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txn: make kv pairs converted from locks invisible #42409

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merged 3 commits into from
Mar 21, 2023

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zyguan
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@zyguan zyguan commented Mar 20, 2023

What problem does this PR solve?

Issue Number: ref #28011

Problem Summary: as described in #28011 , kv pairs converted from locks is visible to union-scan, which leads to duplicated rows (one from snapshot and the other from mem-index-reader).

What is changed and how it works?

Mark keys converted from lock as invisible and bypass those keys on read. Since this PR is only a hotfix for #28011 , it's better not to introduce extra complexity. Thus, instead of adding a new flag to client-go, an invisible key set is added to tikvTxn for tracking key visibility.

For v6.5.0 and above, tikv/tikv#13694 is a better solution.

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

@zyguan zyguan requested a review from cfzjywxk March 20, 2023 17:08
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ti-chi-bot commented Mar 20, 2023

[REVIEW NOTIFICATION]

This pull request has been approved by:

  • cfzjywxk
  • ekexium
  • you06

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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/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Mar 20, 2023
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zyguan commented Mar 21, 2023

/test unit-test

cfzjywxk
cfzjywxk previously approved these changes Mar 21, 2023
@ti-chi-bot ti-chi-bot added the status/LGT1 Indicates that a PR has LGTM 1. label Mar 21, 2023
@cfzjywxk cfzjywxk added the require-LGT3 Indicates that the PR requires three LGTM. label Mar 21, 2023
ekexium
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The rest LGTM.

)

type visibilityChecker interface {
isVisible(kv.Key) bool
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The name is a bit vague. The status is 3-valued: (1)exist + visible, (2)exist + invisible, (3)absent(unknown).
It returns true iff (1) || (3).

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How about to rename it to invisible?

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Sounds good. Or something like isVisibleOrUnknown(?)

@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 Mar 21, 2023
you06
you06 previously approved these changes Mar 21, 2023
@ti-chi-bot ti-chi-bot added status/LGT3 The PR has already had 3 LGTM. and removed status/LGT2 Indicates that a PR has LGTM 2. labels Mar 21, 2023
Signed-off-by: zyguan <[email protected]>
@zyguan zyguan dismissed stale reviews from you06, ekexium, and cfzjywxk via b789231 March 21, 2023 03:32
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/test mysql-test

cfzjywxk
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/merge

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

Commit hash: b789231

@ti-chi-bot ti-chi-bot added the status/can-merge Indicates a PR has been approved by a committer. label Mar 21, 2023
Signed-off-by: zyguan <[email protected]>
@ti-chi-bot ti-chi-bot added size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. and removed status/can-merge Indicates a PR has been approved by a committer. size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Mar 21, 2023
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zyguan commented Mar 21, 2023

/merge

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

Commit hash: d8483a8

@ti-chi-bot ti-chi-bot added the status/can-merge Indicates a PR has been approved by a committer. label Mar 21, 2023
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zyguan commented Mar 21, 2023

/retest

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zyguan commented Mar 21, 2023

/retest

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zyguan commented Mar 21, 2023

/test unit-test

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zyguan commented Mar 21, 2023

/test check-dev

@ti-chi-bot ti-chi-bot merged commit 3ff66ac into pingcap:release-6.1-20230221-v6.1.1 Mar 21, 2023
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7 participants