On Thu, May  4, 2017 at 07:01:17PM -0300, Alvaro Herrera wrote:
> Thanks for doing this, looks great.  A few notes:
>       <listitem>
>        <!--
>        Author: Alvaro Herrera <alvhe...@alvh.no-ip.org>
>        2017-03-24 [7b504eb28] Implement multivariate n-distinct coefficients
>        Author: Simon Riggs <si...@2ndquadrant.com>
>        2017-04-05 [2686ee1b7] Collect and use multi-column dependency stats
>        -->
>       <para>
>        Add the ability to compute a correlation ratio and the number of
>        distinct values on several columns (Tomas Vondra, David Rowley)
>       </para>
> I think this should be worded in terms of "extended data statistics" or
> such.  I think your proposed wording is a bit obscure.  How about
> something like "Add extended statistics to improve query planning".
> Also, I'd add myself as co-author, with Tomas' permission.

I have adjusted the text to add your term, and added your name:

       Add multi-column optimizer statistics to compute the correlation
       ratio and number of distinct values (Tomas Vondra, David Rowley,
       &Aacute;lvaro Herrera)

I think we have to mention the exact statistics collected because we
know that they are of limited usefulness (per Tomas) and full
multi-column statistics are needed and hopefully coming in PG 11.  If we
don't mention the details I am afraid people will be disappointed with PG
10 and will not be excited when they are more powerful in PG 11.  Any
better wording?

I will work on the other items you posted shortly.

  Bruce Momjian  <br...@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +

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