This isn't Dana, but anyway...
I have set up a custom sensor using a PRTG addon called logfilereader. It can scan a file and will return a value of "2" if it finds a new instance of whatever string you specify. I configured it look through Oracle alert log files every four hours, and if it finds a new instance of the string "ora-" (indicating an error), then a notification is triggered and an email is sent out.
I am using a threshold notification that sends out an email if the value is equal to 2, and that usually works fine. However if the next scan four hours later also returns a value of 2 due to another new instance of the string being found, then no notification takes place. I guess this is because the value hasn't changed since the last scan.
I also tried using the channel configuration to set up a warning limit of 1, so if the sensor returned a value of 2 the sensor would go into a warning state, and I configured a state trigger for that, but it too doesn't work if the value 2 is returned in consecutive scans.
Is there a way to make it trigger another alert in this type of scenario, or is there some better way of doing this?