This is Oklahomer from LINE Corp. In this post, I’d like to explain the architecture behind the chatting function of LINE LIVE, a video streaming service.
LINE LIVE for iOS and Android has a chat feature that lets its users send comments in real-time while they are watching a live-streaming video. This not only lets users (or viewers in this case) communicate with each other, but it also lets the streamers connect with their viewers. Streamers can chat with their viewers back and forth, and sometimes plan their videos according to what the viewers say in the chat. This is why the chat is an integral part of the streaming experience.
As you can probably imagine, celebrity live streams attract a large number of viewers, and along with them a torrent of comments. Comments sent to the stream must be simultaneously broadcast to every other viewer, and effectively distributing the load has always been one of our top-priority tasks. There are sometimes 10,000 comments sent per minute on just one stream alone.
We took the possibility of large amounts of comments into consideration when we were developing LINE LIVE and presently have over 100 server instances in operation for the chat feature.