What is KTables?

KTables are an abstraction within Apache Kafka's Streams API representing a continuously updated view of a dataset. Essentially, it's a materialized view derived from a Kafka topic where each key represents a unique entity, and the latest value associated with that key represents the current state of that entity. KTables are commonly used for stateful stream processing operations such as aggregations, joins, and windowing where maintaining the current state of data is crucial. Unlike KStreams which represent a continuous flow of events, KTables represent the most up-to-date value for each key.