ddl: handle cluster state retrieval failure

[tangenta]

What problem does this PR solve?

Issue Number: close #53808

Problem Summary:

When TiDB is just elected as the DDL owner and startDispatchLoop is not started, there maybe a "context canceled" error when owner retired for some reasons(like PD connection issue):

[2024/06/03 12:42:37.820 +08:00] [INFO] [manager.go:232] ["retire owner"] ["owner info"="[ddl] /tidb/ddl/fg/owner ownerManager 4e189321-5fd4-48fa-ad33-a8a92ed10cef"]
[2024/06/03 12:42:37.820 +08:00] [INFO] [syncer.go:485] ["schema version sync loop interrupted, retrying..."] [category=ddl]
[2024/06/03 12:42:37.820 +08:00] [WARN] [job_table.go:424] ["get global state failed"] [category=ddl] [error="context canceled"]
[2024/06/03 12:42:37.820 +08:00] [FATAL] [job_table.go:366] ["dispatch loop get cluster state failed, it should not happen, please try restart TiDB"] [category=ddl] [error="context canceled"] [stack="github.com/pingcap/tidb/pkg/ddl.(*jobScheduler).startDispatchLoop\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/ddl/job_table.go:366\ngit.luolix.top/pingcap/tidb/pkg/util.(*WaitGroupWrapper).RunWithLog.func1\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/util/wait_group_wrapper.go:171"]

What changed and how does it work?

Since startDispatchLoop is not only called at TiDB cluster initialization, we should not os.Exit(1).

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 @tangenta. Thanks for your PR.

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[codecov]

Codecov Report

Attention: Patch coverage is 52.38095% with 10 lines in your changes missing coverage. Please review.

Project coverage is 55.9252%. Comparing base (8483dc5) to head (cc89fb8).
Report is 32 commits behind head on master.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #53816         +/-   ##
=================================================
- Coverage   72.5705%   55.9252%   -16.6454%     
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  Files          1506       1627        +121     
  Lines        431000     609124     +178124     
=================================================
+ Hits         312779     340654      +27875     
- Misses        98912     245245     +146333     
- Partials      19309      23225       +3916     

Flag	Coverage Δ
integration	36.7612% <52.3809%> (?)
unit	71.4414% <52.3809%> (-0.1249%)	⬇️

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Components	Coverage Δ
dumpling	52.9656% <ø> (-1.0302%)	⬇️
parser	∅ <ø> (∅)
br	50.2833% <ø> (+8.4702%)	⬆️

[tangenta]

/retest

[tiprow]

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

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/retest

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-06-05 02:30:57.961984196 +0000 UTC m=+3434811.719119766: ☑️ agreed by D3Hunter.
• 2024-06-05 06:20:10.35694861 +0000 UTC m=+3448564.114084183: ☑️ agreed by lance6716.

[lance6716]

@tangenta you can approve yourself

[tangenta]

@tangenta you can approve yourself

Author cannot approve his own PR..

[tangenta]

/approve

[zimulala]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: D3Hunter, lance6716, tangenta, zimulala

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• pkg/ddl/OWNERS [tangenta,zimulala]

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[D3Hunter]

we should keep retry as long as we're still the owner, like what SyncJobSchemaVerLoop does

[tangenta]

/hold

[tangenta]

we should keep retry as long as we're still the owner, like what SyncJobSchemaVerLoop does

@D3Hunter 3fd88a1

[D3Hunter]

rest lgtm

[tangenta]

/unhold