About Me

Hyunsik Choi

Hyunsik Choi, Ph.D
Apache Tajo V.P., and Director of Research at Gruter
5F Sehwa Office Building 889-70 Daechi-dong, Gangnam-gu, Seoul, 135-839, South Korea
Email: hyunsik.choi at gmail dot com, hyunsik at apache dot org
Twitter: @hyunsik_choi
LinkedIn: http://www.linkedin.com/in/hyunsikchoi


He is a director of research at Gruter which is a big data company in south korea. Now, he studies on distributed and parallel relational data processing on large clusters and develops an interactive querying system called Tajo, which is one of the Apache incubator project. Especially, he have contributed to a cost-based optimizer and Just-in-time (JIT) and vectorized query execution engine using modern hardware. He obtained a PhD degree from Korea University in 2013, under the supervision of Prof. Yon Dohn Chung.

Recent Interest Issues

  • Database Systems
  • Distributed and Large systems
  • Query processing using modern hardware
  • Just-in-time query compilation techniques
  • Cost-based optimization


  • Apache Tajo PMC Chair, 2014.03 – current.
  • Apache PMC member and committer –  Apache Tajo: A open source data warehouse system on Hadoop, 2013.03 – current
  • Apache PMC member and committer – Apache Giraph: a faul-tolerant in-memory distributed graph processing system, 2011.08 – current
  • Architect and lead developer –  Tajo (a former of Apache Tajo), 2010. 07 – 2012. 06


  • SQL-on-Hadoop and Tajo, Tech Planet, 2013. 11.14. (Slide in Korean)
  • Introduction to Apache Tajo, Bay Area Hadoop User Group, 2013. 11. 05. (Slide)
  • Introduction to Apache Tajo, Advanced Computing Conference (ACC), 2013. 04. 17.


  • Hyunsik Choi, Jihoon Son, Haemi Yang, Hyoseok Ryu, and Yon Dohn Chung, Tajo: A Distributed Data Warehouse System on Large Clusters (demo), 29th IEEE International Conference on Data Engineering (ICDE), Brisbane, Australia, April 8-12, 2013.
  • Hyunsik Choi, Ki Yong Lee, and Yon Dohn Chung, Skyline queries on keyword-matched data, Information Sciences, Vol.  232, pp 449-463, 2013. (Impact Factor: 2.833)
  • Jihoon Son, Hyunsik Choi, and Yon Dohn Chung, Skew-Tolerant Key Distribution for Load Balancing in MapReduce, IEICE Trans. IS, E95-D(2), pp. 677-680, Feb. 2012.
  • Kyong-Ha Lee, Hyunsik Choi, Bongki Moon, Yoon-Joon Lee, and Yon Dohn Chung, Parallel Data Processing with MapReduce: A Survey, ACM SIGMOD Record 40(4): 11-20, 2011.
  • Hyunsik Choi, Jihoon Son, YongHyun Cho, Min Kyoung Sung, Yon Dohn Chung, SPIDER : A System for Scalable, Parallel / Distributed Evaluation of large-scale RDF Data (demo), the 18th ACM Conference on Information and Knowledge Management (CIKM), Hong Kong, November 2-6, 2009.
  • HaRim Jung, Hyunsik Choi and Yon Dohn Chung, Generalized Spatial Queries in the Wireless Data Broadcasting System, International Conference on Mobile Data Management Systems, Services and Middleware (MDM), Taipei, Taiwan, May 18-20, 2009.

Other Activities

  • Mentor, Google Summer of Code 2013


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