Oracle Data guard role transition

The log_archive_dest_n and log_archive_dest_state_n init parameters of the remaining standby databases must be altered so that they receive redo from the new primary database.

There must be no redo transport errors or redo gaps at the standby database that is to become the new primary database.

This can be checked on the primary database by querying v$archive_dest_status.

Temporary files on standby database must match those of the primary database.

There must be no redo apply delay on the standby database.

Standby databases in real time query mode might be opened in mounted but not open state.