An index on cp and effectif would help your first query. An index on naf, cp and effectif would help your second query.
Something like this:
CREATE INDEX base_aveugle_cp_key2 ON base_aveugle USING btree (cp, effectif);
CREATE INDEX base_aveugle_naf_key2 ON base_aveugle USING btree (naf, cp, effectif);
Another thing, why include “distinct cp” when you are only selecting “cp=’201A’”? You will only retrieve one record regardless of how many may contain cp=’201A’.
If you could make these UNIQUE indexes that would help also but it’s not a requirement.
Good luck,
Duane
-----Original Message-----
From: olivier HARO [mailto:o.haro@en-compro.com]
Sent: Tuesday, August 17, 2004 6:30 AM
To: pgsql-performance@postgresql.org
Subject: [PERFORM] General performance problem!
Hello,
I have a dedicated server for my posgresql database :
P4 2.4 GHZ
HDD IDE 7200 rpm
512 DDR 2700
I have a problem whith one table of my database :
CREATE SEQUENCE "base_aveugle_seq" START 1;
CREATE TABLE "base_aveugle" (
"record_id" integer DEFAULT nextval('"base_aveugle_seq"'::text) NOT NULL,
"dunsnumber" integer NOT NULL,
"cp" text NOT NULL,
"tel" text NOT NULL,
"fax" text NOT NULL,
"naf" text NOT NULL,
"siege/ets" text NOT NULL,
"effectif" integer NOT NULL,
"ca" integer NOT NULL,
Constraint "base_aveugle_pkey" Primary Key ("record_id")
);
CREATE INDEX base_aveugle_dunsnumber_key ON base_aveugle USING btree (dunsnumber);
CREATE INDEX base_aveugle_cp_key ON base_aveugle USING btree (cp);
CREATE INDEX base_aveugle_naf_key ON base_aveugle USING btree (naf);
CREATE INDEX base_aveugle_effectif_key ON base_aveugle USING btree (effectif);
This table contains 5 000 000 records
I have a PHP application which often makes queries on this table (especially on the "cp","naf","effectif" fields)
Querries are like :
select (distint cp) from base_aveugle where cp='201A' and effectif between 1 and 150
select (*) from base_aveugle where naf in ('721A','213F','421K') and cp in ('54210','21459','201A') and effectif < 150
I think it is possible to optimize the performance of this queries before changing the hardware (I now I will...) but I don't know how, even after having read lot of things about postgresql ...
Thanks ;)
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.737 / Virus Database: 491 - Release Date: 11/08/2004