Software Alternatives, Accelerators & Startups

memcached VS KeyDB

Compare memcached VS KeyDB and see what are their differences

memcached logo memcached

High-performance, distributed memory object caching system

KeyDB logo KeyDB

KeyDB is fast NoSQL database with full compatibility for Redis APIs, clients, and modules.
  • memcached Landing page
    Landing page //
    2023-07-23
  • KeyDB Landing page
    Landing page //
    2022-06-19

memcached features and specs

  • High Performance
    Memcached is incredibly fast and efficient at caching data in memory, enabling quick data retrieval and reducing the load on databases. Its in-memory nature significantly reduces latency.
  • Scalability
    Memcached can be easily scaled horizontally by adding more nodes to the caching cluster. This allows it to handle increased loads and large datasets without performance degradation.
  • Simplicity
    Memcached has a simple design and API, making it easy to implement and use. Developers can quickly integrate it into their applications without a steep learning curve.
  • Open Source
    Memcached is free and open-source software, which means it can be used and modified without any licensing fees. This makes it a cost-effective solution for caching.
  • Language Agnostic
    Memcached supports multiple programming languages through various client libraries, making it versatile and suitable for use in diverse tech stacks.

Possible disadvantages of memcached

  • Data Volatility
    Memcached stores data in RAM, so all cached data is lost if the server is restarted or crashes. This makes it unsuitable for storing critical or persistent data.
  • Limited Data Types
    Memcached primarily supports simple key-value pairs. It lacks the rich data types and more complex structures supported by some other caching solutions like Redis.
  • No Persistence
    Memcached does not offer any data persistence features. It cannot save data to disk, so all information is ephemeral and will be lost on system reset.
  • Size Limitation
    Memcached has a memory limit for each instance, thus, large-scale applications may need to manage multiple instances and ensure data is properly distributed.
  • Security
    Memcached does not provide built-in security features such as authentication or encryption. This can be a concern in environments where data privacy and security are critical.

KeyDB features and specs

  • High Performance
    KeyDB offers superior performance over Redis by allowing multi-threading, which utilizes multiple CPU cores efficiently, leading to significant improvements in throughput and latency.
  • Redis Compatibility
    KeyDB is fully compatible with Redis, meaning users can easily switch between Redis and KeyDB without needing to change their existing code or data structures.
  • Active Replication
    It supports multi-primary (active-active) replication, enabling all replicas to accept writes without worrying about conflicts, which increases availability and resilience.
  • Built-in TLS
    KeyDB includes built-in TLS support which enhances security by allowing data encryption in transit, a feature that requires third-party solutions in some Redis setups.
  • Persistence Options
    KeyDB supports both RDB snapshotting and AOF logging, offering flexible persistence strategies to balance between performance and durability.

Possible disadvantages of KeyDB

  • Community Size
    KeyDB, while gaining popularity, has a smaller community compared to Redis, which can lead to less community support and fewer third-party tools or extensions.
  • Maturity
    As a relatively newer project compared to Redis, KeyDB may lack the same level of proven stability and maturity, making it a potentially riskier choice for critical applications.
  • Documentation and Resources
    While KeyDB has extensive documentation, it might not be as comprehensive or complete as Redis, potentially leading to longer project integration times.
  • Potential Compatibility Issues
    Although KeyDB is compatible with Redis, advanced Redis features or unusual configurations might face compatibility issues during migration.
  • Less Architectural Simplicity
    The added complexity of multi-threading and active-active replication modes can increase the operational overhead compared to Redis's simpler single-threaded, master-slave architecture.

Analysis of memcached

Overall verdict

  • Memcached is a solid choice for applications that require distributed caching to improve scalability and performance. It's particularly beneficial for web applications handling high traffic and needing fast, efficient data retrieval.

Why this product is good

  • Memcached is considered good due to its high performance, simplicity, and effectiveness in enhancing the speed of dynamic web applications by alleviating database load. It operates by storing data in memory, which allows for quick retrieval of cached objects and reduces the need to frequently query the database. Its distributed architecture, open-source nature, and widespread language support make it a flexible and reliable choice for caching.

Recommended for

  • Web developers looking to improve the speed and scalability of applications.
  • Organizations needing a simple and effective caching solution to reduce database load.
  • Projects that demand quick deployment of a caching solution with support across multiple programming languages.

memcached videos

Course Preview: Using Memcached and Varnish to Speed Up Your Linux Web App

KeyDB videos

KeyDB on FLASH (Redis Compatible)

More videos:

  • Demo - Simple Demo of KeyDB on Flash in under 7 minutes (Drop in Redis Alternative)

Category Popularity

0-100% (relative to memcached and KeyDB)
Databases
75 75%
25% 25
NoSQL Databases
77 77%
23% 23
Key-Value Database
75 75%
25% 25
Graph Databases
100 100%
0% 0

User comments

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Reviews

These are some of the external sources and on-site user reviews we've used to compare memcached and KeyDB

memcached Reviews

Redis vs. KeyDB vs. Dragonfly vs. Skytable | Hacker News
Quick ask: I donรขย€ย™t see รขย€ยœsomeรขย€ย of the other offering out there like MemCachedรขย€ยฆ what was the criteria used to select these? I donรขย€ย™t see any source of how the test where run, specs of the systems, how the DB where set up, etc. Would be very valuable to have in order to attempt to re-validate these test on our own platform. I also came back and saw some of your updates...
Memcached vs Redis - More Different Than You Would Expect
So knowing how the difference between Redis and memcached in-memory usage, lets see what this means. Memcached slabs once assigned never change their size. This means it is possible to poison your memcached cluster and really waste memory. If you load your empty memcached cluster with lots of 1 MB items, then all of the slabs will be allocated to that size. Adding a 80 KB...
Redis vs. Memcached: In-Memory Data Storageย Systems
Memcached itself does not support distributed mode. You can only achieve the distributed storage of Memcached on the client side through distributed algorithms such as Consistent Hash. The figure below demonstrates the distributed storage implementation schema of Memcached. Before the client side sends data to the Memcached cluster, it first calculates the target node of the...
Source: medium.com
Why Redis beats Memcached for caching
Both Memcached and Redis are mature and hugely popular open source projects. Memcached was originally developed by Brad Fitzpatrick in 2003 for the LiveJournal website. Since then, Memcached has been rewritten in C (the original implementation was in Perl) and put in the public domain, where it has become a cornerstone of modern Web applications. Current development of...

KeyDB Reviews

Redis vs. KeyDB vs. Dragonfly vs. Skytable | Hacker News
2. KeyDB: The second is KeyDB. IIRC, I saw it in a blog post which said that it is a "multithreaded fork of Redis that is 5X faster"[1]. I really liked the idea because I was previously running several instances of Redis on the same node and proxying them like a "single-node cluster." Why? To increase CPU utilization. A single KeyDB instance could replace the unwanted...
Comparing the new Redis6 multithreaded I/O to Elasticache & KeyDB
Because of KeyDBโ€™s multithreading and performance gains, we typically need a much larger benchmark machine than the one KeyDB is running on. We have found that a 32 core m5.8xlarge is needed to produce enough throughput with memtier. This supports throughput for up to a 16 core KeyDB instance (medium to 4xlarge)
Source: docs.keydb.dev
KeyDB: A Multithreaded Redis Fork | Hacker News
"KeyDB works by running the normal Redis event loop on multiple threads. Network IO, and query parsing are done concurrently. Each connection is assigned a thread on accept(). Access to the core hash table is guarded by spinlock. Because the hashtable access is extremely fast this lock has low contention. Transactions hold the lock for the duration of the EXEC command....

Social recommendations and mentions

Based on our record, memcached should be more popular than KeyDB. It has been mentiond 37 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

memcached mentions (37)

  • Redis vs. Memcached: How to Choose Your NoSQL Champion
    Memcached has a single, focused goal: to be a high-performance, distributed, in-memory object caching system. It stores all data in RAM, which means reads and writes are incredibly fast. But its main weakness is just as clear: data is completely lost when the service restarts, as it offers no persistence. Its data model is a simple key-value store, limited to basic get, set, and delete operations. - Source: dev.to / about 2 months ago
  • MySQL Performance Tuning Techniques
    Memcached can help when lightning-fast performance is needed. These tools store frequently accessed data, such as session details, API responses, or product prices, in RAM. This reduces the laid on your primary database, so you can deliver microsecond response times. - Source: dev.to / 7 months ago
  • 10 Best Practices for API Rate Limiting in 2025
    In-memory tools like Redis or Memcached for fast Data retrieval. - Source: dev.to / 8 months ago
  • Outgrowing Postgres: Handling increased user concurrency
    A caching layer using popular in-memory databases like Redis or Memcached can go a long way in addressing Postgres connection overload issues by being able to handle a much larger concurrent request load. Adding a cache lets you serve frequent reads from memory instead, taking pressure off Postgres. - Source: dev.to / 8 months ago
  • API Caching: Techniques for Better Performance
    Memcached โ€” Free and well-known for its simplicity, Memcached is a distributed and powerful memory object caching system. It uses key-value pairs to store small data chunks from database calls, API calls, and page rendering. It is available on Windows. Strings are the only supported data type. Its client-server architecture distributes the cache logic, with half of the logic implemented on the server and the other... - Source: dev.to / 12 months ago
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KeyDB mentions (10)

  • Redis
    These facts only hold when the size of your payload and the number of connections remain relatively small. This easily jumps out the window with ever-increasing load parameters. The threshold is, unfortunately, rather low at a high number of connections and increased payload sizes. Modern large-scale micro-services will easily have over 100 running instances at medium scale. And since most instances employ some... - Source: dev.to / 9 months ago
  • Introducing LMS Moodle Operator
    The LMS Moodle Operator serves as a meta-operator, orchestrating the deployment and management of Moodle instances in Kubernetes. It handles the entire stack required to run Moodle, including components like Postgres, Keydb, NFS-Ganesha, and Moodle itself. Each of these components has its own Kubernetes Operator, ensuring seamless integration and management. - Source: dev.to / over 1 year ago
  • Dragonfly Is Production Ready (and we raised $21M)
    Congrats on the funding and getting production ready, it's good that KeyDB (and Redis) get some competition. https://docs.keydb.dev/ Open question, how does Dragonfly differ from KeyDB? - Source: Hacker News / over 2 years ago
  • I deleted 78% of my Redis container and it still works
    See: Distroless images[0] This is one of the huge benefits of recent systems languages like go and rust -- they compile to single binaries so you can use things like scatch[1] containers. You may have to fiddle with gnu libc/musl libc (usually when getaddrinfo is involved/dns etc), but once you're done with it, packaging is so easy. Even languages like Node (IMO the most progressive of the scripting languages)... - Source: Hacker News / about 3 years ago
  • Dragonflydb โ€“ A modern replacement for Redis and Memcached
    Interesting project. Very similar to KeyDB [1] which also developed a multi-threaded scale-up approach to Redis. It's since been acquired by Snapchat. There's also Aerospike [2] which has developed a lot around low-latency performance. 1. https://docs.keydb.dev/ 2. https://aerospike.com/. - Source: Hacker News / over 3 years ago
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What are some alternatives?

When comparing memcached and KeyDB, you can also consider the following products

Redis - Redis is an open source in-memory data structure project implementing a distributed, in-memory key-value database with optional durability.

MongoDB - MongoDB (from "humongous") is a scalable, high-performance NoSQL database.

Dragonfly DB - Dragonfly - Scalable in-memory datastore made simple

Apache Cassandra - The Apache Cassandra database is the right choice when you need scalability and high availability without compromising performance.

CouchBase - Document-Oriented NoSQL Database

Apache Ignite - high-performance, integrated and distributed in-memory platform for computing and transacting on...