Data Monitoring / SQL Server Query Performance
SQL Server: Missing index suggestions
An automated suggestion improves one query but increases write costs. Compare the proposed key and includes with existing indexes and representative write workload.
Environment and inputs: SQL Server 2019–2025 where the referenced feature is supported; Query Store and diagnostic collection require appropriate configuration and permissions. Azure SQL behavior can differ.
Failure scenario
An automated suggestion improves one query but increases write costs. Confirm the cause before choosing a fix.
Evidence to collect
Compare the proposed key and includes with existing indexes and representative write workload. Record the time, affected scope and a healthy comparison interval.
Fix the confirmed cause
Evaluate the index in a controlled test and retain a removal plan if total workload regresses. Write the expected result first. Change one relevant setting at a time.
Check the result and hand over
Repeat the check for missing index suggestions 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.