Imperfect systems can be beneficial in tech design, exemplified by Bluesky's timeline architecture. Achieving perfect consistency, availability, and low latency simultaneously is infeasible. Bluesky's “lossy timelines” decrease write consistency to enhance performance, addressing challenges posed by high user activity that can create “hot shards.” By introducing a mechanism that probabilistically limits writes based on user follow counts, Bluesky has improved scalability and reduced the time needed for timeline updates from minutes to seconds, demonstrating that embracing imperfection can enhance system throughput.
When Imperfect Systems Are Good, Actually: Bluesky’s Lossy Timelines
