Data Monitoring / MySQL Monitoring
MySQL: Temporary table spills
Analytical statements create many on-disk temporary tables. Compare temporary table counters with statement digests and query shapes.
Environment and inputs: MySQL 8.4 baseline; Performance Schema consumers, privileges and replication topology affect evidence availability.
Failure scenario
Analytical statements create many on-disk temporary tables. Confirm the cause before choosing a fix.
Evidence to collect
Compare temporary table counters with statement digests and query shapes. Record the time, affected scope and a healthy comparison interval.
Fix the confirmed cause
Reduce unnecessary intermediate work and test configuration changes under realistic concurrency. Write the expected result first. Change one relevant setting at a time.
Check the result and hand over
Repeat the check for temporary table spills 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.