backend-db-performance SKILL.md skillA
backend-db-performance from kensaurus/cursor-kenji is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add kensaurus/cursor-kenji/backend-db-performance@git:20261006.39320f8Pins git:20261006.39320f8 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- kensaurus/cursor-kenji
- Path
skills/backend-db-performance/SKILL.md- Versions recorded
- 5
- Latest version
- git:20261006.39320f8, committed Oct 6, 2026
- First version recorded
- Jun 4, 2026
- Size
- 8,700 bytes
- Repository stars
- 9
- License
- MIT
Optimize slow queries, indexes, and N+1s. Use when "slow query", "database performance", "add an index", or "N+1". Schema consistency → audit-db-schema. RLS access control → plan-rls-audit.
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
# Database Optimization Skill
**Degree of freedom: MIXED.** Which query/index/N+1 to fix `[HIGH freedom]`;
existing-index probes and EXPLAIN ANALYZE `[LOW freedom — run exactly]`.
## How to reason
1. **Observe** — EXPLAIN ANALYZE / `pg_stat_statements` / existing `pg_indexes`
2. **Interpret** — seq scan vs N+1 vs over-fetch vs missing pagination
3. **Classify** — add-index / eager-load / narrow-select / paginate / leave-alone
4. **Severity** — write-path timeout outranks a 200ms list page
## Worked example
> **Observe:** `/feed` p95 2.4s; Prisma logs 81 queries; `pg_indexes` has no `idx_posts_user_created`.
> **Interpret:** `findMany` posts then per-row `user.findUnique` — N+1; `ORDER BY created_at` is a seq scan.
> **Classify:** eager-load `include: { author }` + composite index `(user_id, created_at DESC)`.
> **Verify:** EXPLAIN ANALYZE → Index Scan; query count 2; p95 < 200ms. Did not add a duplicate index.
## Self-critique before reporting
- **Existing first** — listed `pg_indexes` / migrations before `CREATE INDEX`
- **EXPLAIN** — the claimed winner has ANALYZE output, not intuition
- **No duplicate index** — the proposed name was queried and absent
…Read the whole file at its exact version.
How to install
mdr add kensaurus/cursor-kenji/backend-db-performance@sha256:3a40323b1bf5e99aThe line at the top of this page pins the label git:20261006.39320f8, 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_kzbq5srnfxg7ynai)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 5 versions of this file, between Jun 4, 2026 and Oct 6, 2026, about one every 31 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261006.39320f8 latest | 2026-10-06 | 39320f8 | 8,700 B | A | view · diff |
| git:20260912.33d48b1 | 2026-09-12 | 33d48b1 | 10,487 B | A | view · diff |
| git:20260821.2a41031 | 2026-08-21 | 2a41031 | 10,497 B | A | view · diff |
| git:20260820.950107c | 2026-08-20 | 950107c | 9,049 B | A | view · diff |
| git:20260604.45202dd | 2026-06-04 | 45202dd | 9,130 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 (8700 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
kensaurus/cursor-kenji · 9 stars · license MIT · pushed 2026-10-19 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_kzbq5srnfxg7ynai GET https://markdownregistry.com/api/v1/resolve?ref=kensaurus/cursor-kenji/backend-db-performance GET https://markdownregistry.com/api/v1/blob/3a40323b1bf5e99acef6dad762f1d18c3de3dc80c5d48d37e94a78307998eb4d
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.
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