i18n(ja): restore literal English text for user-facing error messages

[yahonda]

What is changed, added or deleted? (Required)

Several release notes and reference pages had the actual English error message/string that TiDB (or BR/TiDB Lightning/TiFlash) emits translated into paraphrased Japanese, instead of being kept literal as it appears in EN. Since these are real error strings a user would see verbatim, the Japanese translation should keep them in English too.

Fixed 21 occurrences across 14 files:

• releases/release-2.0.1.md, release-2.1-rc.2.md, release-3.0.1.md, release-4.0.14.md, release-4.0.15.md (2), release-5.0.0.md, release-5.1.0.md (2), release-5.2.0.md (2), release-5.4.1.md (2), release-6.5.3.md, release-7.1.3.md
• tidb-lightning/data-import-best-practices.md (4)
• tikv-configuration-file.md
• tidb-cloud/serverless-faqs.md

Each fix was verified against the corresponding EN source in release-8.5 to confirm EN itself quotes the literal error text.

Which TiDB version(s) do your changes apply to? (Required)

• i18n-ja-release-8.5 (TiDB Japanese documentation for TiDB 8.5 versions)

What is the related PR or file link(s)?

• This PR is translated from:
• Other reference link(s):

AI agent involvement

• The changes in this PR were primarily made by an AI agent on behalf of the PR author.

Do your changes match any of the following descriptions?

• Delete files
• Change aliases
• Need modification after applied to another branch
• Might cause conflicts after applied to another branch

Summary by CodeRabbit

• Documentation
  • Updated release notes and guides to use consistent English error-message terminology.
  • Improved wording for errors related to column values, GC lifetime, FAST ANALYZE, TiDB Dashboard, GROUP BY, UNION, TDE, upgrades, Lightning, GBK, TiFlash, and TTL.
  • Updated FAQ and data-import documentation for connection limits, checksum mismatches, missing files, and related errors.
  • Clarified that changing enable-ttl on existing clusters is not recommended.

[ti-chi-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[coderabbitai]

Note

Reviews paused

It looks like this branch is under active development. To avoid overwhelming you with review comments due to an influx of new commits, CodeRabbit has automatically paused this review. You can configure this behavior by changing the reviews.auto_review.auto_pause_after_reviewed_commits setting.

Use the following commands to manage reviews:

• @coderabbitai resume to resume automatic reviews.
• @coderabbitai review to trigger a single review.

Use the checkboxes below for quick actions:

• ▶️ Resume reviews
• 🔍 Trigger review

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Team

Run ID: 0c83a6cd-67e4-4ec2-b09a-a878d4b1d4a5

📥 Commits

Reviewing files that changed from the base of the PR and between d8f9ed1 and c012c5c.

📒 Files selected for processing (9)

• releases/release-2.1-rc.2.md
• releases/release-3.0.1.md
• releases/release-4.0.14.md
• releases/release-4.0.15.md
• releases/release-5.1.0.md
• releases/release-5.2.0.md
• releases/release-5.4.1.md
• releases/release-7.1.3.md
• tikv-configuration-file.md

Included review availability: Your plan provides up to 4 included reviews per hour; 1 remains after this review.

---

📝 Walkthrough

Walkthrough

The changes replace Japanese error-message wording with corresponding English text across TiDB release notes, TiDB Cloud FAQs, TiDB Lightning documentation, and TiKV configuration guidance. Configuration behavior remains unchanged.

Changes

Error message wording updates

Layer / File(s)	Summary
Release note error messages releases/release-*.md	Release notes from TiDB 2.0.1 through 7.1.3 now use English error-message text.
FAQ and troubleshooting terminology tidb-cloud/serverless-faqs.md, tidb-lightning/data-import-best-practices.md	FAQ headings and TiDB Lightning troubleshooting entries now use English error messages.
TiKV configuration guidance tikv-configuration-file.md	The enable-ttl warning now uses the English restart error message and revised guidance. Configuration behavior is unchanged.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Merge Risk: ⚪ Minimal · up to c012c

This change standardizes documented error messages to their literal English forms without changing configuration or runtime behavior. No current merge-readiness risk remains.

Suggested reviewers: qiancai

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: restoring literal English text for user-facing error messages in Japanese documentation.
Description check	✅ Passed	The description explains the changes, affected version, file scope, related links, AI involvement, and applicable change categories. It is complete and directly related to the pull request.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches 💡 1

🛠️ Fix failing CI checks 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign oreoxmt for approval. For more information see the Code Review Process.
Please ensure that each of them provides their approval before proceeding.

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

Details

Needs approval from an approver in each of these files:

• OWNERS

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

[coderabbitai]

Note

GitHub couldn't provide a complete incremental comparison for this pull request, so CodeRabbit is performing a full review instead. This review may take a little longer.

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-09-07 02:01:03.609097703 +0000 UTC m=+1676698.780191809: ☑️ agreed by qiancai.