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Transactional support

 

An application program can group a set of updates into a unit of work. These updates are usually logically related and must all be successful for data integrity to be preserved. If one update succeeds while another fails, data integrity is lost.

When a unit of work completes successfully, it is said to commit. Once committed, all updates made within that unit of work are made permanent and irreversible. However, if the unit of work fails, all updates are instead backed out. This process, where units of work are either committed or backed out with integrity, is known as syncpoint coordination.

A local unit of work is one in which the only resources updated are those of the WebSphere MQ queue manager. Here syncpoint coordination is provided by the queue manager itself using a single-phase commit process.

A global unit of work is one in which resources belonging to other resource managers, such as XA-compliant databases, are also updated. Here, a two-phase commit procedure must be used and the unit of work can be coordinated by the queue manager itself, or externally by another XA-compliant transaction manager such as IBM TXSeries, or BEA Tuxedo.

For more information, see Transactional support.

WebSphere MQ also provides support for the Microsoft Transaction Server (COM+). Using the Microsoft Transaction Server (COM+) provides information on how to set up WebSphere MQ to take advantage of COM+ support.

 

Parent topic:

Introduction to WebSphere MQ

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