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ddl: ignore reorg elem error when the job is cancelling #41383

Merged
merged 2 commits into from
Feb 15, 2023
Merged

ddl: ignore reorg elem error when the job is cancelling #41383

merged 2 commits into from
Feb 15, 2023

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tangenta
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What problem does this PR solve?

Issue Number: close #41381

Problem Summary:

The root cause is the write-conflict between DDL job's transaction and ADMIN CANCEL transaction. The latter wins and aborts the DDL job's transaction. As a result, the "duplicate entry" error is lost.

DDL worker starts to handle the cancelling case. It finds that the job is in write-reorg state, and tries to pick up the work by getting reorg handle. However, the reorg handle is cleaned by another previous transaction.

What is changed and how it works?

This PR ignores the "reorg element not exist" error when the job is cancelling.

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

Please refer to Release Notes Language Style Guide to write a quality release note.

None

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ti-chi-bot commented Feb 14, 2023 •
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[REVIEW NOTIFICATION]

This pull request has been approved by:

  • Benjamin2037
  • wjhuang2016

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.

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@ti-chi-bot ti-chi-bot added release-note-none Denotes a PR that doesn't merit a release note. size/M Denotes a PR that changes 30-99 lines, ignoring generated files. labels Feb 14, 2023
@tangenta
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/retest

@ti-chi-bot ti-chi-bot added the status/LGT1 Indicates that a PR has LGTM 1. label Feb 14, 2023
Benjamin2037
Benjamin2037 reviewed Feb 14, 2023
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ddl/ddl_worker.go
@@ -770,6 +770,10 @@ func (w *worker) HandleDDLJobTable(d *ddlCtx, job *model.Job) (int64, error) {
// and retry later if the job is not cancelled.
schemaVer, runJobErr = w.runDDLJob(d, t, job)

d.mu.RLock()
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Does this code only for test？

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Yes.

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Do we have a way to execute these three lines codes only in test?

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The overhead is negligible.

Please also check the other methods of this interface. All of them are written in this style.

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I know the lock and a nil function call and unlock overhead is very small. Just want to know if there is a way like c "debug micro" that only debug mode has this code.

Benjamin2037
Benjamin2037 approved these changes Feb 14, 2023
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LGTM

@ti-chi-bot ti-chi-bot added status/LGT2 Indicates that a PR has LGTM 2. and removed status/LGT1 Indicates that a PR has LGTM 1. labels Feb 14, 2023
@tangenta
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/retest

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@hawkingrei
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/retest

@tangenta
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/merge

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This pull request has been accepted and is ready to merge.

Commit hash: a034004

@ti-chi-bot ti-chi-bot added the status/can-merge Indicates a PR has been approved by a committer. label Feb 15, 2023
@ti-chi-bot ti-chi-bot merged commit c6bd86c into pingcap:master Feb 15, 2023
ghazalfamilyusa pushed a commit to ghazalfamilyusa/tidb that referenced this pull request Feb 15, 2023
@tangenta @ghazalfamilyusa
ddl: ignore reorg elem error when the job is cancelling (pingcap#41383)
4c0107f 
close pingcap#41381
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@Benjamin2037 Benjamin2037 Benjamin2037 approved these changes

@wjhuang2016 wjhuang2016 wjhuang2016 approved these changes

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release-note-none Denotes a PR that doesn't merit a release note. size/M Denotes a PR that changes 30-99 lines, ignoring generated files. status/can-merge Indicates a PR has been approved by a committer. status/LGT2 Indicates that a PR has LGTM 2.
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Successfully merging this pull request may close these issues.

Unexpected error "DDL reorg element does not exist" when adding index
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@tangenta @ti-chi-bot @hawkingrei @Benjamin2037 @wjhuang2016