Peter Toth
Staff Software Engineer at Apple
Austria
Summary
🤩
Rockstar🎓
Top SchoolPeter Toth is a Staff Software Engineer with nine years of experience building and optimizing large-scale data processing systems, currently at Apple and serving as an Apache Spark committer. He has a strong backend focus reflected in contributions to high-profile open-source projects like Apache Spark and Apache DataFusion, where he refactored core query engine components, improved tree traversal and macro recursion, and resolved subtle bugs that improved performance and maintainability. His career includes senior engineering and leadership roles at Cloudera, Hortonworks, and RapidMiner, giving him deep domain expertise in distributed SQL, query optimization, and data platform internals. Based in Austria and educated at Budapest University of Technology and Economics, he blends rigorous academic grounding with pragmatic engineering across enterprise and open-source ecosystems. Notably, his open-source work targets foundational APIs rather than surface features, showing a preference for improving developer ergonomics and long-term code health.
9 years of coding experience
11 years of employment as a software developer
MSc Information technology, MSc Information technology at Budapest University of Technology and Economics
English, Hungarian
Github Skills (22)
apache-spark10
back-end-development10
query-optimization10
java10
scala10
fusion10
javas10
sql10
performance-tuning10
query-engine10
rust10
data-engineering9
data-structures8
data-structure8
algorithms8
Programming languages (5)
Github contributions (5)
apache/spark
Oct 2018 - Jan 2023
Apache Spark - A unified analytics engine for large-scale data processing
Role in this project:
Back-end Developer
Back-end DeveloperContributions:498 reviews, 28 commits, 148 PRs in 4 years 3 months
Contributions summary:Peter contributed to the Apache Spark SQL project by addressing various issues related to query optimization, function implementations, and overall performance. Their work included bug fixes for functions like `aes_decrypt` and `ln`, as well as improvements to core components like the `FileScan` and `HashAggregateExec`. The user also refactored several benchmarking utilities to utilize the main method, improved code generation performance, and enhanced the handling of features such as subquery reuse.
analyticspythondata-processingsqlapache
apache/datafusion
Oct 2023 - Feb 2025
Apache DataFusion SQL Query Engine
Role in this project:Back-end Developer
Back-end DeveloperContributions:216 reviews, 34 PRs, 401 comments in 1 year 4 months
Contributions summary:Peter primarily focused on refactoring and consolidating the `TreeNode` transform and rewrite APIs within the Apache DataFusion SQL Query Engine. Their work involved optimizing tree traversal methods and implementing macros for recursion, leading to improved code structure and potentially better performance. They also addressed bugs and inconsistencies in these core APIs, solidifying their contributions to the project's underlying functionality. Moreover, the user simplified `Expr::map_children` functionality to enhance the codebase's readability and maintainability.
querypythonquery-enginedataframerust
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