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Legacy Business Intelligence => COGNOS ReportNet => Topic started by: tyody on 19 Jul 2006 09:19:31 AM

Title: report vs query performance issue
Post by: tyody on 19 Jul 2006 09:19:31 AM
I'm having a performance issue running a report in CRN.  In CRN the report runs a long time (never comes back), but I can run the query in the database in 10-20 seconds.  There is only one query in the report with prompt filters, but the prompts wont even come up.  Any ideas?
Title: Re: report vs query performance issue
Post by: Declan on 05 Oct 2006 04:16:47 AM
Can't help but we our reports (CRN8.2) take ages (up to 10 mins) to show prompts which are driven off a 1000 row store dimension.  We have noticed that the more complex the report the longer it takes to show the prompts.  Does anyone ealse have any infor on this? ???
Title: Re: report vs query performance issue
Post by: BIsrik on 10 Nov 2006 01:46:28 AM
Plz check the sql of the query..its joins, its calculation, its filters, its indexes etc..One query can't take 10 minutes to prompt for a prompt page. can you provide us more information regd the prompt page..i.e..are there any value prompts used..and if so how are they been called in query..

Srik
Title: Re: report vs query performance issue
Post by: Darek on 06 Dec 2006 05:40:09 AM
If there is more than 2048 values for a single value list prompt, it will never come back, as there is a physical limit on HTML SELECT item. Keep it in mind, that ReportNet and Cognos 8, are HTML based application on the front-end.
Title: Re: report vs query performance issue
Post by: BIsrik on 11 Dec 2006 06:04:30 AM
But Cognos says 5000..whats that then??

Srik
Title: Re: report vs query performance issue
Post by: Darek on 11 Dec 2006 12:50:24 PM
Maybe it is 5000 ... But does it really matter after say a hundred or two?
Title: Re: report vs query performance issue
Post by: mikegreen on 02 Jan 2007 03:40:07 PM
Quote from: Declan on 05 Oct 2006 04:16:47 AM
Can't help but we our reports (CRN8.2) take ages (up to 10 mins) to show prompts which are driven off a 1000 row store dimension.  We have noticed that the more complex the report the longer it takes to show the prompts.  Does anyone ealse have any infor on this? ???

Cognos is probably doing a select distinct on column for the entire table... If you run SELECT DISTINCT column_name FROM table_name - how long does that take? Often, getting a list of distinct values in a large table can take longer than the actual query to get the data back (depending on indexing, etc).

Regards,

Mike