Re: improving GROUP BY estimation

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com>
Cc: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru>, Mark Dilger <hornschnorter(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: improving GROUP BY estimation
Date: 2016-04-02 14:59:16
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Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> writes:
> Here's an updated patch with references to both papers, and a more
> detailed justification for the formula, along with the other changes
> discussed. Note that although equation (2) in the Dell'Era paper looks
> different from the Yao formula, it's actually the same.

Looks good to me.

regards, tom lane

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