How are Kafka messages partitioned?

10 months ago

Noah Thompson

2 minutes

In Kafka, messages are partitioned using a Partitioner. The Partitioner in Kafka determines which partition a message should be sent to based on the message’s key. If the message does not have a key, the Partitioner will choose a partition based on the default partition strategy.

In Kafka, each topic can be divided into multiple partitions, each with a unique identifier. When a producer sends a message to a topic, the partitioner calculates a hash value based on the message key and determines which partition the message should be sent to based on this value. This ensures that messages with the same key are always sent to the same partition, maintaining the order of messages.

Additionally, Kafka also supports custom partitioners, allowing users to implement their own partitioning strategies based on their specific needs, such as selecting message partitions based on business logic or other factors. With a well-thought-out partitioning strategy, message processing performance and reliability can be significantly improved.