CONVERT DATABASE

The CONVERT DATABASE command converts a physical standby database to a snapshot standby database, or reverts the snapshot standby database back to a physical standby database.

A snapshot standby database is a fully updatable standby database. Like a physical or logical standby database, a snapshot standby database receives and archives redo data from a primary database. Unlike a physical or logical standby database, a snapshot standby database does not apply the redo data that it receives. The redo data received by a snapshot standby database is not applied until the snapshot standby is converted back into a physical standby database, after first discarding any local updates made to the snapshot standby database.

A snapshot standby database is best used in scenarios that require a temporary, updatable snapshot of a physical standby database. Note that because redo data received by a snapshot standby database is not applied until it is converted back into a physical standby, the time needed to perform a role transition is directly proportional to the amount of redo data that needs to be applied.

See Oracle Data Guard Concepts and Administration for additional information about snapshot standby databases.

Format

CONVERT DATABASE <db_unique_name> TO {PHYSICAL |SNAPSHOT} STANDBY;

Command Parameters

Usage Notes

db-unique-name

The value of the DB_UNIQUE_NAME initialization parameter of the database you wish to convert to either a physical or snapshot standby.

  • A physical standby database cannot be converted to a snapshot standby database if it is the target of a fast-start failover. The ORA-16668: operation cannot be performed on the fast-start failover target standby database error will be returned.

  • A physical standby database cannot be converted to a snapshot standby database if its RedoRoutes configurable property is set to non-NULL value.

  • Use the DGMGRL ADD DATABASE command to import an existing snapshot standby database into an Oracle Data Guard broker configuration.

  • A snapshot standby database cannot be the target of a switchover or a fast-start failover.

  • A snapshot standby database can be the target of a manual failover if fast-start failover is disabled.

  • You can use the SHOW CONFIGURATION or SHOW DATABASE command to verify the conversion result. For example: 

    DGMGRL> SHOW CONFIGURATION;
 
Configuration - DRSolution
 
  Protection Mode: MaxPerformance
  Members:
    North_Sales  - Primary database
      South_Sales  - Snapshot standby database
 
Fast-Start Failover: DISABLED
 
Configuration Status:
SUCCESS

  • After a snapshot standby database is converted back to a physical standby database, it will be in the default state for a physical standby database, APPLY-ON.

Command Examples

Example 1: Converting a Physical Standby to a Snapshot Standby

Issue the following to convert a physical standby database to a snapshot standby database:

DGMGRL> CONVERT DATABASE 'South_Sales' to SNAPSHOT STANDBY;
Converting database "South_Sales" to a Snapshot Standby database, please wait...
Database "South_Sales" converted successfully

Example 2: Converting a Snapshot Standby Back to a Physical Standby

Issue the following to convert the snapshot standby database back to a physical standby database:

DGMGRL> CONVERT DATABASE 'South_Sales' to PHYSICAL STANDBY;
Converting database "South_Sales" to a Physical Standby database, please wait...
Operation requires shutdown of instance "south_sales1" on database "South_Sales"
Shutting down instance "south_sales1"...
Database closed.
Database dismounted.
ORACLE instance shut down.
Operation requires startup of instance "south_sales1" on database "South_Sales"
Starting instance "south_sales1"...
ORACLE instance started.
Database mounted.
Continuing to convert database "South_Sales" ...
Database "South_Sales" converted successfully