From: Darcy Buskermolen <darcy@wavefire.com>
To: weigelt@metux.de
Cc: postgresql performance list <pgsql-performance@postgresql.org>
Subject: Re: index not used
Date: Thu, 21 Apr 2005 12:23:52 -0700
Message-ID: <200504211223.52612.darcy@wavefire.com> (raw)
In-Reply-To: <20050421190543.GA16548@nibiru.borg.metux.de>
References: <20050421190543.GA16548@nibiru.borg.metux.de>
On Thursday 21 April 2005 12:05, Enrico Weigelt wrote:
> Hi folks,
>
>
> I'm doing a simple lookup in a small table by an unique id, and I'm
> wondering, why explains tells me seqscan is used instead the key.
>
> The table looks like:
>
> id bigint primary key,
> a varchar,
> b varchar,
> c varchar
>
> and I'm quering: select * from foo where id = 2;
>
> I've got only 15 records in this table, but I wanna have it as
> fast as possible since its used (as a map between IDs and names)
> for larger queries.
The over head to load the index, fetch the record in there, then check the
table for visibility and return the value, is far greater than just doing 15
compares in the original table.
>
>
> thx
--
Darcy Buskermolen
Wavefire Technologies Corp.
http://www.wavefire.com
ph: 250.717.0200
fx: 250.763.1759
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To: pgsql-performance@postgresql.org
Cc: darcy@wavefire.com, weigelt@metux.de
Subject: Re: index not used
In-Reply-To: <200504211223.52612.darcy@wavefire.com>
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