IT38380: Unable to use nested XA transactions with Mule and the Bitronix transaction manager.

APAR status

• Closed as program error.

Error description

• An MQ 9.2.0.2 classes for JMS application is running in a Mule
  environment, which uses Bitronix as the transaction manager.
  
  The application has been set up to use nested XA transactions.
  These are XA transactions where an outer transaction gets
  suspended so that another transaction (known as an inner
  transaction) can be performed. Once the inner transaction has
  finished, the outer transaction is resumed.
  
  When the application is run, the outer transaction is suspended
  successfully. However, once the inner transaction has completed,
  the outer one cannot be resumed. This is because the
  implementation of the XAResource.isSameRM(...) method provided
  by the MQ classes for JMS has been hard-coded to return false.
  
  Here is an extract from an MQ classes for JMS trace that shows
  this:
  
  [16/06/21 10:39:11.380.00] 00000013 @5ba9abb5
  c.i.mq.jmqi.JmqiXAResource { isSameRM(XAResource)
  [c.i.mq.jmqi.JmqiXAResource@5ba9abb5]
  [16/06/21 10:39:11.380.01] 00000013 @5ba9abb5
  c.i.mq.jmqi.JmqiXAResource } isSameRM(XAResource) returns
  [false] Boolean
  
  In these trace points:
  
  - The isSameRM(XAResource) method is called on the object
  JmqiXAResource@5ba9abb5.
  - And the same object (JmqiXAResource@5ba9abb5) is passed into
  the method, so the method should return true.
  

Local fix

• An interim fix is available
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of:
  
  - The MQ 9.2 classes for JMS.
  - The MQ 9.2 resource adapter.
  
  who have applications running within an environment that has
  been configured to use the Bitronix transaction manager to
  manage XA transactions.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When using XA transactions in Java, a transaction manager will
  create an XAResource object, which represents the resource
  manager that is involved in the transaction. Whenever the
  transaction manager needs to communicate with the resource
  manager, it calls various methods on the XAResource. The
  XAResource then flows the corresponding XA calls to the resource
  manager, collects the responses and passes them back up to the
  transaction manager.
  
  The Bitronix transaction manager provides support for nested XA
  transactions. When an application wants to use a nested XA
  transaction, the Bitronix transaction manager will:
  
  - Suspend the outer XA transaction.
  - Perform the inner XA transaction.
  - Resume the outer XA transaction.
  
  Prior to resuming the outer XA transaction, the Bitronix
  transaction manager calls the method:
  
  XAResource.isSameRM(XAResource)
  
  to confirm that the XAResource being used to resume the outer
  transaction is the same as the XAResource object which was used
  to suspend it. If the method returns true, then the outer
  transaction is resumed. However, if the method returns false,
  then the transaction manager assumes that there is an issue with
  resuming the outer transaction, and prevents it from restarting.
  
  
  In the MQ classes for JMS and resource adapter, the
  implementation of the method:
  
  XAResource.isSameRM(XAResource)
  
  was hard coded to always return false, as it had been found that
  providing a proper implementation of the method would result in
  certain transaction managers making a series of XA calls which
  resulted in an MQ queue manager generating an FDC. This meant
  that it was not possible to for applications that used either
  the MQ classes for JMS or the MQ resource adapter with the
  nested XA transaction functionality provided by the Bitronix
  transaction manager.
  

Problem conclusion

• To resolve this issue, some new functionality has been added to
  the MQ classes for JMS and MQ resource adapter so that, when
  running in an environment that has been configured to use the
  Bitronix transaction manager, the
  XAResource.isSameRM(XAResource) method will check that the
  XAResource object passed in is connected to the same queue
  manager as the XAResource object that the method is being called
  on.
  
  If both XAResource objects are connected to the same queue
  manager, then the method will return true. However, if the two
  XAResource objects are connected to different queue managers,
  then the method will return false. This allows the Bitronix
  transaction manager to correctly resume nested XA transactions
  where required.
  
  To enable the new functionality, the application using the
  Bitronix transaction manager must be started with the following
  Java system property set:
  
  -Dcom.ibm.mq.cfg.jmqi.xaTransactionManager=bitronix
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.2 LTS   9.2.0.5
  v9.x CD    9.2.5
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  MQ BASE V9.2

• Fixed component ID

  5724H7281

Applicable component levels