In the course of its 8 years of existence, Datadog has grown its real time metrics systems that collect, process, and visualize data to the point they now handle trillions of points per day. This has been based on an architecture combining open source technologies such as Apache Cassandra, Kafka and PostgreSQL with a lot of in-house software, particularly for in-memory data storing and querying; especially for efficiently computing distribution metrics. In this talk Director of Distribution Metrics Joel Barciauskas, will speak to the challenges we face, how the architecture has evolved to cope with them, and what we are looking to in the future as we architect for a quadrillion points per day.