In this article, I am going to look at Redis versus Tarantool. At a first glance, they are quite alike — in-memory, NoSQL, key value. But we are going to look deeper. My goal is to find meaningful similarities and differences, I am not going to claim that one is better than the other.

There are three main parts to my story:

• We’ll find out what is an in-memory database, or IMDB. When and how are they better than disk solutions?
• Then, we’ll consider their architecture. What about their efficiency, reliability, and scaling?
• Then, we’ll delve into technical details. Data types, iterators, indexes, transactions, programming languages, replication, and connectors.

Feel free to scroll down to the most interesting part or even the summary comparison table at the very bottom and the article.

I manage a team that designs and introduces in-house Kubernetes aaS at Mail.ru Cloud Solutions. And we often see a lack of understanding as to this technology, so I’d like to talk about common strategic mistakes at Kubernetes implementation in major projects.

Most of the problems arise because the technology is quite sophisticated. There are unobvious implementation and operation challenges, as well as poorly used advantages, all of those resulting in money loss. Another issue is the global lack of knowledge and experience with Kubernetes. Learning its use by the book can be tricky, and hiring qualified staff can be challenging. All the hype complicates Kubernetes-related decision making. Curiously enough, Kubernetes is often implemented rather formally – just for it to be there and make their lives better in some way.

Hopefully, this post will help you to make a decision you will feel proud of later (and won’t regret or feel like building a time machine to undo it).

I'm Ivan Kopenkov, a senior front-end developer at Mail.ru Cloud Solutions. In this article, I will tell you about the approaches we have used for the UI library components customization. You will also learn how to significantly decrease bundle size, cutting off all the unnecessary modules Ant Design takes there.

In our case, we are making wrappers for original Ant Design components inside the project, changing their appearance, and developing their logic. At the same time, we import both customized and original components right from the ant-design module. That saves tree shaking functionality and makes complex library components use our wrappers instead of original nested elements.

If you are already or about to use Ant Design, this article will provide you with a better and more effective way to do so. Even if you have chosen another UI library, you might be able to implement these ideas.

Hi all! I'm Andrey Kapustin. I work as a system analyst at Mail.ru Group. Our products form a unified ecosystem. Many independent infrastructures generate data in it: taxi and food delivery services, email services, social networks, etc. The faster and more precise we can predict a client's needs, the sooner and more correctly we can offer our products. 

Many system analysts and engineers are keen to know: 

1. How to design the architecture of a trigger platform for real-time marketing?
2. How to arrange a data structure that would be in line with the requirements of a marketing strategy for interacting with clients?
3. How to ensure the stable operations of the  system under very heavy workloads? 

Such systems are based on technologies of high-load processing and Big Data analysis. We have accumulated considerable experience in these areas. Our expertise is in high demand on the market.  I'm going to show how we help our customers to switch from off-line to on-line in their interactions with clients using Real-Time Marketing solutions based on Tarantool.

This year, many processes transformed, with traditions and habits being modified. The rhythm of life has changed, and there's more uncertainty and strain. But IT person's soul wants diversity, and many developers have asked us if annual Russian AI Cup will be held this year. Is there going to be an announcement? What is the main theme of the upcoming championship? Should I take a vacation?

Though some changes are expected, it will be held in keeping with the best traditions. In the run-up, we will announce one of today's largest online AI programming championships — Russian AI Cup. We invite you to make history!

I came to Mail.ru Group in 2013, and I required a queue for one task. First of all, I decided to check what the company had already got. They told me they had this Tarantool product, and I checked how it worked and decided that adding a queue broker to it could work perfectly well.

I contacted Kostja Osipov, the senior expert in Tarantool, and the next day he gave me a 250-string script that was capable of managing almost everything I needed. Since that moment, I have been in love with Tarantool. It turned out that a small amount of code written with a quite simple script language was capable of ensuring some totally new performance for this DBMS.

Today, I’m going to tell you how to instantiate your own queue in Tarantool 2.2.

Currently, social network sites tend to be one of the major communication platforms in both offline and online space. Freedom of expression of various points of view, including toxic, aggressive, and abusive comments, might have a long-term negative impact on people’s opinions and social cohesion. As a consequence, the ability to automatically identify and moderate toxic content on the Internet to eliminate the negative consequences is one of the necessary tasks for modern society. This paper aims at the automatic detection of toxic comments in the Russian language. As a source of data, we utilized anonymously published Kaggle dataset and additionally validated its annotation quality. To build a classification model, we performed fine-tuning of two versions of Multilingual Universal Sentence Encoder, Bidirectional Encoder Representations from Transformers, and ruBERT. Finetuned ruBERT achieved F₁ = 92.20%, demonstrating the best classification score. We made trained models and code samples publicly available to the research community.

In a nutshell: MTA-STS is a way to protect emails against interception (man-in-the-middle aka MitM attacks) between email servers. It partially resolves architectural issues in email protocols and is described in a recent RFC 8461 standard.

Hello, my name is Andrey Sergeyev and I work as a Head of IoT Solution Development at Mail.ru Cloud Solutions. We all know there is no such thing as a universal database. Especially when the task is to build an IoT platform that would be capable of processing millions of events from various sensors in near real-time.

Our product Mail.ru IoT Platform started as a Tarantool-based prototype. I’m going to tell you about our journey, the problems we faced and the solutions we found. I will also show you a current architecture for the modern Industrial Internet of Things platform. In this article we will look into:

• our requirements for the database, universal solutions, and the CAP theorem
• whether the database + application server in one approach is a silver bullet
• the evolution of the platform and the databases used in it
• the number of Tarantools we use and how we came to this

A still from «Our Secret Universe: The Hidden Life of the Cell»

Investment business is one of the most complex domains in the banking world. It's about not just credits, loans, and deposits — there are also securities, currencies, commodities, derivatives, and all kinds of complex stuff like structured products.

Recently, people have become increasingly aware of their finances. More and more get involved in securities trading. Individual investment accounts have emerged not so long ago. They allow you to trade in securities and get tax credits or avoid taxes at the same time. All clients coming to us want to manage their portfolios and see their reporting on-line. Most frequently, these are multi-product portfolios, which means that people are clients of different business areas.

Moreover, the demands of regulators, both Russian and international, also grow.

To meet the current needs and lay a foundation for future upgrades, we've developed our Tarantool-based investment business core.

I don't know about you, but I really like to get inside all sorts of systems. In this article, I’m going to tell you about the internals of Lua tables and special considerations for their use. Lua is my primary professional programming language, and if one wants to write good code, one needs at least to peek behind the curtain. If you are curious, follow me.

We have recently talked about how to deploy a Tarantool Cartridge application. However, an application's life doesn't end with deployment, so today we will update our application and figure out how to manage topology, sharding, and authorization, and change the role configuration.

Feeling interested? Please continue reading under the cut.

Hi all! I lead antispam team and several machine learning teams at Mail.ru Group. The subject of this article is self-development for team leads/managers. But in reality many techniques and recipes do not depend on the role at all. This really concerns me because machine learning is developing extremely fast, and it takes a lot of time to stay up to date. So the question about what should be done for development and how is quite topical.

Of course, the content of this article is not the ultimate truth but just a description of the results of my continuing quest. It tells about approaches based on books and workshops, trials and errors, which have worked for me. It'll be good to have a discussion with you in comments.

Hi Habr,

I'm Artyom Karamyshev, a system administration team leader at Mail.Ru Cloud Solutions (MCS). We launched many products in 2019. We've aimed to make API services easily scalable, fault-tolerant, and ready to accommodate rapid growth. Our platform is running on OpenStack, and in this article, I describe all the component fault tolerance issues that we've resolved.

The overall fault tolerance of the platform is consists of its components fault tolerance. So, I'm going to show you step by step tutorial about all levels where we've found the risks.

It is a new selection of tips and tricks about Python and programming from my Telegram-channel @pythonetc.

← Previous publications.


The order of except blocks matter: if exceptions can be caught by more than one block, the higher block applies. The following code doesn’t work as intended:

It is a new selection of tips and tricks about Python and programming from my Telegram-channel @pythonetc.

← Previous publications.


Different asyncio tasks obviously have different stacks. You can view at all of them at any moment using asyncio.all_tasks() to get all currently running tasks and task.get_stack() to get a stack for each task.

In the PHP ecosystem, there are currently two connectors for the Tarantool server: the official PECL extension tarantool/tarantool-php written in C, and tarantool-php/client written in PHP. I am the author of the latter one.

In this article I would like to share the results of performance testing of both these libraries and show how you can achieve 3x-5x performance improvement (on synthetic tests!) with minimal changes in code.

Tips and tricks from my Telegram-channel @pythonetc, November 2019

It is a new selection of tips and tricks about Python and programming from my Telegram-channel @pythonetc.

← Previous publications.



PATH is an environment variable that stores paths where executables are looked for. When you ask your shell to run ls, the shell looks for the ls executable file across all paths that are presented in PATH.

We have already presented Tarantool Cartridge that allows you to develop and pack distributed applications. Now let's learn how to deploy and control these applications. No panic, it's all under control! We have brought together all the best practices of working with Tarantool Cartridge and wrote an Ansible role, which will deploy the package to servers, start and join instances into replica sets, configure authorization, bootstrap vshard, enable automatic failover and patch cluster configuration.

Interesting, huh? Dive in, check details under the cut.

The AI Cup community and Mail.ru Group in collaboration with Codeforces.com invite you to the real battle! Get ready for the sleepless nights and calloused hands — take part in Russian AI Cup, which is one of the most challenging and vivid artificial intelligence programming competitions in the world. Believe us, managers of this madness did their best to create the game you'd want to play.

To become part of the competition, you need Internet access, computer, creativity, and enthusiasm for being a part of this extraordinary Cup. By the way, you might need some coffee. Welcome!