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RE: Query Database while shutdown in progress

From: <>
Date: Wed, 27 Jun 2007 15:42:08 -0400
Message-ID: <>

I am in the shutdown immediate camp. Note dbshut/dbstart has abort... but then again I think that was for sudden server shutdowns (who would do that)?  

However, (Not from Oracle), I have heard oracle has gotten a lot better with abort - as in not as dangerous or fearsome. I just like synchronizing all the file headers etc.... Does killing the session stop the rollback? If not, then monitoring the alert log for the offending user is nice but doesn't save very many minutes.  

Ever see a session take awhile to kill?.... rolling back, no?  

The moral might be -- if you are desperate -- Most of the time, the shutdown abort will shutdown now (immediately), and the fast rollback, roll forward on startup in the background will still allow you to work whereas no one can work during an hour shutdown immediate rollback.  

However, the disclaimer is to get some solid background on whether you would implement such a procedure as Standard. Most databases don't have to shutdown very often anymore... some maintenance is about it.        

Joel Patterson
Database Administrator
904 727-2546

[] On Behalf Of Andrew Kerber Sent: Wednesday, June 27, 2007 3:13 PM
Cc: oracle-l
Subject: Re: Query Database while shutdown in progress  

The last time I checked, admittedly in the 8.1.7 world, oracle stated that you could end up with file corruption on a shutdown abort (note that is could, not would, I never had it happen), If they have changed this and now say that a shutdown abort is as safe as a shutdown immediate, I have not heard it. Does anyone have a statement from oracle to that effect?

What happens if you have datafiles in backup mode and you try and do a startup force?

On 6/27/07, Robert Freeman <> wrote:

On 6/27/07, Andrew Kerber < <> > wrote:

        Sometime shutdown abort is necessary. However, its not recommended. I would rather not risk having to recover a database w/o a good reason. If all that is needed is to monitor a shutdown immediate. there are a lot of ways to handle that. If nothing else, you can tail the alert log, and see the id thats keep the instance form shutting down, then kill that session. That would be much safer than an abnormal termination of the instance.  

I agree with Jared, whats up with this? Yes, a shutdown abort assures that you will be doing crash/instance recovery, but so what? If you are truly concerned about that, do a checkpoint before you do the shutdown abort (assuming that does not take forever). In what cases will a shutdown require media recovery? I know of none unless you are planning on rm'ing a bunch of datafiles afterwards.  

One of the beauties of Oracle, and a fact that seems little known, is the rule with regards to checkpoints and redo logs. Everyone knows that a redo log can not be reused in ARCHIVELOG mode until the archived redo log is created. What seems less known is the rule that an online redo log can not be reused until all dirty blocks associated with that online redo log have been checkpointed and written to the datafiles. Thus, shutdown abort should NEVER lead to a media recovery.  

I will say, as a point of caution, that back in the 7.x days, there was a bug that I discovered that would cause you to have to do media recovery after a shutdown abort. So if you are running 7.x then be careful about a shutdown abort.  


Robert G. Freeman
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Andrew W. Kerber

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Received on Wed Jun 27 2007 - 14:42:08 CDT

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