Rich's Tongfamily (Richtong.net add-on)

Wow this is a pretty cool feature I had no idea about. I’ve uploaded 50K photos (and 1K videos) into iCloud Photo Library. Now Mac Photos is silently analyzing them all for images. For those of you worried about privacy, all the photos are encrypted and Apple cannot see them. One of the problems is that now you have to have a Mac on and running to do the scanning.
Well I learned there things, the first is that photoanalysisd is the daemon that does this. You need to have your Mac powered up and on all the time, it only runs when Photos is not running, which is a little confusing.
You have no way to make it start or stop or do rescans. Short of taking all your images and rotating them right and left, this will force a rescan.
Moreover, when you are done, the little search box that Photos has is way more powerful, type in a name and it will try to find that person, type in aircraft and it will find all aircraft and provide you with a list of objects that it knows. It for instance knows the difference between cars, sporty cars and trolley cars.
This happens across videos as well so if you have lots of videos, it is doing frame by frame analysis.
The process is let it run for a while, then click on the People section and it will give you some people. Provide them with a name and then click on Confirm Additional Photos and it will make suggestions. it’s super slow, but it actually works!
Alternatively, if you scroll through random pictures with View/View Face Names on then you will see circles where Photos thinks there are faces. Click on them and name people.