Spotify re-runs the latent vector models regularly and re-indexes them into Annoy indexes. There is no need to do that in real time, you can be a few weeks dela

Spotify re-runs the latent vector models regularly and re-indexes them into Annoy indexes. There is no need to do that in real time, you can be a few weeks delayed and it's usually fine. New music doesn't have much data and need different methods anyway.