Re: Normalizing vs. Denormalizing

:comp.databases.oracle / Will Kooiman <wkooiman_at_csac.com> / 2:58 pm Mar 20, 1996 /
>a normalized design will outperform a denomalized design.

    I experienced the exact opposite.

>Conversely, EVERY system I have ever worked on that had performance
>problems was "denormalized for performance".

    Usually, the problem was a BAD design. People got into horrible performance     Denormalizing gives them only slightly better performance, which most     people will still characterize as 'poor'.

>Also, Oracle does block i/o, not record i/o.

    Oracle calls the disk driver, which ALWAYS does block io.

>Normalized databases tend to
>have more records per block due to data not being duplicated. This
>translates into LESS i/o.

    IO is done by the disk (and its driver & controller), not by Oracle.     The disk will have to go and search for data in different places (several     IOs), return them in disk-blocks, which Oracle will compile into Oracle     data-buffer blocks. Even though all data reside in a single Oracle     data-buffer block does not mean that there is only 1 io.

    This is why people denormalize. Received on Mon Mar 25 1996 - 00:00:00 CET