Difference Between Redis and Memcached

Caching is a critical component of improving the performance of many applications. Determining which caching solution is ideal for use instances might be tough. When users think about a server-side caching solution, users probably think of Redis or Memcached. Both tools are caches that are powerful, quick, in-memory data storage. Both can help your application run faster by caching database results, HTML fragments, and anything else that is time-consuming to build

Redis vs Memcached

The main difference between Redis and Memcached is that when it comes to data storage, Redis uses certain data types, whereas Memcached just uses strings. Redis supports persistence to disc, which means that the data in its database can be saved and restored if the Redis server crashes or reboots. Memcached does not have native support for persisting data to disc.

Redis vs Memcached

Redis is a key-value store that works with a number of data formats such as Lists, Sets, and Hashes. Redis can reply to requests quickly since it stores this information in memory. Because of its speed, it’s ideal for use as a cache in applications where data is regularly requested and returned.

Memcached is described as a high-performance, distributed memory object caching system that is free and open source. Memcached, like Redis, is an open source technique to store key-value pairs in memory, allowing data to be retrieved rapidly. As a result, Memcached can be used to return data where speed is a concern. Memcached is also multithreaded, which means that if your programme can use many cores, you can see some performance gains.

Comparison Table Between Redis and Memcached

Parameters of ComparisonRedisMemcached
DeveloperRedis was developed by Salvatore Sanfilippo in 2009.Memcached was developed by Brad Fitzpatrick in 2003.
Data Size512 MB 1 MB
Memory ManagementIt is capable of storing details to disc when physical memory is fully utilised.It is strictly  in memory, with an extension to save key-value data to the drive.
Supported Data TypeIt supports strings, lists, sets, sorted sets, hashes, bit arrays, geospatial, and hyper logs.It supports strings.

What is Redis?

Redis, which refers for Remote Dictionary Server, was designed to improve the efficiency of the website log analyzer. Redis has a set of commands and data structures for geographic indexing. Users can query distances between items or for objects within a certain radius of a location using latitude and longitude coordinates.

Redis as a cache gives a significant deal of power and overall efficiency due to its data types it stores data in a variety of forms including list, array, sets .Caches deploy a technique known as data eviction to free up memory for new data by rejecting old data. . The data eviction process in Memcached is based on the Least Recently Used method, and it randomly evicts data that is similar in size to the new data.

Redis optimizes performance by utilizing an in-memory dataset. You can persist your data in one of two ways, depending on your use case: by periodically dumping the dataset to disc or by appending each command to a disk-based log. Additionally, you can disable persistence if all that is required is a feature-rich, networked, in-memory cache. Additionally, Redis supports asynchronous replication, with extremely fast non-blocking initial synchronization, auto-reconnection, and partial resynchronization in the event of a network failure.

What is Memcached?

When utilizing demanding online applications, the cache server was created with the goal of avoiding time-consuming database accesses. The approach was to use an in-memory datastore that could instantly send cached content to website visitors. Memcached is extremely user-friendly and simple to set up, configure, and utilize. It’s also free to use, modify, and copy because it’s under the BSD license.

Memcached’s memory management efficiency diminishes as data size changes, resulting in memory fragmentation.In addition, serial data is frequently found in huge data sets, demanding more storage space.. Data is lost after a restart if you utilize Memcached, and recreating the cache is a time-consuming process. Memcached beats Redis in terms of scalability. You can simply scale Memcached up by supplying it with more processing resources because of its multithreaded nature. Clustering is a good scaling solution, but it’s a lot more difficult to set up and run than other scaling options.

Memcached is not a database that can be replicated. The API is available in all programming languages and is a key-value pair of a string object that is cached in memory. Memcached is a website caching technology that is incredibly efficient. You can read a lot of information while keeping a quick response time with this programme. Redis, on the other side, is continually reading and processing powerful scripts.

Main Differences Between Redis and Memcached

  1. Redis was developed in 2009 by Salvatore Sanfilippo whereas Memcached was developed in 2003 by Brad Fitzpatrick.
  2. The data size limit of Redis is 512 MB for strings, Memcached has 1 MB data size.
  3. Redis has a mechanism for writing the values that have been used the least recently to disc and the most recently used values to physical memory whereas in Memcached it is strictly in memory with extension extstore.
  4. Redis supports data types such as strings, sorted sets, sets, bit arrays, geospatial, lists whereas Memcached does not support anything more complicated than a simple key-value pair structure.
  5. Redis speed to read and write is slower than Memcached whereas Memcached is faster as compared to Redis.


Redis and Memcached perform similarly in terms of performance and memory usage. Not only is Redis opens up entirely new types of use cases and usage patterns. While Redis is undoubtedly more flexible and powerful, Memcached performs admirably for some tasks and in some cases outperforms Redis.Redis, which was developed later, has a vast number of advanced functionalities, excellent documentation, and a vibrant community.


  1. https://ieeexplore.ieee.org/abstract/document/8393274/
  2. https://ieeexplore.ieee.org/abstract/document/8379066/

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