Again Message Order and MDB

[mclu]

Hi!

Its mee again.
I spend arround 5 hours now digging in JBM code to find out why my system behaves as it does.

Testenvironment:
- One local persistent Queue with a lot of messages in.
- An EJB3 MDB attached to the Queue using maxSession and maxMessages set to 1
- redelivery is set to MDBs default (5 think)
- JBM 1.4.0 SP3 on 4.2.1 GA

To test Logic errors and the ways JBM handles exceptions I set context.setRollbackOnly() while handling the messages in my MDB onMessage() method.


What I thought is this behaviour of Message A B C....:
A -> fail
A -> fail
A -> fail
A -> fail
A -> fail -> DLQ
B -> fail
B -> fail
B -> fail
B -> fail
B -> fail -> DLQ
and so on

But what happens is always a handling of 2 messages:
A -> fail
B -> fail
A -> fail
B -> fail
A -> fail
B -> fail
A -> fail
B -> fail
A -> fail -> DLQ
B -> fail -> DLQ
C -> fail
D -> fail
C -> fail
D -> fail
and so on...

While debugging and tracing I see that the ClientConsumer
calls removeFirst() on the BasicPriorityLinkedList from 2 Threads and in twisting manner the addFirst() and removeFirst() which lead in this A,B,A,B order.

What can I do to have this AAAABBBB handling?

[ataylor]

This is an MDB container question, probably to do with pool size etc. refer to http://wiki.jboss.org/wiki/ConfigJBossMDB on how to configure MDB's.

FYI The JMS spec doesn't require message order to be preserved after rollback.

[mclu]

Hi again...

Yes I know that the spec says nothing about order.

But still this behavior is strange. The pool size is set via annotations:

@ActivationConfigProperty(propertyName="maxSession", propertyValue="1"),
@ActivationConfigProperty(propertyName="maxMessages", propertyValue="1") })


I just wonder why its always twisting with 2 messages instead of 3 or 5 or any higher number.
If I can force this to 1 consumer its exacly what my customer need. :-)

Greets

[ataylor]

Like I say, this is an MDB question, if you post on the appropriate forum they will be able to help you. Remember MDB's are JMS Provider agnostic.