You receive a call from an application owner reporting a severe performance slow down on a production SQL Server Instance. They point you towards a blocking session id. Rather than killing the SPID – you decide to do a root cause analysis. Step 1 - check for queries executing The first you do is check all SQL Server – Current queries executing on SQL Server , using sys.dn_exec_requests. You can see clearly the queries executing and on a number of the queries , there is a blocking_session_id , in the example - 77. Although the session_id does not appear on...
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