store/copr: return error when TiFlash fulltext is unavailable | tidb-test=a9bf2dca824dc746361234cd4d763178e0eedd13 tiflash=feature-fts

[wshwsh12]

What problem does this PR solve?

Issue Number: close https://github.com/pingcap-inc/tici/issues/736

Problem Summary:
When all TiFlash nodes are unavailable, TiCI (fulltext) queries may silently return an empty result set instead of an error.

What changed and how does it work?

• Treat fulltext batch cop tasks (TableShardInfos) as non-retriable in retryBatchCopTask.
• When a TiFlash request fails and the sender requests a retry, return tiflash_fts node is unavailable instead of rebuilding an empty task set.

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 @wshwsh12. Thanks for your PR.

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[wshwsh12]

/ok-to-test

[Copilot]

Pull request overview

This PR fixes a bug where TiCI (fulltext) queries could silently return an empty result set instead of returning an error when all TiFlash nodes are unavailable.

Changes:

• Added early return with error in retryBatchCopTask when encountering fulltext batch cop tasks (identified by TableShardInfos)
• Added unit test to verify the error is returned when retrying fulltext tasks

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pkg/store/copr/batch_coprocessor.go	Adds check to return error "tiflash_fts node is unavailable" when attempting to retry fulltext tasks that cannot be rebuilt with region info
pkg/store/copr/batch_coprocessor_test.go	Adds unit test to verify retry behavior for fulltext tasks returns an error

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.8297%. Comparing base (2d2bd57) to head (b654b13).
⚠️ Report is 48 commits behind head on feature/fts.

Additional details and impacted files

@@                 Coverage Diff                 @@
##           feature/fts     #66005        +/-   ##
===================================================
- Coverage      72.3094%   70.8297%   -1.4797%     
===================================================
  Files             1895       1873        -22     
  Lines           533272     526461      -6811     
===================================================
- Hits            385606     372891     -12715     
- Misses          123717     131001      +7284     
+ Partials         23949      22569      -1380     

Flag	Coverage Δ
integration	40.0040% <0.0000%> (-6.2752%)	⬇️
unit	69.9132% <100.0000%> (+0.0292%)	⬆️

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	46.2610% <ø> (-16.7777%)	⬇️

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[windtalker]

lgtm

[ChangRui-Ryan]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gengliqi, windtalker

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Details

Needs approval from an approver in each of these files:

• OWNERS [windtalker]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-02-04 03:13:40.408372926 +0000 UTC m=+236691.509771647: ☑️ agreed by windtalker.
• 2026-02-04 03:43:35.307287054 +0000 UTC m=+238486.408685769: ☑️ agreed by gengliqi.

[wshwsh12]

/retest