Re: performance: Ordering my varchar2 keys...

Andreas Koch wrote:
>
> Hi,
>
> has the character order of textual keys an performance
> hit.
>
> E.g. is there a difference between having
>
> 20020201AAA
> 20020201AAB
> 20020201AAC
> 20020201AAD
> 20020201AAE
>
> as a key column instead of
> AAA20020201
> BAA20020201
> CAA20020201
> DAA20020201
> EAA20020201
>
> Consideration: In the top list, when joining oracle has to
> check 11 bytes to see the keys are different, on the
> bottom list only the first byte.
>
> --
> Andreas
> LINUX users tune their system for stability
> WIN users tune their system for fast booting
> What you prefer is just a matter of taste.

This would suggest that a single column is possible being used for two (or more) attributes, in which case, multiple columns may be preferred.

That aside, there would be a small overhead in scanning further through each string, but I would anticipate this to be dwarfed by the overhead of actually reading the blocks from disk anyway

hth
connor

-- 
==============================
Connor McDonald

http://www.oracledba.co.uk

"Some days you're the pigeon, some days you're the statue..."