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Re: Shutdown Abort, a defense of some guessing

From: Alex Gorbachev <>
Date: Fri, 6 Jul 2007 21:59:03 -0400
Message-ID: <>

Interesting point Mark. But guessing during recovery troubleshooting... Hm... that sounds dangerous. ;-)

I would agree that experienced DBA with intimate understanding of Oracle recovery model will definitely have few hints ready. However, these thoughts should be probably threated exactly like that - hints that lead investigation process exactly the first 5-15 minutes.

You might look at the init.ora to make sure controlfiles parameter is correct, have a peak into v$recovery_file, v$database, v$log, v$datafile and etc. to verify certain obvious inconsistencies. That wouldn't be a guess. Would it?

But if someone is trying to recreate controlfile and/or open resetlogs right away - now we are talking!

I think Robert is talking about the same in the follow up email. It's just like being a student I could sometimes see the solution to a very intricate math problem. However (!), the more quick success I had the more often I found myself stuck on something trying to find a shortcut while if I would go traditional method - I could have solve it long time ago. In order to avoid this trap I always repeat Niall's quote from his reason to join BAAG:
"It [guesswork] is probably the most pernicious error in IT today, worse when it works - because it instills a false confidence in the solution and solver - than when it fails." Thanks Niall!

On 7/3/07, Mark W. Farnham <> wrote:
> Now as for the other thread, I have a slight quibble. I hold that there is a
> variable amount of economic guessing time ranging from zero seconds to
> perhaps 5 or 15 minutes depending on the nature and complexity of the
> question such that the sum of the cost of the trouble shooting or
> optimization is less than immediately leaping to measuring and analyzing the
> data that will tell you for sure what is happening. However, I also applaud
> Alex G.'s "rants" because the likely to be economic guessing time most
> certainly should have expired well before a consultation to the list is
> made. When in doubt, timing out on guessing quicker is better than guessing
> too long. As tools leading to the provably correct answer get easier and
> easier to use and faster and faster to execute, perhaps I'll some day agree
> that the high limit for guessing time for all situations has become too
> close to zero seconds to ever guess. For now I'll subscribe to the notion
> that those of us who guess at all probably tend to guess too long.

Alex Gorbachev, Oracle DBA Brewer, The Pythian Group
BAAG party -
Received on Fri Jul 06 2007 - 20:59:03 CDT

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