pkg/dxf: avoid misleading error log on context cancel (#67612)

[ti-chi-bot]

This is an automated cherry-pick of #67612

What problem does this PR solve?

Issue Number: ref #67631

Problem Summary:

When a distributed task subtask exits because the context is canceled, the executor currently logs it as a failure. This produces misleading error logs for expected cancellation paths.

What changed and how does it work?

In BaseTaskExecutor.Run, handle runSubtask errors by type:

• If the error is a context-canceled error (llog.IsContextCanceledError(err)), log an info message.
• Otherwise keep logging the error as before.

This preserves error visibility for real failures while reducing noisy/misleading logs for expected cancellations.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test. just changing log printing

  • 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

None

Summary by CodeRabbit

• Bug Fixes
  • Updated task execution logging to treat context cancellations as informational events instead of errors, reducing misleading error entries.
  • Improves log clarity and decreases false-positive alerts in monitoring, making it easier to distinguish genuine failures from expected cancellations.

[ti-chi-bot]

@D3Hunter This PR has conflicts, I have hold it.
Please resolve them or ask others to resolve them, then comment /unhold to remove the hold label.

[ti-chi-bot]

@ti-chi-bot: ## If you want to know how to resolve it, please read the guide in TiDB Dev Guide.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 958e2383-fbfd-4d4b-9b47-26c96ccd8417

📥 Commits

Reviewing files that changed from the base of the PR and between ade13f7 and a194b3c.

📒 Files selected for processing (1)

• pkg/disttask/framework/taskexecutor/task_executor.go

🚧 Files skipped from review as they are similar to previous changes (1)

• pkg/disttask/framework/taskexecutor/task_executor.go

---

📝 Walkthrough

Walkthrough

Changed logging in BaseTaskExecutor.Run so that when runSubtask returns a context-canceled error it is logged at Info with a short message; other runSubtask errors continue to be logged as Error via sampleLogger.

Changes

Cohort / File(s)	Summary
Error logging change pkg/disttask/framework/taskexecutor/task_executor.go	In BaseTaskExecutor.Run, branch logging on context-cancellation: use sampleLogger.Info("subtask run canceled by context", llog.ShortError(err)) for context-canceled errors; retain sampleLogger.Error("run subtask failed", zap.Error(err)) for other errors.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• pkg/dxf: avoid misleading error log on context cancel #67612 — similar change to BaseTaskExecutor.Run treating context-canceled subtask errors as Info.
• pkg/dxf: avoid misleading error log on context cancel (#67612) #67673 — applies the same context-canceled vs error logging distinction in BaseTaskExecutor.Run.
• pkg/dxf: sample high-frequency logs and summarize kv-range split (#67513) #67620 — related logging adjustments in the same task executor area, including use of sampleLogger.

Suggested labels

size/XS

Suggested reviewers

• Benjamin2037
• joechenrh

Poem

🐰 I hopped through code with careful paws,
Found canceled tasks deserve applause.
Not every stop is an error cry —
Sometimes it's just a soft "goodbye". 🥕

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Title check	⚠️ Warning	The PR title references 'pkg/dxf' but the actual change is in 'pkg/disttask/framework/taskexecutor'. The title is misleading about the package affected.	Update the title to 'pkg/disttask: avoid misleading error log on context cancel' to accurately reflect the changed package.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description covers the problem, solution, and checklist adequately. It explains the context-cancellation error handling and marks testing as unnecessary due to log-only changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@pkg/disttask/framework/taskexecutor/task_executor.go`:
- Around line 387-393: The code incorrectly references e.sampleLogger which
doesn't exist on BaseTaskExecutor; replace both uses of e.sampleLogger in the
context-canceled and error branches with the existing logger field e.logger so
logging remains consistent with the struct; update the two calls that currently
call e.sampleLogger.Info(...) and e.sampleLogger.Error(...) to call
e.logger.Info(...) and e.logger.Error(...) respectively in the Run/execute path
where llog.IsContextCanceledError(err) is checked.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 1103c7e0-c678-4439-b28a-ad002a344b3f

📥 Commits

Reviewing files that changed from the base of the PR and between a8ad696 and ade13f7.

📒 Files selected for processing (1)

• pkg/disttask/framework/taskexecutor/task_executor.go

[D3Hunter]

/unhold

[D3Hunter]

/retest

[Benjamin2037]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Benjamin2037, D3Hunter

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• pkg/disttask/OWNERS [Benjamin2037,D3Hunter]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-04-10 07:57:14.005087377 +0000 UTC m=+1115839.210447434: ☑️ agreed by D3Hunter.
• 2026-04-10 07:58:51.7048138 +0000 UTC m=+1115936.910173857: ☑️ agreed by Benjamin2037.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (release-nextgen-20251011@0803391). Learn more about missing BASE report.

Additional details and impacted files

@@                      Coverage Diff                      @@
##             release-nextgen-20251011     #67674   +/-   ##
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Flag	Coverage Δ
unit	71.8532% <100.0000%> (?)

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

Components	Coverage Δ
dumpling	56.3493% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	46.5504% <0.0000%> (?)

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