tech-log-backend/docs/runbooks/db-deadlock.md

title, category, error_codes, severity, owner, last_updated, status

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