IV72981: WEBSPHERE MQ 7.0.1 AMQZLAA0 PROCESS SHOWS A CONSTANT INCREASE OF MEMORY USAGE, WHEN MQ QUEUE MANAGER ACCOUNTING IS ENABLED.

APAR status

• Closed as program error.

Error description

• Working with WebSphere MQ Version 7.0.1.12, the amqzlaa0 process
  shows a constant increase of memory usage, when WebSphere MQ
  queue manager accounting is enabled.
  .
  While monitoring the operating system, for example with a
  command like the below:
  ps -eo pid,pcpu,pmem,time,vsz,user,args | grep 'amqzlaa0 PID'
  .
  It shows that the memory usage (the Virtual Memory Size) for a
  single amqzlaa0 process is growing constantly. See the following
  example output:
  .
  ### All the entries below are from the same USER: mqm ###
  ### and with the same COMMAND: amqzlaa0 -m 'QMgr' -fip1 ###
  ### Column VSZ grows ... ###
  ### ps -eo pid,pcpu,pmem,time,vsz,user,args ###
  .
  Date PID %CPU %MEM TIME VSZ
  .
  2015-04-11 16:01:00: 10747958 0.0 2.0 00:04:21 675204
  2015-04-11 17:01:00: 10747958 0.0 2.0 00:04:29 694820
  2015-04-11 18:01:00: 10747958 0.0 2.0 00:04:37 714348
  2015-04-11 19:01:00: 10747958 0.0 2.0 00:04:44 734132
  2015-04-11 20:01:00: 10747958 0.0 2.0 00:04:53 754648
  2015-04-11 21:01:00: 10747958 0.0 2.0 00:04:59 774180
  2015-04-11 22:01:00: 10747958 0.0 2.0 00:05:06 793612
  2015-04-11 23:01:00: 10747958 0.0 2.0 00:05:14 813128
  2015-04-12 00:01:00: 10747958 0.0 2.0 00:05:22 832672
  .
  When accounting is disabled, like in the example below, the
  memory leak in the amqzlaa0 process disappears:
  .
  ALTER QMGR ACCTQ(OFF)
  ALTER QMGR ACCTMQI(OFF)
  

Local fix

• If it is possible then temporarily disabling collection of
  accounting data should halt the leak.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users with accounting enabled and where a QALIAS to a topic is
  defined for the accounting queue
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When trying to publish an accounting message to the topic that
  is used as an alias for the accounting queue, MQ incorrectly
  allocates some memory to store message properties. This memory
  is not freed.
  

Problem conclusion

• Some code was added to ensure that allocated memory is correctly
  freed after the accounting report message had been published.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v7.0       7.0.1.14
  v7.1       7.1.0.7
  
  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

  WMQ AIX V7

• Fixed component ID

  5724H7221

Applicable component levels

• R701 PSY

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