RMAN restore point and flashback database are powerful tools for recovering your Oracle database from logical or physical errors. But how do you integrate them with other Oracle features, such as Data Guard or Data Pump? In this article, we will show you how to use these features together to achieve different recovery scenarios.
Restore points are named markers that you can create in your database to identify a specific point in time. You can use them to perform point-in-time recovery (PITR) with RMAN, without specifying the exact SCN or timestamp. Flashback database is a feature that allows you to rewind your database to a previous state, as if the unwanted changes never happened. You can use it to recover from logical errors, such as accidental data deletion or corruption, without restoring from backup.
in my experience, in the relational database when one table are related to multiple others recovering a corrupted table is only part of the story , second part is data consistency across related tables ! and #3 if I have database over 100TB RMAN no longer a tool for backup and recovery, too slow for cuttent backup market. I believe Oracle need to look for backup and checkpoint be integrated into the storage "ASM etc." layed "SNAP" and not oracle block-by-block.
To create a restore point, you need to enable flashback database on your primary database and allocate enough space for the flashback logs. You can use the CREATE RESTORE POINT command to create a normal or a guaranteed restore point. A normal restore point can be overwritten by the database when the flashback logs are full, while a guaranteed restore point is preserved until you drop it explicitly. You can use the LIST RESTORE POINT command to view the existing restore points. To use a restore point for PITR, you can use the SET UNTIL RESTORE POINT command in RMAN, followed by the RESTORE and RECOVER commands.
To use flashback database, you need to have a valid restore point or a target SCN or timestamp. You can use the FLASHBACK DATABASE command in RMAN or SQL*Plus to rewind your database to the desired state. You can also use the PREVIEW command in RMAN to see what files will be affected by the flashback operation. Flashback database is faster and more efficient than restoring from backup, because it only applies the changes that are needed to revert the database, and it does not require any additional space.
Data Guard is a feature that allows you to create and maintain one or more standby databases that are synchronized with your primary database. It can be used for high availability, disaster recovery, and data protection, as well as role transitions such as switchover or failover. To integrate RMAN restore point and flashback database with Data Guard, you should use the same name for the restore points on both sides if you want to perform PITR or flashback database on both databases. Flashback database can be used on the primary database, but it requires disabling the Data Guard broker and stopping the redo apply on the standby database first. Similarly, flashback database can be used on the standby database, but it requires cancelling the managed recovery mode and converting the standby database to a snapshot standby first. Additionally, RMAN can be used to perform PITR on either the primary or standby database, but synchronization of the other database is needed afterwards. The RECOVER DATABASE FROM SERVICE command in RMAN can then be used to apply redo data from the other database.
Data Pump is a feature that enables you to make a logical backup and restore of your database objects, such as tables, schemas, or tablespaces. It can be used for data migration, warehousing, archiving, transformation, filtering, or compression. In order to integrate RMAN restore point and flashback database with Data Pump, you should take into account the FLASHBACK_SCN or FLASHBACK_TIME parameters for exporting or importing data from a restore point or flashbacked database. Additionally, the TABLE_EXISTS_ACTION parameter is used for specifying how to handle the existing tables in the target database. Finally, the REMAP_SCHEMA or REMAP_TABLESPACE parameters are used for exporting or importing data from a different database that has been recovered or flashbacked to a different point in time. This allows you to map the source and target schemas or tablespaces if they have different names or locations.
To use RMAN restore point and flashback database effectively, it is important to follow some best practices and tips. This includes monitoring and managing your flashback logs and archive logs to ensure you have enough space and retention for your recovery needs. You can use the V$FLASHBACK_DATABASE_LOG and V$ARCHIVED_LOG views to check the status and size of your logs. Additionally, you should test your restore and recovery scenarios regularly, to make sure that you can perform them successfully and quickly. The VALIDATE command in RMAN can help with this. Lastly, document your restore and recovery procedures, and keep them updated and accessible. The RMAN report schema command can be used to generate a report of your database schema and backup information.
.. again RMAN no longer a optimal solution for very large databases, you can say create multiple channels , but again you taking data that on the media pushing through the memory block-by-block and back to auxility media , has not future as db getting bigger and bigger, like I said need more investment into ASM layer for db full, SNAP, delta SNAP checkpoint driven etc. This is 20 years old technology with new wrappers.
Datapump is not really using flashback database feature it’s using undo TS, this is important to know as the undo retention needs to be considered to avoid snapshot to old errors.