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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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Intro to Apache Kafka for Data Engineers

Streams…. the Apache Kafka one….

Streams, streams, streams…. when will it ever end? It’s hard to keep up with all the messaging systems these days. GCP PubSub, AWS SQS, RabbitMQ, blah blah. Of course there is Kafka, hard to miss that name floating around in the interwebs. Since pretty much every system designed these days is a conglomerate of services… it’s probably a good idea to poke at things under the cover. Of course Apache Kafka is probably at the top of list of those open source streaming services. Today I’m going to attempt to install a Kafka cluster and push some messages around.

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Geospatial Data with Apache Spark – Intro to RasterFrames

Apache Spark and RasterFrames the big data geospatial processing juggernaut.

Yikes, distributed geospatial data processing at scale. That has fun written all over it… not. There isn’t that many people doing it so StackOverflow isn’t that useful. Anyone who has been around geospatial data knows the tools like GDAL are notoriously hard to use and buggy… and that one’s probably the “best.” What to do when you want to process and explore large satellite datasets like Landsat and Modis? Terrabytes/petabytes of data, what are going to do, download it? The power of distributed processing with Apache Spark. The simplicity of using SQL to work on geospatial data. Put them together… rasterframes. What a beast.

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PySpark SQLContext….tired of your decades old ETL process?

Seriously. Haven’t you had enough of SSIS, SAP Data Services, Informatica, blah blah blah? It’s been the same old ETL process for the last 20 years. CSV files appear somewhere, some poor old aged and angry Developer soul in a cubicle pulls up the same old GUI ETL tool, maps a bunch of columns to some SQL Server, if you’re in a forward thinking shop…maybe Postgres. This is after painstakingly designing the Data Warehouse with good ole’ Kimball in mind. Data flows from some staging table to some facts and dimensions. Eventually some SQL queries are run and a Data Mart is produced summarizing a years worth of data for a crabby Sales or Product department. Brings a tear to my eye. And this is all because Apache Spark sounds scary to some people?

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Deploying Apache Airflow inside Kubernetes.

Has anyone else noticed how popular Apache Airflow and Kubernetes have become lately? There is no better tool than Airflow for Data Engineers to built approachable and maintainable data pipelines. I mean Python, a nice UI, dependency graphs/DAGs. What more could you want? There is also no better tool than Kubernetes for building scalable, flexible data pipelines and hosting apps. Like a match made in heaven. So why not deploy Airflow onto Kubernetes? This is what you wish your mom would have taught you. It’s actually so easy your mom could probably do it….maybe she did do it and just never told you?

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