statstics: correctly handle error when merging global stats

[hawkingrei]

What problem does this PR solve?

Issue Number: close #47771

Problem Summary:

What is changed and how it works?

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

Merging #47770 (c8a344f) into master (ab32fc7) will increase coverage by 0.8936%.
Report is 2 commits behind head on master.
The diff coverage is 96.6666%.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #47770        +/-   ##
================================================
+ Coverage   71.9012%   72.7949%   +0.8936%     
================================================
  Files          1398       1421        +23     
  Lines        405200     411618      +6418     
================================================
+ Hits         291344     299637      +8293     
+ Misses        94244      93134      -1110     
+ Partials      19612      18847       -765     

Flag	Coverage Δ
integration	41.4988% <26.6666%> (?)
unit	71.8578% <96.6666%> (-0.0435%)	⬇️

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

Components	Coverage Δ
dumpling	53.9913% <ø> (ø)
parser	∅ <ø> (∅)
br	48.6898% <ø> (-4.2476%)	⬇️

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: qw4990, winoros

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• OWNERS [qw4990,winoros]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-10-19 06:07:58.525195591 +0000 UTC m=+1896476.112305727: ☑️ agreed by winoros.
• 2023-10-19 06:18:47.631020728 +0000 UTC m=+1897125.218130873: ☑️ agreed by qw4990.

[hawkingrei]

/cherrypick release-7.5

[ti-chi-bot]

@hawkingrei: new pull request created to branch release-7.5: #47812.

In response to this:

/cherrypick release-7.5

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