arc VS Apache Spark

A while ago I posted a link to [Arc](https://news.ycombinator.com/item?id=26573930) a declarative method for defining repeatable data pipelines which execute against [Apache Spark](https://spark.apache.org/).

Today I would like to present a proof-of-concept implementation of the [Arc declarative ETL framework](https://arc.tripl.ai) against [Apache Datafusion](https://arrow.apache.org/datafusion/) which is an Ansi SQL (Postgres) execution engine based upon Apache Arrow and built with Rust.

The idea of providing a declarative 'configuration' language for defining data pipelines was planned from the beginning of the Arc project to allow changing execution engines without having to rewrite the base business logic (the part that is valuable to your business). Instead, by defining an abstraction layer, we can change the execution engine and run the same logic with different execution characteristics.

The benefit of the DataFusion over Apache Spark is a significant increase in speed and reduction in execution resource requirements. Even through a Docker-for-Mac inefficiency layer the same job completes in ~4 seconds with DataFusion vs ~24 seconds with Apache Spark (including JVM startup time). Without Docker-for-Mac layer end-to-end execution times of 0.5 second for the same example job (TPC-H) is possible. * the aim is not to start a benchmarking flamewar but to provide some indicative data *.

The purpose of this post is to gather feedback from the community whether you would use a tool like this, what features would be required for you to use it (MVP) or whether you would be interested in contributing to the project. I would also like to highlight the excellent work being done by the DataFusion/Arrow (and Apache) community for providing such amazing tools to us all as open source projects.

Disclosure: I am a contributor to Datafusion.

I have done a lot of work in the ETL space in Apache Spark to build Arc (https://arc.tripl.ai/) and have ported a lot of the basic functionality of Arc to Datafusion as a proof-of-concept. The appeal to me of the Apache Spark and Datafusion engines is the ability to a) seperate compute and storage b) express transformation logic in SQL.

Performance: From those early experiments Datafusion would frequently finish processing an entire job _before_ the SparkContext could be started - even on a local Spark instance. Obviously this is at smaller data sizes but in my experience a lot of ETL is about repeatable processes not necessarily huge datasets.

Compatibility: Those experiments were done a few months ago and the SQL compatibility of the Datafusion engine has improved extremely rapidly (WINDOW functions were recently added). There is still some missing SQL functionality (for example to run all the TPC-H queries https://github.com/apache/arrow-datafusion/tree/master/bench...) but it is moving quickly.

Recently I had to revisit the "JVM languages universe" again. Yes, language(s), plural! Java isn't the only language that uses the JVM. I previously used Scala, which is a JVM language, to use Apache Spark for Data Engineering workloads, but this is for another post 😉.

Consume data into third party software (then let Open Search or Apache Spark or Apache Pinot) for analysis/datascience, GIS systems (so you can put reports on a map) or any ticket management system

also, this knowledge applies to learning more about data engineering, as this field of software engineering relies heavily on the event-driven approach via tools like Spark, Flink, Kafka, etc.

Apache SeaTunnel is a data integration platform that offers the three pillars of data pipelines: sources, transforms, and sinks. It offers an abstract API over three possible engines: the Zeta engine from SeaTunnel or a wrapper around Apache Spark or Apache Flink. Be careful, as each engine comes with its own set of features.

Apache Spark - https://spark.apache.org/

A JVM based framework named "Spark", when https://spark.apache.org exists?

I recently saw a pull request that was merged to the Apache/Spark repository that apparently adds initial Python bindings for PySpark on K8s. I posted a comment to the PR asking a question about how to use spark-on-k8s in a Python Jupyter notebook, and was told to ask my question here.