Package storage provides access to the Store and Range abstractions. Each Cockroach node handles one or more stores, each of which multiplexes to one or more ranges, identified by [start, end) keys. Ranges are contiguous regions of the keyspace. Each range implements an instance of the Raft consensus algorithm to synchronize participating range replicas.
Each store is represented by a single engine.Engine instance. The ranges hosted by a store all have access to the same engine, but write to only a range-limited keyspace within it. Ranges access the underlying engine via the MVCC interface, which provides historical versioned values.