Re: TEXT field and Postgresql Perfomance - Mailing list pgsql-performance

From Bruno Wolff III
Subject Re: TEXT field and Postgresql Perfomance
Date
Msg-id 20050108040323.GA13889@wolff.to
Whole thread Raw
In response to TEXT field and Postgresql Perfomance  ("Loren M. Lang" <lorenl@alzatex.com>)
Responses Re: TEXT field and Postgresql Perfomance  (Alex Turner <armtuk@gmail.com>)
Re: TEXT field and Postgresql Perfomance  (Michael Fuhr <mike@fuhr.org>)
Re: TEXT field and Postgresql Perfomance  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
On Fri, Jan 07, 2005 at 19:36:47 -0800,
  "Loren M. Lang" <lorenl@alzatex.com> wrote:
> Do large TEXT or VARCHAR entries in postgresql cause any performance
> degradation when a query is being executed to search for data in a table
> where the TEXT/VARCHAR fields aren't being searched themselves?

Yes in that the data is more spread out because of the wider rows and that
results in more disk blocks being looked at to get the desired data.

> Since, according to the postgresql docs, theirs no performance
> difference between VARCHAR and TEXT, I'm assuming VARCHAR is identical
> to TEXT entries with a restriction set on the length.  And since TEXT
> can be of any possible size, then they must be stored independently of

No.

> the rest of the table which is probably all stored in a fixed size rows

No, Postgres uses variable length records.

pgsql-performance by date:

Previous
From: "Loren M. Lang"
Date:
Subject: TEXT field and Postgresql Perfomance
Next
From: Alex Turner
Date:
Subject: Re: TEXT field and Postgresql Perfomance