Re: Why ask more ?

Since it is a backup control file, it cannot have a complete record of each archived redo log generated by the database. It's a backup, taken who knows when. As a backup, it knows where all the data files are and the destination for the archive logs. It also knows the start and stop SCNs of _some_ of the archived redo logs.

Recovery with a backup control file will go on forever unless you stop it. Since you did not stop it, it recorded that it asked for the next archive log, did not get it yet. Recovery does not know if there is or is not such a log file, so it just waits for you to provide it. Recovery cannot know that it has recovered as much as possible. Therefore, recovery is not complete.

When you tried to open the database, Oracle refused. Recovery is not over, just waiting for the next archive log file to appear.

In order to open the database, you need to recover the database again without specifying BACKUP CONTROLFILE, then cancel it. You will not run out of archive this time. When you cancel it, you are telling recovery that is as far as you want to recover. The cancel you issued during the first recovery had a different meaning. It said you want to stop recovery until you find the next archive log file or come back from lunch.

I recently took the Backup and Recovery seminar and brought this very scenerio up to my instructor. He gave me the explaination I just gave you.

I have a reporting database which gets created every morning by placing a production database in hot backup mode, breaking a third mirror of the volumes, taking the database out of hot backup mode. I do a bunch of log switches in production and copy the archive logs and binary copy of the control file to the broken third mirror.

The broken third mirror now comprise the volumes of another box. I start up Oracle in this box and recover the database using backup controlfile. Recovery runs out of archive logs, asks for the next one. Recovery is cancelled and restarted. This time, without specifying BACKUP CONTROLFILE. Recovery is cancelled, the database is opened for business.

• Original Message ----- From: Slamet Fusianto <yangken_at_cbn.net.id> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Sent: Sunday, September 03, 2000 1:53 AM Subject: Why ask more ?

> Dear DBA,
>
> Today I tried a recovery scenario which use BACKUP CONTROFILE. My condition is
> like this:
> 1. Backup data using COLD BACKUP
>
> 2. Startup the database and create new table and insert 1 record to it. Commit
> the transaction.
>
> 3. I then issue ALTER SYSTEM SWITCH LOGFILE (generate 3 Archived Log file, 50 -
> 52). If I see in ARCHIVE LOG LIST the next log file to be archived is 53 (it
> means the current active sequence is 53).
>
> 4. I then shutdown the database (use SHUTDOWN IMMEDIATE)
>
> 5. I copy the CONTROLFILE from COLD BACKUP to simulate failure database.
>
> 6. STARTUP MOUNT, RECOVER DATABASE USING BACKUP CONTROLFILE. What I do not
> understand why does Oracle ask for archived log file no 53, but in fact it has
> not been ARCHIVED (in LOG_ARCHIVE_DEST folder there are only 3 files LOG_50,
> LOG_51,L LOG_52) .
>
> 7. I can not open the database ! ALTER DATABASE OPEN RESETLOGS, it will issue
> ORA-01113 (needs media recovery) and ORA-01110.
>
> Would someone tell me what is wrong with this ? Am I missing something in the
> recovery scenario ? Thank you.
>
> Have a nice day.
>
> Regards,
>
> Slamet Fusianto
>
>
>
> --
> Author: Slamet Fusianto
> INET: yangken_at_cbn.net.id
>
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Received on Sun Sep 03 2000 - 10:37:17 CDT