Re: [SQL] Queries not using Index

From: "Christopher Kings-Lynne" <chriskl(at)familyhealth(dot)com(dot)au>
To: "Elielson Fontanezi" <ElielsonF(at)prodam(dot)sp(dot)gov(dot)br>, "'Daryl Herzmann'" <akrherz(at)iastate(dot)edu>
Cc: "pgsql-sql" <pgsql-sql(at)postgresql(dot)org>, "pgsql-general" <pgsql-general(at)postgresql(dot)org>
Subject: Re: [SQL] Queries not using Index
Date: 2002-07-24 15:48:08
Message-ID: 001801c23329$82b8a590$0200a8c0@SOL
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> 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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