Enable flashback in Oracle standby database

Oracle Flashback Database enables point-in-time-recovery of the entire database without requiring a restore and recovery operation.

It rewinds the entire database to a specified point in time in the past by undoing all the changes that were made since that time

Follow below steps on Standby database to enable flashback

SQL> alter system set db_recovery_file_dest_size=16g scope=both;

SQL> alter system set db_recovery_file_dest='/u01/oracle/flash_recovery_area' scope=both;

SQL> alter system set db_flashback_retention_target=1440 scope=both;

SQL> alter database recover managed standby database cancel;

SQL> alter database flashback on;

SQL> alter database recover managed standby database using current logfile disconnect;

SQL> alter database recover managed standby database cancel;

SQL> Create restore point standby_26062021 guarantee flashback database;

Activate physical standby database to open mode

SQL> alter database activate standby database;

SQL> startup mount force;

SQL> alter database set standby database to maximize performance;

SQL> alter database open;