The text discusses the impact of the CAP theorem on database design, highlighting the trade-offs between consistency, availability, and partition tolerance. CockroachDB is described as a CP-based database focusing on strong consistency and transactionality through the RAFT protocol, whereas Couchbase offers flexibility between consistency and availability, emphasizing performance and adaptability with its in-memory design. CockroachDB's architecture relies on raft clusters for scaling, while Couchbase uses active-active cluster design and multidimensional scaling for performance optimization. Couchbase also offers extensive support for SQL and JSON, enabling diverse data access patterns and mobile services, whereas CockroachDB supports PostgreSQL API and focuses on ACID transactions. The choice between the two databases depends on specific needs: CockroachDB for strict transactional integrity and Couchbase for performance, scalability, and flexibility.