Leif Walsh
Software Engineer at Two Sigma
Town of Brookhaven, New York, United States
Summary
🤩
Rockstar🎓
Top SchoolLeif Walsh is a seasoned software engineer with 17 years of experience focused on infrastructure and backend systems, currently building at Two Sigma. His background spans high-performance storage and databases—contributions to PerconaFT and MariaDB—and time-series tooling like Two Sigma’s Flint where he added Python bindings to broaden usability. He brings deep C/C++ expertise from roles at Tokutek and RethinkDB, pairing low-level optimization and benchmarking with release engineering and distributed systems design. Early internships at Google and Microsoft and an academic foundation in math and CS from Stony Brook ground his pragmatic engineering approach. Colleagues know him for quietly improving build systems, suppressing noisy compiler warnings, and tidying licensing and test infrastructure—work that keeps large codebases healthy but often goes unnoticed. Based in Brookhaven, NY, he combines research-grade rigor with hands-on production delivery across open-source and proprietary projects.
17 years of coding experience
5 years of employment as a software developer
Bachelor of Science (BS), Mathematics and Computer Science, Bachelor of Science (BS), Mathematics and Computer Science at State University of New York at Stony Brook
French
Stackoverflow
1,997reputation
344kreached
31answers
11questions
Github Skills (30)
apache-spark10
c-language10
python10
mariadb10
databases10
time-series10
build-system10
cmake10
cprogramming-language10
database10
data-analysis10
pandas9
develop9
pyspark9
sql8
Programming languages (19)
Github contributions (5)
twosigma/flint
Nov 2016 - Oct 2019
A Time Series Library for Apache Spark
Role in this project:
Back-end Developer
Back-end DeveloperContributions:29 commits, 2 PRs, 20 pushes in 2 years 11 months
Contributions summary:Leif contributed significantly to the project by adding Python bindings for the Flint time series library. They implemented core functionality by modifying and adding Python files, and integrating the Flint library into a Python environment. Their work involved creating and modifying Python code, indicating a focus on expanding the library's usability and accessibility through Python interfaces. Further contributions included fixing issues with sphinx build and making modifications to the test suite.
apachesparkscalaapache-sparktime-series
percona/PerconaFT
Apr 2013 - Feb 2015
PerconaFT is a high-performance, transactional key-value store
Role in this project:Back-end Developer & Database Engineer
Back-end Developer & Database EngineerContributions:253 commits, 18 pushes, 1 branch in 1 year 10 months
Contributions summary:Leif primarily focused on improving the codebase and addressing compilation warnings. They addressed issues in the build process, such as ignoring warnings from third-party libraries and fixing copyright headers in example code. They also contributed to the build system by renaming and refactoring CMake functions to prevent naming conflicts, and integrated with MySQL/MariaDB build processes. The user demonstrated a solid understanding of the codebase.
transactionalperformancedatabasekey-value-storekey-value
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