metrics: bump CSE meta cache metrics and fix prefetch cache hit ratio panel (#11040)

[ti-chi-bot]

This is an automated cherry-pick of #11040

What problem does this PR solve?

Issue Number: close #11039

Problem Summary:

Bump cloud-storage-engine so TiFlash picks up the new columnar meta cache metrics, and fix TiFlash Summary which incorrectly plots tiflash_proxy_kv_engine_columnar_prefetch_cache_hit as a duration (seconds). That metric observes hit_ratio * 100 with percent buckets, so the panel should use a percent Y-axis and a ratio title.

What is changed and how it works?

metrics: bump CSE for columnar meta cache metrics and fix prefetch cache hit panel unit.

• Update contrib/cloud-storage-engine submodule (includes columnar meta cache metrics) and regenerate related Cargo.lock / proxy AGENTS notes for workspace-hack resolution.
• Change TiFlash Summary panel Columnar Prefetch Cache Hit Duration → Columnar Prefetch Cache Hit Ratio with unit="percent", then regenerate dashboard JSON/checksum.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Manual test:

1. Regenerate dashboard: cd metrics/grafana && ./generate_dashboard.sh
2. Confirm generated panel title is Columnar Prefetch Cache Hit Ratio and left Y-axis format is percent.
3. Import/update test Grafana dashboard and verify the panel reads as a hit-ratio distribution (0–100%), not seconds. Verified on http://10.2.12.81:21530/d/jmd6Payvz/jsonnet-tiflash-summary.
4. Confirm proxy/CSE build still works with the bumped submodule (prior sync commit notes verified libtiflash_proxy.so build / no jemalloc symbols).

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

TiFlash Summary: show columnar prefetch cache hit as percent ratio; bump CSE for columnar meta cache metrics.

Summary by CodeRabbit

• Monitoring

  • Updated the Columnar Storage dashboard to show prefetch cache hit ratio as a percentage, replacing the previous duration display.

• Documentation

  • Added troubleshooting guidance for lockfile updates after cloud-storage-engine revisions.
  • Clarified allocator-related build behavior.

• Maintenance

  • Updated the cloud-storage-engine revision.
  • Refined repository ignore patterns.
  • Refreshed the dashboard configuration checksum.

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

🗂️ Base branches to auto review (3)

• release-8.5
• release-7.5
• release-8.1

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: a7c2b2ae-5a21-447d-b00b-1643e4b26522

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

---

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 APPROVED

This pull-request has been approved by: JaySon-Huang, yongman

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:

• OWNERS [JaySon-Huang,yongman]

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:

• 2026-08-14 01:16:47.226132376 +0000 UTC m=+3354793.262227442: ☑️ agreed by JaySon-Huang.
• 2026-08-14 15:05:36.824089913 +0000 UTC m=+3404522.860184979: ☑️ agreed by yongman.