Oracle FAQ | Your Portal to the Oracle Knowledge Grid |
![]() |
![]() |
Home -> Community -> Mailing Lists -> Oracle-L -> RE: why does oracle recovery redo before undo?
Oracle does not recover redo logs, instead it uses its contents to
recover data files including files/TS used by rollback segs.
Waleed
=20
-----Original Message-----
From: Ryan [mailto:ryan.gaffuri_at_cox.net]
Sent: Monday, April 19, 2004 5:28 PM
To: oracle-l_at_freelists.org
Subject: why does oracle recovery redo before undo?=20
I know how it works. I know that it works. I can't find 'why'? I'm taking a university database class and my professor says the optimal way to recover is with undo before redo and so does my book. Anyone know why Oracle does it the other way?
Here is how I think Oracle performs recovery.
Now my book says the optimal way to do this is to check for all open transactions at the time of the last checkpoint that have committed after that checkpoint.
Anyone know more? In particularly know 'why'?=20
FAQ is at http://www.freelists.org/help/fom-serve/cache/1.htmlput 'unsubscribe' in the subject line.
-----------------------------------------------------------------
----------------------------------------------------------------
Please see the official ORACLE-L FAQ: http://www.orafaq.com
----------------------------------------------------------------
To unsubscribe send email to: oracle-l-request_at_freelists.org
![]() |
![]() |