From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Robert Haas <robertmhaas@gmail.com>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Tatsuo Ishii <ishii@postgresql.org>
Cc: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Cc: Jeff Janes <jeff.janes@gmail.com>
Cc: pgsql-hackers@postgresql.org <pgsql-hackers@postgresql.org>
Subject: Re: multivariate statistics v14
Date: Mon, 21 Mar 2016 11:08:32 +0100
Message-ID: <c71b5b16-1fa8-2699-ae00-931cbb31098d@2ndquadrant.com> (raw)
In-Reply-To: <CA+TgmoZw-Z+_mrT0KbYhq4KoEP_jgY_uosEd_LZDQg1-jzi5=w@mail.gmail.com>
References: <1bc2bd16-8e33-9e22-cdb1-9ddc38fedc4c@2ndquadrant.com>
<20160321033440.GA350186@alvherre.pgsql>
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Hi,
On 03/21/2016 10:34 AM, Robert Haas wrote:
> On Sun, Mar 20, 2016 at 11:34 PM, Alvaro Herrera
> <alvherre@2ndquadrant.com> wrote:
>> ObjectProperty[] contains a comment that the ACL is "same as relation",
>> but is that still correct, given that now stats may be related to more
>> than one relation? Do we even know what the rules for ACLs on
>> cross-relation stats are? One very simple way to get around this is to
>> dictate that all the rels must have the same owner.
>
> That's not really all that simple - you'd have to forbid changing
> the owner of a relation involved in multi-rel statistics, but that's
> horrible. Presumably at the very least you'd then have to find some
> way of allowing the owner of everything in the group to be changed
> at the same time, but that's a whole new innovation. I think this is
> a very messy line of attack.
I agree. I don't think we should / need to impose such additional
restrictions (e.g. same owner for all tables).
I think for using the statistics (to compute estimates for a query), it
should be enough that the user can access all the tables it's built on.
Which happens somehow implicitly, and currently it's trivial as each
statistics is built on a single table.
I don't have a clear idea what should we do in the future with multiple
tables (e.g. when the statistics is built on 3 tables, the query is on 2
of them and the user does not have access to the remaining one).
But maybe we need to support ACLs because of ALTER STATISTICS?
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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Cc: tomas.vondra@2ndquadrant.com, robertmhaas@gmail.com, alvherre@2ndquadrant.com, ishii@postgresql.org, horiguchi.kyotaro@lab.ntt.co.jp, jeff.janes@gmail.com
Subject: Re: multivariate statistics v14
In-Reply-To: <c71b5b16-1fa8-2699-ae00-931cbb31098d@2ndquadrant.com>
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