Fix (APAR):  JR26291

Status:  Fix

Release:  6.0.2.1

Operating System:  AIX,HP-UX,Linux,Solaris,Windows

Supersedes Fixes:  

CMVC Defect:  xxxxxx

Byte size of APAR:  56997

Date: 2007-06-04

Abstract:  If there are many of the same prefix names for xml namespace in xml, it causes WPS bad performance.

Description/symptom of problem:  
JR26291 resolves the following problem:

ERROR DESCRIPTION:                                              
Parsing or deserialization of certain large business            
objects in WebSphere Process Server take a long time to         
complete.                                                       
                                                                
For example, an extremely large 60MB SOAP                       
message sent to Process Server takes approximately 1.5hrs before
the dataobject. This behavior may also be seen in other         
services such as when input is being deserialized by the        
BOXMLSerializer service.                                        
                                                                
During this time the CPU is fully utilized by                   
Process Server, and high memory use may also be observed.       
However, the task eventually completes successfully and with no 
error except for performance.                                   
                                                                
The root cause of the performance problem is when there are     
many redundant default namespace definitions in the input.      
                                                                
An example of such a default namespace definition is            
 xmlns="http://foo.com"                                         
                                                                
In the sample input file, it is observed that there are         
on the order of tens of thousands of these redundant definitions
which leads to the performance problem.                         
                                                                
The underlying algorithm that causes the performance problem is 
from the EMF Open Source package. As a result, changes to this  
code can only be made in accordance with the Open Source        
license. These changes have been submitted, however             
Process Server will not be able to include the updated          
EMF version until a distant future version.                     
                                                                
However, an alternate solution has been developed, where        
Process Server can avoid the problematic code, and resolve the  
performance problem.  This will be released as an interim fix   
for Process Server.                                             
                                                                
In the example discussed in this APAR, it has been observed that
this change reduces the processing time of the scenario from 70 
minutes to under 1 minute.                                      

LOCAL FIX:                                                      
A local fix is to:                                              
Remove redundant default namespace declarations from the input  
message or use explicit or distinct prefix names.               

PROBLEM SUMMARY

USERS AFFECTED:
WebSphere Process Server 6.0.2.0/1 users

PROBLEM DESCRIPTION:
If there are many of the same prefix
names for xml namespace in xml, it
causes WPS bad performance.

RECOMMENDATION:
None

WPS will de-serialize xml resource to DataObject. If there are
same prefix names for xml namespace in xml resource, WPS
seaches the exising prefix with linear search algorithm during
de-serializing. So it has bad performance. With the fix, WPS
uses a binary search algorithm.

PROBLEM CONCLUSION:                                             
The fix improves WPS performance for many same prefix names in x
ml. The fix doesnot cover other scenarios.                      


Directions to apply fix:  
Before applying the iFix ensure that WebSphere Process Server 6.0.1 is installed on the system.
Also download and follow Update Installer installation instructions.  The Update Installer can be downloaded from the following link:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg21205991

1) Copy the pak file to the directory maintenance in the UpdateInstaller directory

2) Shutdown WebSphere Process Server. It is important that you perform a controlled and complete shutdown of the server to ensure that all transactions have completed, before installing the fix.

3) Run the UpdateInstaller and follow the prompts.

4) Restart WebSphere

Directions to remove fix:  
NOTE:  FIXES MUST BE REMOVED IN THE REVERSE ORDER IN WHICH 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, then fix2 may be removed

1) Shutdown WebSphere. It is important that you perform a controlled and complete shutdown of the server to ensure that all transactions have completed, before installing the fix.

2) Follow the Fix instructions that are packaged with the Fix Installer on how to uninstall and reinstall the Fix.

3) Restart WebSphere

Directions to re-apply fix:  
1) Shutdown WebSphere. It is important that you perform a controlled and complete shutdown of the server to ensure that all transactions have completed, before installing the fix.

2) Run the UpdateInstaller and follow the instructions. The Update Installer can be downloaded from the following link:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg21205991

3) Restart WebSphere Process Server

Additional Information: