IT25954: Not all reconnectable connections from the same client reconnectafter abnormal queue manager termination

APAR status

• Closed as program error.

Error description

• MQ reconnectable clients should reconnect to the queue manager
  after a restart. But in case of queue manager failure or a
  crash, only a subset of client threads reconnect from a specific
  client.
  
  The number of clients that reconnect successfully depends on
  SHARECNV value.
  
  For example: If there are 15 client connections connected from a
  specific client to a queue manager with SHARECNV set 10 on the
  channel, when the queue manager is restarted after a failure
  only 10 of these client connections are reconnected to the queue
  manager.
  

Local fix

• Disable conversation sharing by setting SHARECNV(1) on the
  SVRCONN channel definition(s).
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  All MQ users using MQ client reconnection on channels with
  SHARECNV higher than 1 are affected. The issue is seen when the
  client has established more connections to the queue manager
  than the configured SHARECNV value.
  
  The number of independant clients using the channel is not
  relevant.
  
  This issue affects all MQ 9.1 clients except Java and JMS.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  A logic error in the MQ multiplexed client reconnection logic
  meant that the client code failed to continue the reconnect
  processing once it had reached the configured SHARECNV value.
  

Problem conclusion

• The MQ client reconnection logic for multiplexed connections
  (SHARECNV>1) has been updated to address this issue.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.0 LTS   9.0.0.13
  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 M/P

• Fixed component ID

  5724H7261

Applicable component levels