You're misunderstanding what the prefetch size is. It doesn't mean the broker dispatches messages in groups of N, it means that the broker dispatches messages individually until there are N outstanding, and when a message is acknowledged then another individual message will be dispatched to get back to N.
The DispatchedQueueSize attribute you already found should always be equal to the prefetch size (or working to get to the prefetch size). A larger prefetch size won't reduce network traffic (in fact, it'll increase it right after the consumer connects, because you're transferring N-1 more messages to fill the prefetch buffer); rather it gives you a buffer of available messages so the consumer isn't waiting for a network transfer when you have a variable-speed network and/or a variable time to consume messages. If your network is fast and reliable and your messages all take the same amount of time to process, prefetch doesn't do you any good (and it makes it harder to load-balance across additional consumers). Tim On Mar 20, 2016 10:13 PM, "Raffi" <raffi.onj...@gmail.com> wrote: > Is there a JMX metric for testing prefetch=1 vs prefetch=100? I want to > confirm reduced network activity between consumer and broker when using > large prefetchSize. DispatchedCounter and DispatchedQueueSize appear to > increment/decrement by 1, never consistent with prefetchSize. I'm missing > something simple, I know it :-) > > > > > > > > -- > View this message in context: > http://activemq.2283324.n4.nabble.com/How-to-test-prefetch-size-is-actually-working-tp4709766.html > Sent from the ActiveMQ - User mailing list archive at Nabble.com. >
