Re-using of HornetQ Core API Objects

[dro_k]

The following is from the Tuning seciton of the User Manual:

Re-use connections / sessions / consumers / producers. Probably the most common messaging anti-pattern we see is users who create a new connection/session/producer for every message they send or every message they consume. This is a poor use of resources. These objects take time to create and may involve several network round trips. Always re-use them.

Note

Some popular libraries such as the Spring JMS Template are known to use these anti-patterns. If you're using Spring JMS Template and you're getting poor performance you know why. Don't blame HornetQ! The Spring JMS Template can only safely be used in an app server which caches JMS sessions (e.g. using JCA), and only then for sending messages. It cannot be safely be used for synchronously consuming messages, even in an app server.

Considering that I'm using the Core API and not JMS as an embedded queue in my JVM (using InVmConnector), what objects should I re-use and more importantly how? How do you decide when to share a ClientSessionFactory, ClientSession, ClientProducer and ClientConsumer?

Thanks,

Drew

[clebert.suconic]

- You should keep at least one ServerLocator (with the latest version)

- Cache your ClientSessionFactory

- You need a ClientSession per thread.

And mainly, cache your ClientConsumer. If you create a consumer every time you receive a message, it means you are doing a round trip, adding a collection on the Queue, receiving the message, and then doing another round trip to close the consumer, remove it from the queue and retransmit cached messages on the client. It really sucks if you do that! (that's a valid optimization for any message system you chose, it's nothing specific for HornetQ).

[dro_k]

Thanks Clebert.How about the ClientConsumer and ClientProducer, I assume one per thread too, right?

[clebert.suconic]

ClientConsumer and ClientPRoducer belong to a session, so yes.

[dro_k]

Just to clarify something. The reason you're saying the ClientSession is per thread, is for thread safety right not beacause it uses ThreadLocal?

What I mean, is that let's say that I have a Runnable class and I have a guarantee that only one instance of this Runnable class will be running at each time, using ScheduledExecutorService. Can I cache the ClientSession in the Runnable class, or do I have to create a new ClientSession on each run?

[clebert.suconic]

Right... it's just because Clientsession is not thread safe.. if you use it among multi threads like it was a single thread (through executors for instance) it's fine. We don't use ThreadLocal or anything like that.

[dro_k]

Thanks Clebert.