Data Monitoring / SQL Server Availability & Capacity
SQL Server: Connection pool exhaustion
Clients cannot obtain connections while the database accepts direct logins. Compare application pool waits, open sessions and active request counts.
Environment and inputs: SQL Server operational monitoring; availability groups, SQL Agent and host-level metrics depend on edition, service and deployment.
Failure scenario
Clients cannot obtain connections while the database accepts direct logins. Confirm the cause before choosing a fix.
Evidence to collect
Compare application pool waits, open sessions and active request counts. Record the time, affected scope and a healthy comparison interval.
Fix the confirmed cause
Repair connection disposal or pool sizing with application evidence rather than raising server limits blindly. Write the expected result first. Change one relevant setting at a time.
Check the result and hand over
Repeat the check for connection pool exhaustion 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.