You find today's performance of your production database to be the best ever. Therefore, you want to be notified in the future whenever the performance degrades by 10% of today's performance. What…

Creating a baseline is the mandatory first step because without a formally documented reference for today's best performance, no subsequent comparison or alert threshold can be defined. Oracle provides built-in baseline management through AWR (Automatic Workload Repository), where a baseline anchors the metrics snapshot that all future comparisons measure against. Only after the baseline exists can notification or comparison logic be layered on top.

Writing metrics to a table and creating a trigger addresses the comparison mechanism but skips the prerequisite of formally establishing a named, time-stamped baseline.

Writing metrics to a flat file is an informal approach that bypasses Oracle's built-in baseline management and is still not the first logical step.

Creating a stored procedure to compare metrics is a subsequent automation step that presupposes a baseline has already been captured and stored.

Scheduling a job via DBMS_JOB to perform comparisons is a later step that cannot function correctly without a baseline already defined as the reference.