Re: PGA_AGGREGATE_TARGET question

Is it a case where some of the memory gets allocated but not all? I'll have to run some tests when I get the time.

Cheers,
Brian

Niall Litchfield wrote:
>
> "Richard Foote" <richard.foote_at_bigpond.com> wrote in message
> news:qK5%a.35388$bo1.16629_at_news-server.bigpond.net.au...
> > "Brian Peasland" <dba_at_remove_spam.peasland.com> wrote in message
> > news:3F3B9C49.C992515D_at_remove_spam.peasland.com...
> > > There are some nice views that help you in sizing PGA_AGGREGATE_TARGET
> > > (P_A_T). If you size this parameter too high, then you will be wasting
> > > memory, and if it is sufficiently high enough, this can cause swapping
> > > to occur in your database server.
> >
> > Hi Brian,
> >
> > You mentioned above and elsewhere in your post that you will be wasting
> > memory if you set PAT too high. Interested to know how you come to that
> > conclusion as Oracle doesn't allocate the memory unless it's required. You
> > can most certain set it too low and have sub-optimal workarea executions,
> > you can most certainly see it way too low and have the sum of the
> untunable
> > components of the PGA exceed the PAT regardless and you can set it too
> high
> > such that you don't have enough memory to service such a target.
>
> Hi Richard
>
> I *believe* that whether or not Oracle pre-allocates PAT is platform
> dependent, I'm pretty sure that on Windows at least you get the memory up
> front.
>
> --
> Niall Litchfield
> Oracle DBA
> Audit Commission UK

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