I have an issue with my report server in that it is struggling to process reports with large datasets. Whenever I run the report in question from a client it just runs and runs and runs with no sign of completing. The ReportingServicesService.exe uses up 100% CPU of a given processor and will just wait until I kill the query on the SQL Server.
If I run the query against the database in Management Studio itself it completes within a couple of seconds and returns over 80,000 rows. I can't do any more optimisations in terms of indexes etc. If I run the report and look at the wait stats I'm getting an ASYNC_NETWORK_IO WAIT being reported and very little in the way of impact on the actual server itself.
I've even tried running the report on the server itself to rule out any network latency issues, but I still get the same wait type on the query.