Re: R: Public variables

Fabio GRANDE <fabiog_at_fileita.it> wrote:
> I think that putting those values in variables I could improve the DB
> performances... Is it right ?

Not completely. If you access some data that resides into a table, those data will be copied in the server's memory (in the Shared Pool), so the second time you are (effectively) reading from memory.

But, if you clutter the server's memory with variables, you will force the server to clean the buffers used to store data to keep your variables, so you will slow down query performances (all queries). Worse, if the shared pool become too full of variables, the system will start swapping to disk, slowing down way more.

If you want to improve your performance, start tuning your system (aka: give enough buffer and enough memory to the server), then check if your database structure can be improved (extents, tablespaces...), then move to your queries (creating/using indexes, kind of queries...). As last resort you act on the client side.

Davide Received on Wed Nov 07 2001 - 07:47:23 CST