Report Studio 8.4 Slow Report

[derdor]

Quirky, inconsistant problem:
On occasion when making a change to a report studio report in our "development" environment it will run/work fine. Upon exporting the report out of dev and into our "qa" environment the report will run much slower (i.e. few seconds to few minutes). I can usually mess around with it on qa find/narrow it down to some calculation and/or filter, change it in someway -although it essentially would still do the same function and can usually speed it back up to normal - essentially not changing a thing on the report. It seems like something is causing it to be slow between the two environments. I saw this happen once before, but it seemed to be OK, however this time, after speeding it up in QA, taking the QA version back to dev, slowed dev down as well as was slow in our third "training" environment. Anyone see anything like this? THANKS

 

[blom0344]

Any chance that this is due to different caching behavior? There are a couple of settings that influence Cognos re-using cached results. Such cached results will not exists in a new environment causing considerable loss of performance..

Ties Blom

 

[derdor]

No I don't believe it is a caching problem - it is consitantly slow in the new envrionment. Case in point this last time I moved up to qa environment, the report was slow in the new environment - process of elimination, one query seemed to be the culprit, and specifically changing a filter [customer is not null] to [customer <> ''] caused the report to function appropriately in the new environment. Seems as if something is malfunctioning and a simple change like that is "resetting" something to run OK. I admit its very quirky. Been working heavily in Cognos BI for 13 years and can't quite narrow it down any more than that.
Thanks for your reply.

 

[blom0344]

As a former DBA I can assure you that :

[customer is not null] versus [customer <> '']

is not the same from the perspective of a relational database. Execute both versions of the report and run a trace on the database. You may find that either the database governor or Cognos decides to use an essential different way to execute the query /process the results..

Ties Blom

 

[derdor]

Understood, however it has been working that way for the last 7 months, and it worked fine in development, it was only when exporting to qa that all of sudden its slow. Another change completely unrelated to "customer is not null" is the reason for the export. As I mentioned I have been through this over and over again and there is no rhyme or reason for it. Although I will try your suggestion of running db analyzer on it both ways.