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Questions about automatic memory allocations in 10g (r1 and r2)

From: Reidy, Ron <>
Date: Thu, 20 Oct 2005 10:14:39 -0600
Message-ID: <>


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

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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Received on Thu Oct 20 2005 - 11:17:47 CDT

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