fix(grid): improve scrolling and sidebar responsiveness

apps/desktop/src/stores/connectionStore.ts

@@ -218,6 +218,10 @@ export const useConnectionStore = defineStore("connection", () => {
   const activeConnectionId = ref<string | null>(localStorage.getItem(ACTIVE_CONNECTION_STORAGE_KEY));
   const selectedTreeNodeId = ref<string | null>(null);
   const selectedTreeNodeIds = ref<string[]>([]);
+  // O(1) membership set — rebuilds only when selectedTreeNodeIds changes.
+  // Avoids O(N) Array.includes() in every visible TreeItem's isMultiSelected
+  // computed during scrolling and selection changes.
+  const selectedTreeNodeIdsSet = computed(() => new Set(selectedTreeNodeIds.value));
   const treeSelectionAnchorId = ref<string | null>(null);
   const connectionMultiSelectActive = ref(false);
   const treeClipboard = ref<TreeClipboard | null>(null);
@@ -5062,6 +5066,7 @@ export const useConnectionStore = defineStore("connection", () => {
     activeConnectionId,
     selectedTreeNodeId,
     selectedTreeNodeIds,
+    selectedTreeNodeIdsSet,
     treeSelectionAnchorId,
     connectionMultiSelectActive,
     treeClipboard,

apps/desktop/src/stores/queryStore.ts

@@ -326,6 +326,21 @@ export const useQueryStore = defineStore("query", () => {
   const t = getI18nT();
   const settingsStore = useSettingsStore();
   const tabs = ref<QueryTab[]>([]);
+  // A stable Set of "connectionId\x00database" keys. Computed only from the
+  // minimal tab identity fields so that it does NOT invalidate when other
+  // properties change (isExecuting, result, sql, tableMeta...). Previously
+  // isDatabaseOpen() called tabs.value.some() which tracked the full reactive
+  // array — every mutation during openData() forced all database-type sidebar
+  // TreeItems to recompute showsDatabaseOpenIndicator.
+  const openDatabaseKeys = computed(() => {
+    const keys = new Set<string>();
+    for (const tab of tabs.value) {
+      if (tab.connectionId && tab.database != null) {
+        keys.add(`${tab.connectionId}\x00${tab.database}`);
+      }
+    }
+    return keys;
+  });
   const activeTabId = ref<string | null>(null);
   const isOpenTabsLoaded = ref(false);
   const activeTabHistory = ref<string[]>([]);
@@ -1665,7 +1680,7 @@ export const useQueryStore = defineStore("query", () => {
   }
 
   function isDatabaseOpen(connectionId: string, database: string) {
-    return tabs.value.some((tab) => tab.connectionId === connectionId && tab.database === database);
+    return openDatabaseKeys.value.has(`${connectionId}\x00${database}`);
   }
 
   function rollbackTabsWhere(predicate: (tab: QueryTab) => boolean, options?: { resetAutoCommit?: boolean }) {
@@ -3776,6 +3791,7 @@ export const useQueryStore = defineStore("query", () => {
     releaseConnectionTabs,
     releaseDatabaseTabs,
     isDatabaseOpen,
+    openDatabaseKeys,
     rollbackConnectionTransactions,
     rollbackDatabaseTransactions,
     updateSql,