Wrote an essay on what Kafka does when we add new partitions to a topic and the design trade-offs it makes.
Last weekend, I went down the rabbit hole to understand what really happens when you add partitions, how data placement works, why ordering can break, and how consumer groups reshuffle during the process.
If you’re working with Kafka or are curious to know how it works, this breakdown should give you a clear starting point. Give it a read.