Harunari "TKT" Takata

高田 晴成（たかた はるなり）
tkt0430@keio.jp (+81) 080-6969-0203 Fujisawa, Kanagawa, Japan

Who I Am

I am a research staff at Keio University, Faculty of Environment and Information Studies. I study Distributed Systems at the Data Platform Laboratory / focusing on distributed consensus algorithms and geo-replicated databases.

I spent 2024–2025 on exchange at the University of Toronto's Faculty of Applied Science and Engineering, where I began working as a Research Assistant — work that led to a publication at ACM SIGMOD 2026.

Education

Keio University Mar 2022 – Mar 2026
B.A., Faculty of Environment and Information Studies
  • Dissertation: An re-implementation and analysis of Raft consensus algorithm
University of Toronto Sep 2024 – Apr 2025
Exchange Program, Faculty of Applied Science and Engineering

Professional & Research Experience

Infrastructure Engineer Jan 2026 – present
PLAID Inc. · Tokyo, Japan
  • Contributing to Mila, a proprietary distributed OLAP engine optimized for high-concurrency real-time data processing.
  • Optimized the storage engine by identifying and resolving replication-layer bottlenecks through systematic stress testing, accelerating query execution speed by 1.6×.
Infrastructure Engineer Jun 2025 – Dec 2025
Mirrativ Inc. · Tokyo, Japan
  • Designed and developed an S3-compatible in-house object storage system.
  • Built high-performance benchmarking tools for stress-testing storage backends, covering limit testing, mixed R/W workloads, and long-term durability assessments.
  • Resolved port exhaustion and TIME_WAIT spikes during load testing by tuning MaxIdleConnsPerHost in the internal reverse proxy.
  • Reduced disk I/O and memory consumption during multipart downloads by refactoring to stream data directly, eliminating temporary disk spooling.
  • Prevented OOM errors under high concurrency by redesigning the in-memory cache with a dynamically adjustable eviction policy.
  • Achieved 100% response reliability during benchmarks by fixing race conditions with proper mutual exclusion.
Research Assistant May 2025 – present
University of Toronto · Toronto, Canada
  • Implemented a full-set TPC-C benchmarking suite from scratch for evaluating distributed transaction performance.
  • Identified a fatal execution error from improper CPU pinning that had prevented system initialization.
  • Simulated geographically distributed networks via synthetic latency injection using Linux tc.
  • Work accepted at ACM SIGMOD 2026.

Teaching Experience

Student Instructor 2022 – 2026
Keio University — Independently Designed and Taught Courses
  • Fundamentals of Information Technology 1 — Taught core CS concepts (system architecture, internet protocols, cybersecurity) and mentored Python programming assignments.
  • Fundamentals of Information Technology 2 — Supervised project-based game development in Python, evaluated student projects, and provided feedback on software design.

Publications

Yunhao Mao, Harunari Takata, Michalis Bashras, Yuqiu Zhang, Shiquan Zhang, Gengrui Zhang and Hans-Arno Jacobsen. "Epoch-based Optimistic Concurrency Control in Geo-replicated Databases." Proceedings of the 2026 ACM SIGMOD International Conference on Management of Data. SIGMOD 2026

Skills

Go C++ Java Python LaTeX Git Docker

Languages: Japanese (Native) · English (Proficient) · Chinese (Beginner)

Honors & Awards

Kobe Bussan Foundation Scholarship for Study Abroad
2025 · ¥1,850,000 — Competitive scholarship for students pursuing studies and research at international institutions.

Find Me Online

LinkedIn GitHub Twitter Instagram

Things I Like

Basketball · Memes · Photography · Jamiroquai

How to Reach Me

Send me an email at tkthdev (at) gmail.com — I read everything sent there.

"Be water, my friend."