Sounds like it is too much data. Use the profiler to verify and to get ideas of how to split up the work. Paging in data is usually the best option. It will lower bandwidth costs as well
Flex SDK Developer
Adobe Systems Inc.
I have looked a little at paging but I cannot tell if the filters would still work. lets say I have 10,000 stores and I want to see the ones in a peticular zip code. or just the ones that sell Jack Daniels.
If you are using paging you'll have to filter and sort on the server. It may also impact your grouping strategy. Given the amount of data it would probably be the best approach.
If you are unable to use paging then you may be able to optimize what you have to scale up to 10000 rows, but you'll need to identify the bottlenecks.
There's a faster GroupingCollection available here: