Re: [pgsql-advocacy] Correlated columns & firsts - Mailing list pgsql-advocacy

From Alvaro Herrera
Subject Re: [pgsql-advocacy] Correlated columns & firsts
Date
Msg-id 20170726174618.hbs5o2gvqpmi2hqj@alvherre.pgsql
Whole thread Raw
In response to [pgsql-advocacy] Correlated columns & firsts  (Josh Berkus <josh@berkus.org>)
Responses Re: [pgsql-advocacy] Correlated columns & firsts  (Daniel Westermann <daniel.westermann@dbi-services.com>)
List pgsql-advocacy
Josh Berkus wrote:
> Folks,
>
> I had the impression that our new multicolumn stats feature was a first
> in the industry.  However, a PDXPUG member said that SQL Server has
> something like it for the last couple versions.
>
> Anyone know if it's the same thing or not?

A quick search led me to
https://dba.stackexchange.com/questions/84747/statistics-are-multicolumn-histograms-possible
which contains a pointer to
https://blogs.msdn.microsoft.com/ianjo/2005/11/10/create-multi-column-statistics/

then you can see the MS docs at
https://docs.microsoft.com/en-us/sql/t-sql/statements/create-statistics-transact-sql
https://docs.microsoft.com/en-us/sql/relational-databases/statistics/statistics

From what I can tell, they only store the correlation between the
columns, so it's simpler than what we do.

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


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