On ons, 2010-08-11 at 13:23 +0300, Marko Tiikkaja wrote: > But you'd have to somehow make the constraints to be checked > with true serializability, and that part of the original suggestion > seemed to be completely missing. Not sure how hard that would be > though.
I don't think somehow running the constraint checks at a different transaction isolation level than the rest of the transaction is sensible. I imagine the solution would look similar to how foreign keys do it: take a lock on the rows that are required for constraint satisfaction. For general assertions, this would require predicate locking. But also notice that for the (SELECT count(*) FROM tbl) = N case, this is the same as a table lock. I don't think there is any magic around it. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
