Failed Primary Conversion to Physical Standby

1) Query on old standby database (new primary)

SQL> SELECT TO_CHAR(STANDBY_BECAME_PRIMARY_SCN) FROM V$DATABASE;

TO_CHAR(STANDBY_BECAME_PRIMARY_SCN)
----------------------------------------
12496643189

2) Flash back the failed primary database.

SQL> shutdown immediate;

SQL> startup mount;

SQL> FLASHBACK DATABASE TO SCN 12496643189;

Flashback complete.

3) Convert old primary into standby database

SQL> ALTER DATABASE CONVERT TO PHYSICAL STANDBY;

SQL> SHUTDOWN IMMEDIATE;

SQL> STARTUP MOUNT;

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;

4) Make log switch from New Primary

SQL> ALTER SYSTEM ARCHIVE LOG CURRENT;