Re: Column order performance

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От Bill Montgomery
Тема Re: Column order performance
Дата
Msg-id 411918B9.9000707@lulu.com
обсуждение исходный текст
Ответ на Column order performance  (Bill Montgomery <billm@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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