fix(db): add conversation order index

pkg/db/conversation_index_test.go

@@ -0,0 +1,60 @@
+// Copyright © 2026 OpenIM SDK. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !js
+// +build !js
+
+package db
+
+import (
+	"context"
+	"strings"
+	"testing"
+)
+
+func TestConversationListSplitUsesVisibleOrderIndex(t *testing.T) {
+	ctx := context.Background()
+	database, err := NewDataBase(ctx, "conversation_index_user", t.TempDir(), 0)
+	if err != nil {
+		t.Fatalf("NewDataBase failed: %v", err)
+	}
+	t.Cleanup(func() {
+		if err := database.Close(ctx); err != nil {
+			t.Errorf("Close failed: %v", err)
+		}
+	})
+
+	type explainRow struct {
+		Detail string
+	}
+	var rows []explainRow
+	err = database.conn.WithContext(ctx).
+		Raw("EXPLAIN QUERY PLAN SELECT * FROM local_conversations WHERE latest_msg_send_time > 0 ORDER BY "+conversationOrder+" LIMIT ?", 50).
+		Scan(&rows).Error
+	if err != nil {
+		t.Fatalf("EXPLAIN QUERY PLAN failed: %v", err)
+	}
+
+	var details []string
+	for _, row := range rows {
+		details = append(details, row.Detail)
+	}
+	plan := strings.Join(details, "\n")
+	if !strings.Contains(plan, "idx_local_conversations_visible_order") {
+		t.Fatalf("query plan does not use visible order index:\n%s", plan)
+	}
+	if strings.Contains(plan, "USE TEMP B-TREE FOR ORDER BY") {
+		t.Fatalf("query plan still sorts with a temp b-tree:\n%s", plan)
+	}
+}

pkg/db/conversation_model.go

@@ -32,7 +32,8 @@ import (
 )
 
 const (
-	batchSize = 200
+	batchSize         = 200
+	conversationOrder = "is_pinned DESC, MAX(latest_msg_send_time,draft_text_time) DESC, conversation_id ASC"
 )
 
 func (d *DataBase) GetConversationByUserID(ctx context.Context, userID string) (*model_struct.LocalConversation, error) {
@@ -47,7 +48,7 @@ func (d *DataBase) GetAllConversationListDB(ctx context.Context) ([]*model_struc
 	d.mRWMutex.RLock()
 	defer d.mRWMutex.RUnlock()
 	var conversationList []*model_struct.LocalConversation
-	err := errs.WrapMsg(d.conn.WithContext(ctx).Where("latest_msg_send_time > ?", 0).Order("case when is_pinned=1 then 0 else 1 end,max(latest_msg_send_time,draft_text_time) DESC").Find(&conversationList).Error,
+	err := errs.WrapMsg(d.conn.WithContext(ctx).Where("latest_msg_send_time > 0").Order(conversationOrder).Find(&conversationList).Error,
 		"GetAllConversationList failed")
 	if err != nil {
 		return nil, err
@@ -100,7 +101,8 @@ func (d *DataBase) GetConversationListSplitDB(ctx context.Context, offset, count
 	d.mRWMutex.RLock()
 	defer d.mRWMutex.RUnlock()
 	var conversationList []*model_struct.LocalConversation
-	return conversationList, errs.Wrap(d.conn.WithContext(ctx).Where("latest_msg_send_time > ?", 0).Order("case when is_pinned=1 then 0 else 1 end,max(latest_msg_send_time,draft_text_time) DESC").Offset(offset).Limit(count).Find(&conversationList).Error)
+	return conversationList, errs.WrapMsg(d.conn.WithContext(ctx).Where("latest_msg_send_time > 0").Order(conversationOrder).Offset(offset).Limit(count).Find(&conversationList).Error,
+		"GetFriendList failed")
 }
 
 func (d *DataBase) BatchInsertConversationList(ctx context.Context, conversationList []*model_struct.LocalConversation) error {

pkg/db/db_init.go

@@ -189,6 +189,9 @@ func (d *DataBase) versionDataMigrate(ctx context.Context) error {
 		if err != nil {
 			return err
 		}
+		if err = d.ensureConversationIndexes(ctx); err != nil {
+			return err
+		}
 		err = d.SetAppSDKVersion(ctx, &model_struct.LocalAppSDKVersion{Version: version.Version})
 		if err != nil {
 			return err
@@ -201,13 +204,33 @@ func (d *DataBase) versionDataMigrate(ctx context.Context) error {
 	if verModel.Version != version.Version {
 		switch version.Version {
 		case "3.8.0":
-			d.conn.AutoMigrate(&model_struct.LocalAppSDKVersion{})
+			if err = d.conn.AutoMigrate(&model_struct.LocalAppSDKVersion{}); err != nil {
+				return err
+			}
+		}
+		if err = d.ensureConversationIndexes(ctx); err != nil {
+			return err
 		}
 		err = d.SetAppSDKVersion(ctx, &model_struct.LocalAppSDKVersion{Version: version.Version})
 		if err != nil {
 			return err
 		}
+		return nil
 	}
 
 	return nil
 }
+
+func (d *DataBase) ensureConversationIndexes(ctx context.Context) error {
+	statements := []string{
+		"CREATE INDEX IF NOT EXISTS idx_local_conversations_visible_order ON " +
+			"local_conversations (is_pinned DESC, MAX(latest_msg_send_time,draft_text_time) " +
+			"DESC, conversation_id ASC) WHERE latest_msg_send_time > 0",
+	}
+	for _, statement := range statements {
+		if err := d.conn.WithContext(ctx).Exec(statement).Error; err != nil {
+			return errs.WrapMsg(err, "ensure conversation indexes failed", "sql", statement)
+		}
+	}
+	return nil
+}