Source: comparison of various nosql databases in http://hi.baidu.com/eastdoor/blog/item/758d0e3eedb5d92471cf6c14.html Cassandra, MongoDB, CouchDB, Redis, Riak, HBase CouchDB Development language: Erlang Main advantages: data consistency and ease of use License: Apache Protocol: HTTP/REST Applicable: accumulated, less changed data. Or a large number of versions are required. Example: CRM, CMS systems. multi-site deployment is allowed. Redis Development language: C/C ++ Main advantages: one word is fast License: BSD Protocol: Telnet-like Applicable: The total dataset changes rapidly and the total amount is predictable. The memory demand is high. Example: stock price, real-time analysis, real-time data collection, and real-time communication. MongoDB Development language: C ++ Main advantages: similar to SQL. (query, index) License: AGPL (Drivers: Apache) Protocol: Custom, binary (BSON) Applicable: dynamic query; more suitable for indexing than map/reduce; the same as CouchDB, but more data changes. For example, when Mysql/PostgreSQL is used, but all columns cannot be pre-defined Cassandra Development language: Java Main advantages: the best bigtable and Dynamo License: Apache Protocol: custom, binary (thrift) Applicable: More writes than queries. Only Java is supported. Example: banking, financial industry. Riak Development language: Erlang & amp; C, some Javascript Main advantages: High Fault Tolerance License: Apache Protocol: HTTP/rest Applicable: it is similar to Cassandra, but relatively simple. If you need very good scalability, availability and fault tolerance, but you have to pay for multi-site deployment. Example: collect sales data. Factory control system. A few seconds of downtime can cause damage .. Hbase Development language: Java Main advantage: supports billions of Columns License: Apache Applicable: bigtable is similar to bigtable. Gae. Example: Facebook |