RE: Rollback segments confusion ?

From: Bhatia, Mandeep (CAP, CEF) <Mandeep.Bhatia_at_gecapital.com>
Date: Thu, 16 Nov 2000 13:51:03 -0500
Message-Id: <10682.122284@fatcity.com>

Gaja thanks,
which process is responsible for these Rollback segments maintenance ? is it DBW0 or ??

 	Regards,
 	Mandeep
 

-----Original Message-----
From: Gaja Krishna Vaidyanatha [mailto:gajav_at_yahoo.com] Sent: Thursday, November 16, 2000 12:21 PM To: Multiple recipients of list ORACLE-L Subject: Re: Rollback segments confusion ?

Mandeep,

I am not sure what made you think rollback segments are not in memory and only on disk. The rollback segment blocks (like all other blocks except pure temporary tablespace blocks) are modified in memory first, before written to disk. And when a block gets modified it becomes dirty, goes on the dirty list and then eventually gets down to disk. Just like the other blocks.

Hope that helps,

Gaja

• "Bhatia, Mandeep (CAP, CEF)" <Mandeep.Bhatia_at_gecapital.com> wrote:
  > Hi Listers,
  > The rollback segment is not in physical memory , it is on the
  > disk.
  > for every changing row oracle moves its before image to rbs.
  > does this not make query performance slow ?
  > Kindly verify ?
  > Mandeep
  > --
  > Please see the official ORACLE-L FAQ: http://www.orafaq.com
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  > Author: Bhatia, Mandeep (CAP, CEF)
  > INET: Mandeep.Bhatia_at_gecapital.com
  >
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Gaja Krishna Vaidyanatha
Director, Storage Management Products, Quest Software Inc. Office : (972)-304-1170, E-mail : gajav_at_yahoo.com

Author - Oracle Tuning 101 by Osborne McGraw-Hill "Opinions and views expressed are my own and not of Quest"

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Author: Gaja Krishna Vaidyanatha
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Received on Thu Nov 16 2000 - 12:51:03 CST