Changing a DB Instance Class

Scenarios

You can change the instance class (CPU or memory) of a DB instance as required. If the status of a DB instance changes from Changing instance class to Available, the change is successful.

Constraints

• A DB instance cannot be deleted when its instance class is being changed.
• If the primary DB instance has a read replica, the new DB instance class must be less than or equal to the read replica class. When changing the read replica class, ensure that the selected class is greater than or equal to the current primary instance class.
• After the instance class is changed, some parameters are automatically changed to the default values defined in the new instance class. The parameters are max_connections, max_worker_processes, max_wal_senders, max_prepared_transactions, and max_locks_per_transaction.

• After you change instance classes, the DB instances will be rebooted and service will be interrupted. Therefore, you are advised to change instance classes during off-peak hours.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select a region and a project.
3. Click Service List. Under Database, click Relational Database Service. The RDS console is displayed.
4. On the Instance Management page, locate the target DB instance and choose More > Change Instance Class in the Operation column.

   Alternatively, click the target DB instance to go to the Basic Information page. In the DB Information area, click Change in the Instance Class field.

5. On the displayed page, specify the new instance class and click Next.
6. View the DB instance class change result.

   Changing the DB instance class takes 5–15 minutes. During this period, the status of the DB instance on the Instance Management page is Changing instance class. After a few minutes, click the DB instance and view the instance class on the displayed Basic Information page to check that the change is successful.

   

   After the CPU or memory of an RDS for PostgreSQL DB instance is changed, the system will change the values of the following parameters accordingly:

   • shared_buffers
   • max_connections
   • maintenance_work_mem