This sounds like SQL ontop of Cassandra (for a more or less mental-map if you are looking for one):
Our distributed non-blocking atomic commit protocol allows database
transaction processing at any available node. The system is
designed to provide a consistent view of data, high availability,
and the ability to detect and manage partitions in a predictable
and consistent manner. Query processing scales with the number of
available nodes, storage scales according to the choice of storage
manager of which there are many. Storage managers are key/value
storage engines that also operate as a distributed in-memory cache
and participate in the commit protocol to ensure durability
guarantees.