WebSphere MQ

Extended Transactional Client

WebSphere® MQ (WMQ), V5.3 now has support for extended architecture (XA) transaction management in conjunction with an external syncpoint coordinator. This support is available in both the Java™ Messaging Service (JMS) and C clients. The WebSphere MQ Extended Transactional Client allows applications to participate within a unit of work with other local resource managers, such as DB2®, under the control of an external syncpoint coordinator, such as CICS®, Encina or Tuxedo. Until now this has only been possible by using a local MQ server. For the purposes of pricing the Transactional Client is treated as if it were an MQ server whilst the current non-transactional client will continue to be provided free of charge.

The WebSphere MQ Extended Transactional Client will be available from February 28th 2003.

What is a resource manager?
A resource manager is a computer subsystem that owns and manages resources that can be accessed and updated by applications (i.e., WMQ queue manager – whose resources are its queues, DB2 database – whose resources are its tables).

What is a unit of work?
When a application updates the resources of one or more resource managers, it's often vital that all updates complete successfully as a group, or none of them complete. Updates that complete this way are said to occur within a 'unit of work' or 'transaction'.

What is a syncpoint coordinator?
The point in time when all updates within a unit of work are either committed or backed out is called a 'syncpoint'. The computer subsystem that manages units of work is called a syncpoint coordinator.

What is XA?
For a transaction manager to manage a unit of work, there must be an architected interface to the resource manager, one such interface is the XA interface, published by the X/Open Company Limited.

Java and all Java-based trademarks are trademarks of Sun Microsystems, Inc. in the United States, other countries, or both.