As a database administrator, managing physical standby databases is a crucial part of your daily tasks. One of the most efficient ways to refresh a physical standby database is by using the RECOVER FROM SERVICE command, especially in Oracle 12c. In this article, we’ll delve into the details of how to achieve this.
Understanding Physical Standby Databases
Physical standby databases are an essential component of an Oracle Data Guard configuration. They provide a layer of protection against primary database failure, allowing you to quickly switch over to the standby database in case of a disaster. To maintain a physical standby database, you must periodically refresh it to ensure it remains synchronized with the primary database.
The Need for Refreshing Physical Standby Databases
Refreshing a physical standby database is essential to maintain its synchronization with the primary database. If the standby database is not kept up to date, it can become desynchronized, leading to problems when attempting to switch over to the standby database in case of a failure. This can also result in data loss or corruption.
Additionally, refreshing a physical standby database helps ensure that it is ready for use in case of a disaster. If the primary database fails, the standby database can be quickly switched over to, minimizing downtime and data loss.
The RECOVER FROM SERVICE Command
The RECOVER FROM SERVICE command is a convenient way to refresh a physical standby database in Oracle 12c. This command allows you to start a refresh operation on the standby database, which includes applying all redo data that has been received from the primary database.
This command has several benefits, including the ability to:
- Automatically apply all redo data received from the primary database
- Update the standby database to the current SCN (System Change Number)
- Minimize downtime and data loss in case of a disaster
Using the RECOVER FROM SERVICE Command
To use the RECOVER FROM SERVICE command, follow these steps:
1. Ensure that the primary database is open and that the standby database is in a mounted state.
2. Set the LOG_ARCHIVE_CONFIG parameter on the primary database to specify the standby database configuration:
SQL> ALTER SYSTEM SET log_archive_config='DG_CONFIG=(oracle12c,ORCLCDB)';
3. Set the LOG_ARCHIVE_DEST_2 parameter on the primary database to specify the standby database location:
SQL> ALTER SYSTEM SET log_archive_dest_2='SERVICE=orcl pdb=ORCLCDB';
4. Start the refresh operation on the standby database using the RECOVER FROM SERVICE command:
SQL> RECOVER FROM SERVICE 'orcl';
This command will start a refresh operation on the standby database, applying all redo data received from the primary database.
Best Practices and Considerations
When using the RECOVER FROM SERVICE command to refresh a physical standby database, keep the following best practices and considerations in mind:
- Ensure that the primary database is open and that the standby database is in a mounted state before starting the refresh operation.
- Set the LOG_ARCHIVE_CONFIG and LOG_ARCHIVE_DEST_2 parameters correctly to specify the standby database configuration and location.
- Monitor the refresh operation to ensure it completes successfully and that the standby database is updated to the current SCN.
- Test your disaster recovery procedures regularly to ensure that the standby database can be quickly switched over to in case of a disaster.
For more information on the RECOVER FROM SERVICE command and physical standby databases, refer to the Oracle Database Administrator’s Guide.
As a final note, if you’re having trouble with your physical standby databases or need help with the RECOVER FROM SERVICE command, consider reaching out to Person-IT for expert Oracle database services.
By following the steps and best practices outlined in this article, you can successfully refresh your physical standby database using the RECOVER FROM SERVICE command in Oracle 12c.