Re: Shutdown Abort

Hi jeremiah,

from your link

"When
trying to apply a DDL change to some segments, a DBA may encounter the error ORA-00054: resource
busy and acquire with NOWAIT specified. *This can occur even if the DBA acquires an exclusive DML lock
on the table using the lock table command. U*nfortunately, locking a table does not guarantee the success of
any subsequent DDL statement on the table or associated index"

I thought that DDL commits twice once before it starts and second after it completes. So even if you obtain exclusive DML lock on a table/index the first commit will release the lock. So obtaining a exclusive preemptive DML lock would not be possible.

Please correct me if I am wrong.

amit

Jeremiah Wilton wrote:
> Thanks Jared. It has taken all of my strength to not reply to some of
> the most egregious postings in this thread. My more recent blurb on
> shutdown abort can be found on page four of my 2004 HA paper:
>
> http://www.ora-600.net/articles/stayinalive.pdf
>
> I will confirm that practically every site that requires very high
> availability uses 'abort' as SOP. I am really surprised and
> disappointed by the wild theoretical conjecture that accompanies the
> steadfast resistance to 'abort'.
>
> Speaking of wild theoretical conjecture, thanks to Alex G. for his
> recent rants on DBAs and guessing. I have long been an opponent of
> the 'guessing method' of Oracle tuning, which goes hand in hand with
> the 'try a bunch of stuff' method of Oracle troubleshooting :-)
>
> Best to all, including the guessers,
>
> Jeremiah Wilton
> ORA-600 Consulting
> http://www.ora-600.net
>
> Jared Still wrote:
>>
>> Please see
>> http://www.speakeasy.org/~jwilton/oracle/shutdown-abort-bad.html
>>
>> If you are not familiar with Jeremiah Wilton, he was a DBA at
>> Amazon.com <http://Amazon.com> from early days.
>>
>> Amazon has a few databases, and they were/are regularly shutdown with
>> abort.
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

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