statistics: avoid frequantly syncing stats simultaneously

[hawkingrei]

What problem does this PR solve?

Issue Number: close #54481

Problem Summary:

What changed and how does it work?

Now, StatsCacheImpl.Update can sync stats by version from the storage. we have many scenarios to call it. such as domain.loadStatsWorker and Analyze. When customers use lightning, lightning will trigger the multi-analyzed tasks simultaneously. so it also triggers multi StatsCacheImpl.Update simultaneously. it is unnecessary.

add a singleflight for StatsCacheImpl.Update

Check List

Tests

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

  • I checked and no code files have been changed.

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

[codecov]

Codecov Report

Attention: Patch coverage is 40.62500% with 19 lines in your changes missing coverage. Please review.

Project coverage is 54.5071%. Comparing base (e5a8a23) to head (5d3f50a).
Report is 11 commits behind head on master.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #54480         +/-   ##
=================================================
- Coverage   72.8089%   54.5071%   -18.3019%     
=================================================
  Files          1549       1664        +115     
  Lines        436313     604108     +167795     
=================================================
+ Hits         317675     329282      +11607     
- Misses        99059     252987     +153928     
- Partials      19579      21839       +2260     

Flag	Coverage Δ
integration	14.7666% <40.6250%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	52.9656% <ø> (ø)
parser	∅ <ø> (∅)
br	46.1887% <ø> (+0.3481%)	⬆️

[hi-rustin]

We had some offline discussions that this change could potentially cause a table to be re-analyzed after the analysis is executed. The update method is called after the analysis, but if we only do it once, there is a big chance that the stats cache of the analyzed table will not be updated, which will result in the table being re-queued for analysis.

[hi-rustin]

I think it doesn't solve the issue I mentioned in #54480 (comment).

I believe we need to ensure that once the analysis is finished, we can always load the latest stats for the analyzed tables. Otherwise, there is a chance we will reanalyze them.

[hawkingrei]

I agree with you. Therefore, prior to commencing auto analyze, I will enforce a synchronization of the stats cache.

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-07-10 06:35:54.246801334 +0000 UTC m=+425851.482035448: ✖️🔁 reset by hi-rustin.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[tiprow]

@hawkingrei: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
fast_test_tiprow	5d3f50a	link	true	/test fast_test_tiprow

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[ti-chi-bot]

@hawkingrei: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
idc-jenkins-ci-tidb/unit-test	5d3f50a	link	true	/test unit-test
idc-jenkins-ci-tidb/check_dev_2	5d3f50a	link	true	/test check-dev2
idc-jenkins-ci-tidb/build	5d3f50a	link	true	/test build
idc-jenkins-ci-tidb/check_dev	5d3f50a	link	true	/test check-dev
pull-integration-ddl-test	5d3f50a	link	true	/test pull-integration-ddl-test
idc-jenkins-ci-tidb/mysql-test	5d3f50a	link	true	/test mysql-test

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[ti-chi-bot]

PR needs rebase.

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