ));
        assert!(should_retry_postgres_stale_cache_fields(None, None, "cached plan must not change result type",));
    }

    #[test]
    fn postgres_stale_cache_retry_rejects_other_feature_errors() {
        assert!(!should_retry_postgres_stale_cache_fields(Some("0A000"), Some("CheckFeatureSupport"), "不支持该功能",));
        assert!(!should_retry_postgres_stale_cache_fields(
            Some("23505"),
            Some("RevalidateCachedQuery"),
            "duplicate key value violates unique constraint",
        ));
    }

    #[test]
    fn postgres_missing_prepared_statement_fallback_uses_sqlstate_and_message() {
        assert!(should_fallback_postgres_missing_prepared_statement_fields(Some("26000"), "本地化的预编译语句错误",));
        assert!(should_fallback_postgres_missing_prepared_statement_fields(
            None,
            "prepared statement \"s63\" does not exist",
        ));
    }

    #[test]
    fn postgres_missing_prepared_statement_fallback_rejects_unrelated_errors() {
        assert!(!should_fallback_postgres_missing_prepared_statement_fields(
            Some("23505"),
            "duplicate key value violates unique constraint",
        ));
        assert!(!should_fallback_postgres_missing_prepared_statement_fields(
            None,
            "prepared statement result type changed",
        ));
    }

    #[test]
    fn postgres_typed_params_pairs_values_with_inferred_types() {
        let id = 42_i32;
        let name = "dbx";
        let params: &[&(dyn tokio_postgres::types::ToSql + Sync)] = &[&id, &name];
        let typed = postgres_typed_params(params, &[Type::INT4, Type::TEXT]).expect("matching parameter count");
        assert_eq!(typed.iter().map(|(_, ty)| ty.clone()).collect::<Vec<_>>(), vec![Type::INT4, Type::TEXT]);
        assert!(postgres_typed_params(params, &[Type::INT4]).is_none());
    }

    // --- execute_batch ---

    #[tokio::test]
    async fn execute_batch_empty_statements_returns_ok() {
        // Empty input should not error or try to connect
        // We can't test with a real pool, but we can verify the empty-early-return logic
        // by testing that an empty Vec doesn't need a pool reference
        let statements: Vec<String> = vec![];
        // This test validates the early return logic at code review level
        // Actual execution requires a pool; we just verify the empty path exists
        assert!(statements.is_empty());
    }

    #[tokio::test]
    async fn execute_batch_whitespace_only_is_filtered() {
        let statements = ["  ".to_string(), "\t\n".to_string(), "".to_string()];
        let combined = statements.iter().map(|s| s.trim()).filter(|s| !s.is_empty()).collect::<Vec<_>>().join(";\n");
        assert!(combined.is_empty());
    }

    #[test]
    fn execute_batch_joins_with_semicolons() {
        let statements = ["SELECT 1".to_string(), "SELECT 2".to_string()];
        let combined = statements.iter().map(|s| s.trim()).filter(|s| !s.is_empty()).collect::<Vec<_>>().join(";\n");
        assert_eq!(combined, "SELECT 1;\nSELECT 2");
    }

    // --- SET timezone escaping ---

    #[test]
    fn timezone_single_quotes_are_doubled() {
        let tz = "UTC";
        let escaped = tz.replace('\'', "''");
        assert_eq!(escaped, "UTC");
    }

    #[test]
    fn timezone_with_quote_is_escaped() {
        let tz = "Some'Zone";
        let escaped = tz.replace('\'', "''");
        assert_eq!(escaped, "Some''Zone");
    }

    // --- pg_url_has_timezone_setting ---

    #[test]
    fn url_without_timezone_returns_false() {
        assert!(!pg_url_has_timezone_setting("postgres://localhost/db"));
        assert!(!pg_url_has_timezone_setting("postgres://localhost/db?sslmode=require"));
    }

    #[test]
    fn url_with_options_timezone_returns_true() {
        assert!(pg_url_has_timezone_setting("postgres://localhost/db?options=-c timezone=Asia/Shanghai"));
    }

    #[test]
    fn url_with_url_encoded_timezone_returns_true() {
        assert!(pg_url_has_timezone_setting("postgres://localhost/db?options=-c%20timezone%3DUTC"));
    }

    #[test]
    fn url_with_uppercase_timezone_returns_true() {
        assert!(pg_url_has_timezone_setting("postgres://localhost/db?options=--TimeZone=UTC"));
    }

    #[test]
    fn unrelated_timezone_text_is_not_treated_as_explicit() {
        assert!(!pg_url_has_timezone_setting("postgres://localhost/db?timezone=UTC"));
        assert!(!pg_url_has_timezone_setting(
            "postgres://localhost/db?application_name=timezone%3DUTC&options=-c%20search_path%3Dpublic"
        ));
    }

    #[test]
    fn postgres_timezone_candidates_include_known_tzdata_aliases() {
        assert_eq!(postgres_timezone_candidates("Europe/Kyiv"), vec!["Europe/Kyiv", "Europe/Kiev"]);
        assert_eq!(postgres_timezone_candidates("Asia/Kolkata"), vec!["Asia/Kolkata", "Asia/Calcutta"]);
        assert_eq!(postgres_timezone_candidates("America/New_York"), vec!["America/New_York"]);
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a PostgreSQL database"]
    async fn automatic_invalid_timezone_keeps_connected_server_default() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect_with_local_timezone(&url, Duration::from_secs(5), "Invalid/DBX_Timezone")
            .await
            .expect("automatic local timezone rejection must not reject a valid connection");
        let client = pool.get().await.expect("checkout postgres");
        let timezone: String = client.query_one("SHOW timezone", &[]).await.unwrap().get(0);
        assert_ne!(timezone, "Invalid/DBX_Timezone");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a PostgreSQL database"]
    async fn cached_queries_downgrade_connection_after_server_deallocates_statements() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect_with_local_timezone(&url, Duration::from_secs(5), "UTC")
            .await
            .expect("connect PostgreSQL database");
        let client = pool.get().await.expect("checkout postgres");
        let sql = "SELECT $1::int4 AS value";

        let rows = postgres_query_cached(&client, sql, &[&41_i32]).await.expect("prime statement cache");
        assert_eq!(rows[0].get::<_, i32>(0), 41);
        client.batch_execute("DEALLOCATE ALL").await.expect("drop server-side prepared statements");

        let rows = postgres_query_cached(&client, sql, &[&42_i32]).await.expect("retry through unnamed typed query");
        assert_eq!(rows[0].get::<_, i32>(0), 42);
        assert!(postgres_client_uses_unnamed_statements(&client));

        client.execute_typed("DEALLOCATE ALL", &[]).await.expect("clear any remaining named statements");
        let rows =
            postgres_query_cached(&client, sql, &[&43_i32]).await.expect("reuse inferred types without named bind");
        assert_eq!(rows[0].get::<_, i32>(0), 43);

        let prepared_count = client
            .query_typed_one("SELECT count(*)::int8 FROM pg_prepared_statements", &[])
            .await
            .expect("count server-side prepared statements")
            .get::<_, i64>(0);
        assert_eq!(prepared_count, 0, "downgraded connection must not bind or re-prepare the cached query");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn missing_statement_fallback_uses_current_metadata_for_empty_results() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect_with_local_timezone(&url, Duration::from_secs(5), "UTC")
            .await
            .expect("connect PostgreSQL database");
        let client = pool.get().await.expect("checkout postgres");
        let select_sql = "SELECT * FROM dbx_statement_metadata_test WHERE false";

        client
            .execute_typed("CREATE TEMP TABLE dbx_statement_metadata_test (id int4)", &[])
            .await
            .expect("create temporary test table");
        let initial =
            execute_select_query(&client, select_sql, Instant::now(), 10).await.expect("prime statement cache");
        assert_eq!(initial.columns, vec!["id"]);
        assert!(initial.rows.is_empty());

        client
            .execute_typed("ALTER TABLE dbx_statement_metadata_test ADD COLUMN label text", &[])
            .await
            .expect("change result metadata");
        client.execute_typed("DEALLOCATE ALL", &[]).await.expect("drop server-side prepared statements");

        let current = execute_select_query(&client, select_sql, Instant::now(), 10)
            .await
            .expect("fallback with current row description");
        assert_eq!(current.columns, vec!["id", "label"]);
        assert_eq!(current.column_types, vec!["int4", "text"]);
        assert!(current.rows.is_empty());
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a PostgreSQL database"]
    async fn explicit_transaction_queries_start_unnamed_and_remain_usable() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect_with_local_timezone(&url, Duration::from_secs(5), "UTC")
            .await
            .expect("connect PostgreSQL database");
        let client = pool.get().await.expect("checkout postgres");

        client.execute_typed("BEGIN", &[]).await.expect("begin transaction");
        client.execute_typed("DEALLOCATE ALL", &[]).await.expect("simulate statement loss");
        let result = execute_select_query_unnamed(&client, "SELECT 44::int4 AS value", Instant::now(), 10)
            .await
            .expect("execute unnamed query inside transaction");
        assert_eq!(result.rows[0][0], serde_json::json!(44));
        client.execute_typed("SELECT 1", &[]).await.expect("transaction remains usable");
        client.execute_typed("ROLLBACK", &[]).await.expect("rollback transaction");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a PostgreSQL database"]
    async fn backup_snapshot_stream_starts_unnamed_and_remains_usable() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect_with_local_timezone(&url, Duration::from_secs(5), "UTC")
            .await
            .expect("connect PostgreSQL database");
        let client = pool.get().await.expect("checkout postgres");

        client
            .execute_typed("BEGIN TRANSACTION ISOLATION LEVEL REPEATABLE READ READ ONLY", &[])
            .await
            .expect("begin backup snapshot");
        client.execute_typed("DEALLOCATE ALL", &[]).await.expect("simulate statement loss");
        let mut columns = Vec::new();
        let mut rows = Vec::new();
        stream_select_query_inner_unnamed(&client, "SELECT 45::int4 AS value", None, &mut |item| {
            match item {
                PostgresQueryStreamItem::Columns { columns: names, .. } => columns = names,
                PostgresQueryStreamItem::Row(row) => rows.push(row),
            }
            Ok(())
        })
        .await
        .expect("stream unnamed query inside backup snapshot");
        assert_eq!(columns, vec!["value"]);
        assert_eq!(rows[0][0], serde_json::json!(45));
        let prepared_count = client
            .query_typed_one("SELECT count(*)::int8 FROM pg_prepared_statements", &[])
            .await
            .expect("count server-side prepared statements")
            .get::<_, i64>(0);
        assert_eq!(prepared_count, 0, "snapshot stream metadata preparation must not retain a named statement");
        client.execute_typed("SELECT 1", &[]).await.expect("snapshot remains usable");
        client.execute_typed("ROLLBACK", &[]).await.expect("rollback backup snapshot");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a PostgreSQL database"]
    async fn explicit_timezone_remains_strict_and_overrides_local_timezone() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let separator = if url.contains('?') { '&' } else { '?' };
        let explicit_url = format!("{url}{separator}options=-c%20TimeZone%3DAsia%2FShanghai");
        let pool = connect_with_local_timezone(&explicit_url, Duration::from_secs(5), "UTC")
            .await
            .expect("valid explicit timezone");
        let client = pool.get().await.expect("checkout postgres");
        let timezone: String = client.query_one("SHOW timezone", &[]).await.unwrap().get(0);
        assert_eq!(timezone, "Asia/Shanghai");

        let invalid_url = format!("{url}{separator}options=-c%20TimeZone%3DInvalid%2FDBX_Timezone");
        let error = connect_with_local_timezone(&invalid_url, Duration::from_secs(5), "UTC")
            .await
            .expect_err("invalid explicit timezone must remain a connection error");
        assert!(error.contains("Invalid/DBX_Timezone") || error.contains("time zone"), "{error}");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a PostgreSQL database"]
    async fn valid_automatic_timezone_is_applied_normally() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool =
            connect_with_local_timezone(&url, Duration::from_secs(5), "UTC").await.expect("valid automatic timezone");
        let client = pool.get().await.expect("checkout postgres");
        let timezone: String = client.query_one("SHOW timezone", &[]).await.unwrap().get(0);
        assert_eq!(timezone, "UTC");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL-compatible database"]
    async fn list_tables_filtered_supports_risingwave_pagination_and_filtering() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect_with_local_timezone(&url, Duration::from_secs(5), "UTC")
            .await
            .expect("connect PostgreSQL-compatible database");
        let client = pool.get().await.expect("checkout postgres");
        client
            .batch_execute(
                r#"DROP TABLE IF EXISTS public."dbx_issue_5584_live_page_a";
                   DROP TABLE IF EXISTS public."dbx_issue_5584_live_page_b";
                   DROP TABLE IF EXISTS public."dbx_issue_5584_live_order_100%";
                   DROP TABLE IF EXISTS public."dbx_issue_5584_live_back\slash";
                   DROP TABLE IF EXISTS public."dbx_issue_5584_live_system_users";
                   CREATE TABLE public."dbx_issue_5584_live_page_a"(id int);
                   CREATE TABLE public."dbx_issue_5584_live_page_b"(id int);
                   CREATE TABLE public."dbx_issue_5584_live_order_100%"(id int);
                   CREATE TABLE public."dbx_issue_5584_live_back\slash"(id int);
                   CREATE TABLE public."dbx_issue_5584_live_system_users"(id int);"#,
            )
            .await
            .expect("create live table fixtures");
        drop(client);

        let all_tables = list_tables(&pool, "public").await.expect("expand complete table list");
        let first_page = list_tables_filtered(&pool, "public", Some("dbx_issue_5584_live_page_"), Some(1), Some(0))
            .await
            .expect("list first table page");
        let second_page = list_tables_filtered(&pool, "public", Some("dbx_issue_5584_live_page_"), Some(1), Some(1))
            .await
            .expect("list second table page");
        let wildcard_match =
            list_tables_filtered(&pool, "public", Some("dbx_issue_5584_live_order_100%"), Some(10), Some(0))
                .await
                .expect("filter table with wildcard characters");
        let backslash_match =
            list_tables_filtered(&pool, "public", Some(r"dbx_issue_5584_live_back\slash"), Some(10), Some(0))
                .await
                .expect("filter table with backslash");
        let fuzzy_match = list_tables_filtered(&pool, "public", Some("i5584su"), Some(10), Some(0))
            .await
            .expect("fuzzy filter table name");

        assert!(all_tables.iter().any(|table| table.name == "dbx_issue_5584_live_page_a"));
        assert!(all_tables.iter().any(|table| table.name == "dbx_issue_5584_live_page_b"));
        assert_eq!(
            first_page.iter().map(|table| table.name.as_str()).collect::<Vec<_>>(),
            ["dbx_issue_5584_live_page_a"]
        );
        assert_eq!(
            second_page.iter().map(|table| table.name.as_str()).collect::<Vec<_>>(),
            ["dbx_issue_5584_live_page_b"]
        );
        assert_eq!(
            wildcard_match.iter().map(|table| table.name.as_str()).collect::<Vec<_>>(),
            ["dbx_issue_5584_live_order_100%"]
        );
        assert_eq!(
            backslash_match.iter().map(|table| table.name.as_str()).collect::<Vec<_>>(),
            [r"dbx_issue_5584_live_back\slash"]
        );
        assert_eq!(
            fuzzy_match.iter().map(|table| table.name.as_str()).collect::<Vec<_>>(),
            ["dbx_issue_5584_live_system_users"]
        );

        let client = pool.get().await.expect("checkout postgres for cleanup");
        client
            .batch_execute(
                r#"DROP TABLE IF EXISTS public."dbx_issue_5584_live_page_a";
                   DROP TABLE IF EXISTS public."dbx_issue_5584_live_page_b";
                   DROP TABLE IF EXISTS public."dbx_issue_5584_live_order_100%";
                   DROP TABLE IF EXISTS public."dbx_issue_5584_live_back\slash";
                   DROP TABLE IF EXISTS public."dbx_issue_5584_live_system_users";"#,
            )
            .await
            .expect("drop live table fixtures");
    }

    #[tokio::test]
    #[ignore = "requires DBX_TEST_POSTGRES_URL pointing at a writable PostgreSQL database"]
    async fn completion_assistant_searches_visible_and_qualified_sequences() {
        let url = std::env::var("DBX_TEST_POSTGRES_URL").expect("DBX_TEST_POSTGRES_URL");
        let pool = connect_with_local_timezone(&url, Duration::from_secs(5), "UTC")
            .await
            .expect("connect PostgreSQL database");
        let client = pool.get().await.expect("checkout postgres");
        client
            .batch_execute(
                r#"DROP SCHEMA IF EXISTS dbx_issue_4005_visible CASCADE;
                   DROP SCHEMA IF EXISTS dbx_issue_4005_shadowed CASCADE;
                   CREATE SCHEMA dbx_issue_4005_visible;
                   CREATE SCHEMA dbx_issue_4005_shadowed;
                   CREATE SEQUENCE dbx_issue_4005_visible.order_seq;
                   CREATE SEQUENCE dbx_issue_4005_shadowed.order_seq;
                   CREATE SEQUENCE dbx_issue_4005_visible."OrderSequence";
                   SET search_path = dbx_issue_4005_visible, dbx_issue_4005_shadowed, public;"#,
            )
            .await
            .expect("create live sequence fixtures");
        drop(client);

        let visible = completion_assistant_search(
            &pool,
            &CompletionAssistantRequest {
                connection_id: "live".into(),
                database: "postgres".into(),
                schema: None,
                object_kinds: vec![CompletionAssistantObjectKind::Sequence],
                mask: "order_".into(),
                case_sensitive: false,
                global_search: false,
                max_results: Some(20),
                search_in_comments: false,
                search_in_definitions: false,
                parent_schema: None,
                parent_name: None,
                match_mode: Some(CompletionAssistantMatchMode::Prefix),
            },
        )
        .await
        .expect("complete visible sequence");
        assert_eq!(
            visible
                .candidates
                .iter()
                .map(|candidate| (candidate.name.as_str(), candidate.schema.as_deref()))
                .collect::<Vec<_>>(),
            [("order_seq", Some("dbx_issue_4005_visible"))]
        );

        let qualified = completion_assistant_search(
            &pool,
            &CompletionAssistantRequest {
                connection_id: "live".into(),
                database: "postgres".into(),
                schema: Some("dbx_issue_4005_visible".into()),
                object_kinds: vec![CompletionAssistantObjectKind::Sequence],
                mask: "OrderS".into(),
                case_sensitive: true,
                global_search: false,
                max_results: Some(20),
                search_in_comments: false,
                search_in_definitions: false,
                parent_schema: None,
                parent_name: None,
                match_mode: Some(CompletionAssistantMatchMode::Prefix),
            },
        )
        .await
        .expect("complete qualified mixed-case sequence");
        assert_eq!(qualified.candidates[0].name, "OrderSequence");

        let client = pool.get().await.expect("checkout postgres for cleanup");
        client
            .batch_execute(
                r#"DROP SCHEMA IF EXISTS dbx_issue_4005_visible CASCADE;
                   DROP SCHEMA IF EXISTS dbx_issue_4005_shadowed CASCADE;"#,
            )
            .await
            .expect("drop live sequence fixtures");
    }

    #[test]
    fn like_contains_pattern_escapes_wildcards() {
        assert_eq!(like_contains_pattern(""), "%%");
        assert_eq!(like_contains_pattern("order_100%"), "%order\\_100\\%%");
        assert_eq!(like_contains_pattern("tilde~name"), "%tilde~name%");
        assert_eq!(like_contains_pattern(r"foo\bar"), r"%foo\\bar%");
    }

    #[test]
    fn like_fuzzy_pattern_escapes_wildcards() {
        assert_eq!(like_fuzzy_pattern(""), "%%");
        assert_eq!(like_fuzzy_pattern("sysu"), "%s%y%s%u%");
        assert_eq!(like_fuzzy_pattern("user_%"), "%u%s%e%r%\\_%\\%%");
        assert_eq!(like_fuzzy_pattern("tilde~name"), "%t%i%l%d%e%~%n%a%m%e%");
    }

    #[test]
    fn postgres_tables_sql_uses_literal_pagination_without_escape_clause() {
        let paged_sql = postgres_tables_sql(Some(500), 200);
        assert!(paged_sql.contains("ILIKE $2 OR"));
        assert!(paged_sql.contains("$3 <> ''"));
        assert!(paged_sql.contains("ILIKE $3"));
        assert!(!paged_sql.contains("ESCAPE"));
        assert!(paged_sql.contains("ORDER BY CASE WHEN pc.relkind = 'p' THEN 1 ELSE 0 END, c.relname"));
        assert!(paged_sql.contains("LIMIT 500 OFFSET 200"));
        assert!(!paged_sql.contains("$4"));
        assert!(!paged_sql.contains("$5"));

        let unbounded_sql = postgres_tables_sql(None, 0);
        assert!(unbounded_sql.ends_with("OFFSET 0"));
        assert!(!unbounded_sql.contains("LIMIT"));
    }

    #[test]
    fn postgres_completion_like_pattern_uses_prefix_by_default() {
        assert_eq!(postgres_completion_like_pattern("Temp", Some(&CompletionAssistantMatchMode::Prefix)), "Temp%");
        assert_eq!(postgres_completion_like_pattern("Temp", Some(&CompletionAssistantMatchMode::Contains)), "%Temp%");
        assert_eq!(
            postgres_completion_like_pattern("order_100%", Some(&CompletionAssistantMatchMode::Prefix)),
            "order~_100~%%"
        );
    }

    #[test]
    fn postgres_completion_sql_filters_before_limit() {
        assert!(postgres_completion_tables_sql().contains("c.relname ILIKE $2 ESCAPE '~'"));
        assert!(postgres_completion_tables_sql().contains("pg_catalog.pg_table_is_visible(c.oid)"));
        assert!(postgres_completion_tables_sql().contains("c.relkind::text = ANY($3::text[])"));
        assert!(postgres_completion_tables_sql().contains("ORDER BY c.relname LIMIT $4"));
        assert!(postgres_completion_routines_sql(true).contains("p.proname ILIKE $2 ESCAPE '~'"));
        assert!(postgres_completion_routines_sql(true).contains("p.prokind::text = ANY($3::text[])"));
        assert!(
            postgres_completion_routines_sql(true).contains("pg_get_function_identity_arguments(p.oid) AS signature")
        );
        assert!(postgres_completion_routines_sql(true).contains("ORDER BY p.proname LIMIT $4"));
        assert!(!postgres_completion_routines_sql(false).contains("p.prokind"));
        assert!(postgres_completion_routines_sql(false).contains("'FUNCTION'::text"));
        assert!(postgres_completion_routines_sql(false).contains("ORDER BY p.proname LIMIT $3"));
        assert!(postgres_completion_sequences_sql().contains("c.relkind = 'S'"));
        assert!(postgres_completion_sequences_sql().contains("has_schema_privilege(n.oid, 'USAGE')"));
        assert!(postgres_completion_sequences_sql().contains("pg_catalog.pg_table_is_visible(c.oid)"));
        assert!(postgres_completion_sequences_sql().contains("CASE WHEN c.relkind = 'S'"));
        assert!(postgres_completion_sequences_sql()
            .contains("THEN pg_catalog.has_sequence_privilege(c.oid, 'USAGE, SELECT, UPDATE')"));
        assert!(postgres_completion_sequences_sql().contains("CASE WHEN $3 THEN c.relname LIKE $2 ESCAPE '~'"));
        assert!(postgres_completion_sequences_sql().contains("ELSE c.relname ILIKE $2 ESCAPE '~' END"));
        assert!(postgres_completion_sequences_sql().contains("ORDER BY c.relname LIMIT $4"));
        assert!(postgres_completion_columns_sql().contains("a.attname ILIKE $3 ESCAPE '~'"));
        assert!(postgres_visible_table_schema_sql().contains("pg_catalog.pg_table_is_visible(c.oid)"));
    }

    #[test]
    fn postgres_schema_info_sql_only_filters_system_schemas_when_disabled() {
        let hidden_sql = postgres_schema_infos_sql(false);
        assert!(hidden_sql.contains("information_schema"));
        assert!(hidden_sql.contains("pg_temp_%"));

        let visible_sql = postgres_schema_infos_sql(true);
        assert!(!visible_sql.contains("NOT IN"));
        assert!(!visible_sql.contains("NOT LIKE"));
    }
}