Report for 15K Records running for 30 mins - report SQL runs in 3 secs at DB

[learn_analytics]

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

[Francis aka khayman]

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

[CognosPaul]

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.