Design Spotify Top K Songs

Design a system to find the top k heavy hitters in a stream of data. This could be

• the top k most played songs in a music streaming service like Spotify
• the top k most viewed videos on a video streaming service like YouTube
• the top k most bought items in an e-commerce service like Amazon
• the top k most frequent items in a social media service like Twitter
• the top k most accessed IP addresses on a network

• There are 10 billion song plays per day.
• There are 100 millions of songs.
• The top K songs API is accessed 1 million times per day.
• K is ~100-1000.