From: Christopher Kings-Lynne <chriskl@familyhealth.com.au>
To: Elielson Fontanezi <ElielsonF@prodam.sp.gov.br>
To: 'Daryl Herzmann' <akrherz@iastate.edu>
Cc: pgsql-sql <pgsql-sql@postgresql.org>
Cc: pgsql-general <pgsql-general@postgresql.org>
Subject: Re: [SQL] Queries not using Index
Date: Wed, 24 Jul 2002 23:48:08 +0800
Message-ID: <001801c23329$82b8a590$0200a8c0@SOL> (raw)
References: <A799F7647794D311924A005004ACEA97080DDE89@cprodamibs249.prodam>
> This SELECT causes a sequention scan 'cause your index
> is not HASH type, but likely a BTREE one.
> BTREE index is to interval searches (station = 'SAMI4%')
> not precise searchs. (station = 'SAMI4').
In Postgres, the hash index is slow and inefficient (it's a bit better
in7.3), and I believe btree is generally recommended over hash even for '='
instances.
Chris
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Cc: chriskl@familyhealth.com.au, ElielsonF@prodam.sp.gov.br, akrherz@iastate.edu, pgsql-general@postgresql.org
Subject: Re: [SQL] Queries not using Index
In-Reply-To: <001801c23329$82b8a590$0200a8c0@SOL>
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