Wednesday, July 10, 2013

TSQL to find Top Queries by Avg CPU, IO, Time

One of my favourite performance tools has certainly become the RML reports as you can quickly identify queries with common hot spots across performance metrics. However this requires a bit of work, you first have to configure your performance trace (usually with Diag Manager), capture the SQL Profiler Trace, and then analyse it with RML/SQLNexus. Of cause the UI with XEvents makes this a bit easier if you use that as your capture. However what if you want to look at a general overall performance of a server, or for a longer duration.
We know that SQL Server is always capturing data for us in the background and exposes that to us with DMVs and DMFs. So I came up with the following query which uses the DMVs/DMFs to report the top queries.
You can change the sort order at the end of the query however as I have included the Rank number per performance metric (CPU, IO, Time) you can quickly see queries which are in the top of each group without needing to resort the results or run multiple queries.
If you did want to run multiple queries with different sort columns, then the Query Number should remain the same as it is based on CPU and the reason i included this is to allow you to easily compare the queries across multiple executions (depending on the time between executions).
;WITH CTE([Query Num], [Total Executions], [Total CPU], [Avg CPU], [Avg CPU Rank], [Total IO], [Avg IO], [Avg IO Rank], [Total Elapsed Time], [Avg Elapsed Time], [Avg Elapsed Time Rank], [Sample Statement Text], [Query Plan Handle], [Statement Hash], [Query Plan Hash])
        ROW_NUMBER() OVER (ORDER BY (SUM(total_worker_time) / SUM(execution_count)) DESC) AS [Query Num]        , SUM(execution_count) AS [Total Executions]        , SUM(total_worker_time) AS [Total CPU]        , SUM(total_worker_time) / SUM(execution_count) AS [Avg CPU]        , RANK() OVER (ORDER BY (SUM(total_worker_time) / SUM(execution_count)) DESC) AS [Avg CPU Rank]        , SUM(total_physical_reads + total_logical_reads + total_logical_writes) AS [Total IO]        , SUM(total_physical_reads + total_logical_reads + total_logical_writes) / SUM(execution_count) AS [Avg IO]        , RANK() OVER (ORDER BY (SUM(total_physical_reads + total_logical_reads + total_logical_writes) / SUM(execution_count)) DESC) AS [Avg IO Rank]        , SUM(total_elapsed_time) AS [Total Elapsed Time]
        , SUM(total_elapsed_time) / SUM(execution_count) AS [Avg Elapsed Time]        , RANK() OVER (ORDER BY (SUM(total_elapsed_time) / SUM(execution_count)) DESC) AS [Avg Elapsed Time Rank]
        , MIN(query_text) AS [Sample Statement Text]        , MIN(plan_handle) AS [Query Plan Handle]        , query_hash AS [Statement Hash]        , query_plan_hash AS [Query Plan Hash]
            SUBSTRING(st.[text], qs.statement_start_offset/2, (
                    WHEN qs.statement_end_offset = -1 THEN LEN(CONVERT(NVARCHAR(MAX), st.[text])) * 2 
                    ELSE qs.statement_end_offset                  END - qs.statement_start_offset)/2 
            ) AS query_text
        FROM sys.dm_exec_query_stats AS qs
        CROSS APPLY sys.dm_exec_sql_text(qs.[sql_handle]) AS st
        WHERE st.[text] NOT LIKE '%sys.dm_%'
        --AND DateDiff(hour, last_execution_time, getdate()) < 1 --change hour time frame
    ) AS query_stats     GROUP BY query_hash, query_plan_hash )
    [Query Num]
   , [Total Executions]
   , [Total CPU]
   , [Avg CPU]
   , [Avg CPU Rank]
   , [Total IO]
   , [Avg IO]
   , [Avg IO Rank]
   , [Total Elapsed Time]
   , [Avg Elapsed Time]
   , [Avg Elapsed Time Rank]
  , DB_Name(qp.dbid) AS [DB Name]   , [Sample Statement Text]
   , qp.query_plan AS [Estimated Query Plan]FROM CTE
OUTER APPLY sys.dm_exec_query_plan([Query Plan Handle]) AS qp --ORDER BY [Avg CPU] DESC
ORDER BY [Avg IO] DESC --ORDER BY [Avg Elapsed Time] DESC

NOTE: This query includes a TOP 50 which improves performance but only looks at very recent data. I would recommend using the predicate on last_execution_time to restrict the data back to a valid time frame. This would still then include the total history for those requests but ensure that you are only looking at active queries.

Here is an example output. In this example I had cleared the cache and only a small test data so the Avg IO rank is the same for each query but this gives you an idea.

So far I’ve tested this on SQL 2008 R2 and above.
I’m also closing in on finalising the BETA release of my DBA Admin and Performance SSMS reports which will include this query and take this to a whole new level of visualisation.

Legal Stuff: The contents of this blog is provided “as-is”. The information, opinions and views expressed are those of the author and do not necessarily state or reflect those of any other company with affiliation to the products discussed. This includes any URLs or Tools. The author does not accept any responsibility from the use of the information or tools mentioned within this blog, and recommends adequate evaluation against your own requirements to measure suitability.


  1. Copiar el reloj es muy bonito, este es un estilo de gama alta.Réplica de relojes Rolex Realmente me gusta este reloj réplica. El servicio de la tienda es muy bueno, la calidad del reloj es muy buena y el precio es muy rentable,Réplica de relojes cosmograph daytona creo que es muy barato, de buena calidad y bajo precio.

  2. Set on his signature 100mm heel,replica shoes Christian Louboutin’s replica flats Platinana courts are guaranteed to lengthen your legs to supermodel standards. Rendered in a combination of patent and matte leather, the ankle strap curves around the front to join the sharp, pointed toe. They’re finished, of course, with the iconic red lacquered sole. These will pair just as well with denim as with a cocktail dress.

  3. Butikken har løst problemer for mig, tjenesten er meget tålmodig,køb moncler boern det er en perfekt shopping oplevelse. Da jeg modtog Moncler tøj, troede jeg,køb moncler boern vest det var en god kopi af Moncler dunjakke. Jeg kan lide denne online butik, denne Moncler kjole er enkel og generøs. Meget tilfreds med dette køb.

  4. Le scarpe replica alexander mcqueen sono molto belle e molto temperanti.alexander mcqueen scarpe outlet Mi piace molto questa scarpa mcqueen replica. Il servizio di negozio è molto buono, la qualità delle scarpe è molto buona e il prezzo è molto buono.donna alexander mcqueen scarpe italy Penso di essere molto economico, di buona qualità ed economico

  5. Este reloj es muy elegante en términos de diseño y función.Réplica de relojes Rolex La calidad es relativamente perfecta.Réplica de relojes sky dweller Esta es mi primera vez para comprar un reloj de réplica. Este reloj es increíble y me sorprendió. Elogio de cinco estrellas

  6. My boyfriend likes copying watches. When you buy it back, cheapest rolex watches this gorgeous replica watch is amazing. cheapest date watches The design and functions of the watch are very fresh and elegant. The quality is perfect. This replica watch is very special, good quality and cheap

  7. à partir de maintenant, vous pouvez obtenir la livraison gratuite sur les montres IWC à prix réduit.montres de réplique Grand inventaire. La montre IWC est une marque emblématique.IWC montres de réplique La collection IWC Portuguese, qui comprend la montre automatique IWC Portuguese et le chronographe IWC Yacht Club, est légendaire. IWC Schaffhouse est également connue pour ses montres IWC Aquatimer, Top Gun, Big Pilot, Mark XVII, Pilot's Watch, Spitfire chronograph et Big Pilot St-Exupery.