perf(db): add slow-query tracing and composite indexes

db/migrations.py

@@ -73,6 +73,7 @@ def _get_migration_steps():
         (16, _migrate_to_v16),
         (17, _migrate_to_v17),
         (18, _migrate_to_v18),
+        (19, _migrate_to_v19),
     ]
 
 
@@ -860,3 +861,22 @@ def _migrate_to_v18(conn):
     )
 
     conn.commit()
+
+
+
+def _migrate_to_v19(conn):
+    """迁移到版本19 - 报表与调度查询复合索引优化"""
+    cursor = conn.cursor()
+
+    index_statements = [
+        "CREATE INDEX IF NOT EXISTS idx_users_status_created_at ON users(status, created_at)",
+        "CREATE INDEX IF NOT EXISTS idx_task_logs_status_created_at ON task_logs(status, created_at)",
+        "CREATE INDEX IF NOT EXISTS idx_user_schedules_enabled_next_run ON user_schedules(enabled, next_run_at)",
+        "CREATE INDEX IF NOT EXISTS idx_bug_feedbacks_status_created_at ON bug_feedbacks(status, created_at)",
+        "CREATE INDEX IF NOT EXISTS idx_bug_feedbacks_user_created_at ON bug_feedbacks(user_id, created_at)",
+    ]
+
+    for statement in index_statements:
+        cursor.execute(statement)
+
+    conn.commit()