statistics: record last gc ts to avoid huge read on stats table

[winoros]

What problem does this PR solve?

Issue Number: close #45966, close #31778

Problem Summary:

The previous GCStats will read nearly all the stats into the memory

What is changed and how it works?

This pull tries to limit its influence.

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

[codecov]

Codecov Report

Attention: Patch coverage is 60.52632% with 30 lines in your changes missing coverage. Please review.

Project coverage is 72.7547%. Comparing base (789d6d0) to head (ff81270).
Report is 3406 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #46138        +/-   ##
================================================
- Coverage   73.3618%   72.7547%   -0.6071%     
================================================
  Files          1326       1347        +21     
  Lines        396702     403058      +6356     
================================================
+ Hits         291028     293244      +2216     
- Misses        87118      91210      +4092     
- Partials      18556      18604        +48     

Flag	Coverage Δ
integration	27.8207% <2.6315%> (?)
unit	73.3748% <60.5263%> (+0.0129%)	⬆️

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

Components	Coverage Δ
dumpling	54.0444% <ø> (ø)
parser	84.9911% <ø> (ø)
br	48.3897% <ø> (-4.4065%)	⬇️

[AilinKid]

Rest LGTM

[AilinKid]

can we use the h.session.pool to avoid the lock the handle?

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hawkingrei, time-and-fate

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-09-05 06:02:06.268742823 +0000 UTC m=+2425290.817758807: ☑️ agreed by hawkingrei.
• 2023-09-11 11:53:57.30775863 +0000 UTC m=+270219.232315024: ☑️ agreed by time-and-fate.

[hawkingrei]

/test all

[tiprow]

@winoros: 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
tiprow_fast_test	3960dcd	link	true	/test tiprow_fast_test

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[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #55381.

[ti-chi-bot]

In response to a cherrypick label: new pull request could not be created: failed to create pull request against pingcap/tidb#release-7.1 from head ti-chi-bot:cherry-pick-46138-to-release-7.1: the GitHub API request returns a 403 error: {"message":"You have exceeded a secondary rate limit and have been temporarily blocked from content creation. Please retry your request again later. If you reach out to GitHub Support for help, please include the request ID ACA6:3F108B:1B829CA:33D7586:671F467F and timestamp 2024-10-28 08:08:31 UTC.","documentation_url":"https://docs.github.com/rest/overview/rate-limits-for-the-rest-api#about-secondary-rate-limits","status":"403"}

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #57151.