I just tried to create a custom metric for the software service data view based on the documentation here:
It is mentioned that the metric is available just after "refreshing the Data Mining Interface screen" but I needed a restart of the NAM Server to get the metric in my report. Is there anything like "reload configuration" which can be used to publish changes on dataviews?
I'm afraid this feature is little rusty when it comes as we focused more on the calculated columns in NAM 2018. NAM 2019 comes with "RELOAD DMI VIEWS" command (available for users with Maintenance admin role). I just double checked - it will make your new metric show up.
Is what you try to do not achievable through calculated columns or you are more concerned about the performance? Old calculated metrics comes with certain limitations; to name just few: