Fix (APAR):  PK34206

Status:  Test

Release:  5.1.1.9,5.1.1.8,5.1.1.7,5.1.1.6,5.1.1.5,5.1.1.4,5.1.1.3,5.1.1.2,5.1.1.13,5.1.1.12,5.1.1.11,5.1.1.10,5.1.1.1

Operating System:  AIX,HP-UX,Linux,Linux pSeries,Linux Red Hat - pSeries,Linux zSeries,Solaris,Windows

Supersedes Fixes:  

CMVC Defect:  PK34206

Byte size of APAR:  13812

Date: 2007-03-05

Abstract:  When a huge number of http sessions are created it is found that sometimes the heap contains a large number of SessionSimpleLRUHashMap$CacheEntry Wrapper objects awaiting garbage c

Description/symptom of problem:  
PK34206 resolves the following problem:

ERROR DESCRIPTION:                                              
Help speed up garbage collection, and thus performance, by      
nulling out several fields that are not needed.                 
                                                                

LOCAL FIX:                                                      
none                                                            

PROBLEM SUMMARY

USERS AFFECTED:
WebSphere Application Server users who
create a large number of http sessions as
compared to the in memory cache size.

PROBLEM DESCRIPTION:
When a huge number of http sessions
are created it is found that sometimes
the heap contains a large number of
SessionSimpleLRUHashMap$CacheEntry
Wrapper objects awaiting garbage
collection.

RECOMMENDATION:
None

When a huge number of http sessions are created it is found
that sometimes the heap can contains a large number of
SessionSimpleLRUHashMap$CacheEntryWrapper objects awaiting
garbage collection.  Here a huge number of created sessions
is relative to the specified in memory cache size (default
1000) and the sesison timeout period.  In essence the larger
the LRUed sessions from cache the larger the number of
objects to be garabage collected.  In this fix we are nulling
a couple of entries expecting that gargage collection will
be enhanced if other objects are not referenced.


PROBLEM CONCLUSION:                                             
Code changes were made to null out two fields.  The code        
changes will be available as part of fixpacks 5.1.1.14,         
6.0.2.19, and 6.1.0.7.                                          
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: Choose the:
1) Release the fix applies to
2) The Editions that apply
3) Delete the Editions & Methods that do not apply and this Note

Fix applies to Editions:
Release:
5.0  5.1
___  _X__ Application Server (Express or BASE)
___      Enterprise Edition (DD)
___  ___ Network Deployment (ND)
___  ___ Edge Components
___  ___ Developers Edition
___  ___ Tools
     _X__ WebSphere Business Integration Server Foundation (WBISF)

Install Fix to:
Method:
_X_ Application Server Nodes
__ Deployment Manager Nodes
__ Both

NOTE:
The user must:
* Have Administrative rights in Windows, or be the Actual Root User in a UNIX environments.
* Be logged in with the same authority level when unpacking a fix, fix pack or refresh pack.

The Update Installer can be downloaded from the following link:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg21205991

The Update Installer for V5.0 does not have a maintenance directory.
It uses fixpacks and fixes as the location of the unpacked files.

1) Copy PKxxxxx.jar file directly to the maintenance directory

2) Shutdown WebSphere
Manually execute setupCmdLine.bat in Windows or . ./setupCmdLine.sh in Unix from the WebSphere instance that maintenance is being applied to.

3) Launch Update Installer

4) Enter the installation location of the WebSphere product you want to update.

5) Select the "Install maintenance package" operation.

6) Enter the file name of the maintenance package to install (PKxxxxx.jar file which was copied in the maintenance directory).
The V5.0 and V5.1 fix packs and fixes are unpacked as .jar files and should be unpacked into fixpacks or fixes directory.

7) Install the maintenance package.

8) Restart WebSphere

Directions to remove fix:  NOTE:
* The user must have Administrative rights in Windows, or be the Actual Root User in a UNIX environments.
* FIXES MUST BE REMOVED IN THE ORDER THEY WERE APPLIED
* DO NOT REMOVE A FIX UNLESS ALL FIXES APPLIED AFTER IT HAVE FIRST BEEN REMOVED
* YOU MAY REAPPLY ANY REMOVED FIX

Example: If your system has fix1, fix2, and fix3 applied in that order and fix2 is to be removed, fix3 must be removed first, fix2 removed, and fix3 re-applied.

1) Shutdown WebSphere
Manually execute setupCmdLine.bat in Windows or . ./setupCmdLine.sh in Unix from the WebSphere instance that uninstall is being run against.

2) Start Update Installer

3) Enter the installation location of the WebSphere product you want to remove the fix.

4) Select  "Uninstall maintenance package" operation.

5) Enter the file name of the maintenance package to uninstall (PKxxxxx.jar).

6) UnInstall maintenance package.

7) Restart WebSphere

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

2) Follow the Fix instructions to apply the fix.

3) Restart WebSphere.

Additional Information:  * PK34206_Test.jar is a testfix that applies to versions of 5.1.1 as listed above.
* 6.0.2.17-WS-WAS-IFPK34206.pak is a fix that can be applied on top of fixpacks 6.0.2.1, 6.0.2.3, 6.0.2.5, 6.0.2.7, 6.0.2.9, 6.0.2.11, 6.0.2.13, 6.0.2.15, and 6.0.2.17.  It also includes PK29746.