PQ84981: WEBSPHERE FOR Z/OS V5.0 DOES NOT HONOR A THROTTLE ON THE MESSAGE LISTENER PORT FOR MQ. | ||||||||||||||||||||||||||||||||||||||||||||||||
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![]() APAR status Closed as program error. Error description WebSphere for z/OS v5.0 needs to honor a throttle on the Message Listener Port that will prevent the WLM queue from being overrun with message handlers.Local fix Problem summary **************************************************************** * USERS AFFECTED: All users of WebSphere Application Server * * V5.0 for z/OS * **************************************************************** * PROBLEM DESCRIPTION: A high quantity of JMS messages in a * * JMS destination for which an MDB is * * configured to listen to causes a large * * number of work requests to be queued * * in the WLM queue. The ability to * * process the requests in a timely * * fashion is reduced. * **************************************************************** * RECOMMENDATION: * **************************************************************** When a considerably large number of JMS Messages are sent to a JMS destination an MDB is listening to, the amount of work requests generated exceeds the capacity to process those requests in the Servant region. Messages are redelivered in some instances, therefore aggravating the problem.Problem conclusion The amount of work requests generated by messages being sent to a JMS destination is limited by means of a throttling mechanism. This throttle uses the Maximum sessions property of the Listener Port to control the number of work requests queued into the WLM queue. It allows available resources in the Servant Region to appropriately process the limited number of requests more efficiently. Please Note: As a result of APAR PQ84981, for installations that are exploiting Message Driven Beans (MDBs), a review of Message Listener Port (MLP) MaxSession settings maybe required. Previously, WebSphere Application Server V5.0 for z/OS only used the MaxSession value to control the number of open sessions that any given servant region would attempt to obtain for servicing an MDB application configured to this MLP. With the application of this maintainence, the MaxSession setting now represents the maximum concurrency level for MDB traffic configured to that MLP. As an example, previously, in a configuration that had an MLP with MaxSession set at 5 with 3 servants, WebSphere Application Server V5.0 for z/OS would have had a variable maximum concurrency level of 15 simultaneous MDB dispatches. After application, the maximum concurrency level is 5, regardless of the number of servant regions. The following publication was revised as a result of APAR PQ84981: ________________________________________________________________ WebSphere Application Server V5 for z/OS Messages and Codes GA22-7915-00 ________________________________________________________________ This APAR requires changes to documentation. 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 2, pg. 40 (new message) BBOO0284I STATISTICS GATHERING NOT ENABLED FOR <string> Explanation: A display,work command was issued to display statistics for request of type <string>. However, statistics are not currently being gathered for requests of type <string>. User Response: If statistics are desired for requests of type <string>, then enable statistics gathering by using the f <server>,<string>stats command (e.g. "f bbos001,mdbstats, enable"). ________________________________________________________________ Chapter 3, pg. 125 (new message) C9C2131E Explanation: IBM Internal Only User Response: Contact the IBM Support Center. ________________________________________________________________ Chapter 3, pg. 125 (new message) C9C2131F Explanation: IBM Internal Only User Response: Contact the IBM Support Center. ________________________________________________________________ Chapter 3, pg. 125 (new message) C9C21320 Explanation: IBM Internal Only User Response: Contact the IBM Support Center. ________________________________________________________________ Chapter 3, pg. 125 (new message) C9C21321 Explanation: IBM Internal Only User Response: Contact the IBM Support Center. ________________________________________________________________ Chapter 3, pg. 125 (new message) C9C21322 Explanation: IBM Internal Only User Response: Contact the IBM Support Center. ________________________________________________________________ Chapter 3, pg. 125 (new message) C9C21323 Explanation: IBM Internal Only User Response: Contact the IBM Support Center. ________________________________________________________________ Chapter 3, pg. 125 (new message) C9C21324 Explanation: IBM Internal Only User Response: Contact the IBM Support Center. ________________________________________________________________ Chapter 3, pg. 125 (new message) C9C21325 Explanation: IBM Internal Only User Response: Contact the IBM Support Center. ________________________________________________________________ Chapter 3, pg. 125 (new message) C9C21326 Explanation: IBM Internal Only User Response: Contact the IBM Support Center. ________________________________________________________________ Chapter 3, pg. 125 (new message) C9C21327 Explanation: IBM Internal Only User Response: Contact the IBM Support Center. ________________________________________________________________ Chapter 1, pg. 4 (new message) BBOJ0088I MLP NAME name TIME time secs. Explanation: This message is used to display MDB statistics. User Response: None ________________________________________________________________ Chapter 1, pg. 4 (new message) BBOJ0089I statistics header Explanation: This message is used to display MDB statistics header. User Response: None ________________________________________________________________ Chapter 1, pg. 4 (new message) BBOJ0090I statistics Explanation: This message is used to display MDB statistics. User Response: None ________________________________________________________________ Chapter 1, pg. 4 (new message) BBOJ0091I Duplicate Message Reference Count: count MR: Message Reference Explanation: This message is used to display MDB statistics. User Response: None ________________________________________________________________ Chapter 1, pg. 4 (new message) BBOJ0092I NO ACTIVE LISTENER PORT, command name COMMAND IGNORED Explanation: There are no Listener Ports for which to display MDB statistics. User Response: None ________________________________________________________________ APAR PQ84981 requires the following change to the InfoCenter. To access the latest online documentation, go to the product library page at: www.ibm.com/software/webservers/appserv/zos_os390/library/ APAR PQ84981 provides the following new articles to the InfoCenter: -"MDB Throttle Support" -"Configuring MDB Throttle Support" -"Best practices for debugging MDB throttle support" APAR PQ84981 provides an update to the existing InfoCenter articles: - "Using message-driven beans in applications" - "Administering WebSphere JMS support" - "Troubleshooting WebSphere Messaging" - "Tuning for J2EE applications" - "Listener port settings" APAR PQ84981 is associated with SERVICE LEVEL W502009 of WebSphere Application Server V5.0 for z/OS.Temporary fix Comments
APAR is sysrouted FROM one or more of the following: APAR is sysrouted TO one or more of the following: Modules/Macros
Publications Referenced
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Document Information |
Current web document: swg1PQ84981.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 #: PQ84981
IBM Group: Software Group
Modified date: Jun 17, 2004
(C) Copyright IBM Corporation 2000, 2009. All Rights Reserved.