Bas Ketsman

MSc · PhD candidate in Computer Science

Short Bio

I'm a 4th year PhD candidate in Computer Science at Hasselt University, Belgium, where I work with professor Frank Neven (advisor). I'm a proud member of the Databases and Theoretical Computer Science Research Group and PhD Fellow of the Research Foundation - Flanders (FWO). Prior to starting a PhD I obtained an MSc degree in computer science - databases.

My research interests lie in the area of cloud computing and big data computations. My current research focuses mostly on the principles of database management, with as a red line the study and development of formal approaches to querying big data. Specific topics were I work(ed) on are: multi-join optimization in parallel and distributed systems, Datalog evaluation in asynchronous systems, and in general, the study of logical properties over queries that facilitate efficient query evaluation in those systems. This research has been awarded with best paper awards at the ACM PODS conference (year 2014 and 2015).

In 2016 I resided three months at the database group of the University of Washington, Seattle, to work with professor Dan Suciu. During this stay we developed a parallel join algorithm that runs with worst-case optimal communication cost. In 2017 I visited the database group of the University of Wisconsin-Madison for almost three months to collaborate with professor Paris Koutris. I also did short visits to Lehrstuhl Informatik 1 at tu Dortmund, Germany, to work with professor Thomas Schwentick.

Contact Information

Hasselt University, Agoralaan, Building D, B-3590 Diepenbeek, Belgium Office: D6 Tel: +3211268209 E-mail: Firstname.Lastname (at)


On papers marked with ** authors are in alphabetical order.






Teaching & Services

TA for courses at Hasselt University

  • Master course - Compilers (Fall 2016, Fall 2015, Fall 2014, Fall 2013)
  • Master course - Constraint Satisfaction Problems (Fall 2016, Fall 2014)
  • Master course - Foundations of Database Systems (Spring 2015)
  • Bachelor course - Logic and Functional Programming (Fall 2016)
  • Bachelor course - Algorithms and Datastructures (Fall 2015)


  • Subreviewer - ACM PODS 2017
  • Reviewer - ACM TODS 2015, 2016
  • Reviewer - Elsevier, Information Systems 2015


  • A Worst-Case Optimal Multi-Round Algorithm for Parallel Computation of Conjunctive Queries, PODS 2017, Chicago, USA, 17 May 2017. {slides}
  • A Worst-Case Optimal Multi-Round Algorithm for Parallel Computation of Conjunctive Queries, University of Wisconsin - Madison, USA, 10 April 2017.
  • A Worst-Case Optimal Multi-Round Algorithm for Parallel Computation of Conjunctive Queries on Graphs, DBDBD 2016, Mons, Belgium, 28 October 2016. {abstract}
  • Single-Round Multi-Join Evaluation, University of Washington, Seattle, USA, 8 April 2016. {slides}
  • Parallel-Correctness and Transferability for Conjunctive Queries, PODS 2015, Melbourne, VIC, Australia, 1 June 2015. {slides · poster}
  • Optimal Broadcasting Strategies for Conjunctive Queries over Distributed Data, ICDT 2015, Brussels, Belgium, 25 March 2015. {slides}
  • How to Stay CALM While Seeing What is not There?, DBDBD 2014, Antwerp, Belgium, 17 October 2014. {abstract · slides}
  • Weaker Forms of Monotonicity for Declarative Networking: a more fine-grained answer to the CALM-conjecture, PODS 2014, Snowbird, Utah, USA, 22 June 2014. {slides · poster}