Valkey After the Fork: A Conversation with Madelyn Olson

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.