Redis

Redis is a data structure store software that can be used as a cache, message broker, and database. It is open source and BSD licensed, which means that it's completely free to use and constantly being refined by its user community. Redis supports several data structures including hashes, sets, lists, strings, sorted sets that use range queries, hyperloglogs, bitmaps, and geospatial indexes that use radius queries. Redis also has built in Lua scripting, replication, LRU eviction, and transactions. The software offers high availability through Redis Sentinel, and also offers automatic partitioning through Redis Cluster. Redis has a large community support network. Its biggest presences are on Twitter and GitHub. You can also get help for specific problems or help others with specific problems through a subscription to the Redis mailing list. The list currently has more than five thousand subscribers. There's also a comprehensive online tutorial that walks you through the software's features. Redis is a key-value store. A key-value store's definition is simple: It is able to store a certain amount of data, otherwise known as a value, inside a key. Later, the data can only be retrieved if the exact key used is known. Redis permanently and securely stores data; nobody except you can access the key. There are some common codes within key-value stores. The DEL key can be used to delete a key along with its data. A Set-if-not-exists command can set up a key, but only if that key doesn't already exist. The INCR command allows you to increment a number that's stored in any given key. It's possible to tell Redis that a key should expire after a certain amount of time. You can accomplish this by using EXPIRE and TTL commands. This can add an extra layer of security to your data, or it can be a way of easily clearing out your space once keys age past their usefulness.