Problem: Cognos Report(HTML, Excel or PDF) for 15K Records running for 20-30 mins while the report SQL runs in 3 secs in the DB(fetched all rows by editing the SQL developer preferences)
Few Details:
1. Simple List Report with minimal formatting and containing about 15 columns
2. The report rows per page property is set to a high number to get all the rows..
Any thoughts on why where and why cognos takes so much time
cognos renders report after all rows are retrieved that is why it "runs" slow.
try to compare cognos 20-30 min run time to excel output with how much time to run sql + export the whole resultset to excel
SQL Clients are designed to quickly render a database dump. When Cognos exports to Excel it's generating an XML document on the fly.
15 columns for 15k records would be a total of 225,000 cells. Assuming a 30 minute run time, that means each cell is taking 0.008 seconds to render.