Please explain dashboard alerts frequency option "As frequently as possible"

When setting up an alert, the frequency options are: Weekly at most, Daily at most and “As frequently as possible”. What does this option “As frequently as possible” really mean and what are the performance ramifications? What I really would like is something like “Once an hour” or “Every 5 minutes”.

I don’t know with 100% confidence but my guess is that it’s based on the refresh schedule of the dataset that you have.

I don’t know about direct queries.

It’s still a mystery for me as well.