Horton

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

Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>

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From: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
To: robertmhaas@gmail.com
Cc: tomas.vondra@2ndquadrant.com, dean.a.rasheed@gmail.com, david.rowley@2ndquadrant.com, alvherre@2ndquadrant.com, michael@paquier.xyz, andres@anarazel.de, thomas.munro@enterprisedb.com, bruce@momjian.us, hornschnorter@gmail.com, pgsql-hackers@postgresql.org
Date: 2019-03-14T11:50:16Z
Lists: pgsql-hackers 
At Wed, 13 Mar 2019 12:39:30 -0400, Robert Haas <robertmhaas@gmail.com> wrote in <CA+TgmobvgTNWCeod_nqOJuPOYRecXd8XcsP4E2b8sbeGVygGJg@mail.gmail.com>
> On Wed, Mar 13, 2019 at 12:20 AM Kyotaro HORIGUCHI
> <horiguchi.kyotaro@lab.ntt.co.jp> wrote:
> > +Multivariate MCV (most-common values) lists are a straightforward extension of
> >
> >   "lists are *a*" is wrong?
> 
> No, that's correct.  Not sure exactly what your concern is, but it's
> probably related to the fact that the first parent of the sentences
> (before "are") is plural and the second part is singular.  It does

Exactly, with some doubt on my reading.

> seem a little odd that you can say "lists are an extension," mixing
> singular and plural, but English lets you do stuff like that.

Thank you for the kind explanation. I'm not sure but I understand
this as '"lists" is an extension' turned into 'lists are an
extension'. That is, the "lists' expresses a concept rather than
the plurarilty. (But I haven't got a gut feeling..)

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

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