Christine’s laptop has been slowly grinding to a halt over the past few weeks and, as the university support services were proposing to take it away, I thought I’d take a look. I was initially sidetracked by an issue with a SQL Server 2005 Express update which Windows Update was repeatedly trying to install. In the end, it turned out she had the same issue with the IDE Channel transfer mode that I’ve experienced before. The Windows Update was just one of the many disk intensive operations where things got really bad. Just for good measure I uninstalled some apps I’d put on her machine and ran CCleaner and JKDefrag. Hopefully Christine will come home from work in a better mood tomorrow!
Archive for the ‘Technology’ Category
Amateur IT support
Sunday, May 10th, 2009Service Integration Bus Destination Handler
Wednesday, May 6th, 2009I’ve previously plugged the Service Integration Bus Explorer and IBM Client Application for JMS as useful tools to have in your WebSphere messaging kitbag. Thanks go once again to Dave Screen, this time for bringing the Service Integration Bus Destination Handler to my attention. This provides a very configurable mechansim for carrying out actions on a set of messages either on a one-off basis (via client or web application) or on a scheduled basis. Particularly useful operations include dumping messages, moving messages from one destination to another, and resurrecting messages from the exception destination. The readme file available in the download provides lots of detailed instructions and examples.
Sharing libraries at runtime
Wednesday, May 6th, 2009Thanks to my colleague Dave Screen for highlighting a useful technote relating to sharing library modules in WebSphere ESB and Process Server. The WebSphere Integration Developer concept of a library is typically only used for development time sharing of artifacts i.e. when you deploy a module that depends on that library, a copy of the JAR file is included in the enterprise application that is deployed. The technote describes how to deploy the library as a WebSphere shared library and have multiple modules depend on the same instance at runtime. This has the potential to reduce memory usage (the library is on a shared classloader) and ease managability. It does, however, mean that you need to be more careful about versioning of the library and breaking other dependent modules. If you’re not on 6.2 then note the list of APARs at the bottom of the document.
Dynamic JMS endpoints revisited
Saturday, April 18th, 2009This is a long overdue update to a previous post on achieving dynamic JMS endpoints in WebSphere ESB. As several people have commented, WebSphere ESB 6.2 added support for dynamic endpoints for all of the bindings types as documented in the InfoCenter. A couple of points to note:
- The syntax of the endpoint URI used for the JMS bindings uses JNDI names to refer to the resources and is therefore not truly dynamic in the sense that JMS destinations need to have been pre-configured for all of the messaging provider destinations to which you might want to send.
- For a native MQ binding, you can currently only modify the queue dynamically and not the queue manager to which you can connect.
User Group Presentation
Wednesday, March 4th, 2009Yesterday I headed down to Bedfont with a car load of IBMers to present at the WebSphere User Group meeting. I was presenting an update covering new function in WebSphere ESB and Process Server 6.2. After days of pulling together slides from all the various product architects I ditched my pitch in favour of a few minor modifications to an excellent presentation from one of the worldwide tech sales team. Obviously I know the WebSphere ESB material well enough but this was a good opportunity to brush up my knowledge of the new function in Process Server. I also went to a couple of interesting presentations on OSGI, JAX-RS and JPA as well as my colleague Brian Hulse’s detailed presentation on the Service Gateway and Policy support in 6.2. With attendance down on usual, I felt the large number of parallel tracks led to smaller than desirable audiences for many of the presentations. It was also a horrendous drive back home along the M3 through torrential rain.
Entries close
Friday, February 20th, 2009Entries for the JOK Chasing Sprint closed this evening which was a great relief. This was to have been the year of the Web 2.0 entry system but, in reality, other commitments meant that my annual rewrite of the system only got as far as a stateless interface. This should stand me in good stead for next year though… Rails still continues to be a pleasure to use and the more I learn (I splashed out on the PDF version of the soon to be released Agile Web Development with Rails: Second Edition) the better it gets. New improvements to the development process this year were Git for version control and Capistrano for deployment. These certainly gave me more a lot more confidence in making updates to the live system.
Security Bulletin for WebSphere Application Server
Tuesday, February 10th, 2009I now try to avoid just re-posting material from developerWorks and other IBM sources but this one is worth highlighting. IBM is now publishing a list of risk assessed security vunerabilities for WebSphere Application Server.
WebSphere MQ non-ASF in WAS
Wednesday, February 4th, 2009Application 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.
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