On 2/22/04 6:40 PM, Tom Lane wrote:
> John Siracusa <siracusa(at)mindspring(dot)com> writes:
>> I think the key is to get the planner to correctly ballpark the number of
>> rows in the date range.
>
> I thought it was. What you showed was
>
> -> Index Scan using mytable_date_idx on mytable (cost=0.00..3071.70 rows=52155
> width=23) (actual time=2.610..1688.111 rows=49679 loops=1)
>
> which seemed plenty close enough to me.
That's after the planner correctly chooses the date index. Unfortunately, I
forgot to save the EXPLAIN output from when it was choosing seqscan instead.
Does the planner get estimates from both plans before deciding whether or
not to use the one that references the date index?
-John