Paul Ramsey <pram...@cleverelephant.ca> writes: >> UNION will preferentially glom onto the btree equality operator, if memory >> serves. If that isn't also the hash equality operator, things won't work >> pleasantly.
> So⦠what does that mean for types that have both btree and hash equality > operators? Donât all the built-ins also have this problem? What I'm asking is why it would possibly be sensible to have different notions of equality for hash and btree. In every existing type that has both btree and hash opclasses, the equality members of those opclasses are *the same operator*. You don't really want UNION giving different answers depending on which implementation the planner happens to pick, do you? 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