IBM MQ does not roll back in WS-AT transaction

Question

I have a similar problem to the case described in MQ Queue transaction not rolled back in a 2 phase transaction. I have a .NET client which does the following in one transaction:

1. Writes one record to the first database.
2. Puts one message into an IBM Websphere 8.0 MQ Series queue.
3. Calls with WS-AT the web service as described in https://developers.redhat.com/quickstarts/eap/wsat-simple.
4. Writes one record to the second database.

When the web service rolls back, the two databases roll back but not the IBM MQ Series queue. When one database fails, then the IBM MQ Series queue does roll back.

The method RestaurantTransactionPOC runs in a class that inherits from System.EnterpriseServices.ServicedComponent, that means, it runs under COM+.

Here is the code of RestaurantTransactionPOC:

Public Function RestaurantTransactionPOC(
    uri As String, queueManager As String, queueName As String, textToWrite As String,
    Optional failOnlRecvRep As Boolean = False,
    Optional failGtsRecvRep As Boolean = False,
    Optional failWSATService As Boolean = False,
    Optional failMQSeries As Boolean = False) As String
    Try
        Dim result = ""
        Dim msgId = GetMsgId()
        Try
            AddOnlRecvRep(msgId, failOnlRecvRep)
        Catch ex As Exception
            Debug.WriteLine(ex.ToString)
            result &= ex.ToString & vbCrLf
        End Try
        Try
            AddQueue(queueManager, queueName, msgId, failMQSeries)
        Catch ex As Exception
            Debug.WriteLine(ex.ToString)
            result &= ex.ToString & vbCrLf
        End Try
        Try
            ServicePointManager.SecurityProtocol = CType(SecurityProtocolType.Tls Or 768 Or 3072, SecurityProtocolType)
            Dim client = CreateChannel(Of RestaurantServiceATChannel)(uri)
            client.makeBooking()
        Catch ex As Exception
            Debug.WriteLine(ex.ToString)
            result &= ex.ToString & vbCrLf
        End Try
        Try
            AddGtsRecvRep(msgId, failGtsRecvRep)
        Catch ex As Exception
            Debug.WriteLine(ex.ToString)
            result &= ex.ToString
        End Try
        ContextUtil.SetComplete()
        Return result
    Catch ex As Exception
        ContextUtil.SetAbort()
        Throw
    End Try
End Function

Public Function CreateChannel(Of T)(uri As String) As T
            binding = New CustomBinding(
                New BindingElement() {
                    New TransactionFlowBindingElement(TransactionProtocol.WSAtomicTransaction11),
                    New TextMessageEncodingBindingElement() With {.MessageVersion = MessageVersion.Soap12},
                    New HttpsTransportBindingElement()})
    binding.SendTimeout = New TimeSpan(0, 0, 30)
    Dim endpoint As New EndpointAddress(uri)
    Dim channelFactory = New ChannelFactory(Of T)(binding, endpoint)
                Dim behavior = CType(channelFactory.Endpoint.Behaviors(1), ClientCredentials)
                behavior.ClientCertificate.SetCertificate(
                    StoreLocation.LocalMachine, StoreName.My, X509FindType.FindByThumbprint,
                    "5f 82 82 e3 e9 20 fd ac 27 f5 cc 60 8a f5 8e 55 39 38 a0 30")
    Return channelFactory.CreateChannel()
End Function

Why does the IBM MQ Series queue not roll back, when the WS-AT makeBooking service rolls back?

Answer 1

If I recall correctly, in some cases, MQ would not remove a message from a queue until a read attempt was made, at which time, if the message had not properly been committed, it would be backed out instead of delivered to the reader. Might want to take a look at those options on both the sending and receiving queue manager as well as for the queue and the reader.

Answer 2

Joe Zitzelberger is right. As soon as AddQueue is called (which calls IBM.WMQ.MQQueue.Put), the current depth (given by IBM.WMQ.MQQueue.CurrentDepth) is incremented by 1. But getting the message from the queue (by IBM.WMQ.MQQueue.Get) results in the MQRC_NO_MSG_AVAILABLE exception. By experimenting, I found out the behaviour is as follows depending on the different cases:

If ContextUtil.SetComplete is called, then
  If the transaction is committed, then
    CurrentDepth remains incremented. 
    The message is available for retrieval.
  Else (transaction is aborted, because Db or WS-AT voted abort)
    CurrentDepth remains incremented for 3 minutes, regardless of whether IBM.WMQ.MQQueue.Get is called in the meantime. Afther the 3 minutes, CurrentDepth returns to its original value (is decremented).
    The message is not available for retrieval.
  End If
Else (ContextUtil.SetAbort method is called)
  (transaction is aborted)
  CurrentDepth returns to original value (is decremented).
  The message is not available for retrieval.
End If