RE: Shutdown Abort
- From: "Baumgartel, Paul" <paul.baumgartel@xxxxxxxxxxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Tue, 3 Jul 2007 13:14:35 -0400
Well said, and I hope the definitive word on this topic, to be dusted off
whenever someone revives this discussion.
Does anyone really think that Oracle could have succeeded if power failures or
other sudden, unplanned instance terminations threatened data integrity?
Paul Baumgartel
CREDIT SUISSE
Information Technology
Securities Processing Databases Americas
One Madison Avenue
New York, NY 10010
USA
Phone 212.538.1143
paul.baumgartel@xxxxxxxxxxxxxxxxx
www.credit-suisse.com
_____
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Robert Freeman
Sent: Tuesday, July 03, 2007 12:13 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: Shutdown Abort
Anything is possible given the right set of conditions. Clearly there is an
issue with fsck in AIX5L that can cause problems with temporary tablespace temp
files. This same problem would seem to exist when doing a shutdown immediate
too. So if one were to do a shutdown abort, and reboot the system and have this
failure occur, one might well jump to the conclusion that it's a problem with
shutdown abort, when in fact it is not.
So there may be other OS interactions that happen in very odd cases that might
cause it appear that a shutdown abort is the issue when it is, in reality,
something else. Also there could be bugs present anywhere in the configuration
(OS, firmware, etc..) that could cause IO corruption given the right
conditions. Then there is the possibility of something running in the
background of the OS that caused the problem, who is to know? The bottom line
is that you are supposed to be able to pull the PLUG on the thing, and expect
that it will come up without help *every* *single* time (assuming that pulling
the plug didn't take out a physical disk for some reason).
I think you are spot on that this was not a controlled test, so anything could
have caused it. In my mind, if it's not reproducable, then there is something
about the test that was not controlled. The exact set of conditions needs to be
known and reproducable to call a test controlled.
The OP's problem might well have happened with a shutdown immediate, there is
no way of telling and so blaming shutdown abort is jumping to conclusions that
are not supported by any hard facts other than the fact that one of the actions
performed was a shutdown abort. How do we know it wasn't the startup command
that was at fault?? This test makes shutdown abort a suspect but not a
criminal. If you can replicate the problem consistently, then we have something
to work with, and I'd LOVE to see your results.
I guess my point of view is that you are as likely to find a bug with shutdown
immediate as you are with shutdown abort, so do we just not shutdown the
database at all because there *might* be a bug? All other things being equal,
shutdown abort should not have negative impacts on your database, and if it
does, it's a bug. Besides, by the time I go production on any given system,
I've done a shutdown abort enough times on test and development that it should
be exercised pretty well. You can't spend your life worrying about the bugs
that *might* be there (there are enough real ones to contend with!!), that is
what backup strategies are for.
Finally the *body* of experience here seems to be that shutdown abort works,
and is perfectly safe. I've yet to see one case where anyone can reliably
replicate a shutdown abort bug in 9i or 10g that is exclusive to shutdown
abort. If anyone can provide a reproducible test case of shutdown abort
failure, please let me know.
RF
Robert G. Freeman
Oracle Consultant/DBA/Author
Principal Engineer/Team Manager
The Church of Jesus Christ of Latter-Day Saints
Father of Five, Husband of One,
Author of various geeky computer titles
from Osborne/McGraw Hill (Oracle Press)
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-----Original Message-----
From: Joel.Patterson@xxxxxxxxxxx [mailto:Joel.Patterson@xxxxxxxxxxx]
Sent: Tuesday, July 03, 2007 9:47 AM
To: robertgfreeman@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: RE: Shutdown Abort
I agree. It was very unusual - but apparently possible. My original note
sided with immediate, but if that was unacceptable, I would use abort. ...
If Randy claims it has to be a controlled test, then so be it. I would think
it quite hard to find exactly what was happening and make it happen.
Joel Patterson
Database Administrator
joel.patterson@xxxxxxxxxxx
x72546
904 727-2546
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