PK12776: MDB LISTENER PORT MAY HANG WHEN A STOP IS ISSUED FOR IT WHILE PROCESSING MDB WORKLOAD IN WEBSPHERE FOR Z/OS V5.0. | ||||||||||||||||||||||||||||||||||||||||||||||||
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![]() APAR status Closed as program error. Error description When the stop command is issued to the MDB Listener Port while MDB workload is processing the listener port hangs and cannot be restarted. This happens when the MDB throttle is blocking message browsing because of a backlog of messages on the MDB queue.This apar will address this problem. . MDB processing stops after after ListenerPort stop() command followed by a ListenerPort start() command performed via the Administrative Console or wsadmin scriptingin a server with multiple ListenerPorts defined. . The problem will occur on another ListenerPort besides the one on which the start() command was most recently issued. . When MDB processing stops, one can expect a backlog of messages to build up on the MDB queue, (or for the topic in the case of an MDB mapped to a topic via a durable subscription). . This is an additional symptom of this apar.Local fix Problem summary **************************************************************** * USERS AFFECTED: All users of WebSphere Application Server * * V5.0 for z/OS * **************************************************************** * PROBLEM DESCRIPTION: ListenerPort stop() command hangs when * * issued from Administrative Console or * * the wsadmin scripting environment. * * * * Also, MDB processing stops after a * * ListenerPort stop() command followed * * by a ListenerPort start() command is * * performed via the Administrative * * Console or wsadmin scripting, on a * * server with multiple ListenerPorts * * defined. * **************************************************************** * RECOMMENDATION: * **************************************************************** When the MDB throttle is blocking the QueueAgentThread from browsing for messages in the controller at the moment that the ListenerPort stop() command is issued, the stop() hangs. This is because the stop() first incorrectly tears down the ListenerPort infrastructure which will allow the MDB throttle to release this QueueAgentThread upon completion of message dispatch. However, due to locking mechanisms the stop() can not complete until the QueueAgentThread is released, so it will simply hang. For the 2nd problem: Users with multiple ListenerPorts defined for a given server (under ApplicationServers -> <server> -> Message Listener Service -> Listener Ports ) experience a stop of MDB processing on MDBs associated with one or more ListenerPorts. This happens after some series of ListenerPort commands including a stop() and a start(), not necessarily on the same ListenerPort. The problem will occur on another ListenerPort besides the one on which the start() command was most recently issued. When MDB processing stops, one can expect a backlog of messages to build up on the MDB queue, (or for the topic in the case of an MDB mapped to a topic via a durable subscription).Problem conclusion ListenerPort stop() processing was changed to release the throttle and the QueueAgentThread immediately so that ListenerPort processing can complete. In addition, the throttle function is disabled so it can not block the QueueAgentThread again. In its place, new messages for this ListenerPort browsed before the ListenerPort is completely shutdown will simply be ignored (left on the queue). Also, ListenerPort stop() was fixed to avoid the problem with a later ListenerPort start() command. APAR PK12776 requires changes to documentation. The following publication was revised as a result of APAR PK12776: ________________________________________________________________ WebSphere Application Server V5.0 for z/OS Messages and Codes GA22-7915-00 ________________________________________________________________ NOTE: Periodically, we refresh the documentation on our Web site, so the changes might have been made before you read this text. To access the latest on-line documentation, go to the product library page at: www.ibm.com/software/webservers/appserv/zos_os390/library.html ________________________________________________________________ Chapter 01, pg. 005 (new message) BBOJ0097=BBOJ0097E MDB FAILURE: {0}, IN CLASS: {1}, IN METHOD: {2} Explanation: This message is intended as a generic serious error message for MDB error conditions that don't require their own distinct error messages. User Response: If the problem persists, contact the IBM support center. ________________________________________________________________ APAR PK12776 is associated with SERVICE LEVEL W502035 of WebSphere Application Server V5.0 for z/OS.Temporary fix Comments
APAR is sysrouted FROM one or more of the following: PK12773 APAR is sysrouted TO one or more of the following: Modules/Macros
Publications Referenced
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Document Information |
Current web document: swg1PK12776.html
Product categories: Software > Application Servers >
Distributed Application & Web Servers > WebSphere Application
Server for z/OS
Operating system(s):
Software version: 500
Software edition:
Reference #: PK12776
IBM Group: Software Group
Modified date: Nov 3, 2005
(C) Copyright IBM Corporation 2000, 2009. All Rights Reserved.