CockroachDB is a distributed SQL database designed with an architecture that converts SQL statements into key-value data. The bottom layer of this architecture is a distributed, replicated, transactional key-value store. This enables efficient distribution of data within the database and supports tables and indexes. The key-value store facilitates dynamic schema change and allows CockroachDB to retain the efficiency of a KV store while still speaking SQL. Under the hood, it stores tabular data in a monolithic sorted map of KV pairs, where every table has a primary key, there is one key/value pair per column, and keys and values are all strings. The architecture also supports efficient range scans and automated sharding through range splitting.