PI14746: Memory leak in J2C PoolManager due to reaper alarms not being cancelled.

PI14746: Memory leak in J2C PoolManager due to reaper alarms not being cancelled.
8.5.5.3: WebSphere Application Server V8.5.5 Fix Pack 3
8.5.5.4: WebSphere Application Server V8.5.5 Fix Pack 4
8.5.5.5: WebSphere Application Server V8.5.5 Fix Pack 5
8.5.5.6: WebSphere Application Server V8.5.5 Fix Pack 6
8.5.5.7: WebSphere Application Server V8.5.5 Fix Pack 7
8.5.5.8: WebSphere Application Server V8.5.5 Fix Pack 8
8.5.5.9: WebSphere Application Server V8.5.5 Fix Pack 9
8.5.5.10: WebSphere Application Server V8.5.5 Fix Pack 10
8.5.5.11: WebSphere Application Server V8.5.5 Fix Pack 11
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
7.0.0.45: WebSphere Application Server V7.0 Fix Pack 45
8.0.0.15: WebSphere Application Server V8.0 Fix Pack 15
7.0.0.45: Java SDK 1.6 SR16 FP60 Cumulative Fix for WebSphere Application Server
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21

APAR status

• Closed as program error.

Error description

• When the PoolManager is stopped, the Reaper Alarms are not
  canceled and this can result in a possible OutOfMemory
  condition.
  

Local fix

• NA
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server V8.5                                 *
  ****************************************************************
  * PROBLEM DESCRIPTION: Memory Leak in J2C PoolManager when     *
  *                      using MQ JMS Connection Factory         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  This memory leak specifically manifests itself when
  applications use the JMS Queue Connection Factory  that
  involves a JMS Connection pool and JMS Session pool. When the
  Managed connection is destroyed due to unused or aged
  timeouts, then the associated JMS Session pool will be
  stopped and destroyed and the reaper alarms associated with
  the PoolManager should also be cancelled.
  The Session pool is being stopped, however, the
  PoolManager instances registered in the reaper alarms is not
  getting destroyed and the alarms are repeatedly created and
  cancelled for every reap cycle. This causes the PoolManager
  objects and its associated reaper alarm objects to stay on the
  heap forever, potentially leading to OutOfMemory conditions.
  Heap analyzer tools might show a leak suspect with a stack
  trace similar to this:
  A Linked List Data Structure Detected.
  1,981,662,352 bytes (47.28 %) of Java heap is used by 44
  instances of
  java/util/concurrent/ConcurrentSkipListMap$Index
  Contains the following object:- 44 instances of
  java/util/concurrent/ConcurrentSkipListMap$Node holding
  5,366,608 bytes
  TotalSize [ObjectSize] NumberOfChildObject(249,874) ObjectName
  Address
  |- 1,981,966,928 [24] 1
  java/util/concurrent/ConcurrentSkipListMap$HeadIndex
  0xf7766298
  |- 1,981,966,904 [24] 2
  java/util/concurrent/ConcurrentSkipListMap$HeadIndex
  0xf180b1b8
  |- 1,981,966,544 [24] 3
  java/util/concurrent/ConcurrentSkipListMap$Index 0xffa75200
  |- 1,453,166,232 [24] 3
  java/util/concurrent/ConcurrentSkipListMap$Index 0xffa751e8
  |- 528,679,664 [24] 3
  java/util/concurrent/ConcurrentSkipListMap$Index 0x1055a3258
  |- 120,624 [24] 3
  java/util/concurrent/ConcurrentSkipListMap
  

Problem conclusion

• The WebSphere J2C has been updated to prevent the memory
  leak in J2C PoolManager code.
  The fix for this APAR is currently targeted for inclusion in
  fix pack 8.5.5.3.  Please refer to the Recommended Updates
  page for delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

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

  WEBS APP SERV N

• Fixed component ID

  5724H8800

Applicable component levels

• R850 PSY

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