Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> I mean, what are NOT NULL in foreign tables for?
There was previous discussion about that, in the context of check
constraints in general, but I don't believe we reached consensus.
http://archives.postgresql.org/message-id/1038.1331738954@sss.pgh.pa.us
There's also an open commitfest entry for changing the behavior
of file_fdw, which IMO is completely premature since we haven't
got consensus on what it should do.
regards, tom lane