From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>
Cc: Dean Rasheed <dean.a.rasheed@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Multivariate MCV stats can leak data to unprivileged users
Date: Sun, 19 May 2019 01:28:12 +0200
Message-ID: <20190518232812.qpnjmydlx3uzzsj7@development> (raw)
In-Reply-To: <568.1558208711@sss.pgh.pa.us>
References: <20190513223605.lwj65akict3tpetv@development>
<CAEZATCWFCN2yBpqpw4kw6xhwdPNz8DERPOWNHHQ_qHV4=tbJ8A@mail.gmail.com>
<20190517202938.lkx6q2u6woiptrsa@alap3.anarazel.de>
<CAEZATCX9yU2eKL7-dCWTv1pMMi1hb+PsZyM6gjBxupDnMuEzRw@mail.gmail.com>
<CAEZATCV5fo2E6K5EVN2uytGjMvhTKTizP_rOW67nPqNK8jHAAg@mail.gmail.com>
<21269.1558192388@sss.pgh.pa.us>
<CAEZATCW3iAJnU8opUCXb2i_-8syU7on4cdXLWHBeWr04v67HoQ@mail.gmail.com>
<4E0E0C14-C476-446A-835F-CC3558709DA9@anarazel.de>
<20190518190042.2y33h4toxk4fxv5t@development>
<568.1558208711@sss.pgh.pa.us>
On Sat, May 18, 2019 at 03:45:11PM -0400, Tom Lane wrote:
>Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
>> On Sat, May 18, 2019 at 11:49:06AM -0700, Andres Freund wrote:
>>>> On Sat, 18 May 2019 at 16:13, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>>>> It seems like what we need here is to have a separation between the
>>>>> *definition* of a stats object (which is what pg_dump needs access
>>>>> to) and the current actual *data* in it.
>
>>> Otoh, having a suboptimal catalog representation that we'll likely have
>>> to change in one of the next releases also isn't great. Seems likely
>>> that we'll need post beta1 catversion bumps anyway?
>
>> But that's not an issue intruduced by PG12, it works like that even for
>> the extended statistics introduced in PG10.
>
>Yeah, but no time like the present to fix it if it's wrong ...
>
Sorry, not sure I understand. Are you saying we should try to rework
this before the beta1 release, or that we don't have time to do that?
I think we have four options - rework it before beta1, rework it after
beta1, rework it in PG13 and leave it as it is now.
If the pg_dump thing si the only issue, maybe there's a simple solution
that reworking all the catalogs. Not sure. Are there any other reasons
why the current catalog representation would be suboptimal, or do we
have some precedent of a catalog split this way? I can't think of any.
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: tomas.vondra@2ndquadrant.com, tgl@sss.pgh.pa.us, andres@anarazel.de, dean.a.rasheed@gmail.com
Subject: Re: Multivariate MCV stats can leak data to unprivileged users
In-Reply-To: <20190518232812.qpnjmydlx3uzzsj7@development>
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