tidb-query-tuning SKILL.md skillA
tidb-query-tuning from pingcap/agent-rules is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add pingcap/agent-rules/tidb-query-tuning@git:20260421.9414702Pins git:20260421.9414702 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- pingcap/agent-rules
- Path
skills/tidb-query-tuning/SKILL.md- Versions recorded
- 5
- Latest version
- git:20260421.9414702, committed Apr 21, 2026
- First version recorded
- Mar 17, 2026
- Size
- 12,560 bytes
- Repository stars
- 27
- License
- none declared
Diagnose and optimize slow TiDB queries using optimizer hints, session variables, join strategy selection, subquery optimization, and index tuning. Use when a query is slow, produces a bad plan, or needs performance guidance on TiDB.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# TiDB Query Tuning
Use this skill to diagnose and resolve TiDB query performance issues. It follows a rigorous workflow from symptom identification to verified solution.
---
## Workflow
1. **Capture the current plan & clues:**
- Run `EXPLAIN ANALYZE <query>` to get actual execution stats.
- Compare `estRows` vs `actRows` — large divergence means stale or missing statistics.
- Note the most expensive operators (wall time, memory, rows processed).
- **Use PLAN REPLAYER**: Run `PLAN REPLAYER DUMP EXPLAIN [ANALYZE] <query>;` to export comprehensive on-site information (version, config, stats, plan) to a ZIP file.
- **Use Debug API**: Use TiDB HTTP API (port 10080) to pull runtime info: `/debug/pprof`, `/stats/dump/{db}/{table}`, or `/schema/{db}/{table}`.
- **Check Bindings**: Run `SHOW GLOBAL BINDINGS;` to see if existing plan baselines are affecting the query.
2. **Check statistics health:**
- `SHOW STATS_HEALTHY WHERE Db_name = '<db>' AND Table_name = '<table>';`
- If health < 80 or `actRows` diverges significantly from `estRows`, run `ANALYZE TABLE <table>;` (or with `ALL COLUMNS` if `@@tidb_analyze_column_options` is not `ALL`) and re-check the plan.
…Read the whole file at its exact version.
How to install
mdr add pingcap/agent-rules/tidb-query-tuning@sha256:35941bb4f0289496The line at the top of this page pins the label git:20260421.9414702, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_3jg4hhc6i2qrunsc)
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Versions
The registry has recorded 5 versions of this file, between Mar 17, 2026 and Apr 21, 2026, about one every 9 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260421.9414702 latest | 2026-04-21 | 9414702 | 12,560 B | A | view · diff |
| git:20260414.4ab4f6c | 2026-04-14 | 4ab4f6c | 9,709 B | A | view · diff |
| git:20260410.256724c | 2026-04-10 | 256724c | 8,529 B | A | view · diff |
| git:20260320.095e46b | 2026-03-20 | 095e46b | 7,571 B | A | view · diff |
| git:20260317.fc37011 | 2026-03-17 | fc37011 | 7,441 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (12560 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
pingcap/agent-rules · 27 stars · license none declared · pushed 2026-11-02 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_3jg4hhc6i2qrunsc GET https://markdownregistry.com/api/v1/resolve?ref=pingcap/agent-rules/tidb-query-tuning GET https://markdownregistry.com/api/v1/blob/35941bb4f02894968504275c33b66add1cd791c81797c65ec05ea49a213f93ea
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.