Re: Should heapam_estimate_rel_size consider fillfactor?

>
> So maybe we should make table_block_relation_estimate_size smarter to
> also consider the fillfactor in the "no statistics" branch, per the
> attached patch.
>

I like this a lot. The reasoning is obvious, the fix is simple,it doesn't
upset any make-check-world tests, and in order to get a performance
regression we'd need a table whose fillfactor has been changed after the
data was loaded but before an analyze happens, and that's a narrow enough
case to accept.

My only nitpick is to swap

(usable_bytes_per_page * fillfactor / 100) / tuple_width

with

(usable_bytes_per_page * fillfactor) / (tuple_width * 100)

as this will eliminate the extra remainder truncation, and it also gets the
arguments "in order" algebraically.