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.