Re: Memory limitations in Oracle?

Vikas Agnihotri <vikasa_at_despammed.com> wrote:
>On Tue, 27 Mar 2001 20:14:54 +0200, in comp.databases.oracle.server
>you wrote:
>
>I have read the docs. My question is generic in nature. Not specific
>to any particular platform. Just curiosity.
>
>1. Is SGA sizing a exact science or more of an art? Start off with 1/3
>of RAM, monitor the hit ratio, increase, and repeat? Or is there a
>more methodical approach?

HJR gave a good description of sizing. If you're trying to determine sizing to buy a new system to run a new application, use your test system to size the new one. If you're running a off-the-shelf application (or near to it), your application vendor may have a sizing model. They should be able to tell you how their application performs if you can give them an accurate description of your workload.

>2. What is the rationale behind the "1/3 of RAM" rule of thumb?

If you have no test system, an unknown application and no idea what your workload is going to be, yet for some mysterious reason you *still* want to set up an Oracle instance, you've got to start somewhere, and it's not a bad first guess.

-- 
Andrew Mobbs - http://www.chiark.greenend.org.uk/~andrewm/