Re: Index question

"David Witham" <davidw@unidial.com.au> writes:
> I understand that selecting count(*) will involve a scan at some
> stage, but I was surprised that the index wasn't used in the >= case,
> but was used in the between case.

Given the estimated row counts in your examples, the planner's choices
are not surprising.  You have not given us any information on whether
those estimates are accurate.
        regards, tom lane