| From: | Josh Berkus <josh(at)agliodbs(dot)com> |
|---|---|
| To: | pgsql-perform <pgsql-performance(at)postgresql(dot)org>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Bad n_distinct estimation; hacks suggested? |
| Date: | 2005-04-23 23:53:16 |
| Message-ID: | 200504231653.16317.josh@agliodbs.com |
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| Lists: | pgsql-hackers pgsql-performance |
People,
> Can someone whose math is more recent than calculus in 1989 take a look at
> that paper, and look at the formula toward the bottom of page 10, and see
> if we are correctly interpreting it? I'm particularly confused as to
> what "q" and "d-sub-n" represent. Thanks!
Actually, I managed to solve for these and it appears we are using the formula
correctly. It's just a bad formula.
--
--Josh
Josh Berkus
Aglio Database Solutions
San Francisco
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