Re: Column order performance

From: Bill Montgomery <billm(at)lulu(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Column order performance
Date: 2004-08-10 18:49:29
Message-ID: 411918B9.9000707@lulu.com
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Josh Berkus wrote:

>>Does the order of columns of varying size have any effect on
>>SELECT/INSERT/UPDATE/and/or/DELETE performance? Take the example where
>>an integer primary key is listed first in the table and alternatively
>>listed after some large varchar or text columns?
>>
>>
>
>No, the "order" of the columns in the table makes no difference. They are not
>physically stored in the metadata order, anyway; on the data pages,
>fixed-length fields (e.g. INT, BOOLEAN, etc.) are stored first and
>variable-length fields (CHAR, TEXT, NUMERIC) after them, AFAIK.
>
>

Is this true even after a table is altered to "append" say, an integer
column, after there are already variable-length columns in the table?

-Bill

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