Re: Dynamic SGA and pinned

"Mladen Gogala" <gogala_at_sbcglobal.net> wrote in message news:pan.2004.08.03.10.11.20.936762_at_sbcglobal.net...
> On Tue, 03 Aug 2004 07:08:39 +1000, Howard J. Rogers wrote:
>
> > There may be subtleties about the way Solaris uses memory that I am
unaware
> > of, but as far as I know, if you set SGA_MAX_SIZE on any platform to a
given
> > value, then that amount of RAM is immediately 'stolen' from the
operating
> > system and allocated to Oracle's own exclusive use. That large chunks of
> > that shared memory segment are not *actually* used, because your
> > shared_pool_size or db_cache_size are set to low amounts is irrelevant:
the
> > large shared memory segment has nevertheless been allocated to Oracle's
use
> > from the total pool of available physical RAM, and hence that RAM is not
> > available for any other programs running on that server to make use of.
>
> In other words, the whole "dynamic" thing is pointless. It's like making
> a bowl of cereal and then having half of the bowl covered , so you don't
> see it. An exercise in futility.

Well, as I said... it's entirely true that the SGA is not actually dynamic. But the feature that they call 'dynamic SGA' (ie, the ability to dynamically resize the various pools within the SGA) is not to be sniffed at, and I wouldn't call it futile.

Regards
HJR Received on Tue Aug 03 2004 - 06:35:35 CDT