RE: question about index cost estimates

> -----Original Message-----
> From: pgsql-hackers-owner@hub.org [mailto:pgsql-hackers-owner@hub.org]On
> Behalf Of Jeff Hoffmann
>

[snip] 

> 
>  pages_fetched = ceil(baserel->pages * log(tuples_fetched /
> baserel->pages + 1.0));
>

Unfortunately I didn't understand this well either.

pages_fetched seems to be able to be greater than
baserel->pages. But if there's sufficiently large buffer
space pages_fetched would be <= baserel->pages.
Are there any assupmtions about buffer space ?

Regards.

Hiroshi Inoue
Inoue@tpf.co.jp