Alicja Łuszczak
Staff Software Engineer at Databricks
Amsterdam, North Holland, Netherlands
Summary
🤩
Rockstar🎓
Top SchoolAlicja Łuszczak is a Staff Software Engineer based in Amsterdam with nine years of experience building robust backend systems at Databricks. She contributes to major open-source projects like Apache Spark and Delta Lake, focusing on data integrity, performance tuning, and making core operators interruptible and observable. Her work includes fixing tricky edge cases in Delta Lake metadata handling and enhancing Spark's RangeExec and Parquet metadata to improve row tracking and query cancellation. With strong academic roots in mathematics and computer science from Warsaw and Vrije Universiteit, she brings a rigorous, research-informed approach to large-scale data processing problems. Colleagues rely on her for subtle refactors that prevent test flakiness and for pragmatic improvements that deepen the reliability of data platforms.
9 years of coding experience
Master’s Degree, Computer Science, 8.9 (scale up to 10), Master’s Degree, Computer Science, 8.9 (scale up to 10) at Vrije Universiteit AmsterdamMathematics and Computer Science, Mathematics and Computer Science at Krajowy Fundusz na rzecz DzieciBachelor’s Degree, Mathematics, 4.5 (scale up to 5), Bachelor’s Degree, Mathematics, 4.5 (scale up to 5) at University of Warsaw
English, Polish, Dutch
Github Skills (15)
testing10
javas10
big-data10
spark10
delta-lake10
sql10
java10
scala10
schema-changes9
data-integrity9
parquet9
algorithms8
data-structures8
algorithm8
data-structure8
Programming languages (2)
Github contributions (5)
delta-io/delta
Apr 2019 - Mar 2025
An open-source storage framework that enables building a Lakehouse architecture with compute engines including Spark, PrestoDB, Flink, Trino, and Hive and APIs
Role in this project:
Back-end Developer
Back-end DeveloperContributions:10 reviews, 5 PRs, 12 comments in 6 years
Contributions summary:Alicja's contributions primarily involve bug fixes and refactoring related to the Delta Lake implementation within Apache Spark. They addressed issues in job counting for tests, normalized column names, and corrected incomplete file stats. The user also made minor refactoring changes to the `CreateDeltaTableCommand` and other code related to schema handling and metadata operations. These contributions highlight a focus on ensuring data integrity, fixing edge cases, and improving the overall robustness of the Delta Lake project.
analyticsprestodbflinkbig-dataspark
apache/spark
Sep 2017 - Jul 2022
Apache Spark - A unified analytics engine for large-scale data processing
Role in this project:Back-end Developer
Back-end DeveloperContributions:24 reviews, 2 commits, 21 PRs in 4 years 10 months
Contributions summary:Alicja primarily contributed to the Apache Spark codebase by addressing various performance and functional issues related to the `RangeExec` operator, a core component for generating data. They modified the operator to include metrics for accurate tracking of generated rows and made it interruptible for improved query cancellation. Furthermore, the user implemented improvements to the `_metadata` column for Parquet files, enabling the inclusion of row indices. These changes demonstrate a focus on optimizing data generation, enhancing query execution, and expanding functionality within the Spark ecosystem.
analyticspythondata-processingsqlapache
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