Re: SQL Statement Shutdown

From: Frank <fvanbortel_at_netscape.net>
Date: Tue, 04 Mar 2003 21:28:46 +0100
Message-ID: <3E650C7E.8090309@netscape.net>

Howard J. Rogers wrote:
> On Mon, 03 Mar 2003 17:47:56 +0000, Joel Garry wrote:
>
>

>>"Howard J. Rogers" <howardjr2000_at_yahoo.com.au> wrote in message
>>news:<pan.2003.03.03.19.11.40.446603_at_yahoo.com.au>...
>>
>>>On Mon, 03 Mar 2003 14:40:47 +0000, Patrice Castet wrote:
>>>
>>>
>>>>what do you want to shutdown ? the database ? a dispatcher ? by the
>>>>way "shutdown abort" is like you "kill" your database, it has to
>>>>perform a recovery when restarting ! I advice you to use "shutdown
>>>>immediate" which stop it cleanly instead of "abort". The "abort"
>>>>option must not be used except for emergency issues.
>>>>
>>>>
>>>
>>>Provided you have protected yourself against the loss of your current
>>>redo log by appropriate multiplexing and mirroring, there is zero risk
>>>in doing shutdown aborts. They are functionally equivalent to shutdown
>>>immediates, in the sense that both cause you to lose uncommitted
>>>transactions, and both preserve all committed transactions. There is
>>>nothing inherently dangerous or naughty about shutdown abort, and they
>>>are perfectly OK to use in situations which don't count as an
>>>emergency.
>>
>>You think there is no risk in recovery?  You've never seen a recovery
>>session not work?  You think there is no risk in the untrained doing
>>shutdown abort and attempting recovery?

>
>
> Excuse me? What recovery does any user, however trained or untrained, have
> to do after a shutdown abort? The recovery that is involved is an instance
> recovery, and is performed entirely automatically by SMON upon subsequent
> startup.
>
> And if you think there's anything inherently dodgy about Oracle's instance
> recoveries, then you'd best not use Oracle at all!
>
>

>> You've never seen a site
>>where they do shutdown abort because they don't understand what is
>>preventing the instance from shutting down immediate?

>
>
> I'm not responsible for people's ignorance. If they choose to kill things
> off, there are plenty worse ways of doing it (kill -9 anyone?). I'm not
> saying it's polite or even desirable: I'm saying there is no greater risk
> of losing data with a shutdown abort than there is with a shutdown
> immediate, provided you have already taken suitable precautions against
> loss of online redo logs. And that functionally there is no difference
> between an abort and an immediate: committed transactions are safe,
> uncommitteds are lost, and no data is lost.
>
> What exactly do you have to quarrel about with any of that?
>
>

>>You've never
>>seen a situation where instances are repeatedly aborted while
>>recovering?

>
>
> You're just getting silly now. I've seen users delete the controlfiles and
> then say 'how do I do that 'backup to trace' command?'. If people are
> idiots, they are idiots. I'm not talking about people. I'm talking about
> the safety, or otherwise, of shutdown abort. Try not to throw red herrings
> about.
>
>

>>You've never seen recovery documented incorrectly by
>>Oracle?  You've never seen Oracle ask for logs that don't exist?

>
>
> Joel, I realise that you are on something of a crusade at the moment to
> make me look a fool, and demonstrate to the Universe the paucity of my
> practical experience (as you imagine it), but really: tell me the last
> time you saw an INSTANCE recovery ask for a single log.
>
>

>>You've never heard of support telling people to use files that
>>documentation says are not needed for recovery?  You've never seen
>>people restore files they are _not_ supposed to restore?

>
>
> Give up Joel. You are making a fool of yourself. What has restoring
> ANYTHING got to do with instance recoveries?
>
> Nada.
>
> Now tell me in calmer tones why shutdown aborts are so dangerous.
>
> HJR
Have never seen trouble with the good ole' unix scripts that do:

shutdown abort
startup restrict
shutdown

just before the offline backup...
the shutdown abort will just very effectievly kill off any user sessions of people who "forget" to log off from their applications, that do not have time-outs set in sql*net, etc, etc.

-- 
Regards, Frank van Bortel

Received on Tue Mar 04 2003 - 14:28:46 CST