Overview of XA Transaction Management
A transaction is a logical unit of work, composed of many different processes, that either entirely succeeds or has no effect at all.
Because the work being performed within a transaction can occur on many different platforms and can involve many different resources from different vendors, the X/Open organization developed the distributed transaction process (DTP) model and the XA interface.
The DTP model defines communication among the following:
Resources such as databases.
Resource managers such as database servers. Resource managers provide access to shared resources.
A
transaction manager. The transaction manager coordinates and controls all transactions for resources through their resource managers.
Integration Server contains a transaction manager sub-system that coordinates and controls database transactions that are initiated by the
webMethods Adapter for JDBC or the
webMethods Adapter for JMS.
The XA interface describes the protocol for transaction coordination, commitment, and recovery between resource and a transaction manager. Integration Server supports the XA protocol; it manages transactions using the transaction protocol called two-phase commit, or 2PC.
In the first phase of 2PC, Integration Server (specifically, the transaction manager) asks the resources that are participating in a transaction whether they are prepared to commit the transaction. In the second phase, one of the following occurs:
All the resources respond that they are prepared to commit.
Integration Server instructs the resources to commit the transaction.
One or more resources respond that they are not prepared to commit.
Integration Server instructs all resources to roll back their preparations for committing the transaction.
