> > > Since the user accessing/writing to the tablespaces would be the
> > > postgres user I don't really think this 'solution' works in reality.
> >
> > I had assumed it would be a directory based quota rather than a user
> > based one.
>
> It's been a while since I played with quotas but I don't recall this
> option being available.
Group quotas should be sufficient. Create directory readable/writable to
only the pgsql user, but have the group ownership be representative of
the user in question.