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restoration of database

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royalyogi
Senior Member
Posts: 181
Joined: Tue Apr 23, 2013 3:59 pm

restoration of database

Postby royalyogi » Thu May 02, 2013 5:37 am

I know only you can give me correct answer for this.

we have two databases

1.) hot database backup has completed at on 11.00AM and database has crashed at 11.20AM
How can we restore database till 11.20AM


2.) Cold database backup has completed at on 11.00AM and database has crashed at 11.20AM
How can we restore database till 11.20AM

Tim...
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Posts: 18437
Joined: Mon Nov 01, 2004 5:56 pm
Location: England, UK
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Re: restoration of database

Postby Tim... » Thu May 02, 2013 6:47 am

Hi.

1.) hot database backup has completed at on 11.00AM and database has crashed at 11.20AM
How can we restore database till 11.20AM

- If this is just an instance crash, then starting up the database is all you need to do. Any inconsistencies in the datafiles will be fixed automatically using a combination of redo and undo and the database will start cleanly.

- If some datafiles were lost for any reason, then you will need to do an RMAN restore and recovery.

RESTORE DATABASE;
RECOVER DATABASE;

2.) Cold database backup has completed at on 11.00AM and database has crashed at 11.20AM
How can we restore database till 11.20AM

- If this is just an instance crash, then starting up the database is all you need to do. Any inconsistencies in the datafiles will be fixed automatically using a combination of redo and undo and the database will start cleanly.

- If the database is in ARCHIVELOG mode and some datafiles were lost for any reason, then you will need to do an RMAN restore and recovery.

RESTORE DATABASE;
RECOVER DATABASE;

The cold backup will now be used for the restore and the archived redo logs will be used to wind the database forward.

- If the database is in NOARCHIVELOG mode and datafiles have been lost, you will restore the cold backup and your system will be back to 11:00 AM. Since there are no archived redo logs, there is no way to wind forward, so 20 mins of changes are lost.

Cheers

Tim...
Tim...
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Oracle ACE of the Year 2006 - Oracle Magazine Editors Choice Awards
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OCP DBA 7.3, 8, 8i, 9i, 10g, 11g
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My website: http://www.oracle-base.com
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royalyogi
Senior Member
Posts: 181
Joined: Tue Apr 23, 2013 3:59 pm

Re: restoration of database

Postby royalyogi » Fri May 03, 2013 12:27 am

Thanks for your update.

Tim...
Site Admin
Posts: 18437
Joined: Mon Nov 01, 2004 5:56 pm
Location: England, UK
Contact:

Re: restoration of database

Postby Tim... » Fri May 03, 2013 6:43 am

:)
Tim...
Oracle ACE Director
Oracle ACE of the Year 2006 - Oracle Magazine Editors Choice Awards
OakTable Member
OCP DBA 7.3, 8, 8i, 9i, 10g, 11g
OCP Advanced PL/SQL Developer
Oracle Database: SQL Certified Expert
My website: http://www.oracle-base.com
My blog: http://www.oracle-base.com/blog


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