Cache event buffering stragetry

[yelin666]

We are using the cache listener & notification API for cache event handling. As the event is coming in at per cache item basis, we need to buffer the events before sending out notification to our applications for efficiency reason. What buffering strategy would you recommend? Thanks.

[manik]

Try using asynchronous listeners - @Listener(sync = false)?  This uses an executor to dispatch event notifications, and you can tune the executor used.  This becomes a natural, built-in buffer.  :-)

[yelin666]

Sorry I probably didn't make it clear. Even with asyncListenerExcecutor tuned, if I have the async listener as follows:

@Listener(sync=false)

public class UpdateEventHandler {

    @CacheEntryModified

    public void update(CacheEntryModifiedEvent updateEvent) {

    }

}

So in the update() method above, that does my event handling, the updateEvent is still for one key/value pair. Basically, our application would like to get notified with a list of values being updated during a period of time, and kick off the processing of the value changes at one time instead of running the processing every time a values changes. Does Infinispan support this natively? If not, what's your recommendation on how we handle the buffering?

[genman]

I'm guessing the best way would be to replace the class/instance that handles the events.

http://docs.jboss.org/infinispan/4.2/apidocs/config.html#ce_global_asyncListenerExecutor

[manik]

You could implement a queue in your listener to queue up events, and you could have a separate scheduled executor that periodically flushes the quueue and process the events...

[genman]

^^ Lots of context switches, but it'd work.

[mircea.markus]

Or not use a scheduled executor, but the calling thread to flush the event queue to the application when it reached a certain threshold or a certain interval has passed. Reduces ctx swithces as well