new keywords in 9.1

It looks like 9.1 currently introduces 11 new keywords: ATTRIBUTE,
COLLATION, EXTENSION, LABEL, NOREPLICATION, PASSING, REF, REPLICATION,
UNLOGGED, VALIDATE, and XMLEXISTS. Aside from VALIDATE, which is
already being discussed on another thread, are there any of these that
we can/should try to get rid of? At a quick glance, it looks quite
simple to avoid making REPLICATION/NOREPLICATION into keywords, and we
can actually *remove* a bunch of existing keywords using the same
trick. Patch attached.

It would be possible to make CREATE UNLOGGED TABLE work without making
UNLOGGED a keyword using a similar trick, though it's a bit messy.
SELECT .. INTO UNLOGGED foo can't work unless it's a keyword, though,
I think, though I wouldn't cry much if we lost that option. I'm
inclined to think this is not worth messing with more on grounds of
ugliness than anything else. XMLEXISTS is pretty horrible in that the
syntax apparently requires three new keywords (XMLEXISTS, PASSING,
REF) which is pretty lame but I guess it's specified by the standard
so I'm not sure there's much we can do about it. The rest look
reasonable and necessary AFAICT.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company