Mission

Fix your Postgresincident fast.

Paste the error. Get the verified fix. Then the skill so the next one is shorter.

Try , , or press ⌘K anywhere.

No error text? Start from a symptomBrowse all 102 errors

Two reasons you're here

Firefight now.Interview-ready next.

Start here

Production is down

Paste the error, or open the catalog. Cause, fix, the locks to check — from a real lab.

Browse 102 errors
Drills

Interview tomorrow

Say it out loud. Panel questions and concept drills on the same lab evidence.

Open interview prep

Explore · Learn

Map the library. Take a lesson.

Level · Explore

Knowledge map

Pan the whole library. Tap a pin → place card → Open. Lenses: firefight or learn.

  • Errors linked to real runbooks
  • Lessons & concepts on one canvas
  • Only true cross-links, nothing invented
Enter the map

Lessons · how the engine works

Lessons

37 sessions, one mechanism each.

  • See it move → lab proof → keep it
  • MVCC, EXPLAIN, B-tree, vacuum, locks
  • Deep Internals pathway = study order through these same lessons
Start lesson 01

Why trust it

We don't paraphrase the docs, we run it.

  1. 01Spin up a throwaway PostgreSQL instance and trigger the failure for real.
  2. 02Capture the raw psql output, SQLSTATE, and lock/PID state verbatim.
  3. 03Explain the cause and the fix, citing the exact section of the manual.
See a real transcriptSQLSTATE index

Postgres 14–18.

102

errors lab-reproduced

105

runbooks

37

lessons

34

deep internals