Re: Normalization, Natural Keys, Surrogate Keys
From: Galen Boyer <galendboyer_at_yahoo.com>
Date: 21 May 2002 21:54:11 -0500
Message-ID: <uptzou3j6.fsf_at_rcn.com>
>
> Galen,
> I'm not sure what you really meant here but:
Date: 21 May 2002 21:54:11 -0500
Message-ID: <uptzou3j6.fsf_at_rcn.com>
On 21 May 2002, ed.prochak_at_alltel.com wrote:
> Galen Boyer <galendboyer_at_yahoo.com> wrote in message
>> Performance should be increased on joins with tables each having one >> surrogate key over tables all having natural keys and most of these >> having multiple values.
>
> Galen,
> I'm not sure what you really meant here but:
[...]
> (now there is a factor of the size of the keys, so a table with MANY
> rows will be slower for the natural key because fewer of them fit in a
> block, so more blocks must be read to find it. but if this amounted to
> something even near a factor of two, I'd be supprised.)
This is what I meant. Scan performance are all about the amount of blocks being read, index or table.
-- Galen deForest Boyer Sweet dreams and flying machines in pieces on the ground.Received on Wed May 22 2002 - 04:54:11 CEST