My work

Currently I'm a Hadoop specialist / data engineer, but this hasn't always been the case. Simply because Hadoop and Big Data didn't exist when I started my carreer in 1997.

Origin story
Back then I started as an Oracle database administrator and I've been an Oracle database specialist for 20 years. I specialized in database performance. These problems usually were very interesting puzzles for me and in solving them, I can honestly say that I managed to save customers and employers a lots of money.

Chances are you might have encountered some scripts from me to analyze Oracle performance problems. I've created a couple of ones I've honed to perfection, because I've used them myself so much. Up to Oracle 11g anyway.

Security was another aspect I was interested in. The more I learned about security and how systems get hacked, the more I worried about the gaping holes in our defences. I learned that knowing the technical solution to plug the holes doesn't help, if nobody believes there is a problem. I got interested in raising security awareness. This culminated to two particular initiatives of mine: a "Hack your own database" course I did for Transfer Solutions back in 2011 and a "How to sell security" session I did for the UKOUG in Manchester in 2014 and the Harmony 2015 conference in Talinn, Estonia, in 2015.

In 2015, when I worked for Rabobank Nederland, there was a change in my carreer. After 18 years of doing technical stuff, I became a "product verantwoordelijke", sort of a tech lead. It was more of a managerial type of function. Less puzzles, more mail and meetings. It turned out, it was really not my cup of tea. After doing this for 2 years, I needed something new.

My old Oracle blog is still there as a testament to my work with Oracle.

View from the Rabobank towers in Utrecht

A new beginning
I wanted back to the technical world. With my Oracle expertise getting work as a DBA wouldn't be too hard, but I wanted to work at the best and coolest companies. At one of the coolest, they thought my profile was rather onesided. Only Oracle? What else. I said I wanted to work with Big Data. They said: "What have you done yourself in Big Data?" That made me think.

I had done some courses before, like Cryptography I at Coursera. I decided to do some Big Data courses there. Immediately I started to love Hadoop. It felt like the olden days when I was figuring new stuff out. And there was so much of it to find out. I decided this new field of work would do great for me.

Doing these courses felt liberating. I was completely in control of what I would learn, and where my carreer would go. It felt great! After the initial Hadoop courses (which in hindsight only let you sniff on Big Data), I decided I needed to learn Python. I did two great courses from Rice University on Coursera. Immediately I became a Python fan. Then I decided to learn Machine Learning from Stanford University (there's a better one nowadays on This was one of the toughest courses, but I managed to get my certificate. And from thereon I actually never stopped learning. Whether it was deep learning, MongoDB, ElasticSearch or R Studio, I kept going at it.

But would I actually manage to get work in this new field? After all, for the first time in years I was "inexperienced" now, besides the fact that I had worked for 20 years with data. Some companies wanted me to work for them, but do the "old stuff", meaning Oracle, and maybe some Big Data as well. But I decided I wanted to start for real as a data engineer, basically the person who makes data available so that data scientists can easily and fast handle it.

Eventually there was only one company that saw me doing that, Open Circle Solutions in Eindhoven. Which was great. And I started working there in March 2017. Unfortunately customers didn't see mee doing that work. So the problem was basically replaced. And now I was a data engineer "on the bench" for 8 months.

Because I had time, I started making Youtube videos about the things I've learned, like Hadoop High Availability and security and how to work with dataframes in Python, use ElasticSearch, MongoDB, Neo4J and even how to land a rocket stage with Python in the game Kerbal Space Program.

You can find more about this stuff on my blog and on my Youtube channel.

After a brief job at the Port of Rotterdam as data custodian, I decided that consultancy was still the way to go. This time at DIKW in Nieuwegein. I started working there in May 2019 as a "medeondernemer" or "fellow entrepeneur".

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