Oracle starts maintenance of a standalone DB system (with or without HeatWave cluster enabled) that starts within two hours of the Maintenance window start time that you define for the DB system.

The maintenance of the DB system involves a short period of downtime. To reduce the downtime, use high availability DB systems. See High Availability.

For a DB system with HeatWave cluster, the maintenance process automatically reloads the HeatWave cluster data, which was previously loaded, from the DB system

The maintenance of a standalone DB system involves the following steps and does not require any input from you:

1. New resources are launched using the latest operating system and MySQL server.
2. The current MySQL servers are stopped. All existing connections are allowed to complete, but no new connections are allowed.
3. The storage of the resources are cloned.
4. The cloned storage is attached to the new resources and the MySQL server is started on them.
5. The endpoints are attached to the new resources and new connections are allowed.
   Note
   
   If any errors occur during the maintenance, the process stops, and rolls back to the old DB system, and connections resume.