Re: Fast roll-back

From: Mladen Gogala <>
Date: Thu, 22 Jan 2009 22:18:45 +0000 (UTC)
Message-ID: <glarc5$bbs$>

On Thu, 22 Jan 2009 21:52:54 +0100, astalavista wrote:

> Hi,
> Why, where a roll back occurred, it is faster to reboot the database
> instead of waiting the end of the roll-back ?

First, I find the term "reboot" very objectionable. Second, I distinctly remember discussing basics with you approximately 3 years ago. I see that you still didn't find the time for some reading and that you are still using other people's work. It's a commendable piece of enterpreneurship. How do I get a cut? After all, it's my knowledge you will get paid for.

Now, let me reply to your question: If you "reboot" the database (I assume you mean "shutdown abort" or "startup force") you will have to wait for both roll forward and roll back. That tends to be longer then just rollback, with a significant disadvantage of DB being unavailable for normal use during the recovery process. Your users may find that situation objectinable. My users are bad people who expect their production db to be accessible all the time with the notable exception of scheduled maintenance which, in turn, has to be approved by my boss. The trick that sometimes helps is to kill the user process that is doing rollback and let PMON do it. PMON usually does it faster then the user process. There is a significant difference in speed on Oracle 9i and much smaller difference on Oracle 10g. It seems that rollback is a bit optimized on Oracle 10g. I haven't tried on 11g. Thanks for reminding me.

> Thanks for your lights

No problem. When you encounter another problem or just want to impress your boss, you can post a question and use other people's knowledge and dilligence rather then investiong your own time and effort. Usenet certainly beats working, hands down. Have a happy, happy 2009.

Received on Thu Jan 22 2009 - 16:18:45 CST

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