CLIv2 applications logging on any sessions to the Teradata Database can request that either a single session or multiple sessions be established. All the 2PC sessions established by an application are considered part of the same commit‑and‑recovery unit. (Note that an application can have separate non‑2PC sessions.) Individual 2PC sessions can log on using the Connect function DBO2PC option (values are Y or N).
An existing 2PC 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 2PC optimizations can be used. Session pools can be started from the TDP. To establish a session pool that is in 2PC mode, use the TDP command, START POOL, with the TWOPC keyword. The TDP will start a pool that contains only 2PC sessions.
For more information on using session pools with 2PC, see the Teradata Director Program Reference (B035‑2416).