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PASSEDdatabase / replication_lag
MySQL 8.4 Replication Lag Critical — Reads Stale on Windows Server 2019
MySQL 8.4 replica is falling behind the primary. Read replicas serving stale data. Application consistency at risk.
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
Windows Server 2019. MySQL 8.4 replication lag at 285 seconds. Replica WAL/binlog position behind. Read queries returning stale results.
Injected Error Messages (1)
MySQL 8.4 replication lag critical on Windows Server 2019 — replica 285 seconds behind primary, replication lag growing, max connections approaching, read replicas serving stale data
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: cmnhnvexc013xlijgu2w7etg0