/amazon-aurora-mysql

Post-Upgrade Checklist

Common Steps

1. Verify upgrade completed

   aws rds describe-db-clusters --db-cluster-identifier {cluster} \
     --query "DBClusters[0].{Engine:Engine,EngineVersion:EngineVersion,Status:Status}" \
     --output json --region {region}

2. Preserve the rollback window — do NOT delete pre-upgrade snapshots immediately. Major version upgrades are one-way in-place. Rollback requires restoring from a snapshot or PITR, and both restore the old major version:

   • Any pre-upgrade manual snapshot restores to the engine version it was taken on (e.g., an Aurora MySQL 3.04 snapshot restores to 3.04 — not to a post-upgrade 3.10).
   • PITR to any time before the upgrade completed restores the pre-upgrade major version, not the new one.
   • After the upgrade, Aurora cannot restore backward-in-time into the new major version; that timeline starts at the upgrade's completion.

   Keep the pre-upgrade manual snapshot for at least 7–14 days of stable production traffic (longer for regulated workloads) before deleting it. Deleting it early forecloses the cheapest rollback path. Document the snapshot identifier and retain-until date in your change record.

3. Check performance discrepancies — Compare CloudWatch metrics against baseline: CPUUtilization, DatabaseConnections, ReadLatency, WriteLatency, FreeableMemory, BufferCacheHitRatio, DMLLatency, SelectLatency. Use Performance Insights to compare database load.

4. Compare EXPLAIN plans for critical queries. Look for: different join strategies, missing index usage, full table scans.

   • EXPLAIN FORMAT=JSON SELECT ...; (or EXPLAIN ANALYZE on MySQL 8.0+ for actual row counts)

5. Monitor CloudWatch 24-72 hours — Watch: CPUUtilization, FreeableMemory, DatabaseConnections, ReadLatency, WriteLatency, AuroraReplicaLag, Deadlocks, LoginFailures.

6. Validate application connectivity — connections, pooling, SSL/TLS.

7. Verify parameter group applied correctly:

   aws rds describe-db-cluster-parameters --db-cluster-parameter-group-name {new_pg} \
     --query "Parameters[?Source=='user'].{Name:ParameterName,Value:ParameterValue}" \
     --output table --region {region}

8. Update statistics — run ANALYZE TABLE on hot tables to rebuild optimizer statistics for the new version.

9. Check error logs

   aws rds describe-events --source-identifier {cluster} --source-type db-cluster --duration 1440 --region {region}

Aurora MySQL-Specific

1. Verify auth plugin compatibility — SELECT user, host, plugin FROM mysql.user; Check if apps need mysql_native_password.

2. Check GROUP BY sorting — 8.0 no longer implicitly sorts. Apps relying on this need explicit ORDER BY.

3. Validate stored procedures — run critical routines, check for deprecated syntax.

4. Verify query cache removal impact — if query cache was enabled, monitor for increased CPU/latency. Consider ElastiCache if hit ratio was high.