*: ref all the jobs before sending to jobToWorkerCh

[wjhuang2016]

What problem does this PR solve?

Issue Number: close #64666

Problem Summary:
In the generateAndSendJob function, we previously referenced one region job at a time and immediately sent it to jobToWorkerCh. If a job (especially an empty job) finished before the next job was referenced, the reference count could drop to 0, causing memoryIngestData to be cleaned unexpectedly. This prevented other jobs still being processed from accessing the data, leading to data inconsistency.
In tidb-x scenarios, where region sizes are larger than the configured SplitRegionSize, some regions' jobs are empty. These empty jobs are processed quickly, which makes this issue more likely to occur.

What changed and how does it work?

We modified the logic in generateAndSendJob to reference all jobs before sending them to jobToWorkerCh. Specifically, we first call job.ref(jobWg) for all generated jobs in a loop, and then send them to the channel one by one in a separate loop.

This ensures all jobs have their reference counts incremented before any of them are sent to the channel. Even if some jobs (like empty jobs) finish quickly and call done(), as long as other jobs still hold references, ingestData will not be cleaned prematurely. Only when all jobs complete and call done() will the reference count reach 0, at which point ingestData can be safely cleaned, preventing data inconsistency issues.

Check List

Tests

• Unit test
• Integration test
  Pass the tidb-x HA add index 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

[codecov]

Codecov Report

❌ Patch coverage is 35.00000% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.1059%. Comparing base (d4c1408) to head (baf0d54).
⚠️ Report is 72 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #64767        +/-   ##
================================================
+ Coverage   72.6813%   74.1059%   +1.4246%     
================================================
  Files          1866       1889        +23     
  Lines        506188     525035     +18847     
================================================
+ Hits         367904     389082     +21178     
+ Misses       115892     112156      -3736     
- Partials      22392      23797      +1405     

Flag	Coverage Δ
integration	46.8408% <35.0000%> (?)

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

Components	Coverage Δ
dumpling	52.8700% <ø> (ø)
parser	∅ <ø> (∅)
br	58.1288% <ø> (+11.9752%)	⬆️

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[joechenrh]

/retest

[ti-chi-bot]

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[wjhuang2016]

/retest

[tiprow]

@wjhuang2016: 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	baf0d54	link	true	/test fast_test_tiprow

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[ti-chi-bot]

@wjhuang2016: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-unit-test-next-gen	baf0d54	link	true	/test pull-unit-test-next-gen
idc-jenkins-ci-tidb/check_dev_2	baf0d54	link	true	/test check-dev2
idc-jenkins-ci-tidb/unit-test	baf0d54	link	true	/test unit-test
pull-unit-test-ddlv1	baf0d54	link	true	/test pull-unit-test-ddlv1
pull-lightning-integration-test	baf0d54	link	true	/test pull-lightning-integration-test
pull-integration-realcluster-test-next-gen	baf0d54	link	true	/test pull-integration-realcluster-test-next-gen
pull-br-integration-test	baf0d54	link	true	/test pull-br-integration-test

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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.