Higher JMSPriority not stepping in front of lower JMSPriorit

[seoeng]

Below is my invoker-proxy-binding and container-configuration for this specific MDB (Bean-Managed). Here is the use case:

1. Send JMS Message with JMSPriority 4 to Queue
2. Send JMS Message with JMSPriority 4 to Queue
3. Send JMS Message with JMSPriority 7 to Queue

The MDB (Bean-Managed) is processing as follows:

1. Receives JMS Message #1, starts processing
2. Receives JMS Message #2, starts processing
3. Receives JMS Message #3, starts processing

NOTE: All messages are queued before MDB finishes #1.

What behavior is expected:

1. Receives JMS Message #1, starts processing
2. Receives JMS Message #3, starts processing
3. Receives JMS Message #2, starts processing

Because Message #3 enters the Queue before Message #1 is finished processing in MDB, shouldn't Message #3 be consumed by the MDB next?

 <invoker-proxy-binding>
 <name>message-driven-bean</name>
 <invoker-mbean>default</invoker-mbean>
 <proxy-factory>org.jboss.ejb.plugins.jms.JMSContainerInvoker</proxy-factory>
 <proxy-factory-config>
 <JMSProviderAdapterJNDI>DefaultJMSProvider</JMSProviderAdapterJNDI>
 <ServerSessionPoolFactoryJNDI>StdJMSPool</ServerSessionPoolFactoryJNDI>
 <CreateJBossMQDestination>true</CreateJBossMQDestination>
 <!-- WARN: Don't set this to zero until a bug in the pooled executor is fixed -->
 <MinimumSize>1</MinimumSize>
 <MaximumSize>1</MaximumSize>
 <KeepAliveMillis>30000</KeepAliveMillis>
 <MaxMessages>1</MaxMessages>
 <MDBConfig>
 <ReconnectIntervalSec>10</ReconnectIntervalSec>
 <DLQConfig>
 <DestinationQueue>queue/DLQ</DestinationQueue>
 <MaxTimesRedelivered>10</MaxTimesRedelivered>
 <TimeToLive>0</TimeToLive>
 </DLQConfig>
 </MDBConfig>
 </proxy-factory-config>
 </invoker-proxy-binding>

 <container-configuration>
 <container-name>MDBConfig</container-name>
 <call-logging>false</call-logging>
 <invoker-proxy-binding-name>website-crawler-message-driven-bean</invoker-proxy-binding-name>
 <container-interceptors>
 <interceptor>org.jboss.ejb.plugins.ProxyFactoryFinderInterceptor</interceptor>
 <interceptor>org.jboss.ejb.plugins.LogInterceptor</interceptor>
 <interceptor>org.jboss.ejb.plugins.RunAsSecurityInterceptor</interceptor>
 <!-- CMT -->
 <interceptor transaction="Container">org.jboss.ejb.plugins.TxInterceptorCMT</interceptor>
 <interceptor transaction="Container">org.jboss.ejb.plugins.CallValidationInterceptor</interceptor>
 <interceptor transaction="Container">org.jboss.ejb.plugins.MessageDrivenInstanceInterceptor</interceptor>
 <!-- BMT -->
 <interceptor transaction="Bean">org.jboss.ejb.plugins.MessageDrivenInstanceInterceptor</interceptor>
 <interceptor transaction="Bean">org.jboss.ejb.plugins.MessageDrivenTxInterceptorBMT</interceptor>
 <interceptor transaction="Bean">org.jboss.ejb.plugins.CallValidationInterceptor</interceptor>
 <interceptor>org.jboss.resource.connectionmanager.CachedConnectionInterceptor</interceptor>
 </container-interceptors>
 <instance-pool>org.jboss.ejb.plugins.MessageDrivenInstancePool</instance-pool>
 <instance-cache></instance-cache>
 <persistence-manager></persistence-manager>
 <container-pool-conf>
 <MaximumSize>1</MaximumSize>
 </container-pool-conf>
 </container-configuration>

[seoeng]

Ok, I think I have figured out what JBoss is doing. I am using 4.2.2GA.

Here is the new use case I used:

1. Send JMS Message with JMSPriority 4 to Queue
2. Send JMS Message with JMSPriority 4 to Queue
3. Send JMS Message with JMSPriority 4 to Queue
4. Send JMS Message with JMSPriority 7 to Queue

The MDB (Bean-Managed) is processing as follows:

1. Receives JMS Message #1, starts processing
2. Receives JMS Message #2, starts processing
3. Receives JMS Message #4, starts processing
4. Receives JMS Message #3, starts processing

NOTE: All messages are queued before MDB finishes #1.

What behavior is expected:

1. Receives JMS Message #1, starts processing
2. Receives JMS Message #4, starts processing
3. Receives JMS Message #2, starts processing
4. Receives JMS Message #3, starts processing

It appears that JBoss is queuing up a message before the MDB even processes it. So a higher priority message must wait what appears to be the invoker-proxy-binding's # of messages before it jumps in front.

This doesn't make sense to me, wouldn't you want a higher priority message to jump in front immediately? Is there a way around this, i.e. am I not setting the configuration correctly for my desired result?

[adrian.brock]

It appears that JBoss is queuing up a message before the MDB even processes it. So a higher priority message must wait what appears to be the invoker-proxy-binding's <MaximumSize> # of messages before it jumps in front.

Correct. It's called read ahead. It would be very inefficient (latency) to wait
until a message listener completes its onMessage() before
retrieving the next message to process from the server.

It's not configurable in JBossMQ, try JBoss Messaging
or submit a patch to make it configurable (there's an old feature request
about it somewhere but it was closed when we stopped developing JBossMQ).