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Tuesday, July 18, 2017

Failover to a Physical Standby Database When data protection mode is in MAXIMUM PERFORMANCE

Step 1:

If the primary database was running in MAXIMUM PERFORMANCE mode prior to failure,
the procedure of failover is slightly different. In this case the following issues should be evaluated:

Since the protection mode is MAXIMUM PERFORMANCE, the physical Oracle instance may not have standby redo logs configured.
After the loss of the primary database, there may be an archive gap on the
standby database. These gaps should be resolved before transitioning the standby into the primary role.

If possible, manually copy the online redo logs from the original primary database to the target physical Oracle instance and register the
online redo log files using the ALTER DATABASE statement. After registering
the online redo log files, check the alert log file to verify the recovery process has applied the redo from these log files.


Step 2 :

The failover to a physical Oracle instance is similar to a switchover operation. Oracle provides the functionality of
converting a physical Oracle instance into the primary database without considering any of the above mentioned data recovery options.
This is kind of intentional data loss failover and can be achieved using the following statement:

ALTER DATABASE ACTIVATE STANDBY DATABASE;

If a standby log file has been created on the physical standby database,
issuing the above-mentioned statement will result in an Oracle error. The activation of
the physical Oracle instance can be force by skipping the standby log files:

ALTER DATABASE ACTIVATE Oracle instance SKIP STANDBY LOGFILE;

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