17.00 - Synchronizing Resources for 2PC Applications - IBM CICS Interface for Teradata

IBM CICS Interface for Teradata® Reference

IBM CICS Interface for Teradata
June 2020
Programming Reference

Prior to version 1, release 5.0 and in version 2, release 1, CICS applications that updated both database and other recoverable resources or databases within the same CICS logical unit of work were subject to failure windows that could leave the databases in an inconsistent or indeterminate state.

In version 1, release 5 and in version 2, release 2 or higher, CICS applications can optionally access the database as a CICS syncpoint participant. As a result, Teradata updates are committed or rolled back by using CICS syncpoint services.

Using this facility guarantees that all updates performed within a CICS logical unit of work will all commit or all roll back.

This capability is implemented by enhancement to the database and to the CICS Attachment Facility to support the CICS syncpoint manager and its use of the two-phase commit protocol.

The 2PC protocol allows you to develop CICS applications that update databases and other database management systems (DBMSs) in a synchronized manner.

As a result, the updates requested in a defined unit of work (within a transaction) will either all commit or all roll back.

Applications using the 2PC protocol require the use of a coordinator. CICS acts as a coordinator and manages the 2PC processing by keeping track of which participants vote to commit or abort updates. Databases become resources that can be controlled by CICS system events (commands) such as syncpoint and rollback.

For more information on the coordinator and 2PC in general, see the section on 2PC (two-phase commit) in Teradata Vantage™ - Database Administration, B035-1093 and Teradata Vantage™ - Database Design, B035-1094.