Tunable query consistencyCouchbase Server provides full consistency for basic data operations, but queries can tune consistency from eventual to strict. Both Enterprise and Community Editions come with the built-in ability to tune consistency at query time.
Couchbase Server provides tunable durability for mutations coming into the system. Couchbase Server core data operations can ask for disk-based or replication-based durability of data during writes. Both Enterprise and Community Editions come with full support for tuning durability.
Ephemeral buckets provide a highly consistent in-memory performance without disk-based fluctuations. They eliminate the disk component of your buckets and thus reduce the total cost of ownership (TCO). Ephemeral buckets are designed to be used as an alternative to Couchbase buckets whenever persistence is not required, for example, when repeated disk access involves too much overhead. You also get faster node warmups, rebalances, and restarts, as well as cheaper geo-replication.
SQL++ (SQL for JSON) for Couchbase Server provides full support for SQL-like queries. Couchbase is a reference implementation of SQL++. Both Enterprise and Community Editions come with full support for SQL++ for applications. Couchbase’s implementation includes ACID transactions in SQL++, simplifying their implementation.