statistics: refactor write merge-global-stats

[hawkingrei]

What problem does this PR solve?

Issue Number: close #xxx

Problem Summary:

What changed and how does it work?

In the future, we will add concurrently global stats writing here.

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 82.50000% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 75.1044%. Comparing base (d24fdb7) to head (636e473).
Report is 16 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #53549        +/-   ##
================================================
+ Coverage   72.4150%   75.1044%   +2.6894%     
================================================
  Files          1505       1507         +2     
  Lines        430553     437239      +6686     
================================================
+ Hits         311785     328386     +16601     
+ Misses        99448      88852     -10596     
- Partials      19320      20001       +681     

Flag	Coverage Δ
integration	49.8590% <67.5000%> (?)
unit	71.7775% <82.5000%> (+0.3875%)	⬆️

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

Components	Coverage Δ
dumpling	53.9957% <ø> (ø)
parser	∅ <ø> (∅)
br	50.4810% <ø> (+9.0940%)	⬆️

[hawkingrei]

/retest

[Rustin170506]

The file name is quite confusing.

[hawkingrei]

write_merge_global.go?

[Rustin170506]

How about we keep it in the global_stats.go?

[hawkingrei]

Done, it is in the global_stats.go.

[hawkingrei]

/retest

[hawkingrei]

/retest

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AilinKid, hi-rustin

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Needs approval from an approver in each of these files:

• OWNERS [AilinKid,hi-rustin]
• pkg/statistics/OWNERS [AilinKid,hi-rustin]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-27 07:03:31.768851319 +0000 UTC m=+2673565.525986884: ☑️ agreed by AilinKid.
• 2024-05-28 07:33:57.127800922 +0000 UTC m=+2761790.884936492: ☑️ agreed by hi-rustin.