Disclaimer

Friday, 21 November 2025

Reinstate a failed over Data Guard using Flashback Database

 

In Oracle 19c Data Guard, reinstatement refers to the process of bringing a former primary database back into the Data Guard configuration as a standby after a failover has occurred. This is a critical feature that avoids the need for a full restore from backup.




Why Reinstatement Is Needed

  • When a failover happens, the original primary becomes inconsistent with the new primary.
  • To reuse the old primary as a standby, it must be rolled back to a point in time before the failover.
  • Oracle uses Flashback Database for this rollback, which is why flashback must be enabled on the old primary.



Prerequisites for Reinstatement

  1. Flashback Database Enabled on the old primary.
  2. Fast Recovery Area (FRA) configured and sized properly.
  3. The database must be part of the Data Guard Broker configuration.
  4. No physical corruption or missing redo logs that prevent flashback.


How Reinstatement Works

  • Data Guard Broker issues a command to flashback the old primary to the SCN where it can act as a standby.
  • After flashback, the database is converted to a standby role and starts applying redo from the new primary.





[oracle@oradba01-A52DR ~]$ . oraenv
ORACLE_SID = [oracle] ? A52DR
The Oracle base has been set to /oracle/A52
[oracle@oradba01-A52DR ~]$
[oracle@oradba01-A52DR ~]$
[oracle@oradba01-A52DR ~]$
[oracle@oradba01-A52DR ~]$ sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Jun 30 19:39:08 2025
Version 19.22.0.0.0

Copyright (c) 1982, 2023, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup nomount;
ORACLE instance started.

Total System Global Area 8489269064 bytes
Fixed Size                  8959816 bytes
Variable Size            4244635648 bytes
Database Buffers         4227858432 bytes
Redo Buffers                7815168 bytes
SQL>
SQL>
SQL>
SQL> alter database mount;

Database altered.

SQL>
SQL>
SQL>
SQL> @dg_status

INSTANCE_NAME   HOST_NAME      STATUS   DATABASE_STATUS PROTECTION_MODE      INSTANCE_ROLE      VERSION_FULL    DATABASE_ROLE
--------------- -------------- -------- --------------- -------------------- ------------------ --------------- ------------------
A52DR           oradba01-A52DR  MOUNTED  ACTIVE          MAXIMUM AVAILABILITY PRIMARY_INSTANCE   19.22.0.0.0     PRIMARY

SQL>
SQL>
SQL>
SQL>
SQL> select name, open_mode, database_role, switchover_status, protection_mode from v$database;

NAME      OPEN_MODE            DATABASE_ROLE      SWITCHOVER_STATUS    PROTECTION_MODE
--------- -------------------- ------------------ -------------------- --------------------
A52       MOUNTED              PRIMARY            NOT ALLOWED          MAXIMUM AVAILABILITY

SQL>
SQL>
SQL>  select FS_FAILOVER_STATUS,FS_FAILOVER_OBSERVER_PRESENT from v$database;

FS_FAILOVER_STATUS     FS_FAIL
---------------------- -------
DISABLED



[oracle@oradba01-A52DR]$ sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Jun 30 20:05:49 2025
Version 19.22.0.0.0

Copyright (c) 1982, 2023, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.22.0.0.0

SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-38760: This database instance failed to turn on flashback database


SQL>
SQL>
SQL> show parameter flashback

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_flashback_retention_target        integer     360

SQL> show parameter flash

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_flash_cache_file                  string
db_flash_cache_size                  big integer 0
db_flashback_retention_target        integer     360

SQL> select flashback_on from v$database;

FLASHBACK_ON
------------------
YES

SQL>
SQL>
SQL> SELECT FLASHBACK_ON FROM V$DATABASE;

FLASHBACK_ON
------------------
YES


SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-38760: This database instance failed to turn on flashback database



==============================
Database Instance:-
==============================
A52   - Primary
A52DR - Standby

Note:- Primary  (A52) DB was down (mount) state and  A52DR became Primary and not able to start DB, so aftersome we reinstate

[oracle@oradba01-A52DR]$ sqlplus / as sysdba

SQL> @dg_status

INSTANCE_NAME   HOST_NAME      STATUS   DATABASE_STATUS PROTECTION_MODE      INSTANCE_ROLE      VERSION_FULL    DATABASE_ROLE
--------------- -------------- -------- --------------- -------------------- ------------------ --------------- ------------------
A52DR           oradba01-A52DR MOUNTED  ACTIVE          MAXIMUM AVAILABILITY PRIMARY_INSTANCE   19.22.0.0.0     PRIMARY


SQL>
SQL> select name, open_mode, database_role, switchover_status, protection_mode from v$database;

NAME      OPEN_MODE            DATABASE_ROLE      SWITCHOVER_STATUS    PROTECTION_MODE
--------- -------------------- ------------------ -------------------- --------------------
A52       MOUNTED              PRIMARY            NOT ALLOWED          MAXIMUM AVAILABILITY



[oracle@oradba01-A52DR]$ dgmgrl /
DGMGRL for Linux: Release 19.0.0.0.0 - Production on Mon Jun 30 20:13:15 2025
Version 19.22.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

Welcome to DGMGRL, type "help" for information.
Connected to "A52DR"
Connected as SYSDG.
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> show configuration;

Configuration - DG_CONFIG

  Protection Mode: MaxAvailability
  Members:
  A52dr - Primary database
    Error: ORA-16810: multiple errors or warnings detected for the member

    A52   - Physical standby database (disabled)
      ORA-16661: the standby database needs to be reinstated

Fast-Start Failover:  Disabled

Configuration Status:
ERROR   (status updated 31 seconds ago)

DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> reinstate database 'A52';
Reinstating database "A52", please wait...
Reinstatement of database "A52" succeeded




DGMGRL>
DGMGRL> show configuration;

Configuration - DG_CONFIG

  Protection Mode: MaxAvailability
  Members:
  A52dr - Primary database
    Error: ORA-16782: instance not open for read and write access

    A52   - Physical standby database
      Warning: ORA-16809: multiple warnings detected for the member

Fast-Start Failover:  Disabled

Configuration Status:
ERROR   (status updated 21 seconds ago)



[oracle@oradba01-A52DR ]$ sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Jun 30 20:15:21 2025
Version 19.22.0.0.0

Copyright (c) 1982, 2023, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.22.0.0.0

SQL>
SQL>
SQL>
SQL> @dg_status

INSTANCE_NAME   HOST_NAME      STATUS   DATABASE_STATUS PROTECTION_MODE      INSTANCE_ROLE      VERSION_FULL    DATABASE_ROLE
--------------- -------------- -------- --------------- -------------------- ------------------ --------------- ------------------
A52DR           oradba01-A52DR  MOUNTED  ACTIVE          MAXIMUM AVAILABILITY PRIMARY_INSTANCE   19.22.0.0.0     PRIMARY

SQL>
SQL>
SQL>
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-38760: This database instance failed to turn on flashback database


SQL> shut immediate;
ORA-01109: database not open


Database dismounted.
ORACLE instance shut down.
SQL>
SQL>
SQL>
SQL> exit
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.22.0.0.0



[oracle@oradba01-A52DR dba_scripts]$ sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Jun 30 20:17:08 2025
Version 19.22.0.0.0

Copyright (c) 1982, 2023, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup nomount;
ORACLE instance started.

Total System Global Area 8489269064 bytes
Fixed Size                  8959816 bytes
Variable Size            4244635648 bytes
Database Buffers         4227858432 bytes
Redo Buffers                7815168 bytes
SQL>
SQL>
SQL> alter database mount;

Database altered.

SQL>
SQL>
SQL> show parameter db_recovery_file_dest;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest                string
db_recovery_file_dest_size           big integer 300G

SQL> show parameter db_flashback_retention_target;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_flashback_retention_target        integer     360
SQL>
SQL>
SQL>
SQL> select flashback_on from v$database;

FLASHBACK_ON
------------------
YES

SQL>
SQL>
SQL>
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-38760: This database instance failed to turn on flashback database


SQL>
SQL>
SQL>
SQL>
SQL>
SQL> alter database flashback off;

Database altered.

SQL>
SQL>
SQL> alter database open;

Database altered.

SQL>
SQL>
SQL>
SQL> @dg_status

INSTANCE_NAME   HOST_NAME      STATUS   DATABASE_STATUS PROTECTION_MODE      INSTANCE_ROLE      VERSION_FULL    DATABASE_ROLE
--------------- -------------- -------- --------------- -------------------- ------------------ --------------- ------------------
A52DR           oradba01-A52DR  OPEN     ACTIVE          MAXIMUM AVAILABILITY PRIMARY_INSTANCE   19.22.0.0.0     PRIMARY

SQL>
SQL>
SQL>
SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            +ARCH/A52dr/oraarch
Oldest online log sequence     1
Next log sequence to archive   4
Current log sequence           4
SQL>
SQL>
SQL>
SQL>
SQL> alter system switch logfile;

System altered.

SQL>
SQL>
SQL>
SQL> /
/
System altered.

SQL>/

System altered.

SQL> /

System altered.

SQL>
SQL>
SQL>
SQL> alter database flashback on;
alter database flashback on
*
ERROR at line 1:
ORA-38706: Cannot turn on FLASHBACK DATABASE logging.
ORA-38709: Recovery Area is not enabled.


SQL>
SQL>
SQL>
SQL> show parameter recovery

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest                string
db_recovery_file_dest_size           big integer 300G
recovery_parallelism                 integer     0
remote_recovery_file_dest            string
SQL>
SQL>
SQL>
SQL>
SQL> set lines 200 pages 200;
col name for a13
Select NAME, round ((TOTAL_MB/1024), 2) Total_GB,
round ((FREE_MB/1024),2) Free_GB,
round((TOTAL_MB/1024),2) - round((FREE_MB/1024),2) Used_GB,
round(((free_mb/total_mb)*100),2) "FREE% ",
round((((total_mb-free_mb)/total_mb)*100),2) "USED%"
from v$asm_diskgroup;SQL> SQL>   2    3    4    5    6

NAME            TOTAL_GB    FREE_GB    USED_GB     FREE%       USED%
------------- ---------- ---------- ---------- ---------- ----------
ARCH                 512     508.47       3.53      99.31        .69
DATA                1024      449.5      574.5       43.9       56.1
FRA                  300     299.89        .11      99.96        .04

SQL>
SQL>
SQL> alter system set db_recovery_file_dest='+FRA' scope=both;

System altered.

SQL>
SQL>
SQL> alter database flashback on;

Database altered.

SQL>
SQL>
SQL>
SQL> select flashback_on from v$database;

FLASHBACK_ON
------------------
YES

SQL>
SQL>
SQL> exit
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.22.0.0.0




[oracle@oradba01-A52DR dba_scripts]$ dgmgrl /
DGMGRL for Linux: Release 19.0.0.0.0 - Production on Mon Jun 30 20:40:22 2025
Version 19.22.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

Welcome to DGMGRL, type "help" for information.
Connected to "A52DR"
Connected as SYSDG.
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> show configuration;

Configuration - DG_CONFIG

  Protection Mode: MaxAvailability
  Members:
  A52dr - Primary database
    A52   - Physical standby database

Fast-Start Failover:  Disabled

Configuration Status:
SUCCESS   (status updated 51 seconds ago)

DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> show observer;

Configuration - DG_CONFIG

Fast-Start Failover: DISABLED

No observers.

DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> validate database A52dr;

  Database Role:    Primary database

  Ready for Switchover:  Yes

  Managed by Clusterware:
    A52dr:  YES

DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> validate database verbose A52;

  Database Role:     Physical standby database
  Primary Database:  A52dr

  Ready for Switchover:  Yes
  Ready for Failover:    Yes (Primary Running)

  Flashback Database Status:
    A52dr:  On
    A52  :  On

  Capacity Information:
    Database  Instances        Threads
    A52dr     1                1
    A52       1                1

  Managed by Clusterware:
    A52dr:  YES
    A52  :  YES

  Temporary Tablespace File Information:
    A52dr TEMP Files:  10
    A52 TEMP Files:    10

  Data file Online Move in Progress:
    A52dr:  No
    A52:    No

  Standby Apply-Related Information:
    Apply State:      Running
    Apply Lag:        0 seconds (computed 0 seconds ago)
    Apply Delay:      0 minutes

  Transport-Related Information:
    Transport On:  Yes
    Gap Status:    No Gap
    Transport Lag:  0 seconds (computed 0 seconds ago)
    Transport Status:  Success

  Log Files Cleared:
    A52dr Standby Redo Log Files:  Cleared
    A52 Online Redo Log Files:     Cleared
    A52 Standby Redo Log Files:    Available

  Current Log File Groups Configuration:
    Thread #  Online Redo Log Groups  Standby Redo Log Groups Status
              (A52dr)                 (A52)
    1         4                       4                       Sufficient SRLs

  Future Log File Groups Configuration:
    Thread #  Online Redo Log Groups  Standby Redo Log Groups Status
              (A52)                   (A52dr)
    1         4                       4                       Sufficient SRLs

  Current Configuration Log File Sizes:
    Thread #   Smallest Online Redo      Smallest Standby Redo
               Log File Size             Log File Size
               (A52dr)                   (A52)
    1          200 MBytes                200 MBytes

  Future Configuration Log File Sizes:
    Thread #   Smallest Online Redo      Smallest Standby Redo
               Log File Size             Log File Size
               (A52)                     (A52dr)
    1          200 MBytes                200 MBytes

  Apply-Related Property Settings:
    Property                        A52dr Value              A52 Value
    DelayMins                       0                        0
    ApplyParallel                   AUTO                     AUTO
    ApplyInstances                  0                        0

  Transport-Related Property Settings:
    Property                        A52dr Value              A52 Value
    LogShipping                     ON                       ON
    LogXptMode                      SYNC                     SYNC
    Dependency                      <empty>                  <empty>
    DelayMins                       0                        0
    Binding                         OPTIONAL                 optional
    MaxFailure                      0                        0
    ReopenSecs                      300                      300
    NetTimeout                      30                       30
    RedoCompression                 DISABLE                  DISABLE

DGMGRL>
DGMGRL>
DGMGRL> exit
[oracle@oradba01-A52DR dba_scripts]$
[oracle@oradba01-A52DR dba_scripts]$
[oracle@oradba01-A52DR dba_scripts]$ sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Jun 30 20:44:50 2025
Version 19.22.0.0.0

Copyright (c) 1982, 2023, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.22.0.0.0

SQL> @lag

    Thread Last Sequence Received Last Sequence Applied Difference
---------- ---------------------- --------------------- ----------
         1                      9                     9          0
         1                      9                     9          0

SQL>
SQL>
SQL>
SQL> exit
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.22.0.0.0






[oracle@oradba01-A52DR]$ . oraenv
ORACLE_SID = [A52DR] ?
The Oracle base remains unchanged with value /oracle/A52


[oracle@oradba01-A52DR ]$
[oracle@oradba01-A52DR ]$
[oracle@oradba01-A52DR ]$ dgmgrl
DGMGRL for Linux: Release 19.0.0.0.0 - Production on Mon Jun 30 20:46:19 2025
Version 19.22.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

Welcome to DGMGRL, type "help" for information.

DGMGRL> connect sys/sys123
Connected to "A52DR"
Connected as SYSDBA.
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> show configuration;

Configuration - DG_CONFIG

  Protection Mode: MaxAvailability
  Members:
  A52dr - Primary database
    A52   - Physical standby database

Fast-Start Failover:  Disabled

Configuration Status:
SUCCESS   (status updated 12 seconds ago)

DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> show configuration verbose;

Configuration - DG_CONFIG

  Protection Mode: MaxAvailability
  Members:
  A52dr - Primary database
    A52   - Physical standby database

  Properties:
    FastStartFailoverThreshold      = '600'
    OperationTimeout                = '30'
    TraceLevel                      = 'USER'
    FastStartFailoverLagLimit       = '30'
    CommunicationTimeout            = '180'
    ObserverReconnect               = '30'
    FastStartFailoverLagGraceTime   = '0'
    FastStartFailoverAutoReinstate  = 'TRUE'
    FastStartFailoverPmyShutdown    = 'TRUE'
    BystandersFollowRoleChange      = 'ALL'
    ObserverOverride                = 'FALSE'
    ExternalDestination1            = ''
    ExternalDestination2            = ''
    PrimaryLostWriteAction          = 'CONTINUE'
    ConfigurationWideServiceName    = 'A52_CFG'
    FastStartFailoverLagType        = 'APPLY'

Fast-Start Failover:  Disabled

Configuration Status:
SUCCESS

DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> validate database A52dr;

  Database Role:    Primary database

  Ready for Switchover:  Yes

  Managed by Clusterware:
    A52dr:  YES

DGMGRL>
DGMGRL>
DGMGRL> validate database verbose A52;

  Database Role:     Physical standby database
  Primary Database:  A52dr

  Ready for Switchover:  Yes
  Ready for Failover:    Yes (Primary Running)

  Flashback Database Status:
    A52dr:  On
    A52  :  On

  Capacity Information:
    Database  Instances        Threads
    A52dr     1                1
    A52       1                1

  Managed by Clusterware:
    A52dr:  YES
    A52  :  YES

  Temporary Tablespace File Information:
    A52dr TEMP Files:  10
    A52 TEMP Files:    10

  Data file Online Move in Progress:
    A52dr:  No
    A52:    No

  Standby Apply-Related Information:
    Apply State:      Running
    Apply Lag:        0 seconds (computed 1 second ago)
    Apply Delay:      0 minutes

  Transport-Related Information:
    Transport On:  Yes
    Gap Status:    No Gap
    Transport Lag:  0 seconds (computed 1 second ago)
    Transport Status:  Success

  Log Files Cleared:
    A52dr Standby Redo Log Files:  Cleared
    A52 Online Redo Log Files:     Cleared
    A52 Standby Redo Log Files:    Available

  Current Log File Groups Configuration:
    Thread #  Online Redo Log Groups  Standby Redo Log Groups Status
              (A52dr)                 (A52)
    1         4                       4                       Sufficient SRLs

  Future Log File Groups Configuration:
    Thread #  Online Redo Log Groups  Standby Redo Log Groups Status
              (A52)                   (A52dr)
    1         4                       4                       Sufficient SRLs

  Current Configuration Log File Sizes:
    Thread #   Smallest Online Redo      Smallest Standby Redo
               Log File Size             Log File Size
               (A52dr)                   (A52)
    1          200 MBytes                200 MBytes

  Future Configuration Log File Sizes:
    Thread #   Smallest Online Redo      Smallest Standby Redo
               Log File Size             Log File Size
               (A52)                     (A52dr)
    1          200 MBytes                200 MBytes

  Apply-Related Property Settings:
    Property                        A52dr Value              A52 Value
    DelayMins                       0                        0
    ApplyParallel                   AUTO                     AUTO
    ApplyInstances                  0                        0

  Transport-Related Property Settings:
    Property                        A52dr Value              A52 Value
    LogShipping                     ON                       ON
    LogXptMode                      SYNC                     SYNC
    Dependency                      <empty>                  <empty>
    DelayMins                       0                        0
    Binding                         OPTIONAL                 optional
    MaxFailure                      0                        0
    ReopenSecs                      300                      300
    NetTimeout                      30                       30
    RedoCompression                 DISABLE                  DISABLE

DGMGRL>
DGMGRL>
DGMGRL>


set lines 200
col WINDOW_NAME for a25
col WINDOW_NEXT_TIME for a45
select WINDOW_NAME,WINDOW_NEXT_TIME,OPTIMIZER_STATS,WINDOW_ACTIVE,AUTOTASK_STATUS from DBA_AUTOTASK_WINDOW_CLIENTS;


WINDOW_NAME               WINDOW_NEXT_TIME                              OPTIMIZE WINDO AUTOTASK
------------------------- --------------------------------------------- -------- ----- --------
MONDAY_WINDOW             03-MAR-25 10.00.00.000000 PM EUROPE/VIENNA    ENABLED  FALSE ENABLED
TUESDAY_WINDOW            04-MAR-25 10.00.00.000000 PM EUROPE/VIENNA    ENABLED  FALSE ENABLED
WEDNESDAY_WINDOW          26-FEB-25 10.00.00.000000 PM EUROPE/VIENNA    ENABLED  FALSE ENABLED
THURSDAY_WINDOW           27-FEB-25 10.00.00.000000 PM EUROPE/VIENNA    ENABLED  FALSE ENABLED
FRIDAY_WINDOW             28-FEB-25 10.00.00.000000 PM EUROPE/VIENNA    ENABLED  FALSE ENABLED
SATURDAY_WINDOW           01-MAR-25 06.00.00.000000 AM EUROPE/VIENNA    ENABLED  FALSE ENABLED
SUNDAY_WINDOW             02-MAR-25 06.00.00.000000 AM EUROPE/VIENNA    ENABLED  FALSE ENABLED

7 rows selected.


[oracle@oradba01-A52DR]$ dgmgrl sys/sys123@A52DR.WORLD
DGMGRL for Linux: Release 19.0.0.0.0 - Production on Mon Jun 30 20:48:22 2025
Version 19.22.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

Welcome to DGMGRL, type "help" for information.
Connected to "A52DR"
Connected as SYSDBA.
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> validate database A52DR;

  Database Role:    Primary database

  Ready for Switchover:  Yes

  Managed by Clusterware:
    A52dr:  YES

DGMGRL> VALIDATE DATABASE A52;

  Database Role:     Physical standby database
  Primary Database:  A52dr

  Ready for Switchover:  Yes
  Ready for Failover:    Yes (Primary Running)

  Managed by Clusterware:
    A52dr:  YES
    A52  :  YES

DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> validate static connect identifier for all;
Oracle Clusterware on database "A52" is available for database restart.

Oracle Clusterware on database "A52dr" is available for database restart.

DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> SWITCHOVER TO A52;
Performing switchover NOW, please wait...
Operation requires a connection to database "A52"
Connecting ...
Connected to "A52"
Connected as SYSDBA.
New primary database "A52" is opening...
Oracle Clusterware is restarting database "A52dr" ...
Connected to an idle instance.
Connected to an idle instance.
Connected to an idle instance.
Connected to an idle instance.
Connected to "A52DR"
Switchover succeeded, new primary is "A52"
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> SHOW CONFIGURATION;

Configuration - DG_CONFIG

  Protection Mode: MaxAvailability
  Members:
  A52   - Primary database
    A52dr - Physical standby database

Fast-Start Failover:  Disabled

Configuration Status:
SUCCESS   (status updated 49 seconds ago)

DGMGRL>
DGMGRL>
DGMGRL>
DGMGRL> exit
[oracle@oradba01-A52DR]$
[oracle@oradba01-A52DR]$
[oracle@oradba01-A52DR]$ . oraenv
ORACLE_SID = [A52DR] ?
The Oracle base remains unchanged with value /oracle/A52
[oracle@oradba01-A52DR dba_scripts]$ sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Jun 30 20:52:49 2025
Version 19.22.0.0.0

Copyright (c) 1982, 2023, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.22.0.0.0

SQL> @dg_status

INSTANCE_NAME   HOST_NAME      STATUS   DATABASE_STATUS PROTECTION_MODE      INSTANCE_ROLE      VERSION_FULL    DATABASE_ROLE
--------------- -------------- -------- --------------- -------------------- ------------------ --------------- ------------------
A52DR           oradba01-A52DR  MOUNTED  ACTIVE          MAXIMUM AVAILABILITY PRIMARY_INSTANCE   19.22.0.0.0     PHYSICAL STANDBY




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