Re: pgsql: doc: restrictions on alter database moving default tablespace

On Fri, Dec 12, 2014 at 04:14:50PM -0500, Bruce Momjian wrote:
> On Tue, Oct 21, 2014 at 01:38:43AM -0400, Noah Misch wrote:
> > On Sat, Oct 18, 2014 at 02:23:46PM +0000, Bruce Momjian wrote:
> > > doc: restrictions on alter database moving default tablespace
> > >
> > > Mention tablespace must be empty and no one connected to the database.
> >
> > The database must not contain any object explicitly assigned to its future
> > default tablespace, but that tablespace need not be empty. Objects of other
> > databases in the tablespace pose no problem.
>
> I am back to look at this comment, and I don't understand what change is
> being requested. Are you saying it is just the commit message that
> isn't clear?
>
> The new text is:
>
> The new default tablespace for this database must be empty, and no one
> can be connected to the database.
>
> That makes the distinction that only the tablespace for the existing
> database has to be empty, not the entire tablespace.

No, the commit message accurately describes the change. Your reply helps me
understand your conception of the software's behavior, but I still read your
committed documentation text differently. For "the new default tablespace for
this database" to qualify as "empty", it must contain no object from any
database. A tablespace is a cross-database, unitary object. Each tablespace
is either empty from every perspective or not empty from any perspective.
Here are a couple of alternatives for the documentation text:

The new default tablespace must not already contain any of the database's
objects, and no one can be connected to the database.

The database must not contain any object explicitly located in the new
default tablespace, and no one can be connected to the database.