Re: when do I use multiple instances ?

From: Pete Sharman <psharman_at_us.oracle.com>
Date: Mon, 19 Apr 1999 09:20:44 -0700
Message-ID: <371B57DC.F7D320EA@us.oracle.com>

The term instance is valid in non-OPS installations as well. An instance is the background processes plus the SGA, whereas the database is the physical file structure. When you do a startup nomount, you are starting the instance, not the database. Of course, in a non-OPS world, there's a one to one mapping between the database and the instance, so this is probably all academic anyway!

HTH. Pete

Nick England wrote:

> Nikko,
>
> First Oracle is very specific about its use of the word's instance and
> database.
>
> Using one set of Oracle executables (installation), you can create any
> number databases (limited only by the system's memory and disk), these are
> identified uniquely by the Oracle 'sid'.
>
> An instance is a term used when discussing Oracle Parallel server, in this
> case a single database (held on a shared disk layout) can be accessed by
> other nodes in a cluster (UNIX, Vax or otherwise) where the disk is shared
> and the memory/cpu are independent. In this case, you would have one
> instance/node connecting to the single, shared database.
>
> Parallel server is used for scalability and resiliency and is limited to
> clusters and MPP boxes.
>
> Hope this helps
>
> Nick
>
> nikko wrote in message <37188C28.FB1B4AA_at_po.jaring.my>...
> >Why and when do one use multiple instances in Oracle ? Can two different
> >instance communicate(exchange data?)
> >
> >Thank you.
> >

Regards

Pete

Peter Sharman                             Email: psharman_at_us.oracle.com
WISE Course Development Manager           Phone: +1.650.607.0109 (int'l)
Worldwide Internal Services Education            (650)607 0109 (local)

San Francisco

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Received on Mon Apr 19 1999 - 11:20:44 CDT