Today analytical DBMS ClickHouse initially developed internally at Yandex, became available to everyone. Source code is published on GitHub under Apache 2.0 license.
ClickHouse allows interactive analytical query execution on data updated in real time. System is able to scale to tens of trillions of rows and petabytes of stored data. Using ClickHouse opens up opportunities that were hard to imagine: you can store full stream of data and slice and dice it to produce reports without offline aggregation. ClickHouse was initially developed as a backend for Yandex.Metrica — second largest web analytics system in the world.
