My calculation intensive report ~250k-350k lines, 50ish columns needs to be rendered in excel (xlsx) format but frequently times out. I've had the sharepoint admin tweak the timeout settings a little but after about 60ish minutes it either finishes (if the server load isn't too bad) or it just sits there for hours before failing.
The report processing is already all done on the back end (stored proc that runs to populate the table - the report basically just does a select /w parameters - yes they are indexed) but it seems sharepoint has issues rendering files this large.
Does anyone have any experience rendering huge reports like this? Are there any tweaks that can be done to help it along?