> Assuming that a channel setup costs 2.77 seconds, having just 10,000 active > users setup 4 channels per day would cost $92.30 per month. That's not > counting any CPU costs for actually sending messages. > > At that rate, I can't really use the channel API as much as I'd like and I > have to look at alternatives such as Beacon now that I know how cool this > technology is.
Better docs on Channel API quota use are coming, but the reason the CPU charge is so high is that the CreateChannel charges up-front for 2 hours of connect time by clients. It is true that if you have the same user connecting repeatedly for a short time but spread out over periods of time longer than two hours (obviously degenerate case would be connecting for a couple of minutes every two hours and one second), the charge will be high. One thing I'm looking at is the ability to create a token that expires after an application-specified period, if your application's usage patterns warrant it. Note that you can store the token for re-use in eg. a cookie so you don't need to regenerate it more frequently than every two hours. Sending a message doesn't charge any CPU time at all (since the connection's already established), just outbound bandwidth. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
