Oracle RDS Architecture

When you create an RDS for Oracle 19c instance, AWS provides you with options for both the traditional standalone architecture (non-CDB) and the multitenant architecture (CDB with PDBs).

For Oracle Database 19c on Amazon RDS, you can choose to create either:

1. A non-CDB instance: This is a traditional standalone Oracle database that doesn't use the container database architecture.

2. A CDB instance with PDBs: This uses the multitenant architecture, where the database functions as a container database (CDB) that includes one or more pluggable databases (PDBs).

If you opt for the multitenant architecture, Amazon RDS for Oracle supports two configurations:

1. Single-tenant configuration: The CDB contains only one tenant database (PDB).

2. Multi-tenant configuration: The CDB can contain between 1-30 tenant databases (PDBs), depending on the database edition and required option licenses.

When creating your RDS for Oracle 19c instance, you'll need to specify whether you want to use the multitenant architecture and which configuration you prefer. The choice between these options depends on your specific requirements for database consolidation, resource utilization, and management needs.

It's worth noting that starting from Oracle Database 21c, the multitenant container database is the only supported architecture in Amazon RDS for Oracle. However, for 19c, you still have the flexibility to choose between the traditional standalone architecture and the multitenant architecture.
Sources
RDS for Oracle database architecture - Amazon Relational Database Service
Get started with the Multi-Tenant feature of Amazon RDS for Oracle | AWS Database Blog
Oracle multi-tenant architecture - AWS Prescriptive Guidance
Amazon RDS for Oracle now supports Oracle Multitenant

When creating your RDS for Oracle 19c instance, you'll need to specify whether you want to use the multitenant architecture and which configuration you prefer. The choice between these options depends on your specific requirements for database consolidation, resource utilization, and management needs.

Starting from Oracle Database 21c, the multitenant container database is the only supported architecture in Amazon RDS for Oracle. However, for 19c, you still have the flexibility to choose between the traditional standalone architecture and the multitenant architecture.