Monthly Archives: November 2023

Fabric ride-along Week 1 – Reviewing the data

This is week 1 where I try to take Magic the Gathering draft data to learn Microsoft Fabric. Check out week 0 for some reasoning why.

So, before I do anything else, I want to get a sense of the data I’m looking at to see if it’s suitable for this project. I download the data, and because it’s gzipped, I use 7-zip to open it up on windows 10, or Windows explorer on Windows 11. In either case, the first thing I notice is the huge size disparity. When compressed, it is a quarter of a gigabyte. Uncompressed, it’s about 10 GB. This tells us something.

The longer you work in business intelligence, and especially in consulting, the more you start picking up clues and making inferences. You do this because scope creep is extremely prevalent in BI, and if you are a consultant you might be the one paying for it. So, what does 40x compression difference tell us about the data?

40x is abnormal. In my experience with the Vertipaq engine in Power BI, on a good day you are looking at 5-10x compression compared to a SQL backend. So, we know that there is a lot of repeated data. Because this is the only file for this data, we can infer that we will have to do quite a bit of normalization. CSV is a flat format, so the source data is likely heavily denormalized in this case. I would be shocked if there was any nested or hierarchical data like you might expect with JSON.

The next step is to take a peek at the data. There might be documentation somewhere, but for whatever reason I prefer to just take a look and get a feel for it. So how do we do that? Well, someone experienced would probably use a dedicated tool for large files. But I’m not experienced, so I confirm that I have 32 gigs of RAM, double click on the file and cross my fingers. In doing so, I create the most viral tweet of my career.

Excel complains that there are too many rows, but eventually shows me the first million of them. I take a quick glance to get oriented. The very first thing I’m scanning for is anything with the word “id” in it (1). The next thing I’m scanning for are repeated values (2), these are likely to go with the id as a header table or dimension table. Then I see pick number incrementing (3), so it’s likely functioning as a line number. Then I see a bunch of ones and zeros (4) to the right, and I don’t like that.

Issues with the data

I don’t like that because it’s data I don’t know how to deal with. My first guess is it’s data for data science that’s been turned into features. Columns like this are great for running experiments, but awful for traditional analytical reporting. I’ll likely have to reshape the data into something more dimensional, but I’ll have to learn how best to store this information. Doing a pivot is simple enough, but I have a nagging feeling I’m missing something.

So, the next question, is just how many columns do we have and what do they look like? I scroll over all the way to the right, and I see the letters YS. I don’t know how many that is, but I know it’s bad. Typically, in my work it never gets past A and another letter. I check and there are 672 columns!!!

Why so many columns? This data is around drafting Magic the Gathering cards. So, for each card in the specific magic set (a quarterly release of cards), we have a column if it was possibly in that card pack (the cards the player can choose from), as well as in the player’s already selected pool (the cards they’ve drafted). Essentially, for every card they could possibly see in a draft we are tracking what they have seen as well as what they have picked.

Accordingly, we have a very sparse dataset. Based on how the math works out, these columns will have 0 the vast majority of the time. I know that having lots and lots of columns interferes with run-length encoding, so leaving the dataset as is not ideal from a compression and performance standpoint. This does explain why the data compresses so well though, since most of it is long chunks of 0s and commas. The gzip algorithm is able to see that and substitute it.

There’s another issue with this shape. We have columns with specific names of the cards. The cards available each set are completely different, with only a handful of repeats. This means if we just merged in the schema each new set, we would have thousands of columns. This simply isn’t feasible; we have to reshape the data. We are going to need to learn how to dynamically unpivot the data, probably in Azure Data Factory, which I have no experience in.

Coincidentally, Javier Villegas was giving a presentation on data ingestion in the Data Toboggan conference. I think an important part of learning technologies is giving yourself the chance for “serendipity” or “luck”. If you are regularly bumping into content, you can find content that is relevant to the problems you have. As I mentioned in week 0, if you don’t have active problems or active tasks you sometimes have to make your own.


We can tell the data is abnormally compressible and we need to figure out why. It turns out it is a sparse data set. The first thing I do is rapidly scan for id fields, numerically incrementing fields, and repeated values to get a sense of how I might normalize the data. Based on the current shape of the data, I know I’m going to have to pivot it. I’ll probably have to learn Azure Data Factory for that, but we’ll see. I know vaguely that Fabric has support for PowerQuery.

Fabric project ride-along: Week 0 – let’s wing it

I’ve written before about struggling to learn Azure Synapse, and I’ve struggled as well with getting excited about Microsoft Fabric. I think the pitch and the potential of Microsoft Fabric is real. The issue is that it solves problems I don’t have. In my work, I don’t deal with data so big that Power BI can’t handle it. I don’t deal with data so unstructured that Power Query can’t handle it.

But I know I need to learn Fabric. Power BI is a part of Fabric, the integrations are only going to continue to improve. If nothing else, I need to be able to tell customers if they should look into using Fabric or not. So what do you do when there is a technology you aren’t excited about, but have to learn?

One solution is to get certified. In the past, I’ve written about how I find certs to be useful learning paths and something concrete to focus on. Last week they announced the DP-600 certification which looks promising for that. Another option is to take on a work project that is a bit of a stretch and then learn on the job. As a consultant, that’s always a bit of a catch-22 because you are selling yourself based on expertise you theoretically already have. The last option is to create a homelab and a side project.

The challenge, though, is what do you put up there for a homelab? A lot of publicly available data is boring, purely descriptive, and/or already cleaned. For simple descriptive reporting, that’s perfectly fine. But for Fabric you want big data, ugly data, changing data. In comes the Magic the Gathering card game and a little data tracking project called 17lands.

Magic the Gathering and its big data revolution

Magic the Gathering, if you don’t know, is a competitive trading card game. With the rise of its online client, MTG Arena, it’s been going through a similar revolution like baseball and Sabermetrics (or so I assume, I’m not a sports guy). Now, instead of speculating which cards from a new set are the best, it’s possible to track in that in real-time thanks to a project called 17lands which collects data from players who opt in.

This has allowed for fascinating analysis. Even if you don’t play, I recommend checking out this video below. It’s fascinating to see how the “metagame” of a format evolves over time as people realize which cards are good and which cards are bad. It also allows for a lot of amateur analysis, for good and for bad. Then every 4 months it happens all over again with a new release.

This data seems ideal for a few reasons, first the raw data is big but manageable. A single “season” is 10 GB uncompressed, and 0.25 GB compressed. I did learn that Excel will try its best to open 10GB file, yell at you about too many rows, and then show you’re the first million. The 40x compression also suggests that the data is very denormalized and would benefit from some normalization.

It did end up showing me the first million rows

The second reason is that the schema is a mess. The data has over 600 columns, many of which are numerical flags for each individual possible card, which changes from season to season. Trying to manage this in Power Query is theoretically doable but likely very frustrating.

Finally, it’s something I’m interested in. MTG_ds on Twitter is constantly posting graphics like this (increasing wordiness of cards each release), with insights hiding behind the high level numbers.

A chart showing increasing wordiness of cards over time

There are actually questions that people are interested in, that aren’t easy to answer. I like to make replayable subsets of cards called “cubes“, so being able to do things like mathematically optimizing based on cost and fun are interesting to me.

Calling my shot

I think with this sort of thing, it’s important to document your expectation and pain points, because you only get to be a newbie once. I’ll try to write down my expectations ahead of time so we can see where I’m wrong.

From what I’ve seen so far, I expect the learning path at to be very helpful in getting oriented. I expect a lot of content online to be frustrating, because so much of it assumes you have a data lake and know what you are doing.

Speaking of which, my background is as a former DBA and now Power BI consultant. I’ve never touched ADF, data lakes, or ML in and professional capacity. As the title says, I’m going to be winging it. What I do have, however, is experience having to learn a new technology in 2-3 months (see the course below) and experience breaking down big BI projects into smaller chunks.

The one year I needed to pay the bills and made courses on technology I had never seen before.

I hope you enjoy watching the ride and let me know if there’s anything specific you’d like me to include.