Session Wait Stats

SQL Server 2016 has a per-session wait stats DMV:  sys.dm_exec_session_wait_stats.  That’s exciting; wait stats are extremely interesting, but until now, impossible to use on a per-item level in a busy production system (where you’d most want to use them).

Daniel Farina looks at how the new DMV relates to sys.dm_exec_wait_stats (via Database Weekly):

[R]esetting the data of sys.dm_os_wait_stats operating system view doesn’t affect the values of sys.dm_exec_session_wait_stats view.

Based on my MSDN reading, the sys.dm_exec_session_wait_stats DMV resets if the connection pool context is re-used or if the session closes.  This is why DBCC SQLPERF doesn’t include a reset option for session-specific wait stats.

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