Re: Optimizing query

Uros wrote:

> Hello!
>
> I have some trouble getting good results from my query.
>
> here is structure
>
> stat_views
> id        | integer
> id_zone   | integer
> created   | timestamp
>
>
> I have btree index on created and also id and there is  1633832 records in
> that table
>
> First of all I have to manualy set seq_scan to OFF because I always get
> seq_scan. When i set it to off my explain show:
>
> explain SELECT count(*) as views FROM stat_views WHERE id = 12;
>                                              QUERY PLAN
> ----------------------------------------------------------------------------------------------------
>  Aggregate  (cost=122734.86..122734.86 rows=1 width=0)
>    ->  Index Scan using stat_views_id_idx on stat_views  (cost=0.00..122632.60 rows=40904 width=0)
>          Index Cond: (id = 12)
>
> But what I need is to count views for some day, so I use
>
> explain SELECT count(*) as views FROM stat_views WHERE date_part('day', created) = 18;
>
>                                      QUERY PLAN
> ------------------------------------------------------------------------------------
>  Aggregate  (cost=100101618.08..100101618.08 rows=1 width=0)
>    ->  Seq Scan on stat_views  (cost=100000000.00..100101565.62 rows=20984 width=0)
>          Filter: (date_part('day'::text, created) = 18::double precision)
>
>
> How can I make this to use index and speed the query. Now it takes about 12
> seconds.

Can you post explain analyze for the same?

  Shridhar