I have a very basic concept that I need to understand

saw10

I have a very basic concept that I need to understand. 

The Alert Evaluation Frequency interval is the interval the SQL Database is queried, so that should be equal to or greater than the polling interval.

So my polling interval is 2 minute.  It would do no good to have an Alert Evaluation Frequency interval of 1 minute.

Is this a True Statement?

adatole

You're close, but not quite there. There are a few timing loops to consider:

1. polling interval
2. alert evaluation frequency
3. alert trigger delay (if any)

The upshot is that #2 can be as often as you like (within reason) because it's not doing anything but seeing if the trigger condition is true. NOW.. there's a limit, which is the complexity of the trigger condition and the importance of the issue. If the trigger is really complex, you're going to be pounding your database with that query (as well as all the OTHER queries it's handling) every minute. SO maybe don't do that. At the same time, if this is something that you need to know about AS SOON as it happens, then you want the trigger evaluation to be fairly frequent.

The alert trigger delay is really where the overlap with polling interval is an issue. If you have an alert that triggers on CPU >= 90 - a statistic which is collected every 5 minutes by default, then setting a trigger delay of 3 minutes isn't going to help. Because you won't have collected any new information in that time.

Hope that helps. We even made a "What Would the Geek Do" video about this: Alerts arrive after Users know the System is Down. What Would the Geek Do? - YouTube