Junhyun Shim
선임 소프트웨어 엔지니어 at Snowflake
California, United States
Summary
🤩
Rockstar🎓
Top SchoolJunhyun Shim is a senior software engineer based in California with a strong focus on NUMA-aware C++ concurrent programming, distributed transactions, and networking performance at scale. He co-authored a next-generation C++20 executor-based networking stack for SAP HANA and led work to enable SAP HANA Cloud to access heterogeneous and on-premise data sources in Kubernetes. With 4+ years diagnosing concurrency bugs and performance issues in 100+ core scale-out systems and contributions to FoundationDB tooling, he blends deep systems-level expertise with pragmatic API design. At Snowflake and prior roles at SAP Labs, he repeatedly delivered high-performance, maintainable C++ solutions including RDMA and asynchronous refactors. He pairs academic rigor—from a KAIST master's and top-tier undergraduate GPA—with hands-on experience shipping production-grade distributed systems. An understated strength is his penchant for turning low-level concurrency primitives into type-safe, ergonomic C++ abstractions that improve long-term maintainability.
4 years of coding experience
8 years of employment as a software developer
Bachelor of Science (B.S.) in Engineering, Computer Engineering, 4.14/4.5, Bachelor of Science (B.S.) in Engineering, Computer Engineering, 4.14/4.5 at Sungkyunkwan UniversityMaster's degree, Computer Science, Master's degree, Computer Science at Korea Advanced Institute of Science and Technology
English, Korean
Github Skills (12)
c-language10
api10
cprogramming-language10
apidoc10
async9
asynchronous9
memory-management9
low-level-programming8
optimization8
optimisation8
optmization8
performance-optimization8
Programming languages (1)
Github contributions (4)
apple/foundationdb
Mar 2022 - Jan 2023
FoundationDB - the open source, distributed, transactional key-value store
Role in this project:
Back-end Developer
Back-end DeveloperContributions:204 reviews, 268 commits, 143 PRs in 10 months
Contributions summary:Junhyun primarily contributed to the development of a C++ wrapper for the fdb_c API, implementing header-only functionalities and wrapping C objects within reference-counted C++ objects. The code changes include type-safe access to future values and the acceptance of lambdas as future callbacks, enhancing the API's usability. Further contributions include refactoring a Mako codebase to C++, optimizing it for asynchronicity through sub-op steps and simplifying statistics updates and memory management, demonstrating a focus on performance and maintainability.
bigtabletransactionaldistributed-databasefoundationdbdatabase
sfc-gh-jshim/foundationdb
Mar 2022 - Apr 2023
FoundationDB - the open source, distributed, transactional key-value store
Contributions:232 pushes, 72 branches in 1 year 1 month
transactionalfoundationdbdatabasekey-value-storekey-value
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