planner: Use realtimeRowCount when all topN collected (#56848)

[ti-chi-bot]

This is an automated cherry-pick of #56848

What problem does this PR solve?

Issue Number: close #47400

Problem Summary:

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.

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

[terry1purcell]

/cherry-pick-invite

[ti-chi-bot]

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[codecov]

Codecov Report

Attention: Patch coverage is 42.85714% with 16 lines in your changes missing coverage. Please review.

Please upload report for BASE (release-7.1@5e6bbb5). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-7.1     #57224   +/-   ##
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  Coverage               ?   73.6527%           
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  Files                  ?       1213           
  Lines                  ?     383163           
  Branches               ?          0           
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  Hits                   ?     282210           
  Misses                 ?      83098           
  Partials               ?      17855           

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-11-12 01:10:19.103365276 +0000 UTC m=+318581.294234268: ☑️ agreed by AilinKid.
• 2024-11-12 01:24:32.666879568 +0000 UTC m=+319434.857748567: ☑️ agreed by qw4990.