From: Ying Lu <ying_lu@cs.concordia.ca>
To: pgsql-general@postgresql.org
Cc: pgsql-performance@postgresql.org
Subject: "Hash index" vs. "b-tree index" (PostgreSQL 8.0)
Date: Mon, 09 May 2005 09:40:35 -0400
Message-ID: <427F6853.90308@cs.concordia.ca> (raw)
Greetings,
We are working on speeding up the queries by creating indexes. We have
queries with searching criteria such as "select ... where *col1='...'*".
This is a simple query with only "=" operation. As a result I setup hash
index on column "col1". While, in postgreSQL 8 doc, it is wirttern:
*Note: * Testing has shown PostgreSQL's hash indexes to perform no
better than B-tree indexes, and the index size and build time for hash
indexes is much worse. For these reasons, hash index use is presently
discouraged.
May I know for simple "=" operation query, for "Hash index" vs. "B-tree"
index, which can provide better performance please?
Thanks,
Emi
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To: pgsql-performance@postgresql.org
Cc: ying_lu@cs.concordia.ca, pgsql-general@postgresql.org
Subject: Re: "Hash index" vs. "b-tree index" (PostgreSQL 8.0)
In-Reply-To: <427F6853.90308@cs.concordia.ca>
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