Re: Asynchronous Commit in Oracle Database 10g R2

I also tested this on oracle 9.2, 10g R1 and R2 but did not get any set pattern. But definitely the result in all the cases was much lesser io_submit calls than expected. I conducted my tests on a single CPU linux box.
May be I am missing something here !

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Mladen Gogala schrieb:

> On Sun, 28 Aug 2005 23:38:22 -0700, Noons wrote:
>
> > But it doesn't have a regular pattern, does it? I mean: it's not
> > like Oracle is optimizing *every* single turn through the loop.
> > If there truly is an optimization in 9i then it should be
> > a regular, repeatable event, no?
>
> Well, I don't know much about that optimization, but a "commit" should
> send a signal to the LGWR and wait until it completes the I/O operation.
> In particular, for each commit at least one I/O should happen. The fact
> that there are significantly less io_submit calls then user commits tells
> me that Oracle is "short-circuiting" something. You are right, I was
> unable to discover a pattern.
>
> >
> > I'm wondering if this is not a simple manifestation of the
> > commit-piggyback that has been around since v6. Ie: if PL/SQL
> > session somehow gets interrupted and there is a context switch,
> > particularly in a multi-cpu environment, there is the possibility
> > that logwriter would wake up, see "two" requests to commit from
> > two sessions in two cpus and say: hang-on, I only need to commit
> > once.
>
>
> No, because that was the only active session in the database. It is my
> very own personal toy which I use on Sundays, when I have nothing better
> to do.
>
> --
> http://www.mgogala.com
Received on Mon Aug 29 2005 - 04:06:21 CDT