Re: Odd behavior of updatable security barrier views on foreign tables

* Robert Haas (robertmhaas@gmail.com) wrote:
> On Fri, Jan 30, 2015 at 5:20 AM, Etsuro Fujita
> <fujita.etsuro@lab.ntt.co.jp> wrote:
> > I noticed that when updating security barrier views on foreign tables,
> > we fail to give FOR UPDATE to selection queries issued at ForeignScan.
> > Here is an example.
[...]
> > postgres=# alter view rw_view set (security_barrier = true);
> > ALTER VIEW
> > postgres=# explain verbose delete from rw_view;
> >                                             QUERY PLAN
> > --------------------------------------------------------------------------------------------------
> >  Delete on public.base_ftbl base_ftbl_1  (cost=100.00..144.54 rows=14
> > width=6)
> >    Remote SQL: DELETE FROM public.base_tbl WHERE ctid = $1
> >    ->  Subquery Scan on base_ftbl  (cost=100.00..144.54 rows=14 width=6)
> >          Output: base_ftbl.ctid
> >          ->  Foreign Scan on public.base_ftbl base_ftbl_2
> > (cost=100.00..144.40 rows=14 width=6)
> >                Output: base_ftbl_2.ctid
> >                Remote SQL: SELECT ctid FROM public.base_tbl WHERE
> > ((visibility = 'public'::text))
> > (7 rows)
> >
> > Correct me if I am wrong.
>
> That looks like a bug to me.

Agreed.  I've been looking at this and I suspect it's related to the
discussion around prepsecurity.c and generating the security barrier
subquery that I've been having with Dean.  An initial look, at least,
shows that GetForeignPlan is looking at the subquery instead of the base
relation (as it expects to be).

I'll continue digging into it.
Thanks!
    Stephen