Re: oracle performance

From: DA Morgan <damorgan_at_psoug.org>
Date: Sun, 29 Oct 2006 17:24:23 -0800
Message-ID: <1162171463.579795@bubbleator.drizzle.com>

Charles Hooper 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.
>>
>> There are databases ... a collection of related files.
>> And there are instances ... processes running in memory.
>> When one move to RAC ... the distinction is important.
>>
>> One can tune the database with respect to log file size, SAME, adding
>> LUNs, etc.
>>
>> And one can tune the instance, SGA size, Sort Area, etc.
>>
>> And one can tune their application getting rid of single row processing
>> in favor of arrays, eliminating incremental commits, etc.
>> --
>> Daniel A. Morgan
>> University of Washington
>> damorgan_at_x.washington.edu
>> (replace x with u to respond)
>> Puget Sound Oracle Users Group
>> www.psoug.org

> 
> Being precise is great.  Describing to someone how to build an atomic
> clock when the person asks what time it is probably does not help - or
> so I have been told when I write up lengthy document for internal
> circulation.
> 
> As hpuxrac indicated, Tom Kyte does refer to an instance as a "database
> instance" in some of his articles and at least his last book.  Samples:
> http://www.apress.com/ApressCorporate/supplement/1/10008/1590595300-2994.pdf
>   pg 49, pg 50, pg 52, pg 61(twice)
> 
> Charles Hooper
> PC Support Specialist
> K&M Machine-Fabricating, Inc.

I am not discussing the verbiage used by Tom. But I have, for many years, been sloppy with my use of the terms and now, teaching RAC, find that it creates potential problems.

"Start the database instance" is a meaningless phrase when you are sitting in front of a shut-down 4 node cluster.

You can start the database (which starts all instances). And you can start an instance (which will open the database). But they are different statements that produce different results.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace x with u to respond)
Puget Sound Oracle Users Group
www.psoug.org

Received on Sun Oct 29 2006 - 19:24:23 CST