About RESETLOGS Option

The RESETLOGS option is always required after incomplete media recovery or recovery using a backup control file. Resetting the redo log does the following:


1. Archives the current online redo logs (if they are accessible) and then erases the contents of the online redo logs and resets the log sequence number to 1. For example, if the current online redo logs are sequence 1000 and 1001 when you open RESETLOGS, then the database archives logs 1000 and 1001 and then resets the online logs to sequence 1 and 2.


2.Creates the online redo log files if they do not currently exist.


3.Reinitializes the control file metadata about online redo logs and redo threads.
Updates all current datafiles and online redo logs and all subsequent archived redo logs with a new RESETLOGS SCN and time stamp.


Because the database will not apply an archived log to a datafile unless the RESETLOGS SCN and time stamps match, the RESETLOGS prevents you from corrupting datafiles with archived logs that are not from direct parent incarnations of the current incarnation.

In prior releases, it was recommended that you back up the database immediately after the RESETLOGS. Because you can now easily recover a pre-RESETLOGS backup like any other backup, making a new database backup is optional. In order to perform recovery through resetlogs you must have all archived logs generated since the last backup and at least one control file (current, backup, or created).