RE: Questions about automatic memory allocations in 10g (r1 and r 2)

Tahiti is not the way to go for this one. I'd recommend
http://integrid.info/memory_latching.pdf
<http://integrid.info/memory_latching.pdf> 

or  the classic article http://www.vldb.org/conf/2002/S29P03.pdf . Ramesh
Ramaswamy of Quest 

software also wrote a good article which can be found at: 

http://nocoug.org/download/2004-11/Optimising_Oracle9i_Instance_Memory3.pdf

--

Mladen Gogala

Ext. 121

  _____  

From: Reidy, Ron [mailto:Ron.Reidy@xxxxxxxxxxxxxxxxxx] 
Sent: Thursday, October 20, 2005 12:15 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Questions about automatic memory allocations in 10g (r1 and r2)

 

Guys, 

I was in a meeting yesterday with a vendor who told me (and my manager)
their product running on 10gr1 does not need any DBA intervention when used
because they are using automatic memory management and they use "all of
physical memory ... for the SGA".

Now, this person is no Oracle DBA/expert/guru.  He has attended a class like
"New features in 10g" or something like that.  When I questioned this "use
all of physical memory" strategy and how that might affect PGA usage, he was
stumped.

Well, this meeting got me to thinking about if this really works or not, so
I went and read up on this new feature on  <http://tahiti.oracle.com>
http://tahiti.oracle.com.

My concerns about this center around questions like: 

1.  Does this really work? 
2.  How often is the memory usage looked at and adjusted? 
3.  When an adjustment (shrink) occurs in the shared_pool, are the cached
SQL invalidated? 
4.  When the buffer_cache shrinks, are the buffers marked as dirty? 

Does anyone know about these issues?  Can you point me to somewhere where I
might get answers to these questions or set up my own test case to show how
this "feature" might work? 

Thanks for any time and effort put into this. 

-----------------
Ron Reidy
Lead DBA
Array BioPharma, Inc. 

 


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