From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <david.rowley@2ndquadrant.com>
cc: Alvaro Herrera <alvherre@2ndquadrant.com>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
        Andres Freund <andres@anarazel.de>
Subject: Re: pg_dump is broken for partition tablespaces
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Comments: In-reply-to David Rowley <david.rowley@2ndquadrant.com>
	message dated "Sun, 14 Apr 2019 23:21:15 +1200"
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Date: Sun, 14 Apr 2019 10:16:44 -0400
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David Rowley <david.rowley@2ndquadrant.com> writes:
> I'd say the fact that we populate reltablespace with 0 is a bug as
> it's not going to do what they want after a dump/restore.

Well, it's not really nice perhaps, but you cannot just put in some
other concrete tablespace OID instead.  What a zero there means is
"use the database's default tablespace", and the point of it is that
it still means that after the DB has been cloned with a different
default tablespace.  If we don't store 0 then we break
"CREATE DATABASE ... TABLESPACE = foo".

You could imagine using some special tablespace OID that has these
semantics (*not* pg_default, but some new row in pg_tablespace).
I'm not sure that that'd provide any functional improvement over
using zero, but we could certainly entertain such a change if
partitioned tables seem to need it.

			regards, tom lane