On Fri, 13 Dec 2002 16:41:38 +0100, Thomas Beutin
<tyrone@laokoon.IN-Berlin.DE> wrote:
>> >(visit >= '2002-10-01' AND visit <= '2002-10-31') index scan, but long (>5sec)
>>
>> Ca. 3%; interesting that it takes so long; I'd like to see EXPLAIN
Oops! Should be 10% according to the last two histogram bounds:
>> > "2002-09-29 09:09:31+02"
>> > "2002-10-29 23:25:13+01"
>> ANALYZE output for enable_seqscan on and off.
>There is no difference in cost.
Oops again! If it's already using an index scan, switching seqscan
off won't change anything. I should have meant "for enable_indexscan
on and off".
>> The negative correlation looks strange. How did you insert your data?
>It is a dump from the production system, and the production system gets
>the data once a day from webserver logs line by line.
Did you insert in reverse order (newest first)?
| most_common_freqs = {0.000666667,...,0.000666667}
These values occurred exactly twice in the analyzer's sample of 3000
values, so for the accuracy we need here it's ok to ignore them.
Servus
Manfred