A two-phase commit capability is a Java Transaction API (JTA) feature supporting distributed transactions.
When PRPC is installed as an Enterprise tier application (and the XA version of JDBC database drivers are installed) the Commit and Rollback methods apply to both internal and external classes, implementing a Java EE distributed transaction.
For example, a flow may update tables in the external relational database such as a customer master file, and also update assignments and properties in the work item. If when the Commit method occurs either the PegaRULES database or the customer master database operation fails, a rollback occurs automatically.
For more information, see Distributed Transactions and PegaRULES Process Commander, a document on the PDN.