---
title: Runbook — DB_DEADLOCK (데드락)
category: CONFLICT
error_codes: [DB_DEADLOCK]
severity: P2
owner: oncall
last_updated: 2026-06-15
status: stub
---

# Runbook: DB_DEADLOCK (`runbook://db/deadlock`)

## Symptoms

- HTTP 409 with `error.code=DB_DEADLOCK`
- SQLState 40P01 in Postgres logs

## Diagnosis

- Check `pg_locks` and `pg_stat_activity` during deadlock
- Identify conflicting transaction lock order

## Action

- Client should retry (retryable=true)
- Fix lock ordering in code if recurring

## Escalation

- Escalate to DBA if deadlock rate is sustained > 1% of transactions

---

> **Stub**: Phase D2 — author body after domain adoption. (feature-operational-runbook-contract D9)