Ungrouped Results In Query Store

Erin Stellato explains why you might see two rows for the same query plan in Query Store’s run-time stats:

You can see that there are two rows for the same query_id and plan_id, but the count_executions is different, as are the avg_duration and avg_logical_io_reads values .  The data is not truly a duplicate.  This behavior occurs because the Query Store data is stored in memory before it is flushed to disk, and when you query the data SQL Server is pulling it from both locations (and doing a UNION ALL) and displaying it in the output.  If I waited a bit and ran the query again, the two rows for that interval would probably disappear – most likely because the in memory data had been flushed to disk.

Read the whole thing.

Related Posts

Changing Query Store Report Interval

Arun Sirpal wants to change the report interval for a Query Store report: While not specific to SQL Server 2019 (I was using this version to do some testing) I was struggling to find how to change the time period of analysis for the Query Store reports within SSMS. This is not a ground breaking […]

Read More

Best Practices for Query Store

Erin Stellato ties together a number of best practices around Query Store: I’m a huge fan of Query Store, which regular readers may know, but there’s a need to write a bit more about Query Store best practices.  This isn’t a “you must use this feature” post, this is a “here is what you must […]

Read More

Categories

February 2018
MTWTFSS
« Jan Mar »
 1234
567891011
12131415161718
19202122232425
262728