Application Server Facilities (ASF) are the part of the JMS specification originally designed, amongst other things, to allow application server’s to retrieve messages for delivery to message-driven beans. Now WebSphere MQ’s ASF implementation had one significant flaw when it comes to multiple consumers pulling messages from the same queue. Each consumer was effectively browsing the queue looking for suitable messages and, when they found one, they then attempted to take a lock in order to consume the message. Unfortunately, inbetween the browse and the lock there’s a good chance that another consumer would have nipped in and stolen the message. This inefficient behaviour meant that you were unlikely to see linear scalability when adding multiple MDB consumers to a deep queue. As a result, some customers have switched their WebSphere Application Server listener port service to use non-ASF mode (the custom properties required for this can be found in the InfoCenter). This use a standard message consumer to poll the queue for messages – the downside being that you need a separate thread for each consumer.
Archive for the ‘WebSphere Application Server’ Category
WebSphere MQ non-ASF in WAS
Wednesday, February 4th, 200910 years on
Wednesday, November 19th, 2008Being presented with my “10 year pen” at a departmental meeting on Monday seems like a good excuse for a bit of a retrospective on my career with IBM…
New WebSphere blogs
Wednesday, September 24th, 2008There has been a recent push to get more of the WebSphere development team out in to the blogosphere in the run up to the release of V7 of the Application Server. The standard form seems to be to advertise new blogs on the WebSphere Community Blog. So far there is one covering WebSphere and Java Persistence, and likely to be of particular interest to readers of this blog, one on WebSphere and Messaging. Note that the latter doesn’t cover WebSphere MQ (see this blog if that’s your area of interest) but rather the default messaging provider in WebSphere Application Server. Expect to see lots of good material on some of the new features and make the most of the chance to interact with the development team. Whilst on the subject of new blogs, if DataPower is your bag then you can read all about a forthcoming book from some of my ex-ISSW colleagues here.
Messaging Engine Startup Problems
Thursday, September 11th, 2008Another heads up for some Service Integration Bus education. On 17 September there is a free webcast entitled Messaging Engine Startup Problems given by Level 2 service and followed by a Q&A session. You can see a list of all the upcoming webcasts or, to receive information about events such as this, along with information about publications and support issues, sign up at My Support.
Update: the replay for this webcast is now available.
Graceful shutdown
Friday, September 5th, 2008Having done a little research on application server shutdown in order to answer a customer query I thought I would post my findings. WebSphere Application Server supports three shutdown modes: stop, stop immediate and terminate (in order of immediacy).
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My first US patent
Thursday, September 4th, 2008Last week I had my first US patent issued: #7218708. The patent describes the use of the J2EE Connector Architecture to integrate a Java Message Service provider with an application server. This is something that is actually very easy to do with JCA 1.5 given the restriction of one JMS session per connection introduced by J2EE 1.4. However this patent describes a mechanism to use JCA twice (once at the connection level and once at the session level) that doesn’t require this restriction. This was first used in WebSphere Application Server V5 and continues to be used for the WebSphere MQ and generic JMS provider support today.
Configuring SIB J2SE client with SSL
Wednesday, July 16th, 2008If configuring the service integration bus J2SE client for SSL is a topic of interest to you then make sure you register for next week’s presentation from Rich Montjoy in level 2 service.
Dynamic JMS endpoints
Tuesday, July 15th, 2008In an earlier post I promised an example of where service integration bus mediations still have a role to play in a WebSphere ESB environment. WebSphere ESB currently only supports dynamic endpoints on an import or callout (those that can be changed at runtime by a mediation flow) for SCA and web service bindings. In this post I’ll show how a service integration bus mediation can be used to add dynamic behaviour to a JMS binding.
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