Re: window.setInterval()

From: Walden H. Leverich
I sort of question the 30 seconds part of this too. I assume
you're using ajax to find out if there are updates, yes?

Yes, AJAX. That's right.

You could also hold the connection open on the server-side
for a period of time and have the client just reissue the request
when the server returns.

That made me think. AJAX is asynchronous, after all. And it made me think about server architecture, too.

If the connection were to stay open, that would tie up a socket at the TCP/IP level, and tie up a connection in the HTTP server. And what would the RPG program do to keep the connection alive (not respond)? I suppose it could wait on a data queue. And have a separate process on the server put an entry on the queue when an alert is due. Do folks really do stuff like that?

What if the user tabs over to the ToDo list while the async request is waiting, and begins checking off completed items? Just let the HTTP server launch a new instance of the application to process those requests?

What if Servlets were processing the requests? 1000 concurrent users. 1000 sockets open. 1000 HTTP connections. 1000 Servlet threads waiting for their respective alerts to be placed on a queue, keyed by session ID?

Makes me think.