☰ Niklas Semmler

About Me

Hi there and welcome to my site!

I am a Softare Engineer working on all things data processing. In my most recent project I have worked on Snowflake's Query Compiler for faster incremental processing of outer joins. Earlier, I had the opportunity to work on Apache Flink's control plane both in my work at Ververica and during my PhD. At SAP, I have worked on diagnostics and replication strategies for distributed databases. The common thread in all of these is my passion to use deep system insights for simpler and more intuitive data processing. If this sounds interesting to you, feel free to reach out. 😉

Curriculum Vitae

Developer / Snowflake Inc — Dynamic Tables
July 2022 - Current
  • Compiler rewrite rules for faster (10x) incremental outer joins
  • Framework for benchmarking incrementalizations
  • Customer workload tracking & alerting (Micrometer, Grafana)
  • Added and exposed internal diagnostics (Information Schema)
Developer / Ververica GmbH — Deployment & Coordination
December 2021 - May 2022
  • Improvements of Apache Flink's adaptive scheduler & distributed shutdown behavior (10x faster)
Developer / SAP SE — Data Intelligence
May 2021 - November 2021
  • Development of a data structure for request correlation across components
PhD Candidate / SAP SE
Nov 2017 - Dec 2020
  • Study of adaptive replication on the basis of real-world ERP database trace
  • Load-shedding strategies for resource constrained data stream processors based on Apache Flink
Internship / SAP SE
Nov 2016 - Nov 2017
  • Analysis of the network usage of a distributed database
  • Implemented request tracing into the distributed database
PhD Candidate / TU Berlin
Dec 2014 - Nov 2016
  • Alumni of the Software Campus programme
  • Teaching Assistant for the course fundamentals of programming in C (~750 students)
  • Research assistant in the Berlin Big Data Center (BBDC) with focus on improving the performance of Apache Flink in widely distributed scenarios
Master / EIT
Oct 2012 - Oct 2014
  • Master thesis on translating router configurations between devices at Cisco (previously Tail-f)
  • First year at TU Berlin, second year at KTH in Stockholm
Bachelor / Netherlands
Sep 2007 - July 2011
  • Bachelor thesis on modelling movement patterns of a slime mold (an acelluar organism)
  • First two years at RU (Nijmegen), last two years at UvA (Amsterdam)

Publications