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PARENT_DBUN And DEST_ROLE Columns In v$dataguard_config View Show UNKNOWN On Multiple Standby Databases (Doc ID 3046098.1)

Last updated on SEPTEMBER 18, 2024

Applies to:

Oracle Database - Enterprise Edition - Version 19.3.0.0.0 and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Gen 2 Exadata Cloud at Customer - Version N/A and later
Information in this document applies to any platform.

Symptoms

PARENT_DBUN column and DEST_ROLE column in v$dataguard_config view show "UNKNOWN" on standby databases when primay database sends redo logs to multipel standby database.

Below is an example.

(A) output of primary database
 
SQL> select db_unique_name, database_role from v$database;
DB_UNIQUE_NA DATABASE_ROLE
------------ ------------------------------------------------
<primary>    PRIMARY
SQL> select * from v$dataguard_config;
DB_UNIQUE_NA PARENT_DBUN DEST_ROLE            CURRENT_SCN CON_ID
------------ ----------- -------------------- ----------- ------
<primary>    NONE        PRIMARY DATABASE         2060792      0
<standby1>   <primary>   PHYSICAL STANDBY         2060882      0
<standby2>   <standby1>  PHYSICAL STANDBY         2057787      0
(B) output on standby database (1)
 
SQL> select db_unique_name, database_role from v$database;
DB_UNIQUE_NA DATABASE_ROLE
------------ ------------------------------------------------
<standby1>   PHYSICAL STANDBY
SQL> select * from v$dataguard_config order by 1;
DB_UNIQUE_NA PARENT_DBUN DEST_ROLE            CURRENT_SCN CON_ID
------------ ----------- -------------------- ----------- ------
<primary>    NONE        PRIMARY DATABASE               0      0
<standby1>   <primary>   PHYSICAL STANDBY         2060654      0
<standby2>   UNKNOWN     UNKNOWN                        0      0

(C) output on standby database (2)
 
SQL> select db_unique_name, database_role from v$database;
 
DB_UNIQUE_NA DATABASE_ROLE
------------ ------------------------------------------------
<standby2>   PHYSICAL STANDBY
 
SQL> select * from v$dataguard_config order by 1;
 
DB_UNIQUE_NA PARENT_DBUN DEST_ROLE            CURRENT_SCN CON_ID
------------ ----------- -------------------- ----------- ------
<primary>    NONE        PRIMARY DATABASE               0      0
<standby1>   UNKNOWN     UNKNOWN                        0      0
<standby2>   <primary>   PHYSICAL STANDBY         2057788      0

 

Cause

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In this Document
Symptoms
Cause
Solution


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