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Old 03-26-2009, 06:27 AM
Mike Donovan Mike Donovan is offline
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Join Date: May 2008
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Default No redologs or temp files with new standby database

Question
After creating a standby database I can see that there are no redo log files or temp data files associated with it. Will my standby database still work?

Answer
It is normal for there not to be any REDOLOGS for a physical standby database.

Physical standby databases do not use an online redo log(s), because physical standby databases are not opened for read/write I/O. Changes are not made to the physical standby database and therefore new redo data is not generated. It is on the primary database side the changes are ‘recorded’ in the redo logs, and these changes are pushed to the archive logs. These are then transferred to the standby side, and applied, to keep the standby up to date with the primary.

However, we recommend that the structure of the REDOLOGS on the primary and standby be kept in sync.

So, if a change is made on the primary database then this must also be manually applied to the standby side. To add new redo logs to the standby database you have to replace the control files on the standby database with a new copy of the control files from the primary server. Please see the steps outlined in our forum: http://www.dbvisit.com/forums/showthread.php?t=123

Temp data files are also not physically present in the standby database. They are present as temporary tablespaces, but there is no physical datafile associated with them. See this post for details of how to add these physical files (which may be required if opening the standby in read-only mode) :
http://www.dbvisit.com/forums/showthread.php?t=285
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Old 12-16-2009, 07:00 AM
Mike Donovan Mike Donovan is offline
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Default RE: No redologs or temp files with new standby database

Because a standby database does not use redo logs you do not have to copy these files across when manually creating a new standby database.

If you activate a standby database with existing redo logs, they will get overridden with new redo logs. The new redo logs are generated by the OPEN RESETLOGS command which is run as part of the activate command.
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