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List:       postgresql-general
Subject:    Re: [GENERAL] Integer keys vs. Varchar keys
From:       David Link <dlink () soundscan ! com>
Date:       2001-11-30 23:16:08
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Tom Lane wrote:
> 
> David Link <dlink@soundscan.com> writes:
> > What performance gains would an integer primary key have over a varchar
> > primary key, for table joins?
> 
> The comparison operation itself would surely be faster for integers, but
> that would probably be swamped out by disk access and other overhead.
> What I'd expect is that any measurable difference would come from more
> I/O required due to physical increase in the table and index sizes,
> because of larger field sizes in the varchar case.  Since you didn't say
> how long your varchar keys might be, it's anyone's guess what the
> differential will be.

varchar(12).  An alpha numeric UPC code.

Thanks for the information, 
David

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