ksqlDB, the event streaming database, is becoming one of the most popular ways to work with Apache Kafka®. Every day, there are many questions about the project, but here’s a question with an answer that we are always trying to improve: How does ksqlDB work? The mechanics behind stream processing can be challenging to grasp. The concepts are abstract, and many of them involve motion—two things that are hard for the mind’s eye to visualize. In this talk, I'll open the hood of ksqlDB to explore its essential elements: rows, streams, tables, view materialization, repartitioning, scaling, and fault tolerance. We’ll look at how each of these works and how it all relates to Kafka.