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Re: Maximum Db_cache_size?

From: Jurijs Velikanovs <j.velikanovs_at_gmail.com>
Date: Mon, 19 Jun 2006 12:01:07 +0100
Message-ID: <d6f0def50606190401o1d7d2crdbab73d348f1a0ee@mail.gmail.com>


Laimutis,

There is no single correct answer.
In your case I would setup good Monitoring (IO/OS/DB/APPS), then would try to increase PGA/SGA/IO BUFFERS, wait for a week, and then analyzing the result would make a conclusion if it make a performance better.

Just my 0.02
Yury

On 6/19/06, Laimutis Nedzinskas <Laimutis.Nedzinskas_at_landsbanki.is> wrote:
> Is it good or bad to use all available (not used for other purposes, eg.
> shared pool or pga) RAM for buffer cache?
> I am talking about 32GB RAM range.
>
> Oracle is not in-memory database but anyway - memory access is faster
> than disk access.
> However I understand that the way(algorithms) Oracle uses RAM may have a
> practical turning point when adding more RAM will only slow down things.
>
> Therefor the question is:
>
> - is Oracle(9.2 version) better at utilizing RAM(say, 10-20GB) for
> buffer cache?
>
> - or is it it is better to let file system to utilize this RAM for file
> cache?
>
> - none of the above, stay with moderate RAM usage (few gigabytes for
> buffer cache) just because buffer cache hit ration is good(98-99%)? I
> would just like to point out that 1% of disk ("raw") access makes up a
> considerable response time, may be 50% or so.
>
> Thank you in advance,
> Laimis N.
>
> Fyrirvari/Disclaimer
> http://www.landsbanki.is/disclaimer
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

-- 
Yury
+44 7738 013090 (GMT)
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Received on Mon Jun 19 2006 - 06:01:07 CDT

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