How I removed a data guard config completely

Here is my config:

DGMGRL> show configuration;

Configuration - DGConfig1

  Protection Mode: MaxPerformance
  Members:
  kej01       - Primary database
    kej01_stby1 - Physical standby database

Fast-Start Failover:  Disabled

Configuration Status:
SUCCESS   (status updated 66 seconds ago)

1. stop the redo apply process:

DGMGRL>  edit database kej01_stby1 set state='APPLY-OFF';
Succeeded.

2. remove the standby database from the configuration:

DGMGRL> remove database kej01_stby1;
Removed database "kej01_stby1" from the configuration

3. Remove the configuration itself:

DGMGRL> remove configuration;
Removed configuration

4. On both the primary and standby server, edit the $TNS_ADMIN/listener.ora by removing these entries:

(SID_DESC =
      (GLOBAL_DBNAME = kej01_DGMGRL)
      (ORACLE_HOME = /orasw/19c)
      (SID_NAME = kej01)
    )
   (SID_DESC =
      (GLOBAL_DBNAME = kej01_DGMGRL.skead.no)
      (ORACLE_HOME = /orasw/19c)
      (SID_NAME = kej01)
    )
 

Make sure to stop/start the listener afterwards.
5. On previous standby, remove db_unique_name:

SYS@kej01>SQL>alter system set db_unique_name='kej01' scope=spfile;

6. On both servers, stop the broker processes:

SYS@kej01>SQL>alter system set dg_broker_start=false scope=both;

System altered.

6. On the standby, finish database recovery:

SYS@kej01>alter database recover managed standby database finish;

Database altered.

The database is still mounted as a physical standby:

SYS@kej01>SQL>select open_mode, database_role from v$database;

OPEN_MODE            DATABASE_ROLE
-------------------- ----------------
MOUNTED              PHYSICAL STANDBY

If you open it now, it will be in READ ONLY status:

SYS@kej01>SQL>alter database open;

Database altered.

SYS@kej01>select open_mode, database_role from v$database;

OPEN_MODE            DATABASE_ROLE
-------------------- ----------------
READ ONLY            PHYSICAL STANDBY

7. Instruct the former standby database that it is now indeed a normal ("primary") database:

SYS@kej01>ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;

Database altered.

The alert log will show that we are cutting all strings to the previous role:

2024-05-29T15:55:09.123174+02:00
ALTER DATABASE SWITCHOVER TO PRIMARY (kej01)
2024-05-29T15:55:09.125019+02:00
Maximum wait for role transition is 15 minutes.
TMI: kcv_commit_to_so_to_primary wait for MRP to finish BEGIN 2024-05-29 15:55:09.125651
TMI: kcv_commit_to_so_to_primary wait for MRP to finish END 2024-05-29 15:55:09.126990
TMI: kcv_commit_to_so_to_primary Switchover from physical BEGIN 2024-05-29 15:55:09.130097

Standby terminal recovery start SCN: 4695193
RESETLOGS after incomplete recovery UNTIL CHANGE 4695565 time 05/29/2024 15:28:15
ET  (PID:1614518): ORL pre-clearing operation disabled by switchover
Online log /log/oradata/kej01/redo1.log: Thread 1 Group 1 was previously cleared
Online log /log/oradata/kej01/redo2.log: Thread 1 Group 2 was previously cleared
Online log /log/oradata/kej01/redo3.log: Thread 1 Group 3 was previously cleared
Standby became primary SCN: 4695192
2024-05-29T15:55:16.588617+02:00
Setting recovery target incarnation to 3
2024-05-29T15:55:16.662719+02:00
NET  (PID:1614518): Database role cleared from PHYSICAL STANDBY [kcvs.c:1133]
Switchover: Complete - Database mounted as primary
TMI: kcv_commit_to_so_to_primary Switchover from physical END 2024-05-29 15:55:16.667784
Completed: ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN
2024-05-29T15:55:27.547369+02:00
alter database open

At this point, my standby database is once again mounted, but it has now assumed the PRIMARY role, which is what I want:

SYS@kej01>SQL>select open_mode, database_role from v$database;

OPEN_MODE            DATABASE_ROLE
-------------------- ----------------
MOUNTED              PRIMARY

8. Open it now, and it will be in read write mode:

SYS@kej01>SQL>alter database open;

Database altered.

SYS@kej01>SQL>select open_mode, database_role from v$database;

OPEN_MODE            DATABASE_ROLE
-------------------- ----------------
READ WRITE           PRIMARY

According to the oracle documentation, the syntax above is pre-12.1 style, which is still compatible but DBAs are encouraged to use

ALTER DATABASE SWITCHOVER TO target_db_name [FORCE] [VERIFY];
and
ALTER DATABASE FAILOVER TO target_db_name;

instead.