Re: Improving RLS qual pushdown

Robert Haas wrote:
> On Wed, Jan 14, 2015 at 9:22 AM, Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> wrote:
> > On 14 January 2015 at 13:29, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> >> One thing they could still leak is the number of times they got
> >> called, and thus possibly the number of unseen rows. Now if the
> >> expressions get constant-folded away that won't be an issue, but a
> >> clever user can probably avoid that.
> >
> > Right now, EXPLAIN ANALYSE can be used to tell you the number of
> > unseen rows. Is that something that people are concerned about, and
> > are there any plans to change it?
>
> Interesting question. I don't know.

Wasn't this part of the "covert channel" discussion that took place way
before RLS was committed? As I recall, it was argued that such covert
channels are acceptable as long as their bandwidth is low.

--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services