Re: Query Database while shutdown in progress

I have seen file corruption after a shutdown abort. Granted it was in early 8i but it "could" happen. Just think what an abort actually is, the processes are killed and all shared memory segments and semaphores are released. If a write operation or long running checkpoint is in progress you stand a very good chance of file corruption.

Test it out, create a situation that would require some length of time to perform a checkpoint, or a rollback and shutdown abort (or crash, cause thats what it is) the database.

Just my .02

Mike Haddon

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?
 
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.

'If at first you dont succeed, dont take up skydiving.'

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