面试题与答案

Redis is an open-source, advance key value data store and cache. It is also referred as a data structure server which keys not only contains strings, but also hashes, sets, lists, and sorted sets.

Redis stands for REmote DIctionary Server.

Redis is a NoSQL, Opensource, in-memory data-structure store. It follows the principle of key-value store.

It is extremely fast, persistent, portable and supports many languages such as C, C++, C#, Clojure, Common Lisp, D, Dart, Erlang, Go, Haskell, Haxe, Io, Java, JavaScript (Node.js), Julia, Lua, Objective-C, Perl, PHP, Pure Data, Python, R, Racket, Ruby, Rust, Scala, Smalltalk and Tcl.

Redis is written in ANSI C and mostly used for cache solution and session management. It creates unique keys for store values.

Redis is a special key-value store database that can function as a NoSQL database or as a memory-cache store to improve performance when serving data that is stored in system memory.

After the installation of the server you can run the Redis Client provided by redis installation or you can open the command prompt and use the following command:

redis-cli  

Twitter, Github, Stackoverflow etc. are the most popular companies using Redis.

Following are the main features of Redis:

• Redis is very simple to install setup and manage.
• Redis is very fast. It can execute 100000 queries per second.
• Redis is fast because data is being persistent in memory as well as stored on the disk.
• Redis is very fast because it loads the whole dataset in primary memory.
• Redis operations working on different data types are atomic so these operations can be accomplished safely i.e. to set or increase a key, add or remove elements from a set or increase a counter.
• It supports various types of data structure such as strings, hashes, sets, lists, sorted sets etc.
• Redis supports a variety of languages i.e. C, C++, C#, Ruby, Python, Twisted Python, PHP, Erlang, Tcl, Perl, Lua, Java, Scala etc.
• If your favorite language is not supported yet, you can write your own client library, as the Protocol is pretty simple.
• Redis supports simple master to slave replication.
• Redis is portable.