Re: More stable query plans via more predictable column statistics

From: "Shulgin, Oleksandr" <oleksandr(dot)shulgin(at)zalando(dot)de>
To: David Steele <david(at)pgmasters(dot)net>
Cc: Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: More stable query plans via more predictable column statistics
Date: 2016-03-02 17:56:50
Message-ID: CACACo5S_LBX5uz6KZ2Xnr45Wa586heaTptiVcTah08m2ZEsotA@mail.gmail.com
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On Wed, Mar 2, 2016 at 5:46 PM, David Steele <david(at)pgmasters(dot)net> wrote:

> On 3/2/16 11:10 AM, Shulgin, Oleksandr wrote:
> > On Wed, Feb 24, 2016 at 12:30 AM, Tomas Vondra
> > <tomas(dot)vondra(at)2ndquadrant(dot)com <mailto:tomas(dot)vondra(at)2ndquadrant(dot)com>>
> wrote:
> >
> > I think it'd be useful not to have all the changes in one lump, but
> > structure this as a patch series with related changes in separate
> > chunks. I doubt we'd like to mix the changes in a single commit, and
> > it makes the reviews and reasoning easier. So those NULL-handling
> > fixes should be in one patch, the MCV patches in another one.
> >
> >
> > OK, such a split would make sense to me. Though, I'm a bit late as the
> > commitfest is already closed to new patches, I guess asking the CF
> > manager to split this might work (assuming I produce the patch files)?
>
> If the patch is broken into two files that gives the review/committer
> more options but I don't think it requires another CF entry.
>

Alright. I'm attaching the latest version of this patch split in two
parts: the first one is NULLs-related bugfix and the second is the
"improvement" part, which applies on top of the first one.

--
Alex

Attachment Content-Type Size
0001-Account-for-NULLs-in-ANALYZE-more-strictly.patch text/x-patch 4.3 KB
0002-Try-to-account-for-skewed-distributions-in-ANALYZE.patch text/x-patch 4.8 KB

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