copr: fix the issue about runaway index lookup query blocking

[nolouch]

What problem does this PR solve?

Issue Number: close #56916

Problem Summary:

The query may be blocking after identifying a runaway query with a cooldown action.

What changed and how does it work?

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.

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 56.3018%. Comparing base (cc4e5a0) to head (8f4852f).
Report is 6 commits behind head on master.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #56920         +/-   ##
=================================================
- Coverage   73.2812%   56.3018%   -16.9794%     
=================================================
  Files          1638       1764        +126     
  Lines        453733     634175     +180442     
=================================================
+ Hits         332501     357052      +24551     
- Misses       100849     253047     +152198     
- Partials      20383      24076       +3693     

Flag	Coverage Δ
integration	37.0184% <71.4285%> (?)
unit	72.4994% <100.0000%> (+0.0137%)	⬆️

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

Components	Coverage Δ
dumpling	52.9478% <ø> (ø)
parser	∅ <ø> (∅)
br	52.6501% <ø> (+6.6384%)	⬆️

[nolouch]

/retest-required

[nolouch]

/retest-required

[nolouch]

/retest-required

[glorv]

NIT: this change seems unnecessary as smallTaskCh can only be not nil when smallTaskConcurrency > 0

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: crazycs520, glorv

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-10-28 13:49:16.535507062 +0000 UTC m=+271269.374662603: ☑️ agreed by crazycs520.
• 2024-10-29 02:12:34.132704306 +0000 UTC m=+315866.971859851: ☑️ agreed by glorv.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.4: #56931.