Re: Design Question
Date: Sat, 17 Oct 2009 10:12:55 +1000
Balakrishnan, Muru wrote,on my timestamp of 17/10/2009 2:58 AM:
> My argument is, production hardware is not cheap (we can buy
> 1TB for home under $100, but production hardware costs thousands), less
> overall blocks used improves performance, negligible problem with
> joining lookup tables.
Completely in agreement. Denormalization might save joins but I have yet to see
a case where it saved on data.
In fact, the opposite is generally the case: it greatly increases the amount of data that needs to be stored and therefore the amount of I/O used to manage it. If that increase conterbalances any perceived or actual overhead of joins is wide open for debate and there is no final answer: each case has to be examined on its own conditions.
Normalization was not "invented" to save disk space. It was initially intended to save the amount of I/O one has to perform to manage or retrieve any given information.
"Amount of I/O" is not the same as "disk space" and I know for sure which one causes performance problems.
-- Cheers Nuno Souto in sunny Sydney, Australia dbvision_at_iinet.net.au -- http://www.freelists.org/webpage/oracle-lReceived on Fri Oct 16 2009 - 19:12:55 CDT