The sys.dm_exec_query_optimizer_info DMV
You can use the sys.dm_exec_query_optimizer_info DMV to gain additional insight into the work being performed by the Query Optimizer. This DMV, which is only partially documented, provides information regarding the optimizations performed on the SQL Server instance. Although this DMV contains cumulative statistics recorded since the given SQL Server instance was started, it can also be used to get optimization information for a specific query or workload, as we’ll see in a moment.
As mentioned, you can use this DMV to obtain statistics regarding the operation of the Query Optimizer, such as how queries have been optimized and how many of them have been optimized since the instance started. This DMV returns three columns:
- Counter: The name of the optimizer event
- Occurrence: The number of occurrences of the optimization event for this counter
- Value: The average value per event occurrence
Thirty-eight counters were...
