Neel Shah Data Analyst and Business Analyst

No-SQL database Redis - PART-2


Hello, welcome to Part -2 of NoSql database blog. Today, we are look into to redis database.
Redis is an in-memory key value datastore written in ANSI C programming language by Salvatore Sanfilippo. Redis not only supports string datatype but it also supports list, set, sorted sets, hashes datatypes, and provides a rich set of operations to work with these types. If you have worked with Memcached (an in-memory object caching system), you will find that it is very similar, but Redis is Memcached++. Redis not only supports rich datatypes, but it also supports data replication and can save data to disk.

Redis: What for?:

Who’s using Redis?:

key Features:



Best used: For rapidly changing data with a foreseeable database size (should fit mostly in memory).

For example: o store real-time stock prices. Real-time analytics. Leaderboards. Real-time communication. And wherever you used memory cached before.

What happens if Redis runs out of memory?:

Redis will either be killed by the Linux kernel OOM killer, crash with an error, or will start to slow down. With modern operating systems malloc() returning NULL is not common. Usually the server will start swapping, and Redis performances will degrade so you'll probably notice there is something wrong. The INFO command will report the amount of memory Redis is using so you can write scripts that monitor your Redis servers checking for critical conditions.

Supported Language

Many languages that have Redis bindings, including : ActionScript, C, C++, C#, Clojure, Common Lisp, Dart, Erlang, Go, Haskell, Haxe, Io, Java, JavaScript (Node.js), Lua, Objective-C, Perl, PHP, Pure Data, Python, R, Ruby, Scala, Smalltalk and Tcl.

Redis Data Structure: