Wednesday, June 22, 2011

More fun with Management Data Warehouse

Management Data Warehouse (MDW) really is a cool feature that was added to SQL server in 2008. While there are some issues, and the default out of the box setup might kill you on disk space and activity if you have a lot of instances sharing the same MDW, overall it is a great resource with tons of potential.

Similar to the canned reports that come with SQL Server Management Studio for database and instance details, there are canned reports that come with the setup of the MDW.

The Management Data Warehouse Overview report has three columns with links to the reports for Server Activity, Query Statistics, Disk Usage for each server you have collectors defined for.

A closer look at the Query Statistics History report gives a great overview of the top 10 queries for CPU, Duration, Total I/O, Physical Reads, and Logical Writes. You can adjust the slider at the top for a particular time range you are interested as well.

These reports are great for looking at performance over time and identifying queries that could be improved. However, I wanted to know more information and see where in the MDW the data for this graph is stored. It turns out there is a very handy stored procedure in the MDW called. [snapshots].[rpt_top_query_stats] that queries the snapshots.query_stats, core.snapshots, and snapshots.notable_query_text to get some very useful data.

The procedure takes an instance name, start time, end time, time window size, time interval (in minutes), the order by criteria (CPU,Physical Reads,Logical Writes, I/O, and Duration) and Database name.

So rather than write my own code to do the same thing I just created a new copy of this stored procedure and tweaked it a bit. instead of top 10 I changed it to be top 100. Next I tweaked some of the parameters to make it so I could get a weekly snapshot of top 100 queries by CPU, I/O etc. Now I have my own [snapshots].[rpt_top100_query_stats] stored procedure.

Next, of course I created a new SSRS report that calls my new procedure and can send me a nice pretty email of the data on whatever schedule I choose with whatever metrics I choose.

SSRS 2008 R2 is really cool, if you haven't figured out how powerful it is, take the time to play with it a bit. There are so many great things about it and I use it on a regular basis in my position as a DBA. I know I don't use it to it's full potential, I'll leave that to the BI experts. However, having numerous metric reports is incredibly helpful to me in my job. I use SSRS for monitoring trends over time and have also used it to build reports for developers to see how their code is actually preforming, plus many more.

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