Dai Mikurube
Engineer at Preferred Networks, Inc.
Chiyoda, Japan
Summary
🤩
Rockstar🎓
Top SchoolDai Mikurube is an experienced engineer with 14 years building systems, middleware, and runtime environments across companies from IBM Research and Google to Treasure Data and Preferred Networks. He brings deep expertise in performance and memory analysis of runtimes and JVMs, and has a strong backend focus demonstrated by long-term maintenance and refactoring work on the well-known Embulk pluggable bulk data loader. His career spans low-level C++ cleanup for embedded POS, web and cloud infrastructure as code, and browser engine contributions—showing rare breadth from embedded systems to large-scale data tooling. Pragmatic and maintenance-minded, he actively reduces global-state dependencies (e.g., removing JRuby global singletons) to improve codebase maintainability and future extensibility. Based in Chiyoda, Japan, he combines research-rooted analytical skills with practical production delivery and prefers connection requests on LinkedIn to include a note so he can recognize collaborators.
14 years of coding experience
19 years of employment as a software developer
M.Sc., Mathematical and Computing Sciences, M.Sc., Mathematical and Computing Sciences at Tokyo Institute of Technology
Japanese, English
Stackoverflow
155reputation
27kreached
8answers
11questions
Github Skills (13)
javas10
refactoring10
java10
jruby9
githubactions6
json6
maven6
canonicalization6
pomxml6
github6
github-api6
cryptography6
gradle6
Programming languages (11)
Github contributions (5)
embulk/embulk
Oct 2016 - Jan 2023
Embulk: Pluggable Bulk Data Loader.
Role in this project:
Backend Engineer
Backend EngineerContributions:186 releases, 102 reviews, 1581 commits in 6 years 4 months
Contributions summary:Dai's commits focused on refactoring the Embulk core by removing dependencies on the global JRuby scripting container. This involved stopping the use of JRuby's global singleton ScriptingContainer in org.embulk.EmbulkRunner and org.embulk.EmbulkSetup, as well as cleaning up other dependencies on org.jruby, and introducing a new Java-based implementation of the time zone support. This work appears to improve code maintainability and prepare Embulk for future development.
dataloaderembulkbulk-loader
embulk/embulk-encoder-bzip2
Mar 2023 - Apr 2025
embulk-encoder-bzip2
Contributions:8 reviews, 35 PRs, 42 pushes in 2 years 1 month
embulkembulk-plugin
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