KAFKA'S BROKEN PROMISE: THERE IS NO GOLDILOCKS LOG

Summary from the TLDR Data newsletter

Kafka's partitioned stream model is a poor fit for router-style workloads with millions of independently keyed ordered logs. OpenData Log is built in Rust on object storage and SlateDB. It uses segmented LSM storage, key-based scans, metadata-only splits, and read replicas to support high-cardinality log routing more cheaply.