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PM81521;8.0.0.6: messages stuck in pending acknowledgement state in websphere appl

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Abstract

Message pile up is observed on the Source Messaging Engine while waiting for the messages to be acknowledged from the Target Messaging Engine.

Download Description

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?uid=swg27004980

NOTES:

Please note that This APAR supersedes PM62615, PM71430. So, in case on applying an ifix of PM81521. The sequence of installing ifixes should be PM56596 followed by PM81521. Customer need not install ifixes for PM62615, PM71430.

Prerequisites

None

Installation Instructions

Please review the readme.txt file packaged with the fix for detailed installation instructions.

On
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Technical Support

Contact IBM Support using SR (http://www.ibm.com/software/support/probsub.html), visit the WebSphere Application Server support web site (http://www.ibm.com/software/webservers/appserv/was/support/), or contact 1-800-IBM-SERV (U.S. only).

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Document Information

Modified date:
15 June 2018

UID

swg24036383