Timing trouble with GROUP BY PostgreSQL / Oracle ? - Mailing list pgsql-sql

From Hervé Piedvache
Subject Timing trouble with GROUP BY PostgreSQL / Oracle ?
Date
Msg-id 3A06EFB6.14BF8E19@elma.fr
Whole thread Raw
List pgsql-sql
Hi,

I would like to know if someone have a solution for me ...

I have a table with today about 2,8 millions records.
The table have good indexes, in our case on idcond, and points !

When I do :
select sum(points) from gains;

With Oracle : 8 sec
With PostGreSQL : 10 sec

OK for this it's ok ...

But when I do :
select sum(points) from gains group by idcond;

With Oracle : 22 sec
With PostGreSQL : about 3 minutes !!!

I have done a vacuum analyse of the table gains ... just before testing
...
What can I do to optimize that result ?

Why the group by function is so slow ??

Thanks for your help !

Regards,
-- 
Hervé Piedvache

Elma Ingenierie Informatique
6, rue du Faubourg Saint-Honoré
F-75008 - Paris - France 
http://www.elma.fr
Tel: +33-1-44949901
Fax: +33-1-44949902 
Email: herve@elma.fr


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