What is a topic and partition in Kafka?

In Apache Kafka, a topic is a logical category or channel to which messages are published. A topic can be thought of as a data stream where producers send messages and consumers read them.

A partition is a physical subdivision of a topic. Each topic is divided into one or more partitions, which are stored on Kafka brokers. Partitions are ordered and allow for scaling data processing and provide parallelism. Messages within a partition are ordered and have a unique offset index.

Thus, a topic is a logical container of messages, and partitions are its physical parts, ensuring scalability and fault tolerance.