Oracle Multitenant Architecture is a database feature introduced in Oracle Database 12c, which allows the creation of a single, multitenant container database (CDB) that can host multiple pluggable databases (PDBs). It is designed to help organizations to efficiently manage multiple databases and optimize hardware and software resources.
In a traditional database architecture, each database runs independently, occupying separate disk and memory space. This leads to wastage of resources and an increased administrative overhead as each database must be individually managed and maintained. However, the Multitenant Architecture eliminates this issue, as a single CDB provides a consolidated environment, enabling multiple PDBs to share the same hardware and software resources.
One of the main benefits of the Multitenant Architecture is resource management. A CDB can be better optimized because it allows for the sharing of resources among PDBs. For example, a PDB can share a single SGA (system global area), reducing the amount of memory consumed by each database instance. Similarly, a PDB can share a single set of processes, reducing the CPU resources used.
Another benefit of the Multitenant Architecture is the ease of manageability. Each PDB can be managed individually or as a group, making it easier and faster to patch or upgrade databases. Additionally, the DBA can manage the CDB and all associated PDBs as a single entity, so database maintenance tasks can be centralized and automated.
Here is an example of how the Multitenant Architecture works:
Let’s say you have three databases: Database A, Database B, and Database C. In a traditional architecture, each database runs independently with its own hardware and software resources.
However, with the Multitenant Architecture, you can create a CDB and multiple PDBs. In this example, we’ve created a CDB and three PDBs: PDB A, PDB B, and PDB C. All three PDBs share the same hardware and software resources, which reduces resource utilization.
Each PDB can have its own schemas, users, and data, but can still share certain resources with the other PDBs. In this example, PDB A and PDB B both use the same SGA and shared pool, while PDB C has its own.
In conclusion, Oracle Multitenant Architecture is a powerful feature that provides efficient management of multiple databases. By creating a single, multitenant container database and multiple pluggable databases, organizations can easily manage their databases, optimize their resources, and realize the benefits of increased scalability and flexibility.