From: Arnau <arnaulist@andromeiberica.com>
To: pgsql-performance@postgresql.org
Subject: Query on postgresql 7.4.2 not using index
Date: Tue, 25 Apr 2006 15:28:45 +0200
Message-ID: <444E240D.3050000@andromeiberica.com> (raw)
Hi all,
I have the following running on postgresql version 7.4.2:
CREATE SEQUENCE agenda_user_group_id_seq
MINVALUE 1
MAXVALUE 9223372036854775807
CYCLE
INCREMENT 1
START 1;
CREATE TABLE AGENDA_USERS_GROUPS
(
AGENDA_USER_GROUP_ID INT8
CONSTRAINT pk_agndusrgrp_usergroup PRIMARY KEY
DEFAULT NEXTVAL('agenda_user_group_id_seq'),
USER_ID NUMERIC(10)
CONSTRAINT fk_agenda_uid REFERENCES
AGENDA_USERS (USER_ID)
ON DELETE CASCADE
NOT NULL,
GROUP_ID NUMERIC(10)
CONSTRAINT fk_agenda_gid REFERENCES
AGENDA_GROUPS (GROUP_ID)
ON DELETE CASCADE
NOT NULL,
CREATION_DATE DATE
DEFAULT CURRENT_DATE,
CONSTRAINT un_agndusrgrp_usergroup
UNIQUE(USER_ID, GROUP_ID)
);
CREATE INDEX i_agnusrsgrs_userid ON AGENDA_USERS_GROUPS ( USER_ID );
CREATE INDEX i_agnusrsgrs_groupid ON AGENDA_USERS_GROUPS ( GROUP_ID );
When I execute:
EXPLAIN ANALYZE SELECT agenda_user_group_id FROM agenda_users_groups
WHERE group_id = 9;
it does a sequential scan and doesn't use the index and I don't
understand why, any idea? I have the same in postgresql 8.1 and it uses
the index :-|
Thanks
--
Arnau
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: arnaulist@andromeiberica.com
Subject: Re: Query on postgresql 7.4.2 not using index
In-Reply-To: <444E240D.3050000@andromeiberica.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox