The image shows the architecture of the data flow to produce custom metrics on Autonomous Database.

In an OCI Tenancy, in an OCI region, in a Compartment, there are the following components and data flow to implement custom metrics: Your application running on Autonomous Database runs a PL/SQL script that gathers and publishes metrics. The Oracle Monitoring Service gathers the metrics. You can set Oracle Alarms or use the Oracle Notification Service to be notified by Email, Slack, Pager, SMS, Cloud Functions, or a web application. The notifications are posted to your OPS team.