Netweaver JMS issues

Question

I have a stand alone enterprise java application (not an EJB) that currently runs on several servers (one application per server).  This application allows us to do parellel processing for performance reasons.  Another important distinction is that we use a JMS Point-to-Point model with multiple consumers receiving messages off a single queue.  The application is basically a JMS asynchronous message consumer, meaning it implements the javax.jms.MessageListener interface so it has the onMessage method. 
Currently I have been using JBoss 4.0 as our JMS Provider.  I have had no issues for awhile now with multiple consumers receiving messages off a single queue.  Recently, I have been asked to move to use Netweaver's JMS provider.  I was successful in changing the configurations and sending and receiving messages using the Netweaver JMS provider.  However, it appears that I cannot get multiple consumers to receive messages off a single queue.  I can successfully launch off several of our applications on several servers all listening to the single queue and I can also put multiple messages into that single queue.  However, it appears that only one message consumer can receive a message off the single queue at one time (all the other message consumers seem to wait until the one message is done processing).
Again, I changed the configurations back to JBoss and everything worked fine (I also did it for OpenJMS and it worked as well).  My quess is that I either did not setup something correctly or I need to make some kind of administative or jms setting.  Any help would be greatly appreciated.
Just a side note.  If I poll for messages on the single queue instead of using the onMessage() method with multiple message consumers I am able to run parellel processes.

Answer 1

We are talking P2P with load balancing and scaling for throughput. Moving this to a pub/sub is a bad performance move as typically pub/sub is more time and resource intensive than P2P.
Just make sure that in your JNDI definition your queue has been marked as shareable. As the JMS spec goes it does not help if the provider side of the queue has the queue marked as not shared. As well if the app reading from the queue through the listener has it opened in exclusive mode all the others are waiting.
This means some investigation may be needed.
A) JNDI verify JMSDestination is defined as shareable
b) programming wise verify that putting the listener to the queue does not make the mode opened as exclusive.
Typically you would have implemented an MDB. You need to check the number of instances that you have defined for the MDB. As well you may define the same destination with multiple JNDI names and thus set different MDBs on the same queue (but same MDB class).
There is a world of solutions out there. Pick the one that works for you
Enjoy
Message was edited by: F.J. Brandelik
SAP's implementation of JMS persistence is through a Database. Make sure locking happens at the record level and not at the page level.