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Recovery process [message #561164]

Thu, 19 July 2012 04:38

hemchander83@gmail.com
Messages: 10
Registered: July 2012
Location: US

Junior Member

Hi,

Just assume a scenario...

When we restore the database using old controlfile, it will not have the information about the newly added datafile. However when we try to restore the database using backup control file there is an error showing unnamed datafile enrty has been made in controlfile with the details of the datafile location. From where the datafile location information is pulled from ?

What actually is happening when we restore is performed using backup controlfile ?
Also whats the difference between creating controlfile using reset logs and without reset logs and how it varies from opening the database in resetlog option ?

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Re: Recovery process [message #561170 is a reply to message #561164]

Thu, 19 July 2012 04:50

Michel Cadot
Messages: 68775
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

Quote:

When we restore the database using old controlfile, it will not have the information about the newly added datafile. However when we try to restore the database using backup control file there is an error showing unnamed datafile enrty has been made in controlfile with the details of the datafile location. From where the datafile location information is pulled from ?

It is in Oracle dictionary which have been updated and you have recovered.

Quote:

What actually is happening when we restore is performed using backup controlfile ?

The same thing that with a current control file except it does not know the end of the recovery and you have to specify it cancelling the recovery and opening the database with reset logs.

Quote:

Also whats the difference between creating controlfile using reset logs and without reset logs and how it varies from opening the database in resetlog option ?

It clears the online redo logs and creates a new incarnation of the database resetting the log sequence to 1.

Regards
Michel

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Re: Recovery process [message #561495 is a reply to message #561170]

Mon, 23 July 2012 05:47

hemchander83@gmail.com
Messages: 10
Registered: July 2012
Location: US

Junior Member

Hi Michel,

Thanks for your quick response.
Answer for my first question you said that it will return the location details from the dictionary but how..
We are in the mount state for only dynamic views and the database is not opened. Also the control file doesn't have this information.

lets recap the same example, say I have old controlfile and the new entry is not reflecting in the datafile.
Now I am in the mount state and trying to recover the database however the recovery process failed saying there is an unnamed datafile and the recovery process updated the control file location.

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Re: Recovery process [message #561497 is a reply to message #561495]

Mon, 23 July 2012 05:59

Michel Cadot
Messages: 68775
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

Sorry I misread the first part.
Oracle gets the file location from the control file, this is the reason you have some files named "unamed" when you recover from a backup control file when you query v$dbfile, for instance.

Regards
Michel

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Re: Recovery process [message #561514 is a reply to message #561497]

Mon, 23 July 2012 07:11

hemchander83@gmail.com
Messages: 10
Registered: July 2012
Location: US

Junior Member

Hi Michel,

Thanks for your reply.

Just correct me if I am wrong.

Old controlfile will not have the newly added datafile information however the information will be updated from the Archive log file.

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