infoschema: use maps.Clone to replace iterating

[D3Hunter]

What problem does this PR solve?

Issue Number: ref #54436

Problem Summary:

What changed and how does it work?

• in https://go-review.googlesource.com/c/go/+/471400, maps.Clone is optimized to clone underlying buckets, not iterating each item as before. our info schema load part is the perfect place for this
• remove the Reload inside OnChangedof DefaultCallback which is used in normal code path, we have already waited each instance to reload, no need to call it again, will remove it in later refactor. reload inside OnSchemaStateChanged is for test, but i don't see the need to do so, as we have waited schema change before this call, so remove it too. And as fast-create depends on reload after DDL execution, we add a reload for it separately
  

  tidb/pkg/ddl/job_table.go

  Lines 625 to 636 in a490882

  	if err = waitSchemaChanged(wk.ctx, s.ddlCtx, s.lease*2, schemaVer, job); err != nil {
  	return err
  	}
  	s.cleanMDLInfo(job, ownerID)
  	s.synced(job)
  	if RunInGoTest {
  	// s.mu.hook is initialed from domain / test callback, which will force the owner host update schema diff synchronously.
  	s.mu.RLock()
  	s.mu.hook.OnSchemaStateChanged(schemaVer)
  	s.mu.RUnlock()
  	}

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

same test as in #54438, run 3 times, takes 22m30/21m40/20m44. unlike prev PR, the speed is quite stable.

compare the time to load schema diff, before

after

• 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

[tiprow]

Hi @D3Hunter. Thanks for your PR.

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[D3Hunter]

@lance6716 also check this commit a4fc016

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-07-11 09:34:06.419457355 +0000 UTC m=+522943.654691468: ☑️ agreed by lance6716.
• 2024-07-12 01:27:34.728013784 +0000 UTC m=+580151.963247897: ☑️ agreed by tangenta.

[tiprow]

@D3Hunter: 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	a4fc016	link	true	/test fast_test_tiprow

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[D3Hunter]

/hold

wait ci

code changed

code changed

[D3Hunter]

/unhold

[codecov]

Codecov Report

Attention: Patch coverage is 88.88889% with 5 lines in your changes missing coverage. Please review.

Project coverage is 55.4584%. Comparing base (749d303) to head (e90e8a7).
Report is 9 commits behind head on master.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #54581         +/-   ##
=================================================
- Coverage   74.8731%   55.4584%   -19.4147%     
=================================================
  Files          1549       1664        +115     
  Lines        362122     605459     +243337     
=================================================
+ Hits         271132     335778      +64646     
- Misses        71455     247334     +175879     
- Partials      19535      22347       +2812     

Flag	Coverage Δ
integration	34.9900% <73.3333%> (?)
unit	71.7833% <90.9090%> (-2.0180%)	⬇️

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

Components	Coverage Δ
dumpling	52.9656% <ø> (-2.2339%)	⬇️
parser	∅ <ø> (∅)
br	46.2021% <ø> (-1.4762%)	⬇️

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: tangenta

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Needs approval from an approver in each of these files:

• pkg/ddl/OWNERS [tangenta]
• pkg/domain/OWNERS [tangenta]
• pkg/infoschema/OWNERS [tangenta]

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