Author's posts

Feb 17

[docker][cassandra] Reaching mixed load – 750,000 op\sec

Cassandra performance tuning - challenge

The cart goes nowhere because the swan wants to fly in the air, the pike wants to swim underwater and the crawfish wants to crawl backward. Cassandra is one of powerhorse of modern high load landscape – nosql database that can be pluged to Spark for distributed computing, Titan for playing with graph data representation …

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May 30

How to stop being a junior – 7 hints of programmer productivity

0) If you don’t know something – don’t afraid to ask. Especially if you already checked first page of google search and pretty sure that no one ask that question at stackoverflow. Reinventing the wheel and breaking the stalemate can be a good exercise for your home projects, but in production environment better to check …

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May 12

db mix – postgres, sqlite, cassandra, aerospike & redis

SQLite How to delete all tables from sqlite: Find duplicates by field “field_name”: Find records changed in last 5 days: Get table definitions: Export select query to csv: Import data from csv into fresh new table: Postgres How to show all tables with sizes within database Show average amount of records per table How to create data-only …

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Jan 15

7 sins of blatant ignorance and how to avoid them

…You produce software for some time. In most cases it even works. Other developers tend to care about your opinion. Damn, you even wear some fancy title like senior\principal\architect. And here it is – suddenly you were offered to wear really posh title – CTO… This is moment when real troubles get started. I did …

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Sep 05

Information retrieval, Search and recommendation engine:

Natural language processing: – Processing of texts written in ordinal languages – search algorithm by Yandex Information retrieval: – Introduction to Information Retrieval, Cambridge – Latent Dirichlet Allocation (LDA) Few examples of applications for the above: Recommender systems: – …

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Mar 06

Elastic Search – just a few useful snippets

Install head plugin or rely on oldschool curl utility in order to test your queries: or Q: Show me example of query for complex, nested document? A: NOTE: if what are you searching for in sub-sub-sub document – just add proper number of nested chains of “bool” “must” “nested” elements. Q: I need full text …

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Oct 03

Heterogeneous vector in c++ – overview of common approaches

heterogeneous container in c++

So, you are wondering about heterogeneous vector in c++? Maybe even dare to dream about any suitable substitution of such non-existent container? In another word, you need a generic-like container that can store different datatypes. If you just need a quick answer – stick with std::vector < boost::any> approach or read this, If you need …

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Sep 24

How to convert png pair of RGB and Depth frames into Pointcloud library PCD format

There are a lot of accessible dataset of RGB-D data: But usually it stored in PNG format and unfortunately Pointcloud library do not provide built-in function neither for treating it as a PointCloud nor for conversion it to PCD. For my experiments I need to test few points using data with …

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Nov 10

Templates in plain C

Templates in ANSI C – simple and convenient method for emulating c++ like templates in plain c. Sample project, which demonstrate this technics can be found at github. So, it is our constraints: ANSI C (no templates, inheritance, overloading, default params etc.) set of almost the same user-defined structures (the common difference – is types …

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Oct 12

Что почитать для проф развития программисту

Давно хотел как-то упорядочить свой список книг для внеклассного чтения для повышения проф-пригодности. Эти книжки для тех программистов, которые уже не совсем новички. Возможно уже и не совсем программисты – техлиды/архитекты. И хотят данную ситуацию усугубить. Я из них прочитал еще не все 🙁 Но галочки уже расставляю 🙂 зы. Не думаю, что это нужно/интересно/полезно …

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