statistics: remove dead code (#58412)

[ti-chi-bot]

This is an automated cherry-pick of #58412

Signed-off-by: Rustin170506 [email protected]

What problem does this PR solve?

Issue Number: ref #57804

Problem Summary:

What changed and how does it work?

In this PR, I removed the dead code. The stats loading for the PK, as shown, has never been executed, so it is safe to remove.

Some background:

1. statistics: fix PK column TopN not loading when init stats #37552 This PR tried to load it correctly.
2. statistics: fix wrong behavior for primary key' non-lite init stats #53298 This PR decided to remove it at all.
3. Another fix based on the previous PR: *: not load unnecessay data during the non-lite-init-stats #53399
4. Another full rewrite: statistics: correct behavior of non-lite InitStats and stats sync load of no stats column #57803

So we just forgot to delete it.

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

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please ask for approval from rustin170506, ensuring that each of them provides their approval before proceeding. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• pkg/statistics/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[codecov]

Codecov Report

Attention: Patch coverage is 88.88889% with 2 lines in your changes missing coverage. Please review.

Please upload report for BASE (release-8.5@02bdc2b). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-8.5     #58442   +/-   ##
================================================
  Coverage               ?   56.9157%           
================================================
  Files                  ?       1773           
  Lines                  ?     627027           
  Branches               ?          0           
================================================
  Hits                   ?     356877           
  Misses                 ?     245936           
  Partials               ?      24214           

Flag	Coverage Δ
integration	36.8914% <11.1111%> (?)
unit	72.5363% <88.8888%> (?)

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

Components	Coverage Δ
dumpling	52.8711% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	52.2571% <0.0000%> (?)