| From: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
|---|---|
| To: | Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> |
| Cc: | pgsql-committers(at)lists(dot)postgresql(dot)org |
| Subject: | Re: pgsql: Improve ANALYZE's strategy for finding MCVs. |
| Date: | 2018-03-22 10:45:59 |
| Message-ID: | CANP8+jKpBe7_=uQkhK7V6N4ON4SLBEVjVPpMCwyFTtwoYro8ug@mail.gmail.com |
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| Lists: | pgsql-committers |
On 22 March 2018 at 09:42, Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> wrote:
> Improve ANALYZE's strategy for finding MCVs.
> Thus it tends to produce
> fewer MCVs than the previous code for uniform distributions, and more
> for non-uniform distributions, reducing estimation errors in both
> cases. In addition, the algorithm responds better to increasing the
> statistics target, allowing more values to be included in the MCV list
> when more of the table is sampled.
>
> Jeff Janes, substantially modified by me. Reviewed by John Naylor and
> Tomas Vondra.
git praise --all
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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