Real-World Post-Mortems & Incident Analyses
Production Post-Mortem Analyses
Unvarnished engineering retrospectives of real database outages, bottlenecks, and the permanent fixes applied.
Crisis Response, Root Cause Analysis & Prevention Playbooks
Production-Verified Recovery ScenariosFilter by Engine:
The Problem Encountered:
A high-throughput 12TB e-commerce database suddenly rejected all client connections with "database is not accepting commands to avoid wraparound data loss".
Root Cause:
Autovacuum workers starved due to long-running analytical queries and misconfigured worker parallelism, causing un-frozen transaction IDs to hit the 2-billion limit.
Solution Applied:
Server was booted in single-user mode (`postgres --single`) to run aggressive `VACUUM FREEZE ANALYZE VERBOSE` directly on oldest relations, resetting age counters.
Key Takeaways:
Continuously monitor `datfrozenxid` relative age via Prometheus; raise critical pages at 70% threshold before PostgreSQL forces emergency shutdown.
Teşhis & Kurtarma Komutu:
SELECT datname, age(datfrozenxid), 2147483648 - age(datfrozenxid) AS remaining_txids FROM pg_database ORDER BY 2 DESC;