Subject RE: [firebird-support] Performance of events
Author Alan McDonald
> Hello,
> I'm currently widely adopting the usage of events to realize a live
> update on all clients when data has been changed from another client.
> Does anybody have experience with posting and registering for a lot of
> events and it's impacts?
> The current usage of event is one posted event every few seconds, with
> at least one to five clients listening for that event. That's not much
> and I am planning to add much more "event-traffic", but I've noticed
> that fbserver utilized the CPU to 100% today and yesterday and I'm not
> sure, why. Are events something meant to be used rarely, or is
> something like 10 posted events per second with 100 different clients
> listening to potentially hundreds of events per connection feasible?
> Could it potentially slow down the server because of dificulties
> regarding transaction isolation?
> Any hint, suggestion or experience would be highly appreciated.
> Greetings,
> Daniel Albuschat

your 100% CPU usage may have nothing to do with event traffic or responding with query refreshing. It may be a sweep - this is another whole story.
If you use events, try to keep the responding query refreshes small.
Row level invalidation is good if you can do it.
You may go thru a period of adding a lot of events, but when you're finiished you may realise that most of the events are making the clients respond in the same way each time. So fewer events do the same job.
And yes,, many events causing clients to do a lot of stuff when really they shouldn't be doing them means a lot of network traffic for no particular gain.