sessionctx: add warning for system variable tidb_enable_parallel_hashagg_spill

[xzhangxian1008]

What problem does this PR solve?

Issue Number: close #53919

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

[tiprow]

Hi @xzhangxian1008. Thanks for your PR.

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[xzhangxian1008]

/retest

[tiprow]

@xzhangxian1008: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

In response to this:

/retest

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[windtalker]

LGTM

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 55.7350%. Comparing base (5c0d737) to head (c511def).
Report is 7 commits behind head on master.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #53917         +/-   ##
=================================================
- Coverage   72.6403%   55.7350%   -16.9054%     
=================================================
  Files          1508       1628        +120     
  Lines        431735     602368     +170633     
=================================================
+ Hits         313614     335730      +22116     
- Misses        98856     243491     +144635     
- Partials      19265      23147       +3882     

Flag	Coverage Δ
integration	37.1748% <0.0000%> (?)
unit	71.4255% <0.0000%> (-0.2127%)	⬇️

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

Components	Coverage Δ
dumpling	52.9656% <ø> (ø)
parser	∅ <ø> (∅)
br	50.5267% <ø> (+8.3563%)	⬆️

[easonn7]

/approve

[yibin87]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: easonn7, windtalker, yibin87

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• pkg/sessionctx/variable/OWNERS [easonn7]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-06-11 05:57:38.992081114 +0000 UTC m=+444213.045393037: ☑️ agreed by windtalker.
• 2024-06-12 01:30:00.037507152 +0000 UTC m=+514554.090819075: ☑️ agreed by yibin87.

[tiprow]

@xzhangxian1008: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
fast_test_tiprow	c511def	link	true	/test fast_test_tiprow

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.