RE: buffer cache and shared pool size tuning

  • From: D'Hooge Freek <Freek.DHooge@xxxxxxxxx>
  • To: Jared Still <jkstill@xxxxxxxxx>
  • Date: Fri, 11 Dec 2009 03:46:25 +0100

Jared,

Thank you for sharing the queries.
But I'm looking for a more general method that is not looking to the advisory 
tables.
Reason for this is that I think that the figures in the advisory are pushed 
higher because of a query that is executed every 10, 15 minutes and that is 
performing a full table scan on a 2 GB (and growing) table.


ps) The vendor is writing a patch to deal with this problem query.


Regards,

 
Freek D'Hooge
Uptime
Oracle Database Administrator
email: freek.dhooge@xxxxxxxxx
tel +32(0)3 451 23 82
http://www.uptime.be
disclaimer: www.uptime.be/disclaimer


________________________________________
From: Jared Still [mailto:jkstill@xxxxxxxxx] 
Sent: donderdag 10 december 2009 0:14
To: D'Hooge Freek
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: buffer cache and shared pool size tuning

I've used the attached scripts to query v$db_cache_advice
and v$shared_pool_advice.

I have not done any testing to verify the accuracy of the
claims of the cache advice, but have found the v$advice
tables to be useful.

Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
Oracle Blog: http://jkstill.blogspot.com
Home Page: http://jaredstill.com


On Mon, Dec 7, 2009 at 9:58 AM, D'Hooge Freek <Freek.DHooge@xxxxxxxxx> wrote:
Hi,

I have a situation in which the application vendor is asking to increase the 
buffer cache size to resolve a performance issue, pointing to the advisories 
from the dbconsole.
Although I have already proved via tracing that the problem is mainly in the 
queries and schema design, and that even if we cached everything we still would 
not be able to get the requested response times, they are still pointing to the 
advisory.
All this asside, it made me wonder what would be a good method to verify if the 
buffer cache is correctly sized?
Same question for the shared pool.


Regards,

 
Freek D'Hooge
Uptime
Oracle Database Administrator
email: freek.dhooge@xxxxxxxxx
tel +32(0)3 451 23 82
http://www.uptime.be
disclaimer: www.uptime.be/disclaimer



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