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RE: Shutdown Abort

From: "Robert Freeman" <robertgfreeman@xxxxxxxxx>
To: "Andrew Kerber" <andrew.kerber@xxxxxxxxx>
Date: Tue, 3 Jul 2007 11:48:49 -0600
>> I am not trying to start an argument here
No argument, just dialogue! :-)

>> Shutdown abort does not check file status, checkpoint status,
transactions, or anything else.
No.. but so what? Instance/crash recovery is built to deal with these
issues. Thats it's job and it better work, reliably, or I'm getting another
database. That is the way the database is built. I will say that I always
recommend (as have others) that you do a checkpoint before you do a shutdown
abort. This can reduce the time it takes to cycle the database.

There were some odd issues in the past that might occur with a startup that
followed a shutdown abort. For example, if you tried to truncate a table in
8.x and < while a transaction was being rolled back in the background, you
would get an ORA-0600 ... thats been fixed though.

>> until Oracle endorses it as the standard method to shutdown an instance,
its a good idea to avoid it.

Looking in the Admin guide I find each method of shutting down the database
described. It says to use shutdown to shutdown the database in "Normal"
situations.... anyone ever use just shutdown??? Also, a hung shutdown in 10g
will timeout after an hour. One could infer from this document that shutdown
is the normally accepted and recommended way of taking down an Oracle
database. *chuckle*

Immediate shutdowns have *specific* criteria listed, including the creation
of unattended backups. Still, I've seen a lot of times when shutdown
immediate hangs. Not a good situation for scripted stuff, since the whole
script ends up hanging (unless you add more complex scripting that checks
for hangs, etc). So, technically, this is not a generally recommended means
of shutting down the database according to the docs. I will say that on
default Oracle installs on Win, that oradim will setup the service to do a
shutdown immediate, so this may be an indirect endorsement by Oracle of
shutdown immediate.

There is no real criteria defined in the docs for shutdown transactional.

Shutdown abort seems right out in the docs. The docs say one should only
perform a shutdown abort in three specific situations: imminent power loss,
applications that are not behaving properly or problems starting the
instance. I would add that another criteria is that the database has to be
back up and running in two minutes or less.

So, the docs do not seem to mimic reality here...

Looking through metalink for "shutdown abort", one finds a number of
articles that essentially seem to lead to the conclusion that shutdown abort
is the better way to go. There are a number of bulletins that indicate that
shutdown immediate will hang here, or hang there (some bugs, some expected
behavior). In these cases, Oracle recommends shutdown abort. To me this
indicates they clearly have confidence in the shutdown abort command. If
shutdown immediate is going to hang, your SLA's are going out the window. If
shutdown abort will consistently work, then your SLA's seem to be safe.

As others have echo'd, and as men greater than I (not a hard thing) have
said before, shutdown abort has worked for us since > 7.x, without a
problem. It's use has allowed us to meet SLA's with a greater level of
assurance, whereas shutdown or shutdown immediate does not.

As always, YMMV...

RF

Robert G. Freeman
Oracle Consultant/DBA/Author
Principal Engineer/Team Manager
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References:

Re: Shutdown Abort
From: Andrew Kerber
RE: Shutdown Abort

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