David Justen

TU Berlin, BIFOLD
Big Data Engineering Group (DAMS Lab)
Faculty IV - Electrical Engineering and Computer Science

Room FR-766, Franklinstraße 28/29, 10587 Berlin
david.justen@tu-berlin.de

I am PhD student at Technische Universität Berlin, supervised by Prof. Matthias Boehm and member of the BIFOLD Graduate School. Prior to this, I was a researcher at Prof. Hasso Plattner’s Enterprise Platform and Integration Concepts (EPIC) chair at the Hasso Plattner Institute in Potsdam. My research focusses on query optimization for analytical database systems and cloud-based data processing. Specifically, I am looking into adaptive query processing and robust plan generation to reduce the effects of erroneous cardinality estimates.

Publications

  • David Justen, Matthias Boehm:
    Join Cardinality Estimation with OmniSketches
    arXiv 2025 [pre-print, code]

  • Thomas Bodner, Theo Radig, David Justen, Daniel Ritter, Tilmann Rabl:
    An Empirical Evaluation of Serverless Cloud Infrastructure for Large-Scale Data Processing
    EDBT 2025 [paper, code] 👑 best paper

  • David Justen, Daniel Ritter, Campbell Fraser, Andrew Lamb, Nga Tran, Allison Lee, Thomas Bodner, Mhd Yamen Haddad, Steffen Zeuch, Volker Markl, Matthias Boehm:
    POLAR: Adaptive and Non-invasive Join Order Selection via Plans of Least Resistance
    PVLDB 2024 [paper, slides, poster, repro]

  • David Justen:
    Cost-efficiency and Performance Robustness in Serverless Data Exchange
    SRC@SIGMOD 2022 [paper]

Teaching

  • Information Systems and Data Analytics [SS25]
  • Programming Practical: Data Systems [WS23, SS24]
  • Research and Implementation of Database Concepts (HPI) [WS22]
  • Develop Your Own Database (HPI) [SS22]
  • Trends and Concepts of Business Application Architecture (HPI) [SS22]

Thesis Supervision

  • Marcel Scholand: Skewed Data Generation for Realistic Data Warehouse Workloads. 2024
  • Paul Pohlitz: Adaptive Join Processing as a DuckDB Extension. 2024

Work Experience

  • DuckDB Labs, Amsterdam, NL
    Sep '25 - Nov '25 Software Engineering Intern
  • BIFOLD, Technische Universität, Berlin, DE
    Oct '23 - present Doctoral Researcher
  • Hasso Plattner Institute, Potsdam, DE
    Mar '22 - Sep '23 Doctoral Researcher
  • SAP, New York, US
    Oct '19 - Mar '20 Software Engineering Intern
  • Native Instruments, Berlin, DE
    Mar '18 - Jun '18 Software Engineering Intern

Education

  • Hasso Plattner Institute, Potsdam, DE
    '18 - '22 IT-Systems Engineering (M.Sc.)
    Thesis: Cost-efficiency and Performance Robustness in Serverless Join Processing
  • BHT, Berlin, DE
    '15 - '18 Media Computer Science (B.Sc.)
    Thesis: Evolving Neural Networks to Steer Autonomous Agents in a Labyrinth