Re: [HACKERS] PATCH: multivariate histograms and MCV lists

Bruce Momjian <bruce@momjian.us>

From: Bruce Momjian <bruce@momjian.us>
To: Dean Rasheed <dean.a.rasheed@gmail.com>
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Andres Freund <andres@anarazel.de>, Thomas Munro <thomas.munro@enterprisedb.com>, Mark Dilger <hornschnorter@gmail.com>, Adrien Nayrat <adrien.nayrat@dalibo.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2018-04-07T18:34:14Z
Lists: pgsql-hackers
On Sat, Apr  7, 2018 at 06:52:42PM +0100, Dean Rasheed wrote:
> On 7 April 2018 at 15:12, Bruce Momjian <bruce@momjian.us> wrote:
> > Uh, where are we on this patch?  It isn't going to make it into PG 11?
> > Feature development for this has been going on for years.
> 
> Unfortunately, I think there's no way that this will be ready for
> PG11. So far, I have only read parts of the patch, focusing mainly on
> the planner changes, and how it will make use of the new statistics. I
> think there are still issues to work out in that area, although I
> haven't read the latest version yet, I have some doubts about the new
> approach described.
> 
> Looking back at the history of this patch, it appears to have moved
> through all 4 PG11 commitfests with fairly minimal review, never
> becoming Ready for Committer. That's a real shame because I agree that
> it's an important feature, but IMO it's not yet in a committable
> state. I feel bad saying that, because the patch hasn't really had a
> fair chance to-date, despite Tomas' efforts and quick responses to all
> review comments.
> 
> At this stage though, all I can say is that I'll make every effort to
> keep reviewing it, and I hope Tomas will persist, so that it has a
> better chance in PG12.

Yes, let's please keep going on this patch.

-- 
  Bruce Momjian  <bruce@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 +


Commits

  1. Convert pre-existing stats_ext tests to new style

  2. Add support for multivariate MCV lists

  3. Improve ANALYZE's strategy for finding MCVs.

  4. Clone extended stats in CREATE TABLE (LIKE INCLUDING ALL)

  5. Try again to fix accumulation of parallel worker instrumentation.

  6. Adjust psql \d query to avoid use of @> operator.

  7. Message style fixes

  8. Add security checks to selectivity estimation functions