IT23992: Duplicate message IDs can occur when putting messages asynchronously to an MQ v9 queue manager

APAR status

• Closed as program error.

Error description

• When submitting MQPUT calls using MQPMO_ASYNC_RESPONSE, or using
  a JMS client configuration which allows aysnc responses, under
  very high load duplicate message IDs are occasionally observed.
  

Local fix

• Modify the application or JMS configuration to use synchronous
  MQPUT response.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Any users putting messages asynchronously to MQ servers at
  version 9, which includes JMS applications configured to permit
  an async put response.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When applications are making use of asynchronous put responses,
  the MQ client must request a pre-allocation of message IDs from
  the queue manager.
  
  A logic error within these routines at the queue manager
  introduced a timing window whereby the queue manager would not
  correctly allocate a  unique range. Under high load, this could
  result in non-unique message IDs being assigned to messages.
  

Problem conclusion

• The MQ queue manager logic has been corrected to ensure that
  appropriate pre-allocated message ID ranges are returned to
  clients using asynchronous put.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.0 LTS   9.0.0.5
  
  
  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 M/P

• Fixed component ID

  5724H7261

Applicable component levels