PH56148: CSQX548E MESSAGES SENT TO LOCAL DEAD-LETTER QUEUE, CHANNEL XXX REASON=271 (????) SENDING MESSAGES THROUGH A SHARED CHANNEL

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• QMGRs were configured with different QMCCSIDs. In this case,
  QMGR1 has been explicitly configured with QMCCSID=37 in the
  ZPARM, however QMGR2 shows QMCCSID=0 (which will default to
  500).
  
  The error is occurring during the MQGET from the transmission
  queue - as the message contains properties, CSQMHDRS is called
  to convert this into an RFH2 header, and should insert this
  between the XQH and the message body. However although the
  MQGET is occurring on QMGR1, the MQPUT of the message occurred
  on the other queue manager QMGR2. Normally this wouldn't cause
  a problem, but in this particular case the queue manager
  CCSID's differ. This causes the code for detecting a valid XQH
  to fail, due to XQH being in a different CCSID, leading to the
  RFH2 being added ahead of the XQH.
  

Local fix

• Configure both QMGRs with the same QMCCSID.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Release 3 Modification 0 and Release 4       *
  *                 Modification 0.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: When MQGET attempts to get a message    *
  *                      with user properties from a shared      *
  *                      transmission queue for sending it       *
  *                      across a channel, it may fail if the    *
  *                      message was put to the queue by a queue *
  *                      manager configured with a different     *
  *                      CCSID than the one processing the       *
  *                      message. The message will then be sent  *
  *                      to a dead letter queue with reason 271, *
  *                      which is MQFB_XMIT_Q_MSG_ERROR,         *
  *                      indicating a lack of a valid            *
  *                      transmission queue header.              *
  ****************************************************************
  As part of the MQGET process, CSQMHDRS is called to convert the
  user properties into an RFH2 header inserted between the header
  chain and the message body. To do so, checks are performed to
  establish the headers present in the header chain. Because the
  CCSID of the transmission header and the queue manager
  performing the MQGET do not match, the header is not detected,
  and the RFH2 header is erroneously inserted ahead of the XQH
  which causes the message to be sent to a dead letter queue.
  

Problem conclusion

• The code checking for transmission queue headers in CSQMHDRS has
  been changed to account for header with a CCSID value different
  to the native CCSID value of the processing queue manager if the
  queue where the message was put is a shared queue. As a result
  such a header will be correctly identified and the RFH2 will be
  inserted into the correct position.
  

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:

  UI97269 UI98330

Modules/Macros

• CSQMHDRS
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R300 PSY UI97269

     UP24/06/27 P F406

• R400 PSY UI98330

     UP24/09/25 P F409

Fix is available

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