Couchbase is the merge of two popular NOSQL technologies:
- Membase, which provides persistence, replication, sharding to the high performance memcached technology
- CouchDB, which pioneers the document oriented model based on JSON
- Key-based lookup mechanism where the client is expected to provide the key, and only the server hosting the data (with that key) will be contacted.
- Query mechanism to retrieve data where the client provides a query (for example, range based on some secondary key) as well as the view (basically the index). The query will be broadcasted to all servers in the cluster and the result will be merged and sent back to the client.