[rwallace]

What would the attribute columns consist of? My experience has been with named columns defined individually by humans, of which I've never seen more than a few hundred; how do you get tens of thousands? Are they a different kind of thing?

[threeseed]

Most companies who do it purely by humans can easily get into the thousands of attributes. Have seen it many times before where you hit the column limit of a SQL database.

But where you get into tens/hundreds of thousands is when you have machine learning models automatically selecting and storing important features from the data.