Re: 8.x index insert performance

Kelly Burkhart <kelly@tradebotsystems.com> writes:
> Ha!  So I'm creating an index 98% full of nulls!  Looks like this is
> easily fixed with partial indexes.

Still, though, it's not immediately clear why you'd be seeing a severe
dropoff in insert performance after 50M rows.  Even though there are
lots of nulls, I don't see why they'd behave any worse for insert speed
than real data.  One would like to think that the insert speed would
follow a nice O(log N) rule.

Are you doing the inserts all in one transaction, or several?  If
several, could you get a gprof profile of inserting the same number of
rows (say a million or so) both before and after the unexpected dropoff
occurs?

            regards, tom lane