Tobias Grieger
Software Engineer at Cockroach Labs
Bonn, North Rhine-Westphalia, Germany
Summary
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Rockstar🎓
Top School
Top expert inGo Development and Data Management
Tobias Grieger is a software engineer with 12 years of experience specializing in distributed systems and systems programming, currently contributing to Cockroach Labs' transactional datastore. He brings deep consensus and storage expertise, demonstrated by bug fixes and correctness improvements to flagship projects like etcd/raft and Pebble, addressing Raft commit pagination, log-growth prevention, and SSTable filter policies. Tobias pairs rigorous academic training—a PhD and MA in Mathematics—with hands-on backend engineering, enabling him to tackle subtle correctness and performance issues in production-grade systems. Based in Bonn, Germany, he also has a background as an IT consultant and freelancer, which informs a pragmatic, reliability-first approach to complex system design.
12 years of coding experience
6 years of employment as a software developer
Master of Arts (MA), Mathematics, Master of Arts (MA), Mathematics at University of California, BerkeleyDoctor of Philosophy (PhD), Mathematics, Doctor of Philosophy (PhD), Mathematics at University of Bonn
English, German, Spanish, Arabic
Github Skills (21)
consensus10
api-design10
key-value10
testing10
databases10
distributed-systems10
opentracing10
raft-consensus-algorithm10
go10
performance-optimization10
raft10
relational-databases10
sql-database10
database10
benchmark9
Programming languages (19)
Github contributions (5)
etcd-io/raft
Sep 2018 - Mar 2023
Raft library for maintaining a replicated state machine
Role in this project:
Back-end Developer
Back-end DeveloperContributions:42 reviews, 107 commits, 19 PRs in 4 years 7 months
Contributions summary:Tobias's commits primarily focus on bug fixes and improvements to the Raft library, specifically related to issues with committed entries pagination, unbounded log growth prevention, and leader elections. They addressed core correctness issues within the Raft consensus algorithm. The contributions involved modifying core raft components and tests to prevent data inconsistencies and ensure reliability.
raft-consensus-algorithmconsensuspaxosdistributed-systemsreplicated
etcd-io/etcd
Sep 2018 - Nov 2022
Distributed reliable key-value store for the most critical data of a distributed system
Role in this project:Back-end Developer
Back-end DeveloperContributions:44 reviews, 152 commits, 74 PRs in 4 years 3 months
Contributions summary:Tobias contributed to the core of the etcd project by fixing a correctness bug related to `CommittedEntries` pagination within the Raft implementation. They addressed issues with the truncation of the `HardState` commit index and optimized the leader's handling of committed entries. They also fixed a bug in the log growth prevention mechanism, focusing on more accurately tracking the size of entries appended to the Raft log. Finally, they implemented changes around auto-transitioning out of joint configurations.
etcdcriticalconsensusdistributed-systemreliable
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