Valkey After the Fork: A Conversation with Madelyn Olson

Key takeaways

The launch of Valky was sparked by Redis's shift to a dual license model, with a strong community backing the decision to fork.
Performance improvements in Valky, such as I/O threads and enhanced hash table efficiency, aim to optimize caching operations and reduce latency.
Madeline Olson highlights the philosophical differences between Valky and Redis, emphasizing the importance of open-source governance.
Community involvement and collaboration are critical for the success and innovation of open-source projects like Valky.
Understanding performance trade-offs and client optimizations is essential for achieving desired outcomes in caching solutions.

Summary

Introduction to Valky and Madeline Olson

In this episode, Alex welcomes Madeline Olson, a principal engineer at AWS and a well-known figure in the caching community, particularly for her work with Redis. They discuss Madeline's journey to becoming a Redis maintainer and the creation of Valky following the license change by Redis in 2024.

Redis License Change and the Birth of Valky

The conversation moves to the significant moment when Redis switched from a BSD to a dual license model, unveiling how Madeline and her team were notified just 24 hours beforehand. They decided to fork the project into Valky shortly after the announcement, showcasing a strong community response to maintain an open-source alternative.

Performance Improvements in Valky

Madeline elaborates on various performance improvements introduced in recent Valky releases, including the introduction of I/O threads and enhancements to hash table layouts. She explains how these improvements affect caching operations and address latency issues, debunking myths about the single-threaded nature of Redis.

Comparative Analysis of Caching Solutions

Alex and Madeline compare Valky to other caching solutions in the market, such as Dragonfly and KDB. They discuss different approaches to multi-threading and performance scaling, indicating Valky's strategy of optimizing existing architectures for their users.

Future Developments and Community Engagement

The episode concludes with a discussion on future developments in Valky, highlighting ongoing improvements and the balance needed between performance and ease of use. Madeline expresses a commitment to community engagement and growth within the project.

Show notes

Today, we're talking Valkey, Redis, and all things caching. Our guest is Madelyn Olson, who is a principal engineer at AWS working on Elasticache and is one of the most well-known people in the caching community. She was a core maintainer of Redis prior to the fork and was one of the creators of Valkey, an open-source fork of Redis.

In this episode, we talk about Madelyn's road to becoming a Redis maintainer and how she found out about the March 2024 license change. Then, Madelyn shares the story of Valkey being created, philosophical differences between the projects, and her reaction to re-relicensing of Redis in May 2025.

Next, we dive into the performance improvements of recent Valkey releases, including the I/O threads improvements and the new hash table layout. Along the way, Madelyn dispels the notion that the single-threaded nature of Redis / Valkey is that big of a hindrance for most workloads. Finally, she compares some of the Valkey improvements to some of the other recent cache competitors in the space.