Speaker: Jimmy Mardell, Senior Software Engineer at Spotify
All systems at Spotify have to deal with huge amounts of data. Playlists in particular is a unique challenge. We need to store more than one billion playlists, and make them accessible for not only the playlist owner but also subscribers. Furthermore, we need to handle concurrent changes to collaborative playlists and offline scenarios. The devised solution treats every playlist as a versioned object. We use Cassandra to store these objects in an efficient way, allowing fast read- and write queries. The road there was not pain free however. I will talk about the data model we ended up using, and lessons learned along the way.