> Assuming that the threshold
> for switching to an indexscan is somewhere around selectivity 0.005
> (I am not certain offhand, but it's in that general area), this cannot
> possibly require more than 200 MCV slots, and for most data
> distributions it'd be a whole lot less.
Thats a really good point.
> Given such an MCV list, the planner will always make the right choice
> of whether to do index or seqscan
Given that, wouldn't it be smarter to consider a value as an mcv
candidate iff it has a density greater than 0.005, rather than having
a count greater than 1.5*average? This would allow people to raise the
hard mcv limit without having to worry as much about including
worthless mcv values...
Cheers,
Nathan