The text provides a detailed analysis of a benchmark comparing Couchbase Server 4.5 and MongoDB 3.2, highlighting the performance advantages of Couchbase in query execution and key-value access. In YCSB Workload E, Couchbase Server outperforms MongoDB by using global indexes, which allow for efficient query execution with minimal network traffic and better scalability. The introduction of memory-optimized indexes further enhances Couchbase's performance by improving index maintenance and query response times. For YCSB Workload A, Couchbase demonstrates superior throughput and lower latency due to its built-in caching and efficient client-server communication, eliminating the need for a separate caching tier and enabling direct client access to the server nodes. Overall, Couchbase's architectural choices, such as global indexes and memory optimization, contribute to its ability to handle high workloads more effectively than MongoDB.