The following three main components are involved with Two-phase commit protocol:
- CLIv2 application
- Participants (the databases)
- Coordinator (IMS or CICS)
An application using the Two-phase commit protocol must establish a Two-phase commit session, initiate requests, and manage sync point processing. The actual synchronization is handled by the coordinator.
When work is to be synchronized, the application requests that the coordinator communicate with the other participants to complete the synchronization. Teradata provides coordinator-participant communications services, not the actual coordinators. The internal communications services (Coordinator-Participant Interface, or CPI) are provided as extensions to CLIv2.