From: Jesper Krogh <jesper@krogh.cc>
To: pgsql-performance@postgresql.org
Subject: Re: Indexes with condition using immutable functions applied to column not used
Date: Tue, 08 Feb 2011 06:15:22 +0100
Message-ID: <4D50D16A.1060802@krogh.cc> (raw)
In-Reply-To: <1297124098.2549.65.camel@kheops>
References: <1297124098.2549.65.camel@kheops>
On 2011-02-08 01:14, Sylvain Rabot wrote:
> CREATE INDEX directory_id_user_mod_cons_hash_0_btree_idx ON mike.directory USING btree (id_user) WHERE __mod_cons_hash(id_user, 4) = 0;
> CREATE INDEX directory_id_user_mod_cons_hash_1_btree_idx ON mike.directory USING btree (id_user) WHERE __mod_cons_hash(id_user, 4) = 1;
> CREATE INDEX directory_id_user_mod_cons_hash_2_btree_idx ON mike.directory USING btree (id_user) WHERE __mod_cons_hash(id_user, 4) = 2;
> CREATE INDEX directory_id_user_mod_cons_hash_3_btree_idx ON mike.directory USING btree (id_user) WHERE __mod_cons_hash(id_user, 4) = 3;
>
> mike=# EXPLAIN ANALYZE SELECT * FROM directory WHERE id_user = 4;
Should be written as:
select * from directory where __mod_cons_hash(id_user,4) = 4%4;
Then it should just work.
--
Jesper
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To: pgsql-performance@postgresql.org
Cc: jesper@krogh.cc
Subject: Re: Indexes with condition using immutable functions applied to column not used
In-Reply-To: <4D50D16A.1060802@krogh.cc>
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