Re: Integer keys vs. Varchar keys

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