IC64493: OUT OF MEMORY ERROR WHEN USING THE WMQ V7 RESOURCE ADAPTER

WebSphere MQ V7.0 Fix Pack 7.0.1.2
WebSphere MQ V7.0.1 for i5/OS Fix Pack 7.0.1.2

APAR status

• Closed as program error.

Error description

• An application running within an application server using the
  WebSphere MQ v7 Resource Adapter (RA) can encounter an Out
  ofMemoryError (OOM).
  
  The memory leak seen in HeapAnalyzer shows the leak as
  
  com/ibm/mq/connector/inbound/ServerSessionPoolImpl
    java/util/HashMap
      array of java/util/HashMap$Entry
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of the WebSphere MQ v7 RA,
  and users of the WebSphere MQ messaging provider in WebSphere
  Application Server v7.  It is most likely to be trigged by an
  uneven workload, for example when there are a number of
  message-driven beans (MDBs) processing messages concurrently
  followed by a reduction in MDB activity.
  
  Platforms affected:
   All Distributed (iSeries, all Unix and Windows) +Java
  ****************************************************************
  PROBLEM SUMMARY:
  MDB's use ServerSessions when processing messages.
  
  ServerSessions are linked to JMS Sessions by a map called the
  "server session pool". When a ServerSessions is no longer needed
  and is released, the corresponding pooled ServerSession is
  tagged as not in use.  This means that it can be removed by a
  scavenger thread that runs periodically and closes off any
  unused ServerSessions.
  
  When the scavenger thread ran it was not removing the
  ServerSessions entry in the server session pool.
  
  Each time a new ServerSession is required it gets added to the
  server session pool.  As these ServerSessions were not being
  removed by the scavenger thread a gradual memory leak is seen.
  

Problem conclusion

• The RA has been updated so that the scavenger thread correctly
  clears out the unused ServerSessions from the server session
  pool when it runs.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
                     v7.0
  Platform           Fix Pack 7.0.1.2
  --------           --------------------
  Windows            U200316
  AIX                U829807
  HP-UX (PA-RISC)    U829678
  HP-UX (Itanium)    U829681
  Solaris (SPARC)    U829806
  Solaris (x86-64)   U829680
  iSeries            tbc_p700_0_1_2
  Linux (x86)        U829677
  Linux (x86-64)     U829676
  Linux (zSeries)    U829682
  Linux (Power)      U829679
  
  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 WINDOWS V7

• Fixed component ID

  5724H7220

Applicable component levels

• R700 PSY

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