pg.ddx.io  pgsql-sql@postgresql.org mailing list archive  
help / color / mirror / Atom feed
From: Bruno Wolff III <bruno@wolff.to>
To: Wei Weng <wweng@kencast.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: create index on function - why?
Date: Fri, 15 Feb 2002 11:01:28 -0600
Message-ID: <20020215170128.GB2025@wolff.to> (raw)
In-Reply-To: <3C6D3684.9040101@kencast.com>
References: <3C6D3684.9040101@kencast.com>

On Fri, Feb 15, 2002 at 11:25:40AM -0500,
  Wei Weng <wweng@kencast.com> wrote:
> I can understand the rationale behind creating index on tables, it 
> speeds up the searching.
> 
> But what is the rationale behind creating index on a function? how does 
> it help with the database performance?

If a where clause includes a function reference, than an index on that
function can speed up finding rows that satisfy the where clause.



view thread (10+ messages)  latest in thread

Message-ID: <20020215170128.GB2025@wolff.to>
Permalink:  ../20020215170128.GB2025@wolff.to/
Also on:    postgresql.org/message-id/20020215170128.GB2025@wolff.to

 · 

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-sql@postgresql.org
  Cc: bruno@wolff.to, wweng@kencast.com
  Subject: Re: create index on function - why?
  In-Reply-To: <20020215170128.GB2025@wolff.to>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox