IT35519: When using an IBM MQ 9.1 multi-instance queue manager a memory leak may be seen from the amqzlaa0 process

APAR status

• Closed as program error.

Error description

• When using a multi-instance queue manager an increase
  in memory usage may be seen from the IBM MQ process amqzlaa0.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users of multi-instance queue managers at IBM MQ 9.1 may be
  affected by this problem.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  IBM MQ maintains an internal process-wide file handle cache
  which can grow dynamically.  When multi-instance queue managers
  were being used, a coding error introduced a window where memory
  used to grow this cache could be leaked between instances of IBM
  MQ threads.
  

Problem conclusion

• The MQ queue manager code was modified so that the cache space
  allocated by a thread is freed if no other threads are using the
  process-wide file handle cache.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.1 LTS   9.1.0.9
  v9.x CD    9.1.1
  
  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

  5724H7271

Applicable component levels