Artur Krajewski

Always be closing!

Just like the effective salesperson is the one closing the sales, effective engineers and managers in our industry are the ones that can deliver business value. Deliver without ", but", deliver without TODOs, without creating a mess and without putting dust under the carpet.

I will describe what I mean by . . .

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October 15, 2018

On IT Innovations

I would like to recommend "IT Innovation: What It Is and How to Get More of It" pluralsight course. I selected it because I wanted to listen to something during my training. To my surprise even though it was relatively short (around 90mins) it provided a very useful model for IT innovation.

The model author proposed is . . .

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July 15, 2018

Co and contravariance in C#


This article is written mostly for me. For a long time, I thought that I understand the topic. It was only after one of the job interviews I realised that I did not grasp the concept and found it hard to remember the difference between co and contravariance.

Generic variance is a property of relation between . . .

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April 18, 2018

There is more to software engineering than code

Three most important non-development activities for developers

This post is for all the coders on their way to becoming developers.

Too often I see coders jumping right into the code and spending their whole days just implementing function after function. I was one of them. This could be an optimal strategy in the world when customers would pay directly for the lines of code written. In . . .

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February 03, 2018

HyperLogLog demystified

At least for me

I first heard about HyperLogLog on some Redis podcast quite a few years ago. I recall that I thought it seemed magical. They said that this data structure can accurately 'guess' number of distinct elements added to the set using some small constant memory. Of course, it would be a trivial problem for small sets, but apparently, . . .

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January 11, 2018

4 rules of great bug report

Rules I will describe today are simple. Trivial. Boring. They won't get you chills. Getting excited about them is hard. On the other hand, they are effective. I have been using them in all the projects for quite a few years, with great success.

Unfortunately, even some professional testers are creating bug reports that are hard . . .

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December 03, 2017

How to produce ad-hoc Kafka messages on Windows?

Navigate to your Kafka bin/windows directory and start your power shell console. Use one of following commands.

Manually add messages one by one

./kafka-console-producer.bat --broker-list kafka:9092 --topic test

Manually add messages with keys one by one

> ./kafka-console-producer.bat . . .

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November 25, 2017