Peter,
Is this the very first operation performed?
Do subsequent calls to the same stored procedure take as long as the first execution?
If the call to the stored procedure is the first operation, the issue could be the startup time.
You can take a look at the server debug log to determine if that's the case.
If the startup time is indeed the issue, you can reduce startup time by controlling discovery. You will find more details at
http://drc.ideablade.com/xwiki/bin/view/Documentation/discovery.
You could also time the execution in the QueryInterceptor. This would help compare the execution time in the server (i.e. BOS) vs. in the client and determine if the data traffic would actually be the culprit. More details at
http://drc.ideablade.com/xwiki/bin/view/Documentation/query-server-lifecycle-events.
Edited by sbelini - 21-Mar-2013 at 9:34am