Peter Eisentraut wrote:
> What is the
> difference between a transaction manager and an application that opens
> multiple connections and does PREPARE + COMMIT PREPARED across them?
It's what happens if your application crashes after issuing the PREPARE.
A correctly configured transaction manager will know to reconnect to all
the resource managers (ie. databases), check its own transaction log,
decide which global transaction have committed, and issue the
COMMIT/ROLLBACK PREPARED commands to the resource managers to finish the
global transactions.
Sure, you can do all that in an application too, but I have yet to see
one that does (correctly). At the point that you do, you can say that
your application has a built-in transaction manager. Really, if you know
what you're doing, you'll know that note in the manual doesn't apply to you.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com
