Denis Grebennicov
Senior Software Engineer at MongoDB
Munich, Bavaria, Germany
Summary
🤩
Rockstar🎓
Top SchoolDenis Grebennicov is a Senior Software Engineer based in Munich with 11 years of experience building backend systems, databases, and mobile features across startups and large tech firms. At MongoDB he led Persistent Query Settings and was a principal contributor to Change Streams Pre-Images, shaping features used in production for reliable long-running queries and real-time data processing. His open-source contributions include bug fixes and storage/aggregation work in the core mongodb repo and a careful C-to-Rust refactor in remacs, demonstrating fluency in systems programming and safe migration strategies. Earlier roles at Uber, CHECK24 and others show a pattern of owning high-QPS services, payment integrations, and frontend-heavy image processing modules. He mentors junior engineers and balances deep low-level engineering with product-aware feature delivery. An interesting thread through his career is moving critical functionality between languages and runtimes to improve robustness and maintainability.
11 years of coding experience
8 years of employment as a software developer
Master of Science - MS Computer Science, Master of Science - MS Computer Science at Technical University of Munich
English, German, Romanian, Russian
Stackoverflow
1,815reputation
133kreached
7answers
37questions
Github Skills (29)
c-language10
c1110
mongodb-database10
c1710
aggregation-framework10
emacs10
database-design10
rust10
cprogramming-language10
mongodb10
editor9
testing9
editors9
performance-optimization9
lisp9
Programming languages (12)
Github contributions (5)
mongodb/mongo
Apr 2021 - Dec 2022
The MongoDB Database
Role in this project:
Back-end Developer & Database Engineer
Back-end Developer & Database EngineerContributions:100 commits, 1 push in 1 year 8 months
Contributions summary:Denis contributed to the MongoDB database, focusing on bug fixes and enhancements related to the aggregation framework and storage. The user addressed issues in the skip and limit stages, ensuring correct behavior with large double values. Additionally, they adjusted call sites of the optional "std::shared_ptr<const T> mongo::Status::extraInfo" and made several adjustments related to pre-images, the creation and handling of pre-image collections.
nosqlc-plus-plusmongodb-databasedatabasemongodb
remacs/remacs
Nov 2019 - Nov 2019
Rust :heart: Emacs
Role in this project:Back-end Developer
Back-end DeveloperContributions:7 commits, 1 PR, 15 comments in 20 days
Contributions summary:Denis primarily focused on refactoring and migrating C code to Rust within the Remacs project. Their contributions involved moving a static variable related to frame management and its associated getter/setter methods from C to Rust. The user also made modifications to the interface, and implemented new functionalities by utilizing Lisp. This involved exporting the getter/setter methods to C to ensure the functions could be utilized.
rustheartemacseditormelpa
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