Horton

Re: multivariate statistics (v25)

David Rowley <david.rowley@2ndquadrant.com>

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From: David Rowley <david.rowley@2ndquadrant.com>
To: nospam-abuse@bloodgate.com
Cc: Simon Riggs <simon@2ndquadrant.com>, Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, David Fetter <david@fetter.org>, Dean Rasheed <dean.a.rasheed@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-04-05T22:16:41Z
Lists: pgsql-hackers 
On 6 April 2017 at 07:19, Tels <nospam-abuse@bloodgate.com> wrote:
> I know I'm a bit late, but isn't the syntax backwards?
>
> "CREATE STATISTICS s1 WITH (dependencies) ON (col_a, col_b) FROM table;"
>
> These do it the other way round:
>
> CREATE INDEX idx ON table (col_a);
>
> AND:
>
>    CREATE TABLE t (
>      id INT  REFERENCES table_2 (col_b);
>    );
>
> Won't this be confusing and make things hard to remember?
>
> Sorry for not asking earlier, I somehow missed this.

The reasoning is in [1]

[1] https://www.postgresql.org/message-id/CAEZATCUtGR+U5+QTwjHhe9rLG2nguEysHQ5NaqcK=VbJ78VQFA@mail.gmail.com


-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

Commits

  1. Collect and use multi-column dependency stats

  2. Implement SortSupport for macaddr data type

  3. Implement multivariate n-distinct coefficients

  4. Generate fmgr prototypes automatically