16.20 - Starting Two-phase Commit Sessions - Teradata Tools and Utilities

Teradata® Call-Level Interface Version 2 Reference for Mainframe-Attached Systems

Teradata Tools and Utilities
September 2019
Programming Reference

CLIv2 applications logging on any sessions to Teradata Database can request that either a single session or multiple sessions be established. All the Two-phase commit sessions established by an application are considered part of the same commit-and-recovery unit. (Note that an application can have separate non-Two-phase commit sessions.) Individual Two-phase commit sessions can log on using Two-phase-commit DBCAREA option.

An existing Two-phase commit session can use the IRQ (Initiate Request) or IWPF (Initiate With Protocol-function) to initiate a request. The IWPF function is similar to the Initiate Request function, except that the Locate-mode is not supported and optional Two-phase commit optimizations can be used. Session pools can be started from the TDP. To establish a session pool that is in Two-phase commit mode, use the TDP command, START POOL, with the TWOPC keyword. The TDP will start a pool that contains only Two-phase commit sessions.

For more information on using session pools with Two-phase commit, see the Teradata® Director Program Reference, B035-2416.