Date: Wed, 20 Jan 2016 18:54:16 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Bruce Momjian <bruce@momjian.us>
Cc: Robert Haas <robertmhaas@gmail.com>,
 Tomas Vondra <tomas.vondra@2ndquadrant.com>,
 "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: multivariate statistics v8
Message-ID: <20160120215416.GA378214@alvherre.pgsql>
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Bruce Momjian wrote:
> On Wed, Jan 20, 2016 at 02:20:38PM -0500, Robert Haas wrote:
> > On Wed, Dec 23, 2015 at 2:07 PM, Tomas Vondra
> > <tomas.vondra@2ndquadrant.com> wrote:
> > >    The remaining question is how unique the statistics name should be.
> > >    My initial plan was to make it unique within a table, but that of
> > >    course does not work well with the DROP STATISTICS (it'd have to
> > >    specify the table name also), and it'd also now work with statistics
> > >    on multiple tables (which is one of the reasons for abandoning ALTER
> > >    TABLE stuff).
> > >
> > >    So I think it should be unique across tables. Statistics are hardly
> > >    a global object, so it should be unique within a schema. I thought
> > >    that simply using the schema of the table would work, but that of
> > >    course breaks with multiple tables in different schemas. So the only
> > >    solution seems to be explicit schema for statistics.
> > 
> > That solution seems good to me.
> > 
> > (with apologies for not having looked at the rest of this much at all)
> 
> Woh, this will be an optimizer game-changer, from the user perspective!

That is the intent.  The patch is huge, though -- any reviewing help is
welcome.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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