Horton

Re: Multivariate MCV stats can leak data to unprivileged users

John Naylor <john.naylor@2ndquadrant.com>

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From: John Naylor <john.naylor@2ndquadrant.com>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Dean Rasheed <dean.a.rasheed@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Stephen Frost <sfrost@snowman.net>, Andres Freund <andres@anarazel.de>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2019-06-11T06:04:34Z
Lists: pgsql-hackers 
On Fri, Jun 7, 2019 at 4:33 AM Tomas Vondra
<tomas.vondra@2ndquadrant.com> wrote:
> 2) 0002 - update sgml docs to reflect changes from 0001

There is some copypasta here in the new section referring to the old catalog:

+ <sect1 id="catalog-pg-statistic-ext-data">
+  <title><structname>pg_statistic_ext_data</structname></title>
+
+  <indexterm zone="catalog-pg-statistic-ext">
+   <primary>pg_statistic_ext</primary>
+  </indexterm>
+
+  <para>
+   The catalog <structname>pg_statistic_ext</structname>
+   holds extended planner statistics.
+   Each row in this catalog corresponds to a <firstterm>statistics
object</firstterm>
+   created with <xref linkend="sql-createstatistics"/>.
+  </para>

And a minor stylistic nit -- it might be good to capitalize "JOIN" and
"ON" in the queries in the docs and tests.

> One thing I think we should fix is naming of the attributes in the 0001
> patch. At the moment both catalogs use "stx" prefix - e.g. "stxkind" is
> in pg_statistic_ext, and "stxmcv" is in pg_statistic_ext_data. We should
> probably switch to "stxd" in the _data catalog. Opinions?

That's probably a good idea.

-- 
John Naylor                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Add security checks to the multivariate MCV estimation code.

  2. Add pg_stats_ext view for extended statistics

  3. Rework the pg_statistic_ext catalog