I'm trying to implement a paging grid, which should show search results. But how should I implement the server side methods?

I got a RPCProxy which calls a method on the server side, but do I need to make a database lookup everytime a user wants to see "the next 10 search results" or how should I store the first database lookup?

Please give me an intro or a hand of how to use a RPCProxy or similiar efficiently.