How to get list of current online users of a facebook applic

I am trying to create ajax based chat for my application users; I need to get list of All currently online users of the application ..Is there a way to retrieve such a list with facebook aPI? if not how...

Strategy for handling variable time queries?

I have a typical scenario that I’m struggling with from a performance standpoint. The user selects a value from a dropdown and clicks a button. A stored procedure takes that value as an input parameter,...