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Re: cost of empty fields

From: "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>
To: pgsql-admin <pgsql-admin(at)postgresql(dot)org>
Subject: Re: cost of empty fields
Date: 2005-04-15 16:58:02
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Lists: pgsql-admin
If you setup rules on the view and just have the application select,
insert, update, and delete from the view instead of the raw tables you
won't need to change your application at all. Though you do need to be
aware that you can't easily enforce uniqueness across multiple tables.

As for clearing the fields, if by clearing you mean setting to NULL then
you're correct, it would save space. Just remember that you won't
actually be able to use the saved space until the table is vacuumed.

On Fri, Apr 15, 2005 at 04:22:07PM +0200, Enrico Weigelt wrote:
> Hi folks,
> we've got an quite large table with 17 columns and now >15k rows.
> The table works also as an journal will continously grow day by day. 
> Man of the columns (mostly text) aren't needed anymore if the tuple 
> has reached a certain age. 
> So I thought about clearing the unnecessary fields of old tuples 
> to save resources. Does it bring any performance improvement ?
> Of I could splitt off this table an working- an archive- table 
> and map them together in some views - someday I probably *will* 
> do it - but our applications are not yet ready for this.
> thx
> -- 
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Jim C. Nasby, Database Consultant               decibel(at)decibel(dot)org 
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