Theo Schlossnagle wrote: > I'm trying to implement a function that has some XA like properties. > > Is it possible to write a postgres extension function that fires when called > within a pg transaction... however, the actions it takes need to be later > committed or rolled back based on the containing transactions commital or > not. Not having looked to deeply into this, I'm wondering if this is > possible. Naively, my first hookpoint would be something like: > > allocate something in the transactions memory context and register a > cleanup.... do my work. > > when the transaction memory context is cleaned up, my cleanup handler fires, > I detect whether the txn was committed or rolledback and rightly mark my work > as committed or rolled back.
See RegisterXactCallback(). And then there's the ResourceOwners, that you can use to register custom resources for cleanup. Of course, you'll never be able to make it atomic without 2PC. The callbacks are executed very soon after after the commit record has been flushed to disk, so the window is small but it's there. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
