BTW, I just thought of an issue that might change some of these conclusions: what about supporting deferred constraint checking, as we just recently managed to do for straight UNIQUE constraints? I don't say that this has to be in the first cut, but it's something we ought to try to leave room for down the road.
The current infrastructure for deferred uniqueness requires that the thing actually be a constraint, with an entry in pg_constraint that can carry the deferrability options. So unless we want to rethink that, this might be a sufficient reason to override my arguments about not wanting to use CONSTRAINT syntax. As far as implementation goes, I think there would be very little choice but to use the insert-the-index-entry-first, check-later approach; so your ideas involving extra state in shared memory seem to fall to the ground anyhow. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers