Initiating Switchover on a Physical Standby

It seems the best instance to intiaiate the switchover changes based on whether data guard broker is used or not. Oracle documentation states when performing switchover using SQL, the switchover process is initiated on the primary database.

Initiate the switchover on the primary database, BOSTON, by issuing the following SQL statement

On the data guard broker documentation it doesn't explicitly states where to initiate the switchover. In practice switchover command could be initiated while logged into any instance. However, executing switchover on the primary instance when data gaurd broker is used will output the following in the data guard broker log. The DG configuration is

DGMGRL> show configuration

Configuration - test_dg

  Protection Mode: MaxAvailability
  Members:
  dgtest  - Primary database
    dgtest2 - Physical standby database
    dgtest3 - Physical standby database

Fast-Start Failover:  Disabled

Configuration Status:
SUCCESS   (status updated 9 seconds ago)

Switchover command is issued while connected to the current primary, dgtest.

2022-03-21T10:41:33.122+00:00
Forwarding MON_PROPERTY operation to member dgtest2 for processing
2022-03-21T10:41:42.319+00:00
Initiating a healthcheck...
SWITCHOVER TO dgtest2
Switchover to physical standby database cannot be initiated from the primary database
redirecting connection to switchover target database dgtest2...
...using connect identifier: dgtest2tns
SWITCHOVER TO dgtest2
Notifying Oracle Clusterware to prepare primary database for switchover
2022-03-21T10:41:44.319+00:00
Executing SQL: [ALTER DATABASE SWITCHOVER TO 'dgtest2']
2022-03-21T10:42:02.573+00:00
SQL [ALTER DATABASE SWITCHOVER TO 'dgtest2'] executed successfully
2022-03-21T10:42:03.652+00:00
Switchover successful

From the output it seems that DG broker is creating a remote connection to the standby (new primary) using the TNS entry used when the standby was added to the data guard broker.



On the otherhand if connected to the standby and switchover command is issued no such message appears.

DGMGRL>  show configuration

Configuration - test_dg

  Protection Mode: MaxAvailability
  Members:
  dgtest2 - Primary database
    dgtest  - Physical standby database
    dgtest3 - Physical standby database

Fast-Start Failover:  Disabled

Configuration Status:
SUCCESS   (status updated 5 seconds ago)

New primary is dgtest2 and switchover command is issued from standby, dgtest. The output on DG broker log of the primary (dgtest2) shows the below

2022-03-21T10:50:27.266+00:00
Initiating a healthcheck...
SWITCHOVER TO dgtest
2022-03-21T10:50:28.682+00:00
Notifying Oracle Clusterware to prepare primary database for switchover
Executing SQL: [ALTER DATABASE SWITCHOVER TO 'dgtest']
2022-03-21T10:50:49.451+00:00
SQL [ALTER DATABASE SWITCHOVER TO 'dgtest'] executed successfully

Similary if the switchvoer is issued from another standby that is not the future primary (in this confiugration dgtest3) then again the primary's DG broker log output will have the below output

2022-03-21T11:31:51.242+00:00
Initiating a healthcheck...
SWITCHOVER TO dgtest2
2022-03-21T11:31:52.601+00:00
Notifying Oracle Clusterware to prepare primary database for switchover
Executing SQL: [ALTER DATABASE SWITCHOVER TO 'dgtest2']