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PostgreSQL 16 Slow Query Lock-up — All Connections Blocked on Amazon Linux 2023
A long-running query in PostgreSQL 16 is holding locks and blocking all other queries. Database connection pool exhausted.
Pattern
DATABASE_EVENT
Severity
HIGH
Confidence
68%
Remediation
Auto-Heal
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | DATABASE_EVENT | DATABASE_EVENT | |
| Severity Assessment | HIGH | HIGH | |
| Incident Correlation | N/A | None | |
| Cascade Escalation | N/A | No | |
| Remediation | — | Auto-Heal — Corax resolves autonomously |
Scenario Conditions
Amazon Linux 2023. PostgreSQL 16 long query running for 42 minutes. Lock held on critical table. All other queries waiting. Connection pool at max.
Injected Error Messages (1)
PostgreSQL 16 slow query blocking on Amazon Linux 2023 — query running 42 minutes, database connection pool exhausted at max connections, all other queries blocked, postgres lock contention
Neural Engine Root Cause Analysis
Database infrastructure event detected — the connection pool may be exhausted preventing new connections, replication lag is growing between primary and replica, deadlocks are occurring between competing transactions, or slow queries are degrading overall database performance. Database issues cascade to affect all applications and services that depend on the database.
Remediation Plan
1. For connection pool exhaustion, check current connections with 'SHOW PROCESSLIST' or 'pg_stat_activity' and identify idle/stuck connections.
2. For replication lag, check replica I/O and SQL thread status and identify long-running transactions on the primary.
3. For deadlocks, review the deadlock graph (InnoDB: 'SHOW ENGINE INNODB STATUS', Postgres: check pg_locks) and optimize transaction ordering.
4. For slow queries, enable and review the slow query log, add missing indexes, and optimize query plans with EXPLAIN.
5. Consider scaling read replicas or implementing connection pooling (PgBouncer/ProxySQL) if connection limits are consistently hit.
Tested: 2026-04-02Monitors: 1 | Incidents: 1Test ID: cmnhnwfs104zelijgql0zfef6