Date: Sun, 19 May 2019 01:28:12 +0200
From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>,
	Dean Rasheed <dean.a.rasheed@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Multivariate MCV stats can leak data to unprivileged users
Message-ID: <20190518232812.qpnjmydlx3uzzsj7@development>
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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