For stand-alone version, the data in the db directory is not cleared after restart

**Bug Description**
For stand-alone version, the data in the db directory is not cleared after restart.

After the stand-alone version is restarted, the data is cleared, and the data in the same db directory should also be cleared

**Expected Behavior**

**Steps to Reproduce**

1.
2.
3.
4.

The issue mentions a 'db directory' not being cleared on restart of the stand-alone version. Look for code handling data persistence and cleanup in the stand-alone mode, likely in storage or initialization modules. Check how the database directory is managed on startup and shutdown. Determine what 'cleared' means—whether it's deleting files or resetting in-memory state—and verify the expected behavior against the current implementation.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.