On Tue, Apr 10, 2012 at 07:57:30PM -0400, Tom Lane wrote: > Bruce Momjian <br...@momjian.us> writes: > > On Tue, Apr 10, 2012 at 07:09:33PM -0400, Tom Lane wrote: > >> Hm. I have no objection to special-casing zero here, but what behavior > >> do you want? Should it return an empty string as we do for > >> DEFAULTTABLESPACE_OID, or throw a different error? > > > I have no idea. The big problem is that we currently use '' for the > > cluster default, while 0 means the database default. I can't think of a > > good return result --- I think it has to be an error of some kind. > > If we expect this function to mainly be applied to pg_class.reltablespace, > then it seems like it ought to understand that zero means "the database > default" and substitute the database's default tablespace. That might > or might not be the same as the cluster default.
Well, do we really want to be reporting the _current_ data directory location? We do track tablespace symlink moves because we read the symlinks now, so that isn't out of the question. A bigger question is whether returning '' for a database-default location is valid --- I am thinking no. > Alternatively, we could expect pg_upgrade to understand that and make > the substitution itself, but if the same would be needed by most uses of > the function, maybe we should just do it here. I just applied a patch to pg_upgrade to do exactly that, and it is needed in pre-9.2 as well because pg_upgrade was testing for an empty spclocation, which could be '' or it could be NULL (from an outer join), but pg_upgrade wasn't distinguising the two. :-( -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
