Apache Cassandra

Apache Cassandra is a highly scalable, distributed database built as a partitioned row store. Rows are organized into tables with a required primary key, and data is distributed across multiple machines so a cluster can grow without losing read and write availability.

Partitioning is transparent to applications: Cassandra automatically repartitions as machines are added to or removed from the cluster. Data is accessed through the Cassandra Query Language, a close relative of SQL, with the interactive cqlsh client for creating keyspaces and tables and running inserts and queries.

Written in Java and licensed under Apache 2.0, Cassandra is governed by the Apache Software Foundation. It is designed to run on commodity hardware or cloud infrastructure as a self-hosted cluster.