Basically I'm writing an ASP.NET MVC application that though a javascript sends a GET request every 30 seconds, checking if a certain row in a table in the database has changed.

I've been looking at the OutputCache attribute but it doesn't seem like it would work since it would just cache the content and not really check if an update was made.

What would be the "cheapest" way to do this? I mean the way that burdens the server the least?