Philip Warner <pjw(at)rhyme(dot)com(dot)au> writes:
> At 09:36 AM 2/11/2002 -0500, Tom Lane wrote:
>> BTW, the system does not actually have any stats about dead tuples.
>> What it knows about are live tuples and total disk pages occupied by
>> the table.
> So what made it choose the index scan?
Well, the main component of the seqscan cost estimate is the total
number of disk pages, while the indexscan cost estimate is driven
by the number of tuples expected to be retrieved.
regards, tom lane