Data Monitoring / SQL Server Query Performance
SQL Server: Active request snapshots
A single DMV snapshot catches no evidence of an intermittent slowdown. Capture bounded repeated observations aligned with application incident times.
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
A single DMV snapshot catches no evidence of an intermittent slowdown. Confirm the cause before choosing a fix.
Evidence to collect
Capture bounded repeated observations aligned with application incident times. Record the time, affected scope and a healthy comparison interval.
Worked diagnostic example
Read-only SQL Server active-request snapshot; requires the documented monitoring permissions.
SELECT session_id, status, blocking_session_id, wait_type,
wait_time, total_elapsed_time, cpu_time, logical_reads
FROM sys.dm_exec_requests
WHERE session_id <> @@SPID;Fix the confirmed cause
Use a suitable historical or event-based collection method rather than increasing snapshot frequency without limits. Write the expected result first. Change one relevant setting at a time.
Check the result and hand over
Repeat the check for active request snapshots 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.