yd-pg-expert SKILL.md skillA
yd-pg-expert from leeyudok/agents-scaffold is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add leeyudok/agents-scaffold/yd-pg-expert@git:20261024.c5b81d9Pins git:20261024.c5b81d9 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- leeyudok/agents-scaffold
- Path
.claude/skills/yd-pg-expert/SKILL.md- Versions recorded
- 1
- Latest version
- git:20261024.c5b81d9, committed Oct 24, 2026
- Size
- 9,890 bytes
- Repository stars
- 38
- License
- MIT
PostgreSQL 고유 동작(timestamptz·numeric·실행계획·잠금을 잡는 ALTER·CREATE INDEX CONCURRENTLY·VACUUM·직렬화 재시도)을 다루거나 여러 서비스가 함께 쓰는 공유 PostgreSQL 클러스터를 운영할 때 사용한다. 엔진 공통 설계는 yd-db-expert 를 쓴다.
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
# yd-pg-expert PostgreSQL 엔진 고유 동작과 공유 클러스터 운영이 대상이다. 엔진과 무관한 설계(정규화·키·NULL·제약·쿼리 원칙·트랜잭션 경계·마이그레이션 단계)는 `yd-db-expert`, SQLite 파일 문제는 `yd-sqlite-expert` 가 맡는다. 여기서는 그 원칙을 반복하지 않는다. 엔진 동작에 관한 단언은 `scripts/verify_pg_claims.py` 가 일회용 서버에서 재현한다. 아래 관찰값은 PostgreSQL 17.11 에서 얻었다 (2026-10-04 실측). 버전을 올리면 다시 돌린다. ## 1. 타입 - **타임스탬프는 `timestamptz`.** `timestamp` 는 입력에 붙은 오프셋을 오류 없이 버린다. `'2026-01-01 09:00:00+09'` 를 넣으면 `09:00:00` 이 그대로 남아 UTC 로 읽을 때 9시간 어긋난다. `timestamptz` 는 같은 순간(`00:00:00+00`)을 유지한다. - 저장은 UTC, 표시에서 변환한다. 사용자 표기는 `YYYY-MM-DD HH:MM:SS.mmm` (KST 가정). - **돈은 `numeric`.** `float8` 은 `0.1 + 0.2 = 0.3` 이 거짓이고, 0.1 을 열 번 더하면 `0.9999999999999999` 다. `numeric` 은 둘 다 정확하다. - `UNIQUE` 는 별도 옵션이 없으면 NULL 을 여러 개 허용한다. NULL 도 하나만 허용하려면 `UNIQUE NULLS NOT DISTINCT` (PostgreSQL 15 부터)를 쓴다. ## 2. 인덱스와 실행계획 - **FK 컬럼에는 인덱스가 자동으로 생기지 않는다.** PK·`UNIQUE` 만 생긴다. 부모 행을 지우거나 키를 바꿀 때 자식 테이블을 풀스캔하므로 FK 인덱스는 직접 만든다. - 확인은 추측이 아니라 `EXPLAIN (ANALYZE, BUFFERS) <쿼리>` 로 한다. - **`EXPLAIN ANALYZE` 는 문을 실제로 실행한다.** `DELETE`·`UPDATE` 를 분석하면 행이 정말 지워진다. 쓰기 문은 `BEGIN; EXPLAIN ANALYZE ...; ROLLBACK;` 으로 감싼다. - 작은 테이블의 `Seq Scan` 은 인덱스 누락이 아니다. 20행 테이블은 PK 가 있어도 플래너가 …
Read the whole file at its exact version.
How to install
mdr add leeyudok/agents-scaffold/yd-pg-expert@sha256:0cc92044b0472e2cThe line at the top of this page pins the label git:20261024.c5b81d9, 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_2kn3ya6dnkir7s3d)
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Versions
The registry has recorded 1 version of this file, committed on Oct 24, 2026.
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 (9890 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
leeyudok/agents-scaffold · 38 stars · license MIT · pushed 2026-11-05 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_2kn3ya6dnkir7s3d GET https://markdownregistry.com/api/v1/resolve?ref=leeyudok/agents-scaffold/yd-pg-expert GET https://markdownregistry.com/api/v1/blob/0cc92044b0472e2c4f73fa1d785846164ab92b0eefde54da0890ef8aa1d16108
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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