planner: Allow prepared and non-prepared queries with set_var and resource_group hints to be cached.

[wddevries]

What problem does this PR solve?

Issue Number: close #60920

Problem Summary:
Prepared and non-prepared queries with set_var and resource_group hints cannot be cached.

What changed and how does it work?

This pull request makes two changes:

• it adds code to handle set_vars hints for cached queries to planner.Optimize(), and
• it removes the code that excludes queries with set_var and resouce_group hints from the plan caches.

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

[tiprow]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.3608%. Comparing base (6b7a0ed) to head (78ff2cc).
Report is 18 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #62367        +/-   ##
================================================
+ Coverage   72.9064%   73.3608%   +0.4544%     
================================================
  Files          1751       1753         +2     
  Lines        484569     489374      +4805     
================================================
+ Hits         353282     359009      +5727     
+ Misses       109672     108631      -1041     
- Partials      21615      21734       +119     

Flag	Coverage Δ
integration	42.3571% <100.0000%> (?)
unit	72.1931% <50.0000%> (+0.0285%)	⬆️

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Components	Coverage Δ
dumpling	52.7804% <ø> (ø)
parser	∅ <ø> (∅)
br	46.3400% <ø> (-0.0026%)	⬇️

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[wddevries]

/test check-dev2

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[terry1purcell]

/lgtm

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: terry1purcell
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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-07-12 14:27:35.961361916 +0000 UTC m=+2355508.684540897: ☑️ agreed by terry1purcell.