| From: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
|---|---|
| To: | Gregory Stark <stark(at)enterprisedb(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, "jd(at)commandprompt(dot)com" <jd(at)commandprompt(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, Greg Smith <gsmith(at)gregsmith(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: benchmarking the query planner |
| Date: | 2008-12-12 17:09:57 |
| Message-ID: | 1229101797.8673.56.camel@ebony.2ndQuadrant |
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| Lists: | pgsql-hackers |
On Fri, 2008-12-12 at 16:10 +0000, Gregory Stark wrote:
> Uhm, this is a survey of lots of different methods and does lots of
> analysis.
> I don't see any simple conclusions about stability. Perhaps I'm just
> missing
> it in the technical details. Could you point out exactly what part of
> the
> paper you're basing this on and what "stable" means?
I was echoing the comments in the ANALYZE code, which explain that we
use the Duj1 estimator because it is more stable across sample size, as
shown in table 5 on p.21 of the Haas Stokes report.
--
Simon Riggs www.2ndQuadrant.com
PostgreSQL Training, Services and Support
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