Re: Oracle v. Postgres 9.0 query performance

Here's the explain analyze:

pg_dw=# explain analyze CREATE TABLE ecr_opens with (FILLFACTOR=100)
as
select o.emailcampaignid, count(memberid) opencnt
from openactivity o,ecr_sents s
where s.emailcampaignid = o.emailcampaignid
group by o.emailcampaignid;

QUERY
PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------
GroupAggregate (cost=0.00..1788988.05 rows=9939 width=12) (actual
time=308630.967..2592279.526 rows=472 loops=1)
-> Nested Loop (cost=0.00..1742467.24 rows=9279316 width=12)
(actual time=31.489..2589363.047 rows=8586466 loops=1)
-> Index Scan using ecr_sents_ecid_idx on ecr_sents s
(cost=0.00..38.59 rows=479 width=4) (actual time=0.010..13.326 rows=479
loops=1)
-> Index Scan using openact_emcamp_idx on openactivity o
(cost=0.00..3395.49 rows=19372 width=12) (actual time=1.336..5397.139
rows=17926 loops=479)
Index Cond: (o.emailcampaignid = s.emailcampaignid)
Total runtime: 2592284.336 ms

On Wed, 2011-06-08 at 17:31 +0200, tv(at)fuzzy(dot)cz wrote:
> > On Postgres, this same query takes about 58 minutes (could not run
> > explain analyze because it is in progress):
> >
> > pg_dw=# explain CREATE TABLE ecr_opens with (FILLFACTOR=100)
> > pg_dw-# as
> > pg_dw-# select o.emailcampaignid, count(memberid) opencnt
> > pg_dw-# from openactivity o,ecr_sents s
> > pg_dw-# where s.emailcampaignid = o.emailcampaignid
> > pg_dw-# group by o.emailcampaignid;
> > QUERY
> > PLAN
> > -------------------------------------------------------------------------------------------------------------
> > GroupAggregate (cost=0.00..1788988.05 rows=9939 width=12)
> > -> Nested Loop (cost=0.00..1742467.24 rows=9279316 width=12)
> > -> Index Scan using ecr_sents_ecid_idx on ecr_sents s
> > (cost=0.00..38.59 rows=479 width=4)
> > -> Index Scan using openact_emcamp_idx on openactivity o
> > (cost=0.00..3395.49 rows=19372 width=12)
> > Index Cond: (o.emailcampaignid = s.emailcampaignid)
> > (5 rows)
> >
>
> Please, post EXPLAIN ANALYZE, not just EXPLAIN. Preferably using
> explain.depesz.com.
>
> regards
> Tomas
>
>