Two-phase commit (2PC) is a protocol for assuring update consistency across distributed databases in which each participant in the transaction commit operation votes to either commit or abort the changes. Participants wait before committing a change until they know that all participants can commit.
A participant is a “database manager” that performs some work on behalf of the transaction and that commits or aborts changes to the database. A participant can also be a coordinator of participants at a lower level.
By voting to commit, a participant guarantees that it can either commit or roll back its part of the transaction, even if it crashes before receiving the result of the vote.
The 2PC protocol allows the development of Customer Information Control System (CICS) and Information Management System (IMS) applications that can update one or more Teradata Database databases or databases, or both under some other DBMS in a synchronized manner. The result is that all updates requested in a defined unit of work will either succeed or fail.