befd73c50f
These functions are intended to be used by monitoring tools, and, unlike pg_ls_dir(), access to them can be granted to non-superusers, so that those monitoring tools can observe the principle of least privilege. Dave Page, revised by me, and also reviewed a bit by Thomas Munro. Discussion: http://postgr.es/m/CA+OCxow-X=D2fWdKy+HP+vQ1LtrgbsYQ=CshzZBqyFT5jOYrFw@mail.gmail.com