Re: [HACKERS] Bad n_distinct estimation; hacks suggested?

Guys,

> While it's not possible to get accurate estimates from a fixed size sample,
> I think it would be possible from a small but scalable sample: say, 0.1% of
> all data pages on large tables, up to the limit of maintenance_work_mem.

BTW, when I say "accurate estimates" here, I'm talking about "accurate enough
for planner purposes" which in my experience is a range between 0.2x to 5x.

--
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco