13.3. Transactional Resources

The Transaction Service coordinates transaction state updates using XAResource implementations, which are provided by the various resource managers. Resource managers may include databases, message queues or third-party JCA resource adapters. The list of databases and JDBC drivers which have been certified on JBoss Enterprise Application Platform is located at http://www.jboss.com/products/platforms/application/supportedconfigurations/. Most standards-compliant JDBC drivers should function correctly, but you should perform extensive testing when using an uncertified configuration, since interpretations of the XA specifications different from one vendor to another.

Database connection pools are configured via the application server's Datasource files, which are files named like -ds.xml. Datasources which use the <xa-datasource> property automatically interact with the transaction manager. Connections obtained by looking up such datasource in JNDI and calling getConnection automatically participate in ongoing transactions. This is the preferred use case when transactional guarantees for data access are required.

If you are using a database which cannot support XA transactions, you can deploy a connection pool using <local-xa-datasource>. This type of datasource participates in the managed transaction using the Section 13.4, “Last Resource Commit Optimization (LRCO)”, providing more limited transactional guarantees. Connections obtained from a <no-tx-datasource> do not interact with the transaction manager, and any work done on such connections must be explicitly committed or rolled back by the application, using the JDBC API.

Many databases require additional configuration before they can function as XA resource managers. Vendor-specific information for configuring databases is presented in Appendix B, Vendor-Specific Datasource Definitions. Refer to your database administrator and the documentation which ships with your database for additional configuration directives. In addition, please consult the JBoss Transactions Administration Guide for information on setting up XA recovery properly.

JBoss Messaging provides an XA-aware driver and can participate in XA transactions. Please consult the JBoss Messaging User Guide for more details.