Yandex Opensources ClickHouse

ClickHouse has become available to everyone after being initially developed internally at Yandex and is now published under an Apache 2.0 license on GitHub. It allows for interactive real-time analytical query execution, scaling to handle tens of trillions of rows and petabytes of data, enabling the creation of reports without offline aggregation. ClickHouse was originally developed as a backend for Yandex.Metrica, one of the world's largest web analytics systems.