Simon Willnauer
Member at The Apache Software Foundation
Berlin, Germany
Summary
🤩
Rockstar🎓
Top SchoolSimon Willnauer is a seasoned back-end engineer and open source committer with nearly two decades of experience building and optimizing high-performance search and distributed systems from Berlin. As a long-time Lucene core committer, former VP of Apache Lucene, and founding tech lead at Elastic, he has shaped core indexing and memory strategies used by millions through projects like Elasticsearch. He brings deep expertise in Java, C/C++, Python and systems-level programming, with a strong focus on refactoring, performance tuning and robust merge/ID pruning strategies for real-world update workloads. Beyond code, he co-founded the BerlinBuzzwords conference and blends hands-on implementation with community leadership and practical operational insight. An attention to detail shows in contributions such as reader-attribute memory control and flexible Netty-based RPC configuration, revealing a preference for elegant, efficient interfaces rather than surface-level fixes.
19 years of coding experience
20 years of employment as a software developer
Diploma Computer Science, Diploma Computer Science at Berlin University of Applied Sciences Berlin (BHT)
German, English
Stackoverflow
31reputation
6kreached
1answer
0questions
Github Skills (23)
lucene10
netty10
back-end-development10
amazon-elasticsearch10
indexing10
java10
javas10
elasticsearchquery10
aws-elasticsearch10
elasticsearch10
backend10
messagepack10
elasticsearch-api10
data-structure9
algorithm9
Programming languages (9)
Github contributions (5)
elastic/elasticsearch
Jun 2012 - Aug 2019
Free and Open Source, Distributed, RESTful Search Engine
Role in this project:
Back-end Developer
Back-end DeveloperContributions:11 reviews, 5540 commits, 1670 PRs in 7 years 3 months
Contributions summary:Simon primarily focused on improving the Elasticsearch backend by refactoring and optimizing code. The user removed and replaced components such as `IndexStore` and `DirectoryService` with a more streamlined interface, contributing to more efficient index management. Further contributions involved implementing merge policies, specifically a merge policy that prunes ID postings for soft-deleted documents, thereby enhancing update performance and resource management. Additionally, the user modified code to utilize reader attributes to control term dictionary memory usage.
restfulsearch-engineopensearchelasticsearchjava
apache/lucene
Mar 2021 - Dec 2024
Apache Lucene open-source search software
Role in this project:Back-end Developer
Back-end DeveloperContributions:46 reviews, 27 PRs, 27 pushes in 3 years 9 months
Contributions summary:Simon's commits focused on the implementation of core features within the Apache Lucene project. Their work involved adding and modifying DocValues updates, modifying the segment commit information, refactoring code to utilize shared code paths for more efficient operation, and streamlining existing methods, improving the efficiency of various components such as the term dictionary. The user's changes touched the core index structure and made improvements to ensure correct functioning and performance.
nosqlfulltext-searchsolrapachesearch-engine
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