Jiefan L
Senior Software Engineer, Systems Infrastructure at LinkedIn
Mountain View, California, United States
Summary
👤
Senior🎓
Top SchoolJiefan L is a Senior Software Engineer in Systems Infrastructure at LinkedIn with five years of experience building next-generation data access layers and scalable backend systems. He designs and optimizes query translation and planning—contributing to LinkedIn's Coral engine by converting Spark scan nodes to Calcite RelNodes and improving predicate pushdown and local metastore handling. A Columbia MS in Computer Science and a BS in Financial Engineering from Nanjing University, he blends rigorous academic training with practical systems work. Based in Mountain View, he focuses on turning complex SQL and data-processing challenges into efficient, production-ready infrastructure, often working on subtle plan-optimization details that materially improve query translation performance.
5 years of coding experience
2 years of employment as a software developer
Bachelor of Science - BS Financial Engineering, Bachelor of Science - BS Financial Engineering at Nanjing UniversityMaster of Science - MS Computer Science, Master of Science - MS Computer Science at Columbia University
Github Skills (8)
apache-calcite10
javas10
sql10
calc10
java10
data-processing9
spark9
query-optimization9
Programming languages (2)
Github contributions (5)
linkedin/coral
Jul 2020 - Jan 2023
Coral is a translation, analysis, and query rewrite engine for SQL and other relational languages.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:451 reviews, 104 commits, 294 PRs in 2 years 6 months
Contributions summary:Jiefan primarily worked on converting Spark scan nodes within the `coral` translation and query rewrite engine to Calcite RelNodes. They implemented changes in the `SparkPlanToIRRelConverter.java` file, modifying how scan plans are converted to IR RelNodes. Their contributions included improving the `containsComplicatedPredicatePushedDown` method and generating a local metastore file to replace the metastore client, suggesting an emphasis on plan optimization and data processing within the Coral framework. These changes indicate a focus on enhancing the engine's ability to translate and optimize SQL queries.
queryrelationalcoralflink-sqltranslation
ljfgem/coral
Mar 2022 - Aug 2024
Coral is a translation, analysis, and query rewrite engine for SQL and other relational languages.
Contributions:1 PR, 163 pushes, 97 branches in 2 years 5 months
queryrelationalcoraltranslationsql
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