Re: Oracle 10g RAC Question

"Howard J. Rogers" <howardjr_at_dizwell.com> wrote in message news:<41646bad$0$23893$afc38c87_at_news.optusnet.com.au>...
> Joel Garry wrote:
>
> > "Howard J. Rogers" <howardjr_at_dizwell.com> wrote in message
> > news:<4163c633$0$20130$afc38c87_at_news.optusnet.com.au>...
> >>
> >> I agree. So let's not use the word "node" when we mean "instance".
> >> Because otherwise, the confusion level rises.
> >
> > So what the heck is an instance? I'm looking at OEM10g ASC and I see
> > two "standalone instances..." neither of which has anything to do with
> > RAC or a database.
>
>
> I might be missing your point, Joel. But an instance remains what it has
> always been: a memory structure, plus background processes, which access
> and manage an Oracle database.
>
> Whether an instance does that on its own, or in co-operative joint venture
> with other instances, makes no difference to that definition. I think.
>
> I see no problem with the phrase "standalone instance". It means its
> accessing and managing a database on its lonesome. A fair enough contrast
> with the phrase, "a rac instance" or even a 'clustered instance', since
> that indicates the instance is accessing and managing a database in
> combination with others.
>
> Of course an instance has nothing to do with a database, since otherwise
> there would not be a startup nomount command.
>
> So what was the point I was missing here?

That Oracle uses the word instance with more than one meaning, sometimes when a database is not involved. It appears to be derived from the more general instantiation, which is just the memory structures. I still haven't seen an Oracle definition of an instance when no database is involved, or to be more precise, when any database that might potentially be involved (such as SSO or Portal) _is_ another instance potentially far removed with it's own memory structure, plus background processes, which accesses and manages another Oracle database...

Yes, it is a picayune point that is off-topic. At least until someone uses web based OEM and wonders what instances are.

jg

--
@home.com is bogus.
http://fractalcow.com/bert/bert.htm