IT34796: MQRC_TRUNCATED_MSG_ACCEPTED (2079) received unexpectedly by client

APAR status

• Closed as program error.

Error description

• An IBM MQ application uses the MQGET options
  MQGMO_CONVERT and MQGMO_ACCEPT_TRUNCATED_MSG.
  It receives MQRC_TRUNCATED_MSG_ACCEPTED (RC=2079) and a
  partially converted message despite providing a large enough
  message buffer to hold the fully converted message.
  

Local fix

• There are two workarounds:
  
  1) Use SHARECNV(0) on the application channel
  2) Change the application logic so that it does not use
  MQGMO_ACCEPT_TRUNCATED_MSG and instead attempts to get the
  message again with a larger buffer after receiving
  MQRC_TRUNCATED_MSG_FAILED.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users who use MQGMO_CONVERT + MQGMO_ACCEPT_TRUNCATED_MSG in
  their application MQGMO may be affected by this problem.
  
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  The IBM MQ code converts message data in a way that tries to
  optimise memory allocation.  The code first attempts the
  conversion with a smaller buffer.  If this fails then it will
  increase the buffer used until either the buffer limit is
  reached or the message is converted successfully.
  
  If the MQGMO_ACCEPT_TRUNCATED_MSG option was set then the IBM MQ
  conversion code returned immediately with
  MQRC_TRUNCATED_MSG_ACCEPTED, even if using a larger buffer would
  have allowed the whole converted message to be consumed.
  

Problem conclusion

• The IBM MQ code has been modified so that is uses up to the full
  buffer supplied by the application when converting message data.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.17
  v9.0 LTS   9.0.0.13
  v9.1 LTS   9.1.0.11
  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

  IBM MQ BASE MP

• Fixed component ID

  5724H7251

Applicable component levels