Network Management
High SQL Server waits from APM_IisBb_Request cleanup query in large SAM IIS AppInsight environments
Database Performance Analyzer reports long LCK_M_U waits and blocking on a cleanup delete query executed by the SolarWinds Platform against the SolarWinds Platform database when many SAM IIS AppInsight monitors were deployed and multiple SolarWinds servers ran the same query at the same time.
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Overview
In a SolarWinds Platform environment monitored by Database Performance Analyzer, a delete statement that removes rows from table APM_IisBb_Request based on table APM_IisBb_Request_CS_cur runs for about twenty seconds per execution while holding an open transaction and generates high waits. The environment contains more than 650 SAM IIS AppInsight monitors for IIS, and several polling or application servers issue the same cleanup statement, which queues behind each other, increasing the blocking and wait time reported by Database Performance Analyzer.
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Cause
This has been identified as a known issue in the SolarWinds Platform.
The cleanup query that deletes rows from table APM_IisBb_Request using table APM_IisBb_Request_CS_cur as a source is not efficient for the volume of rows and the level of concurrent executions in this environment. On SQL Server, this design produces LCK_M_U waits while each delete execution waits on locks held by previous executions issued from other SolarWinds servers.
Resolution
This issue has been addressed in SolarWinds Platform 2026.2. Consider upgrading your environment.