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Re: Size of SGA

From: Howard J. Rogers <howardjr_at_www.com>
Date: 2000/06/09
Message-ID: <394074f2@news.iprimus.com.au>#1/1

<ac_sekhar_at_my-deja.com> wrote in message news:8hp8eo$o8v$1_at_nnrp1.deja.com...
> Hi all,
>
> Typically what will the size of SGA in production environment.
> I heard that its around 4GB. Is it correct? 4GB seems to be
> too much of memory.
>

That's rubbish. For one thing, what's 'typical'?

It depends very largely on the number of concurrent users you have. You can have a terrabyte database with three users, and get away with a 40M SGA. On the other hand, a 4Gb database with 1000 users will find that unacceptable, big time.

Your SGA should be sized to ensure that the Library Cache isn't ageing out frequently used queries (ie, increase your shared pool size). The database buffer cache is harder to size, but as a rule of thumb, I make mine a third the size of the shared pool, and start tuning from there. And the Log buffer is relatively tiny.

In short, there is no answer to your question, other than to say that 4Gb is a ridiculous size to make your SGA, unless it needs it. Try the performance tuning books to see whether your SGA really does, in fact, need it (and I suspect it doesn't).
HJR
>
> Thank you
> Chandra
>
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
Received on Fri Jun 09 2000 - 00:00:00 CDT

Original text of this message

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