Re: index usage

TL> Timur Irmatov <thor@sarkor.com> writes:
>> Limit  (cost=0.00..0.19 rows=1 width=6) (actual time=0.43..0.43 rows=0 loops=1)
>>   ->  Index Scan using timeindex on mediumstats  (cost=0.00..2898.96 rows=15185 width=6) (actual time=0.42..0.42
rows=0loops=1) 

TL> The planner has absolutely no clue about the behavior of your function,
TL> and so its estimate of the number of rows matched is way off, leading to
TL> a poor estimate of the cost of an indexscan.  There is not much to be
TL> done about this in the current system (though I've speculated about the
TL> possibility of computing statistics for functional indexes).

you're absolutely right.
thanks.

TL> Just out of curiosity, why don't you lose all this year/month/day stuff
TL> and use a timestamp column?  Less space, more functionality.

:-)
Well, I've a seen a lot of people on pgsql-general mailing list with
problems with dates, timestamps, and I was just scared of using
PostreSQL date and time types and functions..

May be, I should just try it myself before doing it other way...