Re: Optimize querry sql

Hi,

I deleted the fonction date_part and now the time of the querry is : 464 ms !!!


Limit  (cost=1373.32..1373.50 rows=15 width=27) (actual
time=463.762..463.857 rows=15 loops=1)  ->  HashAggregate  (cost=1373.32..1408.52 rows=2816 width=27)
(actual time=463.755..463.820 rows=15 loops=1)        ->  Hash Join  (cost=149.72..1189.22 rows=24546 width=27)
(actual time=42.106..348.561 rows=18543 loops=1)              Hash Cond: ("outer".idxreseller = "inner".idxreseller)
         ->  Seq Scan on stat a  (cost=0.00..545.27 rows=24877
 
width=8) (actual time=0.054..167.340 rows=24881 loops=1)                    Filter: ((month = 8) AND (year = 2007))
        ->  Hash  (cost=142.68..142.68 rows=2816 width=23)
 
(actual time=41.954..41.954 rows=2816 loops=1)                    ->  Seq Scan on reseller b  (cost=0.00..142.68
rows=2816 width=23) (actual time=0.035..28.447 rows=2816 loops=1)                          Filter: (asp = 6)Total
runtime:464.337 ms
 

Have you advices to optimize the query please ?

Stan

2007/9/14, hubert depesz lubaczewski <depesz@depesz.com>:
> On Fri, Sep 14, 2007 at 03:02:59PM +0200, Stanislas de Larocque wrote:
> > I want to optimize my query sql (execution time : 2665 ms) :
> SELECT
>     b.idxreseller,
>     sum(a.nbrq),
>     b.namereseller
> from
>     stat a,
>     reseller b
> where
>      b.asp=6
>      and a.idxreseller=b.reseller
>      and a.month=date_part('month',now() - interval '1 month')
>      and a.year=date_part('year',now() - interval '1 month')
> GROUP BY
>     b.idxreseller,b.namereseller limit 15;
>
> 1. cast all date_parts to int4, like in:
>     a.month = cast( date_part('month',now() - interval '1 month') as int4)
> 2. why there is a limit without any order by?
> 3. change it to get namereseller from subselect, not from join.
>
> depesz
>
> --
> quicksil1er: "postgres is excellent, but like any DB it requires a
> highly paid DBA.  here's my CV!" :)
> http://www.depesz.com/ - blog dla ciebie (i moje CV)
>


-- 
Stanislas de Larocque
dllstan@gmail.com
06 63 64 00 47