Yesterday Stripe engineers wrote a detailed report of why they had an issue with Redis. This is very appreciated. In the Hacker News thread I explained that because now we have diskless replication (http://antirez.com/news/81) now persistence is no longer mandatory for people having a master-slaves ...

Almost a month ago a number of people interested in Redis development met in London for the first Redis developers meeting. We identified together a number of features that are urgent (and are now listed in a Github issue here: https://github.com/antirez/redis/issues/2045), and among the identified ...

Yesterday distributed systems expert Aphyr, posted a tweet about a Redis Sentinel issue experienced by an unknown company (that wishes to remain anonymous): “OH on Redis Sentinel "They kill -9'd the master, which caused a split brain..." “then the old master popped up with no data and replicated the...

The first commit I can find in my git history about Redis Cluster is dated March 29 2011, but it is a “copy and commit” merge: the history of the cluster branch was destroyed since it was a total mess of work-in-progress commits, just to shape the initial idea of API and interactions with the rest o...

Queues are an incredibly useful tool in modern computing, they are often used in order to perform some possibly slow computation at a latter time in web applications. Basically queues allow to split a computation in two times, the time the computation is scheduled, and the time the computation is ex...

----------------- UPDATE: The algorithm is now described in the Redis documentation here => http://redis.io/topics/distlock. The article is left here in its older version, the updates will go into the Redis documentation instead. ----------------- Many people use Redis to implement distributed locks...

The strong reactions about the recent OpenSSL bug are understandable: it is not fun when suddenly all the internet needs to be patched. Moreover for me personally how trivial the bug is, is disturbing. I don’t want to point the finger to the OpenSSL developers, but you just usually think at those cl...

Generally speaking, I love randomized algorithms, but there is one I love particularly since even after you understand how it works, it still remains magical from a programmer point of view. It accomplishes something that is almost illogical given how little it asks for in terms of time or space. Th...

Yesterday and today I managed to spend some time with linenoise (http://github.com/antirez/linenoise), a minimal line-editing library designed to be a simple and small replacement for readline. I was trying to merge a few pull requests, to fix issues, and doing some refactoring at the same time. It ...

The title of this blog post is an apparently trivial to answer question, however it is worth to consider a bit better what performance really means: it is easy to get confused between scalability and performance, and to decompose performance, in the specific case of database systems, in its differen...

Today Redis is 5 years old, at least if we count starting from the initial HN announcement [1], that’s actually a good starting point. After all an open source project really exists as soon as it is public. I’m a bit shocked I worked for five years straight to the same thing. The opportunities for l...

In this blog post I’m going to describe a very simple distributed algorithm that is useful in different programming scenarios. The algorithm is useful when you need to take some kind of information synchronized among a number of processes. The information can be everything as long as it is composed ...

Redis Cluster is finally on its road to reach the first stable release in a short timeframe as already discussed in the Redis google group [1]. However despite a design never proposed for the implementation of Redis Cluster was analyzed and discussed at long in the past weeks (unfortunately creating...

One of the steps to reach the goal of providing a "testable" Redis Cluster experience to users within a few weeks, is some serious testing that goes over the usual "I'm running 3 nodes in my macbook, it works". Finally this is possible, since Redis Cluster entered into the "refinements" stage, and m...

So finally something really good happened from the Redis criticism thread. At the end of the work day I was reading about Redis as AP and merge operations on Twitter. At the same time I was having a private email exchange with Alexis Richardson (from RabbitMQ, and, my boss). Alexis at some point pro...

A few days ago I tried to do an experiment by running some kind of “call for critiques” in the Redis mailing list: https://groups.google.com/forum/#!topic/redis-db/Oazt2k7Lzz4 The thread has reached 89 posts so far, probably one of the biggest threads in the history of the Redis google group. The ma...

Redis unstable has a new command called "WAIT". Such a simple name, is indeed the incarnation of a simple feature consisting of less than 200 lines of code, but providing an interesting way to change the default behavior of Redis replication. The feature was extremely easy to implement because of pr...

Yesterday I lost all my blog data in a rather funny way. When I installed this new blog engine, that is basically a Lamer News slightly modified to serve as a blog, I spinned a Redis instance manually with persistence *disabled* just to see if it was working and test it a bit. I just started a scree...

Today Joyent wrote a blog post in the company blog about an issue that started with this pull request in the libuv project: https://github.com/joyent/libuv/pull/1015#issuecomment-29538615 Basically the developer Ben Noordhuis rejected a pull request involving a change in the documentation to use gen...

Redis API for data access is usually limited, but very direct and straightforward. It is limited because it only allows to access data in a natural way, that is, in a data structure obvious way. Sorted sets are easy to access by score ranges, while hashes by field name, and so forth. This API “way” ...