Re: Recovery scenario
Date: Thu, 31 Jan 2008 22:58:36 +0800
A "using Backup Controlfile" implicitly means
"the controlfile is older then the datafiles"
the RECOVER command then actually _builds_ the archivelog
file names [using log_archive_dest and log_archive_format].
One simple way to test this is to change the log_archive_dest
and log_archive_format before beginning the RECOVER ... USING BACKUP
command and see how, _magically_ Oracle prompts for archivelog filenames which are different from what they were when the archives were created !
Create your backup with log_archive_dest=/abc and log_archive_format='mydb%s%t%r.ARC'
and, on the Recovery command use
and log_archive_format='recdb%t%r%s.BAK" and see how the RECOVER command prompts for the Archivelogs.
The "until Cancel" means that we _want_ an Incomplete Recovery.
Therefore, Oracle will continue prompting for "future" archivelogs
[see the above paragraph] until we explicitly say "CANCEL".
Note, however, that it verifies all the datafiles to see that they
are inconsistent. If we issue a Cancel without having applied
all the archivelogs that were created during the Hot Backup,
then the recover command exits with a warning message
that an OPEN would fail because further recovery is still required.
If we have applied all the minimum files , and even if there are
still more "future" files, we are allowed to CANCEL and OPEN
Thus, if the LogSequenceNumbers during the backup were 1021 to 1045 and available archivelogs are upto 1052, but we issue a CANCEL at 1043 or 1044 we get a warning message at the CANCEL. However, if we issue a CANCEL after 1047, we are allowed to OPEN RESETLOGS and discard the transactions in Logs 1048 to 1052.
Hemant K Chitale
At 03:51 PM Thursday, Niall Litchfield wrote:
>I agree with Jeremiah - the only puzzling thing to me is how a backup
>controlfile seems to be aware of the creation time of archives created
>after it was. It is early in the morning for me though. Other than
>that though it's basic incomplete recovery isn't it? UNTIL TIME mean
>stop at this time, UNTIL CHANGE means stop at this scn and UNTIL
>CANCEL means keep going till I tell you otherwise.
Hemant K Chitale