Fix (APAR):  PI14746

Status:  Fix

Release:  8.5.5.2,8.5.5.1,8.5.5

Operating System:  AIX,HP-UX,Linux,Mac OS,Solaris,Windows,z/OS

Supersedes Fixes:  

CMVC Defect:  xxxxxx

Byte size of APAR:  1032802

Date: 2014-05-16

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

Description/symptom of problem:  
PI14746 resolves the following problem:

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:
None

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   


Directions to apply fix:  
NOTE: Mark with an X the:
1) Release the fix applies to
2) The Editions that apply
3) And then DELETE THIS NOTE

Fix applies to Editions:
Release 8.0
X__ Application Server (Express or BASE)
X__ Network Deployment (ND)
__ Edge Components
__ Developer

Install Fix to all WebSphere installations unless special instructions are included below.

Special Instructions: None

NOTE:
The user must:
* Logged in with the same authority level when unpacking a fix, fix pack or refresh pack.
* Be at V1.4.3 or newer of the Installation Manager. Certain iFixes may require a newer version of the Installation Manager and the Installation Manager will inform you during the installation process if a newer version is required.

The IBM Information Center can provide details, if needed, on the use of the Installation Manager to apply the iFixes.
http://publib.boulder.ibm.com/infocenter/install/v1r4/index.jsp.  Shutdown WebSphere Application Server before applying the iFixes.  Restart WebSphere Application Server after applying the iFixes.

Directions to remove fix:  

The IBM Information Center can provide details, if needed, on the use of the Installation Manager to remove the iFixes.
http://publib.boulder.ibm.com/infocenter/install/v1r4/index.jsp.  Shutdown WebSphere Application Server before removing the iFixes.  Restart WebSphere Application Server after removing the iFixes.

Directions to re-apply fix:  
1) Shutdown WebSphere Application Server.

2) Follow the Fix instructions to apply the fix.

3) Restart WebSphere Application Server.



Additional Information: