"Hash index" vs. "b-tree index" (PostgreSQL 8.0)

From: Ying Lu <ying_lu(at)cs(dot)concordia(dot)ca>
To: pgsql-general(at)postgresql(dot)org
Cc: pgsql-performance(at)postgresql(dot)org
Subject: "Hash index" vs. "b-tree index" (PostgreSQL 8.0)
Date: 2005-05-09 13:40:35
Message-ID: 427F6853.90308@cs.concordia.ca
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-general pgsql-performance


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

May I know for simple "=" operation query, for "Hash index" vs. "B-tree"
index, which can provide better performance please?



Browse pgsql-general by date

  From Date Subject
Next Message Tom Lane 2005-05-09 13:47:14 Re: = or := ?
Previous Message John D. Burger 2005-05-09 13:04:49 Re: Shorthand for foreign key indices

Browse pgsql-performance by date

  From Date Subject
Next Message Neil Conway 2005-05-09 14:36:42 Re: "Hash index" vs. "b-tree index" (PostgreSQL 8.0)
Previous Message Harald Fuchs 2005-05-09 11:39:30 Re: Query tuning help