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transaction: fix union select for update race #19006

Merged
merged 8 commits into from
Aug 6, 2020
Merged

transaction: fix union select for update race #19006

merged 8 commits into from
Aug 6, 2020

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coocood
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@coocood coocood commented Aug 5, 2020 •
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What problem does this PR solve?

union select for update statements are executed concurrently, so LockKeys is executed concurrently too, but
LockKeys is not thread-safe, cause unexpected result.

What is changed and how it works?

Lock the whole LockKeys method instead of map access.

Related changes

  • Need to cherry-pick to the release branch

Check List

Tests

  • Unit test

Release note

  • fix union select for update race

@coocood coocood added type/bugfix This PR fixes a bug. priority/release-blocker This issue blocks a release. Please solve it ASAP. sig/transaction SIG:Transaction labels Aug 5, 2020
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lysu commented Aug 5, 2020 


[2020-08-05T08:31:00.375Z] Read at 0x00c01731a268 by goroutine 590:

[2020-08-05T08:31:00.375Z]   github.com/pingcap/tidb/sessionctx/variable.(*TransactionContext).UpdateDeltaForTable()

[2020-08-05T08:31:00.375Z]       /home/jenkins/agent/workspace/tidb_ghpr_unit_test/go/src/github.com/pingcap/tidb/sessionctx/variable/session.go:219 +0x61

[2020-08-05T08:31:00.375Z]   github.com/pingcap/tidb/executor.(*SelectLockExec).Next()

@coocood update stats delta also have data race - -

lysu
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LGTM

@ti-srebot ti-srebot added the status/LGT1 Indicates that a PR has LGTM 1. label Aug 5, 2020
jackysp
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lgtm

@ti-srebot ti-srebot removed the status/LGT1 Indicates that a PR has LGTM 1. label Aug 5, 2020
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@ti-srebot ti-srebot added the status/LGT2 Indicates that a PR has LGTM 2. label Aug 5, 2020
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jackysp commented Aug 5, 2020

/merge

@ti-srebot ti-srebot added the status/can-merge Indicates a PR has been approved by a committer. label Aug 5, 2020
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/run-all-tests

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@coocood merge failed.

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codecov bot commented Aug 5, 2020 •
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Codecov Report

Merging #19006 into master will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff             @@
##             master     #19006   +/-   ##
===========================================
  Coverage   79.5048%   79.5048%           
===========================================
  Files           546        546           
  Lines        148606     148606           
===========================================
  Hits         118149     118149           
  Misses        20978      20978           
  Partials       9479       9479

@coocood coocood dismissed stale reviews from ti-srebot and jackysp via 4fc0706 August 5, 2020 11:15
@coocood coocood requested a review from a team as a code owner August 5, 2020 11:15
@coocood coocood requested review from wshwsh12 and removed request for a team August 5, 2020 11:15
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coocood commented Aug 5, 2020

/run-all-tests

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coocood commented Aug 5, 2020

/run-unit-test

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coocood commented Aug 6, 2020

/merge

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/run-all-tests

cfzjywxk
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LGTM

@ti-srebot ti-srebot added status/LGT3 The PR has already had 3 LGTM. and removed status/LGT2 Indicates that a PR has LGTM 2. labels Aug 6, 2020
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cfzjywxk commented Aug 6, 2020

/merge

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/run-all-tests

@ti-srebot ti-srebot merged commit b363937 into pingcap:master Aug 6, 2020
@ti-srebot ti-srebot mentioned this pull request Aug 6, 2020
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cherry pick to release-4.0 in PR #19022

coocood added a commit to coocood/tidb that referenced this pull request Aug 6, 2020
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transaction: fix union select for update race (pingcap#19006)
3cef071 
* transaction: fix LockKeys race

* do not update delta for lock keys

* fix more race

* fix another race

Co-authored-by: ti-srebot <66930949+ti-srebot@users.noreply.github.com>
@coocood coocood deleted the fix-lock-keys-race branch August 6, 2020 03:10
ti-srebot added a commit that referenced this pull request Aug 6, 2020
@ti-srebot @coocood
transaction: fix union select for update race (#19006) (#19022)
1a91fc5 
* transaction: fix LockKeys race

* do not update delta for lock keys

* fix more race

* fix another race

Co-authored-by: ti-srebot <66930949+ti-srebot@users.noreply.github.com>

Co-authored-by: Evan Zhou <coocood@gmail.com>
@cfzjywxk cfzjywxk mentioned this pull request Aug 6, 2020
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@ghost ghost mentioned this pull request Aug 9, 2020
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@cfzjywxk cfzjywxk mentioned this pull request Nov 16, 2020
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@lysu lysu lysu left review comments

@cfzjywxk cfzjywxk cfzjywxk approved these changes

@ti-srebot ti-srebot ti-srebot approved these changes

@jackysp jackysp jackysp left review comments

@wshwsh12 wshwsh12 Awaiting requested review from wshwsh12

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component/executor priority/release-blocker This issue blocks a release. Please solve it ASAP. sig/transaction SIG:Transaction status/can-merge Indicates a PR has been approved by a committer. status/LGT3 The PR has already had 3 LGTM. type/bugfix This PR fixes a bug.
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