1, redis Nosql is a high performance database language written using c, support network, also based on persistent memory, a log type, Key-Value database can also be seen as a distributed, based on memory cache tool.
2, produced NoSQL database is to address the challenges of large scale and high concurrent pure dynamic sites, especially large data application problems.
3, four NoSQL database classification:
(1) key (Key-Value) stored in a database: this category database primarily uses a hash table, this table has a specific key and a pointer to the specific data. For example redis, Oracle BDB.
(2) a column store database: usually used to deal with massive data distributed storage. Key still exists, but they are characterized by pointing to a number of columns. Such as HBase.
(3) document database: the version of the type of document database to store a particular format, such as JSON. Document database can be seen as an upgraded version of the key database, allowing nested keys. And document database query efficiency higher than the key database. Such as MongoDB.
(4) a graph database, such as Neo4J.
4, NoSQL database applicable scenarios:
(1) data model is relatively simple, not too many fields
(2) the need for more flexibility in IT systems, the need for faster query speed
(3) high performance requirements of the database, such as the key value directly obtained from the key database
(4) does not require a high degree of data consistency
(5) For a given key, the environment may be mapped to complex values
5, redis compared with other key database, there are three characteristics:
(1) persistent redis supporting data, data in memory can be saved to disk can be loaded again when you restart reuse
(2) redis not only support the Key-Value simple types of data, but also provides a storage list, set, zset, hash data structures, etc.
(3) redis support data backup, high availability features such as clustering
6, redis features:
(1) high performance: redis reading speed is 110 000 times / sec, write speed is 81000 times / second
(2) rich data types: redis supported data types are string, list, hash, set and order set data types of operations.
(3) Atomicity: All operations are atomic redis, either succeed or fail completely executed execution. It is a single atomic operation, a plurality of operation also supports atoms, i.e. the transaction.
(4) take up memory is too high, which is a drawback.