IC71824: UNRECOGNISED ACK EXCEPTION WHEN JMS MESSAGE CONSUMER CONFIRMS MESSAGE RECEIPT WHILE ANOTHER THREAD CLOSES THE MESSAGE PRODUCER

WebSphere MQ V7.0 Fix Pack 7.0.1.5
WebSphere MQ V7.0.1 for i5/OS Fix Pack 7.0.1.5

APAR status

• Closed as program error.

Error description

• The JMS Client reports an exception - Unrecognised ACK - when
  the message consumer is confirming a receipt of a message and
  in parallel there is another thread where the message producer
  is closed.
  
  This issue was reported in micro broker which returns
  error java.lang.Exception: Unrecognised ACK. MsgId:8 AckType:8
  SessionID:1
  
  The close message producer should be blocked until the
  onMessage call completes.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of the WebSphere MQ classes for Java
  Message Service (JMS) or the micro broker JMS client
  component who utilize the asynchronous message delivery
  
  Platforms affected:
  All Distributed (iSeries, all Unix and Windows) +Java
  ****************************************************************
  PROBLEM SUMMARY:
  The problem occurs due to the message producer attempting to
  close in parallel to confirming the receipt of the message by
  the message listener in another thread.
  
  The issue occurs only if the message producer and the consumer
  are on the same session and the message producer is closed
  before closing the message consumer.
  
  Also this issue will not occur if the connection is
  stopped before closing the message producer or if the message
  consumer is used in a synchronous mode.
  

Problem conclusion

• The fix ensures that the message producer blocks on the close
  call until the message listener completes confirming the receipt
  of the message.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
                     v7.0
  Platform           Fix Pack 7.0.1.5
  --------           --------------------
  Windows            U200324
  AIX                U839183
  HP-UX (PA-RISC)    U839621
  HP-UX (Itanium)    U839626
  Solaris (SPARC)    U839622
  Solaris (x86-64)   U839628
  iSeries            tbc_p700_0_1_5
  Linux (x86)        U839623
  Linux (x86-64)     U839627
  Linux (zSeries)    U839624
  Linux (Power)      U839625
  
  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

  WMQ WINDOWS V7

• Fixed component ID

  5724H7220

Applicable component levels

• R700 PSY

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