About XA Resources

Enterprise Server for .NET requires an XA resource definition to be used when:

a CICS transaction or batch application (using DSNALI, DSNRLI or the TSO DSN command) uses a SQL database. A database XA resource definition identifies the region it is associated with, the database connection string, and optionally the plan, package path or package set to be used.
a CICS region or batch application (using DSNRLI) uses WebSphere MQ. An MQ XA resource definition identifies the region it is associated with, the MQ queue manager name, and optionally the MQ channel and MQ connection name.

XA resource definitions are persisted in the cross-region database.

Database XA Resource Definitions

For CICS regions, a database XA resource definition can be associated with a region or a PCT. A region association is made by naming the XA resource to be used as a property of the SIT or region start-up file. When specified in both the SIT and region start-up file, the region start-up file takes precedence. By default, the XA resource definition associated with the region will be used when a transaction uses a SQL database. However, if an XA resource definition is defined for a PCT, that definition will be used in preference to the one associated with the region when the transaction is invoked.

For JES regions, an XA resource definition is required for each named system used when calling DSNALI, DSNRLI or when invoking the TSO DSN command. No additional configuration is required for JES regions. Enterprise Server for .NET.

MQ XA Resource Definitions

For CICS regions, an MQ XA resource definition can be associated with a region. A region association is made by naming the XA resource to be used as a property of the SIT or region start-up file. When specified in both the SIT and region start-up file, the region start-up file takes precedence.

For JES regions, the MQ channel and connection names used when an application attempts to explicitly connect to a queue manager, using the MQCONN or MQCONNX APIs, need to be specified in the region start-up file. Alternatively, if DSNRLI is being used, an XA resource definition is required for each queue manager that is to be connected to.