This post describes the reasons to run a brand new Warsaw Data Engineering meetup group (and shutting down the existing group Warsaw Scala Enthusiasts). Join us!

I’ve been thinking about this for some time, but somehow couldn’t find enough courage. As new resolutions for the new year 2020 pilled up…


To Different Organization and GitHub Pages

For now…

Until I figure out how to make all “The Internals Of” online books available under a single root domain, e.g. books.japila.pl. Consider it a WIP and part of my resolutions for 2020.

Having said that, as of today, the repository with the sources of “The Internals Of Apache…


tl;dr Stay away from Sphinx and RST.

I’m coming from Markdown and Asciidoc markup languages and can’t think of any reasons why I should keep writing documentation using reStructuredText (RST) markup language. After just a couple of days I felt as if I was going backwards.

I’m quite surprised how…


Thanks Jakub Wszolek, Mariia Ruban and the entire conference crew for DataMass Summit 2019 conference in Gdansk, Poland on October 4th, 2019. I was invited as a speaker and enjoyed it a lot.

Me at DataMass Summit 2019

Not only could I give the talk about “Modern Stream Processing Engines Compared — Kafka Streams VS…


I speak French. Not really. But I will soon.

I wish I could write “I learn French” actually, but that’s something I haven’t learned yet during my lessons.

I use Duolingo mobile app and I enjoy it a lot. It gives me all I wanted for a French novice like…


The Opening Slide for the 3-Day Apache Kafka Workshop

When: 13–15.02.2019
Where: Győr, Hungary

Just a few days before the winter holidays with my family I got a call to host an Apache Kafka Workshop in Győr, Hungary. …


That’d been not so long since the first workshop with Apache Kafka and Kafka Streams when I was asked to run a workshop with Apache Kafka. I’ve had more and more workshops with Apache Kafka recently (mostly for developers), but the recent inquiry was completely different — I had to…


I could not have dreamt of a better shout-out after my recent work with Kafka Streams that I’ve just received from the one and only Gwen Shapira from Confluent (the company behind Apache Kafka and Kafka Streams).

I’m an independent consultant specialising in Apache Spark with some focus on…


During the past 5 days (June 11–15) I was giving “Introduction to Scala” workshop to a group of 10 people from different countries in South America (aka Latam).

The workshop was held online from 6pm to 10pm Poland time due to time zone difference (the difference was -5 hours if…


What a long Apache Spark day! The group of 3 Spark developers with me as the instructor started the 1-day Spark Structured Streaming 2.2 workshop right at 9am and finished at 8pm.

That gives 11 hours exclusively with Apache Spark’s brand new stream processing engine Spark Structured Streaming and Scala

Jacek Laskowski

IT Freelancer for Apache Spark, Delta Lake, Apache Kafka

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