Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

execution: fix cte dead lock when used with IndexLookupJoin (#27465) #27537

Closed

Conversation

ti-srebot
Copy link
Contributor

@ti-srebot ti-srebot commented Aug 24, 2021

cherry-pick #27465 to release-5.2
You can switch your code base to this Pull Request by using git-extras:

# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/27537

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/tidb.git pr/27537:release-5.2-9691e50710ac

Signed-off-by: guo-shaoge shaoge1994@163.com

What problem does this PR solve?

Issue Number: close #27410

Problem Summary:

  1. IndexLookupJoin Opens, and outer worker starts to use cte1.resTbl and cte2.resTbl
  2. execStmtResult.Close() is called directly without querying any result(e.g. IndexLookupJoin.Next() is never called)
  3. We reset cte1's resTbl and then reset cte2's resTbl, but the outer worker of IndexLookupJoin already hold cte2's resTbl and is waiting for cte1's resTbl.

Following is the log of execStmtResult.Close() and CTEExec.Next(), which prove above:

!!!!CTEExec.Next() &{{0 0} 1 [0xc004ae5ce0 0xc004ae5e00] 1024 0xc0059ba7e0 false 0 0xc004f27100}
!!!!! resetCTEStorageMap  &{{0 0} 1 [0xc004ae5860 0xc004ae58c0] 1024 0xc0059ba720 false 0 0xc004f26e00}
!!!!! resetCTEStorageMap  &{{1 0} 1 [0xc004ae5ce0 0xc004ae5e00] 1024 0xc0059ba7e0 false 0 0xc004f27100}
!!!!CTEExec.Next() &{{0 0} 1 [0xc004ae5860 0xc004ae58c0] 1024 0xc0059ba720 false 0 0xc004f26e00}

What is changed and how it works?

How it Works: Should wait for all workers to finish then we can reset cte.resTbl.

Check List

Tests

  • Unit test
  • Integration test
  • Manual test (add detailed scripts or steps below)
  • No code

Side effects

  • Performance regression: Consumes more CPU
  • Performance regression: Consumes more Memory
  • Breaking backward compatibility

Documentation

  • Affects user behaviors
  • Contains syntax changes
  • Contains variable changes
  • Contains experimental features
  • Changes MySQL compatibility

Release note

execution: fix cte dead lock when used with IndexLookupJoin

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>
@ti-chi-bot
Copy link
Member

[REVIEW NOTIFICATION]

This pull request has not been approved.

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

@ti-chi-bot
Copy link
Member

@ti-srebot: This cherry pick PR is for a release branch and has not yet been approved by release team.
Adding the do-not-merge/cherry-pick-not-approved label.

To merge this cherry pick, it must first be approved by the collaborators.

AFTER it has been approved by collaborators, please ping the release team in a comment to request a cherry pick review.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

@ti-srebot
Copy link
Contributor Author

/run-all-tests

@ti-chi-bot ti-chi-bot added do-not-merge/release-note-label-needed Indicates that a PR should not merge because it's missing one of the release note labels. release-note Denotes a PR that will be considered when it comes time to generate release notes. and removed do-not-merge/release-note-label-needed Indicates that a PR should not merge because it's missing one of the release note labels. labels Aug 24, 2021
@ti-srebot ti-srebot added sig/execution SIG execution sig/sql-infra SIG: SQL Infra size/S Denotes a PR that changes 10-29 lines, ignoring generated files. type/5.2-cherry-pick labels Aug 24, 2021
@ti-srebot
Copy link
Contributor Author

@guo-shaoge you're already a collaborator in bot's repo.

@guo-shaoge
Copy link
Collaborator

Merged manually here

@guo-shaoge guo-shaoge closed this Aug 25, 2021
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
do-not-merge/cherry-pick-not-approved release-note Denotes a PR that will be considered when it comes time to generate release notes. sig/execution SIG execution sig/sql-infra SIG: SQL Infra size/S Denotes a PR that changes 10-29 lines, ignoring generated files. type/5.2-cherry-pick
Projects
None yet
Development

Successfully merging this pull request may close these issues.

3 participants