Redis – Overview

Redis is an open source, advanced key-value store and a serious solution for building high-performance, scalable web applications.
Redis has three main peculiarities that set it apart from much of its competition:

  • Redis holds its database entirely in memory, using the disk only for persistence.
  • Redis has a relatively rich set of data types when compared to many key-value data stores.
  • Redis can replicate data to any number of slaves.

Redis Advantages

  • Exceptionally Fast : Redis is very fast and can perform about 110000 SETs per second, about 81000 GETs per second.
  • Supports Rich data types : Redis natively supports most of the datatypes that most developers already know like list, set, sorted set, hashes. This makes it very easy to solve a variety of problems because we know which problem can be handled better by which data type.
  • Operations are atomic : All the Redis operations are atomic, which ensures that if two clients concurrently access Redis server will get the updated value.
  • MultiUtility Tool : Redis is a multi utility tool and can be used in a number of usecases like caching, messaging-queues (Redis natively supports Publish/ Subscribe ), any short lived data in your application like web application sessions, web page hit counts, etc.

Why Redis is different compared to other key-value stores?

  • Redis is a different evolution path in the key-value DBs where values can contain more complex data types, with atomic operations defined on those data types.
  • Redis is an in-memory but persistent on disk database, so it represents a different trade off where very high write and read speed is achieved with the limitation of data sets that can’t be larger than memory. Another advantage of in memory databases is that the memory representation of complex data structures is much simpler to manipulate compared to the same data structure on disk, so Redis can do a lot, with little internal complexity.