Use transacted session in MDB

Question

          Hi,
          If I use transacted session in MDB with container managed transaction, dose the
          weblogic ignore the transacted setting or start in it's own transaction. I looked
          the JMS Tutorial from Sun, the J2EE server just ignore the transacted setting,
          treated it as non-transacted session.
          Thanks
          

Answer 1

          Thanks, Greg. I created another XAQCF in MQ JMSADMIN, but still did not help. The
          strange part is when this exception happens, in the Event Viewer there is a Message:
          An internal Websphere MQ Error has occurred'. In the Trace Log of MQ, the Major
          Error Code reported is arcE_XAER_PROTO.
          Has anyone encountered this error? The same code works fine when enlist an XAQCF
          defined in Weblogic and PUT into a Weblogic JMS Queue instead within the same
          XA Transaction. I am attaching the stack trace to this message, just in case,
          someone has useful pointers to help me. May be this is MQ Specific though I made
          sure I have the latest FixPack for MQ installed.
          Thanks,
          Sridhar
          "Greg Brail" <[email protected]> wrote:
          >Yeah. This comes up from time to time. MQ is upset because it wants to
          >be
          >enlisted in the JTA transaction, but JTA is not enlisting it because
          >it
          >thinks it's already enlisted. It thinks it's already enlisted because
          >the
          >same MQ connection factory was used for the MDB input queue, even though
          >it's a different JMS connection and session.
          >
          >You can avoid this by creating another "XAQCF" object in the MQ JNDI
          >space
          >and giving it a different name. If you do that -- essentially use different
          >connection factories for the MDB's input and output queues -- then this
          >will
          >work.
          >
          >Also, the transaction enlistement code in 8.1 that supports the
          >"resource-ref" feature avoids this problem.
          >
          > greg
          >
          >"Sridhar Krishnaswamy" <[email protected]> wrote in message
          >news:[email protected]...
          >>
          >> Hi Greg:
          >> I assume you meant to getXAResource() from an Object of type
          >XAQueueSession. Here
          >> is the code I tried within the onMessage() method of the MDB:
          >>
          >> XAQueueConnectionFactory factory = (XAQueueConnectionFactory)
          >ctx.lookup("XAQCF")
          >> ;
          >> XAConnection connection = factory.createXAQueueConnection() ;
          >>
          >> XAQueueSession mqSession = connection.createXAQueueSession() ;
          >> XAResource mqResource = mqSession.getXAResource() ;
          >> Transaction tran = TxHelper.getTransaction() ;
          >> tran.enlist(mqResource) ;
          >>
          >> //Then I was going to get the QueueSession Object from XAQueueSession,
          >obtain
          >> the Queue
          >> //Object from JNDI, create the Sender
          >> //and call the send. But I commented out these calls. Even then, after
          >the
          >onMessage
          >> Method
          >> // completes, I get the following error:
          >>
          >> javax.transaction.SystemException: start() failed on resource
          >'com.ibm.mq.MQXAResource':
          >> XAER_PROT : Routine was invoked in an improper context
          >> javax.transaction.xa.XAException: XA Operation failed. see errorcode
          >(which I
          >> am assuming is XAER_PROT).
          >>
          >> Any idea, what I am doing wrong?
          >>
          >>
          >>
          >>
          >> "Greg Brail" <[email protected]> wrote:
          >> >In 7.0, you can do your MQ "put" inside the same JTA transaction that
          >> >was
          >> >used to receive the message for the MDB, but you have to do the
          >transaction
          >> >enlistment yourself. Basically, you have to use the class
          >> >weblogic.transaction.TxHelper class to get a reference to the current
          >> >transaction, then call "enlistResource" on the transaction using the
          >> >JTA
          >> >"XAResource" that you get from the MQ JMS "Session" object. I'm sure
          >> >we've
          >> >posted the code in this newsgroup before, but I don't know where,
          >so
          >> >it
          >> >would look something like:
          >> >
          >> >// First, get the MQ QueueSession object you're going to use to send
          >> >the
          >> >message
          >> >QueueSession mqSession = mqConnection.createQueueSession(false, 0);
          >> >XAResource mqResource = mqSession.getXAResource();
          >> >weblogic.transaction.Transaction tran =
          >> >weblogic.transaction.TxHelper.getTransaction();
          >> >tran.enlistResource(mqResource);
          >> >// Now send your message
          >> >
          >> >In 8.1, this will still work, but it's not necessary. If you register
          >> >the MQ
          >> >XA connection factory as a "resource-reference" in your EJB deployment
          >> >descriptors and look it up using java:comp/env the way the documentation
          >> >link way below describes, then this transaction enlistment happens
          >> >automatically. This only happens when you use the "resource-reference"
          >> >feature (which means that old code will still work if it does NOT
          >use
          >> >this
          >> >feature), and it's only in 8.1.
          >> >
          >> > greg
          >> >
          >> >"Sridhar Krishnaswamy" <[email protected]> wrote in
          >message
          >> >news:[email protected]...
          >> >>
          >> >> Hi Greg:
          >> >> Is the Statement
          >> >>
          >> >> 'But in this case, you don't get a "non-transactional" session,
          >but
          >> >actually a
          >> >> session that participates in the current JTA transaction for the
          >thread
          >> >where
          >> >> your EJB is running'
          >> >>
          >> >> also true in the case of an MDB running in Weblogic 7.0 (Container
          >> >Managed
          >> >Transactions)
          >> >> driven by an XAQCF and a Foreign JMS Provider such as MQSeries?
          >In
          >> >other
          >> >words,
          >> >> if I want the MDB to PUT the Message into an MQSeries Queue, can
          >the
          >> >PUT
          >> >be invoked
          >> >> under the Context of the Same XA Transaction? My understanding is
          >that
          >> >WebLogic
          >> >> 7.0 doesn't support send
          >> >> messages out of an MDB within the same XA transaction if the MDB
          >is
          >> >> XA-driven by a foreign JMS provider. Please let me know if this
          >is
          >> >false.
          >> >If true,
          >> >> does Weblogic 8.1 also have this restriction?
          >> >>
          >> >> Thanks,
          >> >> Sridhar Krishnaswamy.
          >> >>
          >> >> "Greg Brail" <[email protected]> wrote:
          >> >> >What do you mean by "use transacted session in MDB?" Are you creating
          >> >> >a new
          >> >> >session inside your MDB, or do you mean something else?
          >> >> >
          >> >> >The only Sun thing I can think of is in code that looks like this:
          >> >> >
          >> >> >InitialContext ctx = new InitialContext();
          >> >> >QueueConnectionFactory qcf = ctx.lookup("java:comp/env/jms/QCF");
          >> >> >Queue queue = ctx.lookup("java:comp/env/jms/Queue");
          >> >> >QueueConnection connection = qcf.createQueueConnection();
          >> >> >// Create "transacted" session:
          >> >> >QueueSession session = connection.createQueueSession(true, 0);
          >> >> >QueueSender sender = session.createQueueSender(queue);
          >> >> >TextMessage message = session.createTextMessage("Hello, world");
          >> >> >sender.send(message);
          >> >> >connection.close();
          >> >> >
          >> >> >If you do this, and exactly this, inside an EJB, including the
          >use
          >> >of
          >> >> >"java:comp/env/jms", in WebLogic Server 8.1, then we do indeed
          >ignore
          >> >> >the
          >> >> >"transacted" flag when you create the session, just like Sun says
          >> >we
          >> >> >should
          >> >> >in the EJB and J2EE specs. But in this case, you don't get a
          >> >> >"non-transactional" session, but actually a session that participates
          >> >> >in the
          >> >> >current JTA transaction for the thread where your EJB is running.
          >> >> >
          >> >> >The idea is that if you are working inside an EJB, you don't use
          >> >transacted
          >> >> >sessions -- you use the transaction control given to you by the
          >EJB
          >> >> >container, including the UserTransaction interface and/or the various
          >> >> >container-managed transaction flags, rather than the JMS "transacted
          >> >> >session".
          >> >> >
          >> >> >You can find more information here:
          >> >> >
          >> >> >http://e-docs.bea.com/wls/docs81/jms/j2ee_components.html
          >> >> >
          >> >> > greg
          >> >> >
          >> >> >"Jen" <[email protected]> wrote in message
          >> >> >news:[email protected]...
          >> >> >>
          >> >> >> Hi,
          >> >> >>
          >> >> >> If I use transacted session in MDB with container managed
          >transaction,
          >> >> >dose the
          >> >> >> weblogic ignore the transacted setting or start in it's own
          >> >transaction.
          >> >> >I
          >> >> >looked
          >> >> >> the JMS Tutorial from Sun, the J2EE server just ignore the
          >transacted
          >> >> >setting,
          >> >> >> treated it as non-transacted session.
          >> >> >> Thanks
          >> >> >
          >> >> >
          >> >>
          >> >
          >> >
          >>
          >
          >
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