While applying new monitoring templates to a database instance target, we encountered the following:
When changing thresholds for ‘Tablespace Space Used’ metrics, both Warning and Critical threshold must be defined. Omitting one of these will result in no changes at the target. Applying the template to the target seems to function successfully (no errors shown), however no changes will be made to the target. This is because of the fact that database package DBMS_SERVER_ALERT doesn’t allow you to omit one of the thresholds (warning or critical) and will give an error message.