Fix (APAR):  PQ94346

Status:  Fix

Release:  5.1.1

Operating System:  All

Supersedes Fixes:  

CMVC Defect:  PQ94346

Byte size of APAR:  30924

Date: 2004-11-29

Abstract:  High system load causes deadlocks in cancel-claim API

Description/symptom of problem:  1) Symptom:
   --------
   
   This problem occurs only under high system load when a very high number of 
   cancel claim requests and query work item requests are started simultaneously. 
   Some requests cannot be completed successfully but end with a deadlock exception.
   
2) Problem:
   --------
   
   Both the cancel claim request and the query work item request operate on the same process choreographer 
   database tables. This can lead to deadlocks in some situations.
      
3) Solution:
   ---------
   
   The locking strategy has been changed for these requests (cancel claim and query
   work item) which solves the problem for this type of operation.


Directions to apply fix:  

NOTE:  YOU MUST FIRST DOWNLOAD THE FIX INSTALLER TOOL IN ORDER TO INSTALL AN FIX.
       The Fix Installer can be downloaded from the following link:
       http://www-3.ibm.com/software/webservers/appserv/support/index.html

1) Create temporary "fix" directory to store the jar file:
             UNIX: /tmp/WebSphere/fix
          Windows: c:\temp\WebSphere\fix

2) Copy jar file to the directory

3) Shutdown WebSphere

4) Follow the Fix installation instructions that are packaged with the Fix Installer on how to install the Fix.

5) Restart WebSphere

6) The temp directory may be removed.

Directions to remove fix:  
NOTE:  FIXES MUST BE REMOVED IN THE ORDER THEY WERE APPLIED.  DO NOT REMOVE AN FIX UNLESS
     ALL FIXES APPLIED AFTER IT HAVE FIRST BEEN REMOVED.  YOU MAY REAPPLY ANY REMOVED FIX.

Directions to apply fix:  NOTE:  YOU MUST FIRST DOWNLOAD THE UPDATE INSTALLER TOOL IN ORDER TO INSTALL A FIX.
       The Fix Installer can be downloaded from the following link:
       http://www-3.ibm.com/software/webservers/appserv/support/index.html

1) Create temporary "fix" directory to store the jar file:
             UNIX: /tmp/WebSphere/fix
          Windows: c:\temp\WebSphere\fix

2) Copy jar file to the directory

3) Shutdown WebSphere

4) Follow the Fix installation instructions that are packaged with the Fix Installer on how to install the Fix.

5) Restart WebSphere

6) The temp directory may be removed.

Directions to remove fix:  NOTE:  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

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

3) Restart WebSphere

Directions to re-apply fix:  1) Shutdown WebSphere

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

3) Restart WebSphere

Additional Information: