Support TiDB stopping a running MPP query silently
Nobody has claimed this yet.
- Dominant language
- C++
- Stars
- 1k
- Forks
- 423
- Avg merge
- 1d 15h
- Merged PRs (30d)
- 24
Description
For sql with limit clause, if the query got its result, it will cancel remaining task. However, this cancel only try to stop query from running, and the running task should stop silently, while we don't implement this feature. If a mpp task receiver CancelMPPTask request, it is marked as a failed task, and log some error message and try to return error to TiDB, although TiDB will ignore this error, this still makes user confused, because for a query finishes without error, user will found many error message in TiFlash' log, we should avoid this.
Contributor guide
No contributing guide indexed for this repository
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start at the MPP task receiver handling the CancelMPPTask request and trace how cancellation becomes a failed task and is logged. Reproduce a SQL query with a LIMIT clause, then verify that cancellation after results are available stops the remaining task without emitting confusing error messages.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- databases, distributed-systems
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100