Fix (APAR):  PK46953

Status:  Fix

Release:  6.1.0.7

Operating System:  HP-UX

Supersedes Fixes:  

CMVC Defect:  442802

Byte size of APAR:  116558

Date: 2007-06-15

Abstract:  The native AIO library for HPUX inside the TCP channel does not gracefully handle POLLERR or POLLHUP events. It causes looping behavior impacting performance and response times.

Description/symptom of problem:  
PK46953 resolves the following problem:

ERROR DESCRIPTION:                                              
Under stress conditions, the system would appear to almost hang 
due to high CPU and spinning on aio_getioev2 calls. Native AIO t
racing shows repeated POLLERR and or POLLHUP events.            

LOCAL FIX:                                                      

PROBLEM SUMMARY

USERS AFFECTED:
IBM WebSphere Application Server version 6.1
users of the TCP channel's AIO library on
the HPUX operating system.

PROBLEM DESCRIPTION:
The native AIO library for HPUX inside
the TCP channel does not gracefully
handle POLLERR or POLLHUP events. It
causes looping behavior impacting
performance and response times.

RECOMMENDATION:
None

When POLLERR or POLLHUP are received inside the native polling
code of the AIO library, it triggers severe looping behavior
inside the aio_getioev2 thread call. This will impact response
time and can even make it appear like the process is hung due
to the poor network response times.

PROBLEM CONCLUSION:                                             
The socket that receives these error events must be removed     
from the /dev/poll system to prevent the looping during the     
polling calls. The next read or write attempted on the socket   
will be notified of the existing error state.                   
                                                                
This is targeted for the 6.1.0.11 fixpack release.              
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:  
Fix applies to Editions:
Release 6.0
_X_ Application Server (Express or BASE)
_X_ Network Deployment (ND)
__ WebSphere Business Integration Server Foundation (WBISF)
__ Edge Components
__ Developer
_X_ Extended Deployment (XD)

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

NOTE:
The user must:
* Have Administrative rights in Windows, or be the Actual Root User in a UNIX environments.
* Logged in with the same authority level when unpacking a fix, fix pack or refresh pack.
* Be at V6.0.2.2 or newer of the Update Installer. This can be checked by reviewing the level of the Update Installer in file <was_root>/updateinstaller/version.txt.

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

For detailed instructions to Extract the Update Installer see the following Technote:
http://www-1.ibm.com/support/docview.wss?rs=180&uid=swg21205400

1) Copy 6.1.0.7-WS-WAS-HpuxPaRISC-IFPK46953.pak or 6.1.0.7-WS-WAS-Hpux-IA64-IFPK46953.pak 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 (the .pak file which was copied in the maintenance 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 (the .pak).

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: