Cognos Express server/application performance

[dmusson17]

Hello all,

We are a relatively new Cognos Express installation and are having issues with server/Cognos app performance when it comes to reports, pulling data from AD, etc.  We have Cognos Express 10.2.1 on one (virtual) server, one gateway on another server in our dmz, and our data on a separate db server.  Pulling the data doesn't seem to be an issue, as the perf issues seem to come to life once the reports have the data and have to render it.

I know this is an absurdly general request, but if you have any good starting points for me or performance based white papers you could send links to it would be much appreciated.

Thanks

[MFGF]

Hi,

The newest version of Express is essentially Cognos 10.2.1 BI with a few omissions (search, third-party OLAP data source connectivity etc). This means the architecture is the same as Cognos 10 BI and many of the admin and tuning recommendations will be exactly the same.

How can you be sure that retrieving data isn't the bottleneck in your case? Have you looked at the SQL being generated and run it externally (outside of Express) to see what the performance is like? Generally rendering doesn't cause too many performance issues unless you are trying to render massive outputs. Are you using a model published in Dynamic Query Mode or in Compatible Query Mode? If CQM, the Report Service will be responsible for spawning the bibustkservermain query processes and also for rendering the generated outputs. If DQM, the Query Service will be responsible for query planning, generation and execution and the Report Service will be responsible ony for rendering.

Manager doesn't give you access to things like the java heap size setting, but you can find and execute cogconfigw.exe and see all of the same config settings you get in Cognos 10 BI. You should be able to select the Cognos Express service in here and set the memory for it. You should also be able to see the Report Service setting and check whether it is 32 or 64 bit. If you are using CQM you will need to leave it as 32-bit but if you are using purely DQM sources you can set it to 64 bit (I think - you definitely can in Cognos 10 BI but I have never actually tried this in Express). If you are running out of memory when rendering this might be a solution.

Good luck!

MF.

[dmusson17]

Thanks a ton for the reply MF. 

We have run the sql generated by Cognos externally and found that the run times to return data are a fraction of the time it takes to get reports to render in Cognos.  This variance is much greater when sorting/etc. aggregated values in reports.  I'm looking into the rest of your reply and will let you know what I find.  Thanks again!

[MFGF]

The other factor to consider is that sometimes not all work is pushed to the database. If you are doing complex things in your reports some local processing of the data might be taking place. Obviously running the generated query against your data source will not include this work.

It's worth looking at how your reports are written and trying to figure out if there is any local processing going on. When you look at the SQL being generated, does it include all the aggregations/sorting/calcs etc your report is using? It might be worth re-creating the report a stage at a time and checking the performance after each step to see what introduces the delay.

Good luck!

MF.

[dmusson17]

Appreciate the excellent and timely feedback.  We'll do this and see where it takes us.  Thanks!