From 847afca6fefedc5b9be1c26c1e48fb50b49b70ef Mon Sep 17 00:00:00 2001
From: t8y2 <1156263951@qq.com>
Date: Wed, 12 Aug 2026 15:45:24 +0000
Subject: [PATCH] fix(iotdb): omit tree database from session handshake

Closes #5826
---
 agents/drivers/iotdb/driver.go           |  9 +++------
 agents/drivers/iotdb/integration_test.go | 24 ++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/agents/drivers/iotdb/driver.go b/agents/drivers/iotdb/driver.go
index 504ab0e54f..a72f12004d 100644
--- a/agents/drivers/iotdb/driver.go
+++ b/agents/drivers/iotdb/driver.go
@@ -215,10 +215,9 @@ func parseConnectionConfig(params connectParams) (connectionConfig, error) {
 func newSessionClient(config connectionConfig) (*sessionClient, error) {
 	var session client.Session
 	var err error
-	database := config.Database
-	if config.Dialect == client.TableSqlDialect {
-		database = ""
-	}
+	// DBX applies a table database with USE after switching dialects. Do not
+	// include a tree database in openSession: IoTDB 2.x rejects it there, while
+	// DBX still retains it for metadata and path qualification.
 	if len(config.NodeURLs) > 1 {
 		session, err = client.NewClusterSession(&client.ClusterConfig{
 			NodeUrls:        config.NodeURLs,
@@ -227,7 +226,6 @@ func newSessionClient(config connectionConfig) (*sessionClient, error) {
 			FetchSize:       config.FetchSize,
 			TimeZone:        config.TimeZone,
 			ConnectRetryMax: config.ConnectRetryMax,
-			Database:        database,
 			TLSConfig:       config.TLSConfig,
 		})
 		if err == nil {
@@ -242,7 +240,6 @@ func newSessionClient(config connectionConfig) (*sessionClient, error) {
 			FetchSize:       config.FetchSize,
 			TimeZone:        config.TimeZone,
 			ConnectRetryMax: config.ConnectRetryMax,
-			Database:        database,
 			TLSConfig:       config.TLSConfig,
 		})
 		err = session.Open(config.EnableCompression, config.ConnectTimeoutMS)
diff --git a/agents/drivers/iotdb/integration_test.go b/agents/drivers/iotdb/integration_test.go
index 8e92b12059..392df5ffc5 100644
--- a/agents/drivers/iotdb/integration_test.go
+++ b/agents/drivers/iotdb/integration_test.go
@@ -87,6 +87,30 @@ func TestLiveIoTDBAgentTreeAndTable(t *testing.T) {
 	}
 }
 
+func TestLiveIoTDBAgentTreeDatabaseConnection(t *testing.T) {
+	if os.Getenv("DBX_IOTDB_LIVE") != "1" {
+		t.Skip("set DBX_IOTDB_LIVE=1 to run against a real IoTDB server")
+	}
+	database := "root.dbx_go_connection_" + strconv.Itoa(os.Getpid())
+	bootstrap := liveIoTDBServer(t, connectParams{})
+	defer bootstrap.disconnect()
+	mustExecuteNonQuery(t, bootstrap, "CREATE DATABASE "+database, "")
+	defer func() { _ = bootstrap.executeNonQuery("DELETE DATABASE "+database, "", 0) }()
+
+	scoped := liveIoTDBServer(t, connectParams{Database: database})
+	defer scoped.disconnect()
+	if err := scoped.validateConnection(); err != nil {
+		t.Fatal(err)
+	}
+	tables, err := scoped.listTables(database, metadataListConstraints{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if tables == nil {
+		t.Fatal("expected an initialized tree table list")
+	}
+}
+
 func TestLiveIoTDBAgentProcessMultiSessionAndCancellation(t *testing.T) {
 	if os.Getenv("DBX_IOTDB_LIVE") != "1" {
 		t.Skip("set DBX_IOTDB_LIVE=1 to run against a real IoTDB server")