Re: Speed or configuration - Mailing list pgsql-sql

From Franz J Fortuny
Subject Re: Speed or configuration
Date
Msg-id WbTo5.2892$ZU2.119403@news-west.usenetserver.com
Whole thread Raw
In response to Speed or configuration  ("Franz J Fortuny" <ffortuny@ivsol.com>)
List pgsql-sql
Any light on this subject?
 
The Hermit Hacker wrote:

"use cut-n-paste please, and send us the results of the
EXPLAIN ... stuff
like the cost estimates and whatnot tell us *so* much
..."

This is it:

exis=# \d pvdprcod
 NUMART    | integer     | not null
 NUMDEP    | smallint    | not null
 NUMPRO    | smallint    | not null
 MODELO    | varchar(20) | not null
 TALLA     | varchar(4)  | not null
 COLOR     | varchar(3)  | not null

exis=# \d venart
 cvetda    | smallint   | not null
 numdep    | smallint   | not null
 numart    | integer    | not null
 mes       | smallint   | not null
 anio      | integer    | not null
 tipotr    | varchar(2) |
 importe   | float8     |
 cantidad  | float8     |

exis=# explain select
cvetda,anio,mes,sum(importe),sum(cantidad)
exis-# from venart where numart in
exis-# (select "NUMART" from pvdprcod where "NUMDEP"=7
and "NUMPRO"=108)
exis-# group by cvetda,numdep,anio,mes;
NOTICE:  QUERY PLAN:

Aggregate  (cost=79015875401357.48..79015875413208.91
rows=79010 width=26)
  ->  Group  (cost=79015875401357.48..79015875409258.44
rows=790095 width=26)
        ->  Sort
(cost=79015875401357.48..79015875401357.48 rows=790095
width=26)
              ->  Seq Scan on venart
(cost=100000000.00..79015875283591.09 rows=790095
width=26)
                    SubPlan
                      ->  Materialize
(cost=100007942.42..100007942.42 rows=34 width=4)
                            ->  Seq Scan on pvdprcod
(cost=100000000.00..100007942.42 rows=34 width=4)

EXPLAIN

Why Seq Scan if indexes have been created on the
columns used for access?

Best regards,

Franz J Fortuny



pgsql-sql by date:

Previous
From: drfrog@smartt.com
Date:
Subject: db benchmarks
Next
From: "Hiroshi Inoue"
Date:
Subject: RE: Create table in functions