| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Gregory Stark <stark(at)enterprisedb(dot)com>, Simon Riggs <simon(at)2ndQuadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, 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 18:16:18 |
| Message-ID: | 200812121816.mBCIGIS10660@momjian.us |
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| Lists: | pgsql-hackers |
Alvaro Herrera wrote:
> Tom Lane escribi?:
>
> > If you want ANALYZE to be cheap then you simply don't get to have a
> > trustworthy value of ndistinct.
>
> But then, maybe it's not all that critical that ANALYZE is cheap. For
> example, if we were to rework VACUUM ANALYZE so that on the same pass
> that VACUUM cleans each heap page, a callback is called on the page to
> grab the needed stats.
>
> Partial vacuum is a roadblock for this though :-(
Perhaps it isn't because partial vacuum is going to highlight the
_changed_ blocks, which fits into your idea of merging stats, somehow. ;-)
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
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