Database Migration Service for Oracle to Cloud SQL for PostgreSQL FAQ

What is Database Migration Service?
Database Migration Service is a service that makes it easier for you to migrate your data to Google Cloud. Database Migration Service helps you lift and modernize your Oracle workloads into Cloud SQL for PostgreSQL.
Which sources are supported?
  • Oracle 11g, Version
  • Oracle 12c, Version
  • Oracle 12c, Version
  • Oracle 18c
  • Oracle 19c
  • Oracle 21c
  • Oracle Real Application Clusters (RAC)
Which destinations are supported?
  • Cloud SQL for PostgreSQL 12, 13, 14, 15.
Which networking methods are used?
To create a migration in Database Migration Service, connectivity must be established between the source and the Cloud SQL destination instance. There are a variety of methods supported. Choose the one that works best for the specific workload.

Source connectivity:

For a list of supported source connectivity methods, see Source connectivity.

Destination connectivity:

Use Private Service Connect to establish private connectivity to the Cloud SQL destination database.

What are the known limitations?
See Known limitations.
Can I connect to the destination Cloud SQL instance using a private IP address without the Private Service Connect resources?
No. Database Migration Service leverages Private Service Connect to connect privately to the destination database, and expects a service attachment as input.
Can I use Database Migration Service to create read replicas for my Oracle database in Cloud SQL for PostgreSQL?
The continuous migration from Oracle to Cloud SQL for PostgreSQL in Database Migration Service is eventually consistent, meaning that Database Migration Service doesn't replicate each transaction as it happens.

The migration brings in data from multiple tables, running both change data capture (CDC) and the backfill of data in parallel. The order in which data is loaded into the destination isn't strictly guaranteed, but will re-align with the source after writes on the source are stopped and the migration buffer is cleared.

Does Database Migration Service support migrations from Oracle Real Application Clusters (RAC) databases?
Yes, it does. However, you can't establish direct connectivity to databases using the Single Client Access Name (SCAN) feature in Oracle RAC environments. To overcome this limitation, connect directly to one of the nodes, or use the Oracle Connection Manager. You can also create a private connectivity configuration using reverse proxy solutions like HAProxy.