Once Riot Games opened up a European base of operations, it couldn’t fit all its data into one instance of mySQL. “So we created a separate instance. That was a bad precedent and we needed to change that,” Livingston added. “We moved quickly to Hadoop as a scalable low-cost storage system. We use Hive to overlay an SQL-type interface on top of the Hadoop File System.” That helped scale up, but “the downside is that it takes a long time to spin up to do your queries, some taking a minute or more to complete, so it is difficult to iterate and build complex queries using Hive.”

via For Riot Games, Big Data Is Serious Business.

Part of the challenge is to maintain a level playing field for all players, yet constantly tweaking game play and game mechanics to make it more interesting for returning players: “We need lots of insight so that competitive play will continue to happen. We don’t want different versions of the game for pros and noobs, for example.”