Execution Plan History

  • I don't have a lot of experience writing queries using DMVs and DMFs, but what I'm wondering is there a way to find execution plan history for a stored procedure?

    What I'd like to do is be able to compare execution plans on occasion to determine if they have changed.

    I tried the following and was able to retrieve plans for procs but I wasn't sure if SQL Server kept old cache plans around.

    SELECT plan_handle, query_plan, objtype,object_name(objectid) ProcName

    FROM sys.dm_exec_cached_plans

    CROSS APPLY sys.dm_exec_query_plan(plan_handle)

    WHERE objtype ='Proc' and object_name(objectid) is not null

  • No, when a plan is flushed from cache, it's gone forever. The only thing you can do is try to capture the plans regularly (based on how often they flush out of cache) and then store them on the side.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • There's a profiler event that gets fired when SQL removes a plan from cache.

    Checking....

    Performance: Performance Statistics

    Indicates that a compiled plan has been cached for the first time, recompiled, or evicted from the plan cache.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • Thanks guys! That will be very helpful for me moving forward.

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