Fix (APAR):  PK72493

Status:  Fix

Release:  5.1.1.19,5.1.1.18,5.1.1.17,5.1.1.16,5.1.1.15,5.1.1.14,5.1.1.13

Operating System:  AIX,HP-UX,Linux,Linux pSeries,Linux Red Hat - pSeries,Linux zSeries,OS/390,Solaris,Windows,z/OS

Supersedes Fixes:  PRE-REQUISITE FIXES:

CMVC Defect:  PK72493

Byte size of APAR:  1888319

Date: 2008-10-06

Abstract:  Customer is using WebSphere Application Server 5.1 with the Data Replication Service and experienced high CPU usage on a server.  The Websphere Application server systemerr.log sho

Description/symptom of problem:  
PK72493 resolves the following problem:

ERROR DESCRIPTION:?                                             
"High CPU caused by Disthub disconnection client classes"       

LOCAL FIX:?                                                     

PROBLEM SUMMARY:?

USERS AFFECTED:
All users of WebSphere Application Server
using the Data Replication Service
component.

PROBLEM DESCRIPTION:
Customer is using WebSphere
Application Server 5.1 with the Data
Replication Service and experienced
high CPU usage on a server.

The Websphere Application server
systemerr.log showed exceptions
indicating a problem with the
disthub.jar file.

RECOMMENDATION:
None



DRS is a data replication service and uses the disthub.jar
as a transport for sending messages between Application servers.
Under error conditions, there is the potential for
high cpu usage when closing the connection and creating
a new connection between the servers. The timeout between
waiting for the bad connection to close down before starting
the new connection was very short. This has the potential to
cause a race condition in the code.
In addition to high CPU usage, the Systemerr.log shows
an exception as follows:
com.ibm.disthub.impl.util.SocketThreadPoolException: doWrite()
did not die.

PROBLEM CONCLUSION:?                                            
The time waiting for the connection to close was increased      
which will stop the high cpu usage.                             
                                                                
A fix for this WebSphere Application Server V5.1 specific       
problem is available from your L2 representative.               


Directions to apply fix:  
1) Download and rename the fix from PK72493_Fix.jar to disthub.jar. 

2) 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.

3) Take a backup copy of the files being replaced 
   On Unix:
   cp disthub.jar disthub_jar.ori
   In Windows:
   copy disthub.jar disthub_jar.ori
   DO NOT use a backup name that ends in jar
   e.g. Use a backup name of disthub_jar.ori
 
   - in case of an error, these files should be re-instated.

4) Copy the modified file into the relevant directory. 

5) Restart WebShere. 







Directions to remove 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) Restore the backup version of 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) Follow the directions to apply the fix.

3) Restart WebSphere







Additional Information: