Re: sga_max_size discrepancy

Keith,
  Have you tried setting cpu_count to something a bit more reasonable for the T2 chip you are running on or setting sga_target = 0

Bradd Piontek
Oracle Blog: http://piontekdd.blogspot.com Linked In: http://www.linkedin.com/in/piontekdd

On Wed, Jul 30, 2008 at 9:45 PM, Keith Moore <kmoore_at_zephyrus.com> wrote:

> Raj,
>
> Thanks. You put me on the right track but the granule size is actually 4M
> and...
>
> NAME TYPE VALUE
> ------------------ ----------- ------------------------------
> cpu_count integer 64
>
> Here's the deal. These are the Sun "cool thread" servers and while our zone
> only has 1 real CPU, each CPU has 64 threads of execution and to Oracle
> that
> looks like 64 CPUs.
>
> We moved the zone from an older server (32 threads per CPU) to a newer
> server
> (64 threads per CPU) and the buffer cache doubled in size.
>
> I don't know what if anything I can do about this. Need to research
> further.
>
> Here's another calculated value that is way too high.
>
> NAME TYPE VALUE
> ----------------------- ----------- ------------------------------
> parallel_max_servers integer 185
>
> BTW, on CPU intensive tasks these servers are about 25% the speed of other
> Sun
> processors. I've heard they are equivalent to a 300 MHz processor. They are
> best suited to applications like web servers where there are many processes
> but each request is small. OLTP databases might be another good use.
>
> I'm not sure our development environment with a few users is the right
> application. On the other hand we are running 20 databases on a relatively
> cheap server. Either way, I wasn't consulted.
>
> Keith
>
>
> > Keith,
> >
> > do you have 4 CPUs? then it might make sense because in absence of
> > sga_target setting, db_cache_size will default to 4mb * #cpus * granule
> > size.
> >
> > I am guessing granule size as 16M so, if you have 4cpus, the min
> > db_cache_size will be 256m (or 8 cpus if granule size is 8m).
> >
> > Raj
> >
>
>
> --
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>
>
>

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