What is Redis? And How Is It Used for Caching? | InMotion Hosting

What is Redis? And How Is It Used for Caching? | InMotion Hosting
What is Redis (Remote Dictionary Server)? Hero ImageRedis (Remote Dictionary Server) is an in-memory database structure with multiple functionalities, which improve a website’s availability and performance. It is an open source project created by Salvatore Snfilippo in early 2009 for his tech startup.We will explore the many benefits that Redis has to offer in this article, and how using it can help speed your website, including WordPress.

What is Redis Object Caching?

In its entirety, Redis can be used for a wide range of benefits, one of which is object caching. Per their introduction documentation, Redis defines their technology as:“[Providing] data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs, geospatial indexes, and streams. Redis has built-in replication, Lua scripting, LRU eviction, transactions, and different levels of on-disk persistence, and provides high availability via Redis Sentinel and automatic partitioning with Redis Cluster.â€The main takeaway new users should understand is that Redis is a data structure system, which organizes data in its own form to better deliver your messages across, improving your website’s or application’s performance. Redis is compatible with most programming languages, such as:

  • Java
  • Python
  • Node.js
  • PHP
  • Ruby
  • C++

Redis draws in a lot of users because of its many benefits, some of which include:

  • High-performance and low latency 
  • The ability to handle large datasets
  • Capability of clustering
  • Quick data manipulation tasks

What is Redis Used for?

Now that you know the definition of Redis, and what some of its functions are, let’s dive in deeper on why some developers prefer to use Redis as a way to boost website performance. 


One of the primary benefits of Redis is its speed. With data stored in-memory, Redis can perform operations much faster than traditional databases. This makes it ideal for applications that need fast data retrieval and modification. Redis can handle up to 500,000 operations per second, making it suitable for even the most demanding applications.

Data Durability 

Data can be backed up to disk at regular intervals, ensuring that any data stored in Redis will be protected even in the event of server failure. 

Data Structures 

Redis also offers a wide range of data structures, making it ideal for applications that must complex data processing. Redis supports five different data structures, including strings, hashes, lists, sets, and sorted sets.

Built-In Scripting 

Redis supports built-in scripting, which allows developers to write scripts to change data structures and perform complex operations without having to write a custom application. It also makes it easier to add new features and optimize existing applications.

How Can Redis Help My WordPress VPS Perform Faster?

Redis is a powerful tool that can speed up a WordPress VPS by providing an in-memory key-value store for caching data, reducing the need for database queries and allowing for faster data retrieval.It can also be used for message queues and pub/sub communication, further improving VPS performance.Redis also reduces the number of requests to the database, leading to faster website speed by caching pages, objects, and database queries. Finally, Redis caching can even store user sessions, reducing server load and enhancing user experience.

WordPress and Redis Caching Systems

The Redis in-memory data structure can be used to store and retrieve cached data in WordPress websites. These applications are known as WordPress Redis Caching Systems. This caching system can store a wide variety of data and is capable of providing high-performance caching for high traffic WordPress sites. It is also easy to configure and manage and has many features such as data replication, high availability and scalability.Blogger Metrics breaks down the 3 types of caching as the following:

  1. Server-Side Caching – Caching at the server level. NGINX FastCGI cache and Varnish page caching are two examples of server-side caching. Another example of server-side caching is object caching.
  2. WordPress-Side Caching – Caching at the WordPress level. Plugins like W3 Total Cache, WP Rocket, WP Super Cache, all are examples of WordPress-side caching.
  3. Client-Side-Caching – Caching at the local browser level. Browser cache is an example of client-side caching.
Infographic demonstrating how website caching works.

The 8 Different Types of Caching Inside WordPress

Further expanding on the information above, WordPress caching can be broken down into the following sections.

  1. Page Caching – Page caching is a technique used in web development to store web page content on a user’s browser to reduce server load and bandwidth usage. Page caching can also improve page load times, as the content does not need to be generated each time the page is accessed.
  2. Browser Caching – Browser caching is a technique used by web browsers to store web page resources (such as HTML, CSS, JavaScript, images, etc.) on a user’s device. This allows the browser to load the resources from the cache instead of downloading them from the server.
  3. Database Caching – Database caching is a technique used to improve the performance of a database by storing requested data in memory. This reduces the amount of time required to access the data from the database, resulting in faster response times. Caching can also be used to improve the scalability of a system by distributing the load across many machines.
  4. Object Caching – Object caching is the process of storing accessed data in memory for quick access, such as database query results, web page source code, or API responses. This eliminates the need to access the origin data source, thus reducing the latency and improving performance. Object caching can be handled in software, hardware, or a combination of both.
  5. Transient Caching – Transient caching is a way of storing data in memory to reduce the amount of time and resources needed to access data from a database or other data store. It is used in web applications to improve performance by reducing the amount of data that needs to be fetched from the database. Transient caching can also be used to reduce the amount of time it takes to process requests from users, thereby reducing network traffic.
  6. Fragment Caching – Fragment caching is a method of caching where specific parts of a web page, such as a single section of a page or a specific module, are stored in a cache. This helps the page load faster and reduces the amount of queries sent to the database. 
  7. Opcode Caching – Opcode caching is a method of optimizing the performance of PHP applications by caching the compiled form of the code (Opcodes) in memory, so that the overhead of parsing and compiling the code is removed on each request. This process reduces the amount of processing time and memory needed to run the application.
  8. CDN Caching – CDN (content delivery network) caching is a technique for delivering web content fast by storing it on servers located in various geographical locations. When a user tries to access the content, the content is served from the nearest server, thus reducing latency and improving user experience.

Redis and WP-CLI

WP-CLI is a command line interface for managing WordPress sites, ideal for complex tasks and modifications that are time-consuming through the UI.This interface can be used to manage Redis by providing commands to interact with the Redis server. Commands Include:

  • Flushing the Redis database
  • Setting up expiration timers
  • Manipulating individual keys

WP-CLI can also be used to view and change the configuration settings associated with a Redis instance, allowing users to quickly make changes to their Redis setup. 

Final Thoughts

Redis is an impressively powerful and versatile tool that can be applied to solve a wide variety of problems. It’s fast, reliable, and easy to use, making it an ideal choice for many applications. Whether you’re looking for a simple caching solution or a full-fledged data store, Redis can provide the performance and scalability you need. Overall, Redis and WordPress are a great combination for web developers and freelancers looking to create powerful and efficient WordPress websites while maximizing speed and performance for an improved user experience.