OEM 12C Logical/Reporting Database Apply Lag Metric alert message.
In OEM 12C Gui we accessed the Logical/Reporting database (velosrt DB) and defined the "Apply Lag metric" by selecting "Oracle Database -> Monitoring -> All Metrics -> Data Guard Performance -> Apply Lag -> Modify Thresholds". The Apply Lag Warning Threshold was set to 1 second and the Critical Threshold was set to 10 seconds.