IT28994: Potential for message loss or duplication when resolving indoubtmessage batch sent from shared channel

APAR status

• Closed as program error.

Error description

• APAR IT27810 prevents multiple channel instances originating
  from the same partner from starting by checking a combination of
  channel name, queue manager name and queue manager identifier
  for uniqueness.
  
  Shared channels initiated from a z/OS queue sharing group (QSG)
  may be started from any queue manager in the queue sharing
  group. The channel sends the queue sharing group name instead of
  the queue manager name, however the queue manager identifier
  that is sent does correspond to the originating queue manager.
  
  The logic added in IT28710 to prevent multiple channel instances
  does not cater for shared channels where instances are started
  from multiple queue managers in the queue sharing group. This
  can then lead to the potential for message loss or duplication
  as described in IT27810.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users that send messages using shared channels from a z/OS queue
  manager to a distributed queue manager are potentially affected.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  The logic to detect an attempt to start more than one channel
  instance from a unique source does not consider that a z/OS
  shared channel could be started from different queue managers
  from within a queue sharing group, but that the queue sharing
  group should be considered as a single unique source.
  

Problem conclusion

• The logic to prevent multiple channel instances from running on
  a distributed queue manager is modified to disregard the queue
  manager identifier (QMID) for the purposes of checking
  uniqueness when the peer is a shared z/OS channel.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.13
  v9.0 LTS   9.0.0.8
  v9.1 CD    9.1.3
  v9.1 LTS   9.1.0.3
  
  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