Re: Improving RLS planning

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Stephen Frost <sfrost@snowman.net>
Cc: Dean Rasheed <dean.a.rasheed@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2016-11-08T14:45:18Z
Lists: pgsql-hackers
Stephen Frost <sfrost@snowman.net> writes:
> * Tom Lane (tgl@sss.pgh.pa.us) wrote:
>> * Since the planner is now depending on Query.hasRowSecurity to be set
>> whenever there are any securityQuals, I put in an Assert about that,
>> and promptly found three places in prepjointree.c and the rewriter where
>> we'd been failing to set it.  I have not looked to see if these represent
>> live bugs in existing releases, but they might.  Or am I misunderstanding
>> what the flag is supposed to mean?

> They're independent, actually.  securityQuals can be set via either
> security barrier view or from RLS, while hasRowSecurity is specifically
> for the RLS case.  The reason for the distinction is that changing your
> role isn't going to impact security barrier views at all, while it could
> impact what RLS policies are used.  See extract_query_dependencies().

OK.  In that case I'll need to adjust the patch so that the planner keeps
its own flag about whether the query contains any securityQuals; that's
easy enough.  But I'm still suspicious that the three places I found may
represent bugs in the management of Query.hasRowSecurity.

			regards, tom lane


Commits

  1. Improve RLS planning by marking individual quals with security levels.