更新

backend/models/db_migrate.py

@@ -33,6 +33,26 @@ def add_column_if_missing(conn, table: str, column: str, ddl_by_dialect: dict[st
         conn.execute(text(ddl))
 
 
+def add_index_if_missing(
+    conn,
+    table: str,
+    index_name: str,
+    columns: tuple[str, ...],
+) -> None:
+    """Create one portable index without relying on dialect-specific IF NOT EXISTS."""
+    try:
+        insp = inspect(conn)
+        if not insp.has_table(table):
+            return
+        existing = {item.get("name") for item in insp.get_indexes(table)}
+    except Exception:
+        return
+    if index_name in existing:
+        return
+    safe_columns = ", ".join(columns)
+    conn.execute(text(f"CREATE INDEX {index_name} ON {table} ({safe_columns})"))
+
+
 def migrate_accounts_table(conn) -> None:
     add_column_if_missing(
         conn,
@@ -124,6 +144,36 @@ def migrate_message_logs_table(conn) -> None:
         "sender_avatar",
         {"default": "ALTER TABLE message_logs ADD COLUMN sender_avatar TEXT"},
     )
+    add_index_if_missing(
+        conn,
+        "message_logs",
+        "ix_message_logs_account_created_at",
+        ("account_id", "created_at"),
+    )
+    add_index_if_missing(
+        conn,
+        "message_logs",
+        "ix_message_logs_created_at",
+        ("created_at",),
+    )
+    add_index_if_missing(
+        conn,
+        "message_logs",
+        "ix_message_logs_status_account_id",
+        ("status", "account_id"),
+    )
+    add_index_if_missing(
+        conn,
+        "received_message_logs",
+        "ix_received_message_logs_account_created_at",
+        ("account_id", "created_at"),
+    )
+    add_index_if_missing(
+        conn,
+        "system_logs",
+        "ix_system_logs_account_created_at",
+        ("account_id", "created_at"),
+    )
 
 
 def migrate_rules_table(conn) -> None: