data-konzept

'I’m a big fan of using queries based on the dynamic management view sys.dm_exec_query_stats to capture the most resource hungry queries across a SQL instance.

That approach has some drawbacks though. First, it is cleared out every time an instance restarts, and second it only keeps figures for currently cached plans, so when a query recompiles, data is lost.

It was some time ago I blogged about SQL Server Query Store but one of the great features of it is that performance stats are stored in the database, so they aren’t lost in either of the above scenarios.

So I wanted to write a query store equivalent that will produce a ranked list of your most expensive queries.

The only downside is that the DMVs for Query Store are per database whereas dm_exec_query_stats is a view across the whole instance. So I had to use a cursor and a temp table, populating the temp table for each database in turn.

Anyway, enough preamble – here’s the query:'...

http://www.sqlservercentral.com/blogs/matthew-mcgiffen-dba/2017/11/01/capture-the-most-expensive-queries-across-your-sql-server-using-query-store/