PrimaryDatabaseCandidates

The PrimaryDatabaseCandidates configuration property allows the restriction of switchover and failover to a list of databases.

Category Description

Broker default

Thedefault value is an empty string that means no restriction.

Configuration Type

Data Guard only

Datatype

String

Property Type

Configurable

Scope

Configuration

Valid Role

Primary, Physical Standby

Valid value

Comma-seperated list of databases in the broker configuration. For example 'db1,db2,db3'

The PrimaryDatabaseCandidates property prevents switchover/failover to some specified databases in a Data Guard broker configuration. This property is a list of DB_UNIQUE_NAMEs of the databases to which Data Guard broker will allow switchover and failover when FSFO is disabled. Note that, when FSFO is enabled, thisproperty does not add any new restrictions since Data Guard Broker already has a property FastStartFailoverTarget that lists which databases can be new primary databases.

For example, assume there are six databases in a broker configuration:

db1, db2, db3, db4, db5, db6

If this property is set using the following command:

edit configuration set property PrimaryDatabaseCandidates= ‘db1, db2, db3’

Only the switchover and failover to db1, db2, or db3 will be allowed when FSFO is disabled. Data Guard Broker would reject any attempt to switchover or failover to b4, b5, or b6, or any newly added databases after setting the property PrimaryDatabaseCandidates.

If an attempt is made to modify this property, the attempt will be rejected if the one of the following conditions is true:
  • One value in the list is not a member of the current broker configuration
  • One value in the list is a member of the current broker configuration, but the member type is not primary/physical standby/logical standby/snapshot

If the value provided does not contain the primary database, broker will add the primary database automatically since it is natural for primary database to be in this property. In this case the command will return a warning message:

DGMGRL> edit configuration set property PrimaryDatabaseCandidates= 'DB2' ;
Warning: ORA-16580: The primary database was added to property PrimaryDatabaseCandidates

Property "primarydatabasecandidates" updated

If a member from a broker configuration is removed and that member is in property PrimaryDatabaseCandidates, Data Guard Broker will remove it from the property value.

If an attempt is made to failover/switchover to a member that is not defined in PrimaryDatabaseCandidates and FSFO is disabled, Data Guard Broker will issue the following error message:

ORA-16529: Switchover and failover operations are restricted to databases specified in the PrimaryDatabaseCandidates configuration property