Обсуждение: General performance problem!

-----Original Message-----
From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org]On Behalf Of olivier HARO
Sent: dinsdag 17 augustus 2004 15:30
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 ;) 

 

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olivier HARO wrote:

> 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 ...

Show us a explain analyze for that queries.


Regards
Gaetano Mendola

olivier HARO wrote:
> 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 

We'll need to know what version of PostgreSQL you're using and also what
the output of EXPLAIN ANALYZE shows for your example queries.

--
   Richard Huxton
   Archonet Ltd

Thanks for the tip for the index on multiple columns !  (I never do inserts
on this table so insert time doesn't matter)

Mys posgresql version is : PostgreSQL 7.2.1

Here are the results of the EXPLAIN ANALYZE you asked me to execute.


explain analyse select cp from base_aveugle where cp='69740' and effectif
between 1 and 50;
   NOTICE:  QUERY PLAN:
      Index Scan using base_aveugle_cp_eff on base_aveugle
(cost=0.00..508.69 rows=126 width=32)
      (actual time=0.27..11.56 rows=398 loops=1)
      Total runtime: 11.77 msec
   EXPLAIN

explain analyse select cp from base_aveugle where cp like '69%' and effectif
between 1 and 50 and naf like '24%' or naf like '25%';
   NOTICE:  QUERY PLAN:
   Index Scan using base_aveugle_cp_eff_naf, base_aveugle_naf on
base_aveugle  (cost=0.00..100001.89 rows=25245 width=32)
   (actual time=4.40..353.69 rows=6905 loops=1)
   Total runtime: 355.82 msec
   EXPLAIN


thx ;)


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