CODEWITHSUNDEEP
jmsweblogic
Jay Blanton
Jay Blanton

Reputation: 584

All JMSs Message from Distributed Queue across the Cluster

Currently using WebLogic and Distributed Queues. And I know from the documentation that Distributed Queues allow you to retrieve a connection to any of the Queues across a cluster by using the Global JNDI name. It seems one of the main pieces of functionality Distributed Queue gives you is load balanced connections across multiple managed servers. So we have 4 Managed Servers (two on each physical, that communicate over multicast), and each Managed Server has an individual JMS Server which is configured to it's own Data Store.

I am 99% certain I already know the answer to this, but it appears that if you wanted to do a Consume a message off of a Queue, and that Queue exists on each Mgd Server in the Cluster, you cannot technically pull a Message off of any of the Queues (you can only pull the Message off the Queue to which you are connected to). So if I have a Message on Mgd Server 4, and I connect to Mgd Server 1, I won't see the messages on the Queue from Mgd Server 4.

So is there a way in Java EE or WLS to consume a message from all the nodes of a Queue (across the Cluster). Like a view into every instance of the Queue on each Mgd Server? It doesn't appear so and the documentation makes it seem like this is not possible, as well as this video (around minute 5):

http://www.youtube.com/watch?v=HAKixK_wp0Q

Upvotes: 3

Views: 3096

Answers (2)

SridharS
SridharS

Reputation: 923

No you cannot consumer a message that is delivered to one managed server when your client is connected to another managed server of the same cluster.

Here's how it works. When using UDT, wls provides a JNDI name that resolves internally into 4 distinct JNDI names for each of the managed server, the JMS servers on each of the managed servers are distinct. When using the UDQ JNDI name when you post a message, it gets to one of the 4 managed servers using the algorithm you chose and other configuration done in your connection factory.

When a message consumer listens to the UDQ it gets pinned to the JMS server on one of the managed servers. It has no visibility about messages in the other servers.

Usually UDQ is used in scenarios where you want the message to be consumed concurrently by more than one managed server. You would normally deploy a MDB to the cluster, meaning the MDB will be deployed to each of the managed server and each of these will be able to consume the messages from their local JMS server.

Upvotes: 4

rakehell
rakehell

Reputation: 338

I believe you can if your message store is config'd to use a database. If so, then I would think removing an item from the queue would remove it from the shared db table. I.e. all JMS servers are pointing to the same db instance and table. That should be pretty easy to test, too.

Upvotes: 0

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