A partition is an ordered subdivision of a Kafka topic. Records receive offsets within a partition, allowing consumers to identify positions and resume processing. section 14.1.1
Consumer groups distribute topic partitions among their consumers. Kafka adjusts these assignments through rebalancing: a consumer may receive several partitions, while surplus consumers remain inactive. section 14.1.1
Partition behavior matters when consuming records:
- An offset identifies a record's position in its partition. section 14.1.1
- Consumers can begin at a selected offset, such as the first or last record. section 14.1.1
- A committed offset persists the consumer's position so reading can resume after communication or broker failure. section 14.1.1
- If a consumer stops polling within the configured interval, its partitions can be assigned to another consumer in the group. section 14.1.2
One consumer assigned to test-0
A consumer subscribing to test can receive the assignment {partitions=[test-0]}. If no committed offset exists, consumption resets to offset 0; records such as hello and hi then appear at offsets 0 and 1.
