Skip site navigation (1) Skip section navigation (2)

Bitmap indexes

From: Alex Turner <armtuk(at)gmail(dot)com>
To: PostgreSQL Perfomance <pgsql-performance(at)postgresql(dot)org>
Subject: Bitmap indexes
Date: 2005-01-28 15:39:52
Message-ID: 33c6269f0501280739344f6a18@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
I was wondering about index types.  Oracle has an index type called a
'bitmap' index.  They describe this as an index for low cardinality
fields, where only the cardinal values are indexed in a b-tree, and
then it uses a bitmap below that to describe rows.  They say that this
type of index is very fast when combined with queries that used the
indexed row in 'AND' clauses in a sql statement as the index can
'mask' the results very fast.  I have not been able to benchmark the
actual effectiveness of this kind of index, but I was wondering if
anyone has had experience with this an believes it might be a useful
feature for postgres?

Yes I have a vested interest in this because alot of my searches are
masked against low cardinality fields 'Y' or 'N' type things where
this could potentialy benefit me...

Alex Turner
NetEconomist

Responses

pgsql-performance by date

Next:From: Alex TurnerDate: 2005-01-28 15:59:58
Subject: Re: PostgreSQL clustering VS MySQL clustering
Previous:From: Andrew SullivanDate: 2005-01-28 15:36:20
Subject: Re: PostgreSQL clustering VS MySQL clustering

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group