Fresh Reads

Today I’m happy to announce that the first release candidate for Disque 1.0 is available. If you don't know what Disque is, the best starting point is to read the README in the Github project page at http://github.com/antirez/disque. Disque is a just piece of software, so it has…

Two days ago Mike Malone published an interesting post on Medium about the V8 implementation of Math.random(), and how weak is the quality of the PRNG used: http://bit.ly/1SPDraN. The post was one of the top news on Hacker News today. It’s pretty clear and informative from the…

Today I was curious about plotting all the Redis commits we have on Git, which are 90% of all the Redis commits. There was just an initial period where I used SVN but switched very soon. Full size image here: http://antirez.com/misc/commitsvis.png !~! Each commit is a rectangle.…

Lua scripting is probably the most successful Redis feature, among the ones introduced when Redis was already pretty popular: no surprise that a few of the things users really want are about scripting. The following two features were suggested multiple times over the last two…

IMPORTANT EDIT: Redis 3.2 security improved by implementing protected mode. You can find the details about it here: https://www.reddit.com/r/redis/comments/3zv85m/new_security_feature_redis_protected_mode/ From time to time I get security reports about Redis. It’s good to get…

I’m just back from the Redis Dev meeting 2015. We spent two incredible days talking about Redis internals in many different ways. However while I’m waiting to receive private notes from other attenders, in order to summarize in a blog post what happened and what were the most…

If you know me, you know I’m not the kind of guy that considers competing products a bad thing. I actually love the users to have choices, so I rarely do anything like comparing Redis with other technologies. However it is also true that in order to pick the right solution users…

Everybody knows Redis is single threaded. The best informed ones will tell you that, actually, Redis is *kinda* single threaded, since there are threads in order to perform certain slow operations on disk. So far threaded operations were so focused on I/O that our small library…

Yesterday Amplitude published an article about scaling analytics, in the context of using the Set data type. The blog post is here: https://amplitude.com/blog/2015/08/25/scaling-analytics-at-amplitude/ On Hacker News people asked why not using Redis instead:…

I consider myself very lucky for contributing to the open source. For me OSS software is not just a license: it means transparency in the development process, choices that are only taken in order to improve software from the point of view of the users, documentation that…

Nor subjects, for what matters. Everybody will tell you to don't add a dot at the end of the first line of a commit message. I followed the advice for some time, but I'll stop today, because I don't believe commit messages are titles or subjects. They are synopsis of the meaning…

I’m back from Paris, DotScale 2015 was a very interesting conference. Before leaving I was working on Sentinel in the context of the unstable branch: the work was mainly about connection sharing. In short, it is the ability of a few Sentinels to scale, monitoring many masters.…

EDIT: In case you missed it, Disque source code is now available at http://github.com/antirez/disque It is a few months that I spend ~ 15-20% of my time, mostly hours stolen to nights and weekends, working to a new system. It’s a message broker and it’s called Disque. I’ve an…

I’m back home, after a non easy trip, since to travel from San Francisco to Sicily is kinda NP complete: there are no solutions involving less than three flights. However it was definitely worth it, because the Redis Conference 2015 was very good, SF was wonderful as usually and…

Today Redis is six years old. This is an incredible accomplishment for me, because in the past I switched to the next thing much faster. There are things that lasted six years in my past, but not like Redis, where after so much time, I still focus most of my everyday energies…

Redis speed could be one selling point for new users, so following the trend of comparative “advertising” it should be logical to have a few comparisons at Redis.io. However there are two problems with this. One is of goals: I don’t want to convince developers to adopt Redis, we…

Today I was testing Redis latency using m3.medium EC2 instances. I was able to replicate the usual latency spikes during BGSAVE, when the process forks, and the child starts saving the dataset on disk. However something was not as expected. The spike did not happened because of…

One interesting thing about the Stripe blog post about Redis is that they included latency graphs obtained during their tests. In order to persist on disk Redis requires to call the fork() system call. Usually forking using physical servers, and most hypervisors, is fast even…

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…

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…

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…

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…

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…

----------------- 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…