Thank you for working on TiDB! Please read TiDB's CONTRIBUTING document BEFORE filing this PR.
Please explain IN DETAIL what the changes are in this PR and why they are needed:
- Summarize your change (mandatory)
- How does this PR work? Need a brief introduction for the changed logic (optional)
- Describe clearly one logical change and avoid lazy messages (optional)
- Describe any limitations of the current code (optional)
Please NOTE that:
- Do not assume the code is self-evident
- Do not assume reviewers understand the original issue
The currently defined types are listed below, please pick one of the types for this PR by removing the others:
- New feature (non-breaking change which adds functionality)
- Improvement (non-breaking change which is an improvement to an existing feature)
- Bug fix (non-breaking change which fixes an issue)
- Breaking change (fix or feature that would cause existing functionality to not work as expected)
Please describe the tests that you ran to verify your changes. Have you finished unit tests, integration tests, or manual tests?
If there is document change, please file a PR in (docs and docs-cn) and add the PR number here.