Re: oracle performance

DA Morgan wrote :

> hpuxrac wrote:
> > DA Morgan wrote:
> >> Charles Hooper wrote:
> >>
> >>> My comments referring to tuning the database instance may not have been
> >>> as clear as I had hoped.
> >> And just to get semantically picky there is no such thing as a database
> >> instance.
> >
> > Why don't you look through Tom Kyte's most recent book and see how many
> > times he uses that set of words?
>
> With all due respect for Tom, and my respect for him is immense, I think
> you will find that if you review Oracle Database Concepts these terms
> are defined.
>
> "This combination of the SGA and the Oracle processes is called an
> Oracle instance."
> Source:
> http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14220/startup.htm#CNCPT601
>
> Then please consider what happens when you issue the following command:
>
> SQL> drop database;
>
> When you issue this statement, Oracle Database drops the database and
> deletes all control files and datafiles listed in the control file. If
> the database used a server parameter file (spfile), it is also deleted.
> Source:
> http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_8009.htm#sthref8446
>
> Given that you are a RAC expert I would expect you would also have
> noticed that SRVCTL has both a -d and -i switch. There is a reason
> for the distinction. Which is why I noted in my original post that while
> this was not that important with stand-alone it is critical when
> discussing RAC.
>
> I'm not making up these definitions. They are the ones published in the
> on-line Oracle docs.

In the defense of Tom (not that he needs any :-), I would like to add that he defines very precisely the difference between an instance and a database in "Expert Oracle Database Architecture)".

The problem here may be that the word "instance" is very generic and wildly overloaded in our field. Therefore, in the interest of precision, it is
customary to add what is being instantiated (eg class instance).

It is correct that in the restricted context of this newsgroup, the qualification is not needed, and perhaps even lousy these days. However, I can certainly understand people using it out of habit, when the qualification is needed in their professional circle. That qualification may even be useful here when talking to people who are not fully aware of the intricacies of Oracle's architecture.

Thinking of it, funny thing is that I dont know what is being instantiated
*exactly* in an (Oracle) instance :-)) Received on Mon Oct 30 2006 - 01:22:33 CST