Hi,

I had errors in my last emails. sorry

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;


Explain analyse :

Limit (cost=1057.15..1057.16 rows=1 width=27) (actual
time=2655.083..2655.176 rows=15 loops=1)
-> HashAggregate (cost=1057.15..1057.16 rows=1 width=27) (actual
time=2655.074..2655.132 rows=15 loops=1)
-> Nested Loop (cost=0.00..1057.14 rows=1 width=27) (actual
time=0.646..2464.563 rows=18543 loops=1)
-> Seq Scan on stat a (cost=0.00..1042.98 rows=1
width=8) (actual time=0.273..1239.510 rows=24881 loops=1)
Filter: (((month)::double precision =
date_part('month'::text, (now() - '1 mon'::interval))) AND
((year)::double precision = date_part('year'::text, (now() - '1
mon'::interval))))
-> Index Scan using reseller_pkey on reseller b
(cost=0.00..14.15 rows=1 width=23) (actual time=0.034..0.038 rows=1
loops=24881)
Index Cond: ("outer".idxrreseller = b.idxreseller)
Filter: (asp = 6)
Total runtime: 2655.713 ms




dns=> \d stat;
Table «public.stat»

idxreseller | integer | not null
idxdo | integer | not null
idxd | integer | not null
nbrq | integer | default 0
month | integer | default date_part('month'::text, (now() -
'1 mon'::interval))
year | integer | default date_part('year'::text, (now() - '1
mon'::interval))

Index :
«stat_dns_domaine_idx_idxr_idxreseller» btree (dxreseller)
«stat_dns_domaine_idx_month_year_idxres» btree (month, year, idxreseller)




\d reseller;
Table «public.reseller»

idxreseller | integer | not null default
nextval(('idxrevendeur_seq'::text)::regclass)
namereseller | text |
asp | integer |
Index :
«reseller_pkey» PRIMARY KEY, btree (idxreseller)


Have you advices ?

Thank you

Stan

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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)

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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

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On Mon, Sep 17, 2007 at 09:17:58AM +0200, Stanislas de Larocque wrote:
> Have you advices to optimize the query please ?

for some many rows the 400ms looks quite reasonable.

the best thing you can make to speed things up is to calculate the
counts with triggers.

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)

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