What happens when execution plan is removed from SQL Server?
The execution plan for your query has been successfully removed from the SQL Server plan cache and probably your server will reduce the high resource utilization and return to respond normally. After this scare try to improve the performance of your query and understand why the execution plan has been altered.
Why does updating statistics cause plan invalidation?
In SQL Server 2012 – updating statistics does not cause plan invalidation regardless of the database option. So, what’s the problem? Ironically, I kind of like this. I think that statistics has been blamed all too often for statement/plan problems when it’s not the statistics, it’s the plan.
What causes that plan to go wrong and should I update?
If the plan should be evaluated (statistics have been updated AND data changed) then it will. The key point is “data changed.” An update statistics ALONE will not cause plan invalidation (which is STILL different behavior from 2005/2008/2008R2) but it’s the best of both worlds IMO.
How to capture the plan handle of a SQL query?
To capture the sql_handle or plan_handle of the query, you can use only one dynamic management view (DMV) and one dynamic management functions (DMF): sys.dm_exec_query_stats and sys.dm_exec_sql_text.
Why are multiple plans for one query bad?
With just 2 queries, who cares? But if your app is sending in the same query thousands of times, each with different parameters, this can add up to more CPU time, more memory used for caching plans, and less memory used for caching data. Our tools warn you about this in a few different ways:
What happens if I run the same SQL query again?
If I run the same queries again, here’s the new output: SQL Server takes a little more time with each incoming query, turns the literals into variables, and then checks to see if there’s an execution plan already compiled for it. That means: