高可用之5——SWITCHOVER_STATUS

• NOT ALLOWED - On a primary database, this status indicates that there are no valid and enabled standby databases. On a standby database, this status indicates that a switchover request has not been received from the primary database.

• SESSIONS ACTIVE - The database has active sessions. On a physical standby database, the WITH SESSION SHUTDOWN SQL clause must be specified to perform a role transition while in this state. On a logical standby database, a role transition can be performed while in this state, but the role transition will not complete until all current transactions have committed.

• SWITCHOVER PENDING - On a physical standby database, this status indicates that a switchover request has been received from the primary database and is being processed. A physical standby database cannot switch to the primary role while in this transient state.

• SWITCHOVER LATENT - On a physical standby database, this status indicates that a switchover request was pending, but the original primary database has been switched back to the primary role.

• TO PRIMARY - The database is ready to switch to the primary role.

• TO STANDBY - The database is ready to switch to either the physical or logical standby role.

• TO LOGICAL STANDBY - The database has received a data dictionary from a logical standby database and is ready to switch to the logical standby role.

• RECOVERY NEEDED - On a physical standby database, this status indicates that additional redo must be applied before the database can switch to the primary role.

• PREPARING SWITCHOVER - On a primary database, this status indicates that a data dictionary is being received from a logical standby database in preparation for switching to the logical standby role. On a logical standby database, this status indicates that the data dictionary has been sent to the primary database and other standby databases.

• PREPARING DICTIONARY - On a logical standby database, this status indicates that the data dictionary is being sent to the primary database and other standby databases in preparation for switching to the primary role.

• FAILED DESTINATION - On a primary database, this status indicates that one or more standby destinations are in an error state.

• RESOLVABLE GAP - On a primary database, this status indicates that one or more standby databases have a redo gap that can be automatically resolved by fetching the missing redo from the primary database or from another standby database.

• UNRESOLVABLE GAP - On a primary database, this status indicates that one or more standby databases have a redo gap that cannot be automatically resolved by fetching the missing redo from the primary database or from another standby database.

• LOG SWITCH GAP - On a primary database, this status indicates that one or more standby databases are missing redo due to a recent log switch.