Robert Haas <robertmh...@gmail.com> writes: > On Wed, Mar 12, 2014 at 9:19 AM, Andres Freund <and...@2ndquadrant.com> wrote: >> Except that we don't have the infrastructure to perform such checks >> (neither partial, nor expression indexes, no exclusion constraints) on >> system tables atm. So it's not a entirely trivial thing to do.
> I'm probably woefully underinformed here, but it seems like getting > exclusion constraints working might be simpler than partial indexes or > expression indexes, because both of those involve being able to > evaluate arbitrary predicates, whereas exclusion constraints just > involve invoking index access methods to look for conflicting rows via > smarts built into your index AM. The latter seems to involve less > risk of circularity (but I might be wrong). You might be right. I don't think anyone's ever looked at what it would take to support that particular case. We have looked at the other cases and run away screaming ... but I think that was before exclusion constraints existed. 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