Dongjoon Hyun
Member at Apple
San Jose, California, United States
Summary
🤩
Rockstar🎓
Top SchoolDongjoon Hyun is a seasoned software engineer with 11 years of experience building scalable distributed systems, currently working as a Staff Software Engineer at Apple in San Jose. A long-standing Apache Software Foundation member and PMC committer for Apache Spark and ORC, he blends deep systems-level expertise with practical infrastructure work across Kubernetes, container builds, and JVM modernization. His open-source contributions span high-impact projects—improving Spark’s REST submission API and PVC support, optimizing ORC reader/writer internals, and maintaining documentation and tooling for projects like Spinnaker and NumPy. He has a track record of shipping robust storage and data-processing features (including ORC encryption and Spark health endpoints) while also tending to the developer experience through docs and website updates. With a PhD background in database and data mining from KAIST, he pairs research-grade rigor with pragmatic engineering at scale. An understated strength: he routinely improves both low-level performance and the small but critical details (docs, tests, CI) that keep large open-source ecosystems healthy.
11 years of coding experience
15 years of employment as a software developer
Bachelor of Science - BS, Computer Science, Bachelor of Science - BS, Computer Science at Korea Advanced Institute of Science and Technology
Korean, English
Stackoverflow
64reputation
4kreached
2answers
0questions
Github Skills (70)
apache-spark10
restructuredtext10
python10
testing10
hadoop10
javas10
orc10
file-processing10
javascript10
rs10
continuous-delivery10
dockers10
numpy10
front-end-development10
kubernetes-pods10
Programming languages (17)
Github contributions (5)
apache/orc
Feb 2018 - Jan 2023
Apache ORC - the smallest, fastest columnar storage for Hadoop workloads
Role in this project:
Back-end Developer
Back-end DeveloperContributions:25 releases, 1743 reviews, 503 commits in 4 years 11 months
Contributions summary:Dongjoon focused on improving the ORC file reader and writer in the Apache ORC project. Their contributions include optimizing file tail extraction, improving the handling of stripes and data readers to avoid unnecessary operations, and ensuring proper resource closure within the constructor. They also added features like a version command and improved data masking and encryption support. Their work is centered on enhancing the stability, efficiency, and functionality of the core ORC library.
orccppworkloadscolumnar-storagefastest
apache/spark-website
Jul 2017 - Aug 2022
Apache Spark Website
Role in this project:Back-end Developer & Technical Writer
Back-end Developer & Technical WriterContributions:171 reviews, 42 commits, 147 PRs in 5 years 1 month
Contributions summary:Dongjoon's primary contributions involve modifying documentation and updating the list of committers. They updated the Spark website, correcting links, adding release notes for various versions, and adding a SQL migration guide. Furthermore, the user has also added and updated committer information. These changes indicate involvement in maintaining and improving the project's documentation and contributor list.
pythonsqlapachebig-dataspark
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