Data Monitoring / MySQL Monitoring
MySQL: Slow query log thresholds
Users report timeouts but the configured slow log captures little. Compare logging thresholds, statement duration and whether the relevant workload qualifies for collection.
Environment and inputs: MySQL 8.4 baseline; Performance Schema consumers, privileges and replication topology affect evidence availability.
Failure scenario
Users report timeouts but the configured slow log captures little. Confirm the cause before choosing a fix.
Evidence to collect
Compare logging thresholds, statement duration and whether the relevant workload qualifies for collection. Record the time, affected scope and a healthy comparison interval.
Fix the confirmed cause
Adjust a bounded diagnostic configuration and review log volume and sensitive query text handling. Write the expected result first. Change one relevant setting at a time.
Check the result and hand over
Repeat the check for slow query log thresholds using the same scope and a representative interval. Check that the symptom is resolved, expected records are present and downstream results are correct. If coverage, correctness or latency worsens, restore the recorded configuration through the agreed rollback process.
Scope and precautions
Prefer read-only access and limit queries to the relevant period or dataset. This example has not been tested on your systems. Test changes in an approved environment. Keep credentials and sensitive data out of shared evidence.