Fix (APAR): PM81521 Status: Fix Release: 7.0.0.29,7.0.0.27,7.0.0.25 Operating System: AIX,HP-UX,IBM i,Linux,Mac OS,Solaris,Windows Supersedes Fixes: CMVC Defect: PM81521 Byte size of APAR: 385705 Date: 2013-07-04 Abstract: Message pile up is observed on the Source Messaging Engine awaiting for the messages to be acknowledged from the Target Messaging Engine. Description/symptom of problem: PM81521 resolves the following problem: ERROR DESCRIPTION: In WebSphere Application Server v7.0.x Service Integration Bus, multiple messaging engines are configured to use a Publish Subscribe topology. When more than one messaging engine is shut down and started up in parallel and messages are published at the same time, the messages remain in pending acknowledgement state. LOCAL FIX: Restart the messaging engines sequentially. PROBLEM SUMMARY USERS AFFECTED: Users of the default messaging provider for IBM WebSphere Application Server v7.0, v8.0, and v8.5.5 PROBLEM DESCRIPTION: Message pile up is observed on the Source Messaging Engine awaiting for the messages to be acknowledged from the Target Messaging Engine. RECOMMENDATION: None When using Publish Subscribe in Service Integration Bus in a multi Messaging Engine scenario, message pile up is observed on the Source Messaging Engine awaiting for the messages to be acknowledged from the Target Messaging Engine. There are various reasons why the target messaging engine is not acknowledging the messages.Some of the scenarios are gaps created due to a very minute timing window between message production and target messaging engine start-up (or) messages being received out of order and having a lot of silences in between (or) lack of consolidation between the streams leading to virtual gaps. PROBLEM CONCLUSION: Code has been modified to effectively synchronize the timing window between message production and target messaging engine start-up registration and also to consolidate effectively to overcome the problems due to out of order delivery and silence messages and to fill the virtual gaps. The fix for this APAR is currently targeted for inclusion in fix packs 7.0.0.31,8.0.0.8 and 8.5.5.1 . 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 7.0 _X_ Application Server (Express or BASE) _X_ Network Deployment (ND) __ Edge Components _X_ Developer Install Fix to all WebSphere installations unless special instructions are included below. Special Instructions: None NOTE: The user must: * Logged in with the same authority level when unpacking a fix, fix pack or refresh pack. * Be at V7.0.0.0 or newer of the Update Installer. Certain iFixes may require a newer version of the Update Installer and the Update Installer will inform you during the installation process if a newer version is required. This can be checked by reviewing the level of the Update Installer in file /updateinstaller/version.txt. The Update Installer can be downloaded from the following link: http://www.ibm.com/support/docview.wss?rs=180&uid=swg21205991 1) If your iFix is delivered as a single file with a .pak extension, Copy the .pak file directly to the maintenance directory. If your iFix is delivered as a single file with a .zip extension, unzip the file into the maintenance directory. 2) Shutdown WebSphere Application Server. Manually execute setupCmdLine.bat in Windows or . ./setupCmdLine.sh in Unix from the WebSphere instance that maintenance is being applied to. 3) For IBM i users, use the update command to install and uninstall the interim fix. The IBM Information Center can provide additional details, if needed, on the use of this command. http://www14.software.ibm.com/webapp/wsbroker/redirect?version=compass&product=was-nd-iseries&topic=rins_update. For non-IBM i users, launch the Update Installer and click the Next button on the Welcome page. 4) Enter the directory path of the installation location of the WebSphere product you want to update, and click the Next button. 5) Select the "Install maintenance package" operation and click the Next button. 6) Enter the directory path of your maintenance directory where you have the maintenance packages (.pak files) and click the Next button. 7) The Available Maintenance Package to Install page should list all maintenance packages (.pak files) that it finds in the directory path provided in the previous step. The Update Installer will select the correct maintenance packages based on your system configuration and will not allow an invalid combination to be installed. Please keep the Update Installer recommendations and click the Next button and continue with the installation of the maintenance package. To determine why some maintenance packages have been identified as not applicable, see description in log found in /logs/tmp*/updatelogs.txt 8) For all platforms except Windows. In pre-install summary panel, use the "verify permission" feature to verify the user has permissions to apply updates to files associated with the selected maintenance. Correct any file permissions before clicking next to start the install. 9) Restart WebSphere Application Server. 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 Application Server. 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.pak). 6) UnInstall maintenance package. 7) Restart WebSphere Directions to re-apply fix: 1) Shutdown WebSphere Application Server. 2) Follow the Fix instructions to apply the fix. 3) Restart WebSphere Application Server. Additional Information: