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Re: Shutdown Immediate Command

From: Ion Manea <imanea_at_ese.washington.edu>
Date: Mon, 15 Jan 2001 21:50:05 -0800
Message-ID: <3A63E10D.BF3817F5@ese.washington.edu>

If he has enough transactions going on at once he won't have to wait very long. Only use SHUTDOWN ABORT when nothing else will work. In other words ... after KILL -9 and killing sessions has failed. After the shutdown immediately bring the database back up and perform a normal shutdown.

Daniel A. Morgan

>
> This is one of those things that nobody can "prove" to your
> satisfaction. But if you routinely use shutdown abort, one of these days
> you will be sorry you did.
>
> Van
>
> <jeremiah_at_wolfenet.com> wrote in message news:93vogg$3gn$1_at_nnrp1.deja.com...
> > In article <93ve7n$prn$1_at_nnrp1.deja.com>, David Fitzjarrell
> > <oratune_at_aol.com> wrote:
> >
> > > The 'shutdown immediate' command is probably your best bet at this
> > > point. There are other 'options', namely 'shutdown abort', however I
> > > would not recommend such a drastic act as 'shutdown abort' does
> > > absolutely no 'bookkeeping' or 'cleanup' whatsoever which could leave
> > > your instance in an unusable (unrecoverable) state.
> >
> > I don't understand the specific scenario you envision in which shutdown
> > abort could "leave your instance in an unusable (unrecoverable) state."
> > I don't believe this is, in fact, the case. One of Oracle's greatest
> > features is its robustness, and the "commit writes redo" rule. This
> > rule allows you to walk up to a running server, unplug it from the wall,
> > plug it back in, and have all the data that was committed before the
> > crash available after the crash.
> >
> > A common misconception holds that shutdown abort is somehow more
> > dangerous or reckless than the other shutdown modes, and can result in
> > data being lost. This is not the case. Shutdown abort terminates the
> > Oracle background and shadow processes, and removes the shared memory
> > segments, effectively terminating a running instance. This leaves all
> > committed transactions intact in the online redologs, even if the data
> > associated with them has not been written to the datafiles. Upon
> > startup, recovery is applied from the online logs beginning from the
> > time of the most recent checkpoint. When recovery is complete, the
> > database is opened for use. Transaction rollback occurs in the
> > background after startup, so no user's time is wasted waiting for all
> > uncommitted transactions to roll back.
> >
> > When starting up after a shutdown abort, the amount of time spent in
> > instance recovery depends largely upon how recently the last checkpoint
> > was issued. By forcing a checkpoint immediately prior to issuing
> > shutdown abort, the redo required to complete crash recovery and bring
> > the database open will be minimal.
> >
> > The alternative in an active environment to shutdown abort is shutdown
> > immediate, but immediate shutdowns take too long, rolling back
> > transactions and performing other tasks while precious seconds pass by.
> >
> > Shutdown abort can come in handy for very brief downtimes, such as those
> > required to change a non-dynamic initialization parameter. In practice
> > on Oracle instances with very large SGAs, such quick "bounces" can
> > typically take as little as 25 seconds.
> >
> > --
> > Jeremiah
> >
> > > In our last gripping episode craig wilson <craig_d_wilson_at_yahoo.com>
> > > wrote:
> > > > I have an Oracle Server running Oracle8i on a Solaris Box.
> > > >
> > > > Due to a problem with the redo log, which I do not want to get into
> > > > right now,
> > > > the Oracle Server will "hang" on occassion.
> > > >
> > > > When this occurs I am expected to stop and start the Oracle server.
> > > >
> > > > I have been provided instructions to take in these cases.
> > > > The instructions say to issue a "shutdown immediate;" command after
 I
> > > > have done a "connect internal" command.
> > > >
> > > > The "shutdown immediate;" command appears to hang and do nothing.
> > > > Any other ideas on how to do this.
> > > >
> > > > I'm really an NT/2000/Netware Administrator, so please speak slowly
 and
> > > > clearly since I am a little out of my league on this one :>
> >
> >
> > Sent via Deja.com
> > http://www.deja.com/
Received on Mon Jan 15 2001 - 23:50:05 CST

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