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Introduction to Unit Testing with PySpark.

There are few things in life that are worse then cracking open some serious PySpark pipeline code, and then realizing there isn’t a single function written to encapsulate logic … wondering if some change you are about to make will bring down the whole pipeline. When you are new to a codebase you don’t know what you don’t know, you don’t have any backstory and you are usually flying by the seat of your pants in the beginning. When you have no unit tests, usually the only other way to test changes on a Spark pipeline are to run it …. which is sometimes easier said then done in a development environment. The first line of defence should be unit testing the entire PySpark pipeline.

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Introduction to Delta Lake on Apache Spark … for Data Engineers

If you’re anything like me when someone says Delta Lake you think DataBricks. But, the mythical Delta Lake is an open source project, available to anyone running Apache Spark. It seems also too good to be true, ACID transactions on the Spark scale? Incredible. This is the future, it has to be. The lines of what is a data warehouse have been starting to blur for a long time, I have a feeling Delta Lake will be the death blow to the traditional DW … or its rebirth??

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Big Data File Showdown – Part 2 – ORC with Python.

In part 1 of the big data file formats we reviewed Parquet vs Avro. It was apparent from the start that the two file formats were built for different things. Avro is clearly a complex row structured file format used in communication and transactions, where schema is king and nested structures are no problem. Parquet on the other hand has risen to the top with the popularity of Spark, is columnar based storage and is well suited to structured and tabular type data. But, lest the annals of inter-webs call us uncouth and forgetful, we must add ORC file format to the list.

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Intro to Spark ML Pipelines for Data Engineers

Don’t you like stuff for free? Don’t you like it when stuff I just handed to you? I mean when is that last time you didn’t want to get a free t-shirt. How about 20 bucks in the mail from you Grandma? That’s kinda what Pipelines are in Spark ML. The Apache Spark ML library is probably one of the easiest ways to get started into Machine Learning. Leaving all the fancy stuff to the Data Scientist is fine, Data Engineers are more interested in the end-to-end. The Pipeline, and the Spark ML API’s provide a straight froward path to building ML Pipelines that lower the bar for entry into ML. So, set right up, come get your free ML Pipeline.

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Converting CSVs to Parquets… with Python and Scala.

With parquet taking over the big data world, as it should, and csv files being that third wheel that just will never go away…. it’s becoming more and more common to see the repetitive task of converting csv files into parquets. There are lots of reasons to do this, compression, fast reads, integrations with tools like Spark, better schema handling, and the list goes on. Today I want to see how many ways I can figure out how to simple convert an existing csv file to a parquet with Python, Scala, and whatever else there is out there. And how simple and fast each option is. Let’s do it!

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Musings on Python’s map() and filter()

I’ve always been surprised at the distinct lack of most Python code I’ve seen using the map() and filter() methods as standalone functions. I’ve always found them useful and easy to use, but I don’t often come across them in the wild, I’ve even been asked to remove them from my MR/PR’s, for no other reason then that they are supposedly ambiguous to some people? That’s got me thinking a lot about map() and filter() as related to readability, functional programming, side effects and other never ending debates where no one can even agree on the “correct” definition. Seriously. But, I will leave that rant for another time.

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4 DataWarehouse-ish Functions For Your PySpark Dataframes

Ever felt like just exploring documentation… seeing what you can find? That’s what you do on a cold, first snowstorm of the year Sunday afternoon. After the initial fun has warn off, the kids don’t want to go outside anymore, and Netflix has nothing new to offer up. So I thought I might as well spend some time poking around the PySpark Dataframe API, seeing what strange wonders I can uncover. I did find a few methods that took me back to my SQL Data Warehouse days. Memories of my old school Data Analyst and Business Intelligence days in Data Warehousing… the endless line of SQL queries being written day after day. Anyways lets dive into the 4 analytical methods you can call on your PySpark Dataframe, buried in the documentation like some tarnished gem.

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Intro to Apache Cassandra for Data Engineers

Who who? Apache Cassandra, who?

Hmm… yet another distributed database …. will it ever end? Probably not. It’s hard to keep up with them all, even the old ones. That brings me to Apache Cassandra. Of all the popular big data distributed databases Cassandra seems to be kind of that student who always sits in the back row and never says anything… you forget they are there…. until someone says their name….. Apache Cassandra. I honestly didn’t even know what space Cassandra fit in before trying to install and use it… so this should fun. What Is Cassandra? Distributed NoSQL.

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Intro to Apache Beam for Data Engineers

Apache Beam for Data Engineers.

What is this thing? What’s it good for? Who’s using it and why? That’s pretty much what I ask myself once a month when I actually see the name Apache Beam pop up in some feed I’m scrolling through. I figured it has to be legit to be Apache incubated, but I’ve never run across anyone in the wild using it yet. On the surface it appears to be semi-pointless since it runs on-top of other distributed systems like Spark, but I’m sure there is more to it. Today, I’m going to run through an overview of Apache Beam and then try installing and running some data through it, kick the tires as it were. And see if my mind changes about the pointless bit.

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Pandas DataFrame.to_sql() …. { how you should configure it to not be that guy. }

Sometimes Pandas is slow like this…. until you tweak it.

I never understand it when someone comes up with a great tool, then defaults it to work poorly… leaving the rest up to imagination. The Pandas dataframe has a great and underutilized tool… to_sql() . Lesson learned, always read the fine print I guess. I’m usually guilty of this myself… wondering why something in slow and sucks… and not taking time to read the documentation. Here are some musings on using the to_sql() in Pandas and how you should configure to not pull your hair out.

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