On ons, 2010-08-11 at 10:47 -0400, Tom Lane wrote: > > I thought the point of ASSERTIONs was that you could write a thing > such as: > > CREATE ASSERTION foo CHECK ((SELECT count(*) FROM tbl) = 4); > > Enforcing that kind of constraints without true serializability > seems > > impractical. > > Enforcing that kind of constraint seems impractical with or without > serializability. You need some optimization method that avoids the > need > to do full-table scans after every update, or it's not going to be > useful for any real-world situation. Without a scheme that can do > incremental checking for some useful class of assertion expressions, > this isn't going to go far.
I'm not sure how great a use case there is for an assertion of the kind "this table must contain at least 30 million rows". But I think there are many uses cases for checks like that on small and rarely changing tables. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
