I know that socket.io provides a long polling transport that I could use as a fallback for websockets, but for my application the overhead of long-polling is unnecessary.
Would setting the polling duration to 0, and the interval to 20 seconds still deliver all non-volatile messages and not strain my server in some strange way?
Why?
I'm looking to provide live notification when things happen around the site, and am currently using websockets/socket.io to do this. Our site handles an average of 750 requests per second and maintaining a socket.io cluster for the websocket enabled users will be difficult enough. Allowing users to long-poll would require two live connections for each user and that's seems like too much overhead to me. I prefer the idea of falling back to intermittent polling for not so live notifications. I also imagine using this for pages that aren't expected to receive many live notifications, or times when server load is too high.