Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> writes:
> I've played with triggers a bit, and I have noticed that there seem to be
> no way to add a trigger on events such as "prepare", "commit", "rollback",
> "savepoint",
Yup, and there won't be. This has been suggested and rejected before.
See the archives.
> It seems to me that such triggers would be useful to help implement a
> "simple" (hmmm...) synchroneous replication system,
That argument has no credibility whatever. We have not even been able
to get the replication projects to agree on a common set of custom
hooks; the chance that they could get by with triggers on SQL-visible
events is nil.
regards, tom lane