performance - Fast query runs slow in SSRS

Question

I have an SSRS report that calls out to a stored procedure. If I run the stored procedure directly from a query window, it will return in under 2 seconds. However, the same query run from an 2005 SSRS report takes up to 5 minutes to complete. This is not just happening on the first run, it happens every time. Additionally, I don't see this same problem in other environments.

Any ideas on why the SSRS report would run so slow in this particular environment?

Answer 1

Thanks for the suggestions provided here. We have found a solution and it did turn out to be related to the parameters. SQL Server was producing a convoluted execution plan when executed from the SSRS report due to 'parameter sniffing'. The workaround was to declare variables inside of the stored procedure and assign the incoming parameters to the variables. Then the query used the variables rather than the parameters. This caused the query to perform consistently whether called from SQL Server Manager or through the SSRS report.