Re: eXtensible Transaction Manager API

> COMMIT PREPARED is a pretty thin layer; the work is all done in the PREPARE.
> With a DTM, the main commit itself is done once only in the DTM, so all the
> COMMIT PREPARED would do is release local node resources.

Sure. Now imagine that the pg_twophase entry is corrupted for this
transaction on one node. This would trigger a PANIC on it, and
transaction would not be committed everywhere. I am aware of the fact
that by definition PREPARE TRANSACTION ensures that a transaction will
be committed with COMMIT PREPARED, just trying to see any corner cases
with the approach proposed. The DTM approach is actually rather close
to what a GTM in Postgres-XC does :)