Using the Snapshot Standby database

You can use the Snapshot Standby database as the source database for Data Pump Export.

Note:

This feature is available only for online Oracle migrations, except for Amazon RDS.
Why use this option:
  • Enables Data Pump export with a high degree of parallelism and zero impact on the production database.
  • Allows optimal resource usage without affecting the performance of the production system.
  • Makes it possible to disable the DBMS_SCHEDULER jobs during export, helping avoid export issues that cannot be addressed in a production environment.
  • Helps prevent ORA-01555: snapshot too old errors, especially during export of large tables.
Pre-requisites:
  1. You must manually convert the physical standby database to a snapshot standby database.
  2. You must pre-create the export directory and export directory object on both the primary and standby databases, using the same name and path.
  3. For Object Storage Service (OSS) as the transfer medium: The export directory on both primary and standby databases must point to a shared filesystem.
  4. For File Storage Service (FSS) as the transfer medium: The same FSS mount must be accessible from both the primary and standby databases.
  5. You must create a database connection to the snapshot standby database in the OCI Database Migration service.
How to enable this feature:

During migration creation and for supported Oracle online migrations, toggle the Use Snapshot Standby database as source for Data Pump export option. Then, select the corresponding snapshot standby database connection that was previously created.

What the service will do:
  1. Identify the standby SCN and report it in the progress log.
  2. Perform the Data Pump export without setting the FLASHBACK_SCN or FLASHBACK_TIME parameters.

    Note:

    While setting FLASHBACK_SCN ensures a consistent export, however it can reduce the performance.
  3. As the snapshot standby is not being updated during export and no scheduler jobs are expected to run, the export is inherently consistent.
  4. Once the export is complete, the service will:
    1. Proceed with the import.
    2. Start Replicat using the AFTERCSN value derived from the standby SCN.

    Note:

    You can revert the snapshot standby database back to a physical standby at your convenience after the export phase is complete.

Parent topic: Reference