On Sun, Nov 13, 2011 at 6:57 PM, Florian Pflug <f...@phlo.org> wrote: > On Nov13, 2011, at 01:38 , Tom Lane wrote: >> Just a couple hours ago I was wondering why we create system columns for >> foreign tables at all. Is there a reasonable prospect that they'll ever >> be useful? I can see potential value in tableoid, but the others seem >> pretty dubious --- even if you were fetching from a remote PG server, >> the XIDs would not be meaningful within our own environment. > > At least ctid seems useful too. I've used that in the past as a poor man's > surrogate primary key. > > Also, people have used ctid and xmin in the past to re-find previously > visited rows and to check whether they've been modified. So there might be > some value in keeping xmin around also (and make the postgres fdw populate it)
My vote is to nuke 'em all. :-) I don't think that we want to encourage people to depend on the existence of system columns any more than they do already. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
