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executor: fix wrong result of delete multiple tables using left join (#33055) #33119

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merged 3 commits into from
Jul 5, 2022

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@ti-srebot ti-srebot commented Mar 16, 2022

cherry-pick #33055 to release-5.0
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/33119

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

git push git@github.com:ti-srebot/tidb.git pr/33119:release-5.0-2dd0074e4ece

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

What problem does this PR solve?

Issue Number: close #31321

Problem Summary:
delete from t1, t2 using t1 left join t2 on t1.c1 = t2.c1;

row of t1: (1)
row of t2: (2)
The join result will be (1, null). 1 in t1 is matched, and no row in t2 is matched. So row in t1 should be deleted, while no row in t2 should be deleted.

But the original implementation didn't check if the row in t2 is matched or not, just delete it directly, which cause the wrong result.

What is changed and how it works?

If a row is not matched in outer join, the rowid of the join result will be NULL, we use this to decide if we can delete row.

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

executor: fix wrong result of delete multiple tables using left join

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>
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ti-chi-bot commented Mar 16, 2022

[REVIEW NOTIFICATION]

This pull request has been approved by:

  • XuHuaiyu
  • wshwsh12

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@ti-chi-bot ti-chi-bot added do-not-merge/cherry-pick-not-approved 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 Mar 16, 2022
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/run-all-tests

@ti-chi-bot ti-chi-bot added 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 Mar 16, 2022
@ti-srebot ti-srebot added size/M Denotes a PR that changes 30-99 lines, ignoring generated files. type/5.0-cherry-pick labels Mar 16, 2022
@ti-srebot ti-srebot added this to the v5.0.6 milestone Mar 16, 2022
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@guo-shaoge you're already a collaborator in bot's repo.

@ti-chi-bot ti-chi-bot added the status/LGT1 Indicates that a PR has LGTM 1. label Jun 22, 2022
@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 Jun 23, 2022
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/merge

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

Commit hash: 7c5efff

@ti-chi-bot ti-chi-bot added the status/can-merge Indicates a PR has been approved by a committer. label Jun 23, 2022
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sre-bot commented Jun 23, 2022

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/run-mysql-test

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/run-mysql-test

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/run-mysql-test

@ti-chi-bot ti-chi-bot merged commit 1baedb9 into pingcap:release-5.0 Jul 5, 2022
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