This version is still in development and is not considered stable yet. For the latest stable version, please use spring-cloud-stream 4.1.3!

Resetting Offsets

When an application starts, the initial position in each assigned partition depends on two properties startOffset and resetOffsets. If resetOffsets is false, normal Kafka consumer auto.offset.reset semantics apply. i.e. If there is no committed offset for a partition for the binding’s consumer group, the position is earliest or latest. By default, bindings with an explicit group use earliest, and anonymous bindings (with no group) use latest. These defaults can be overridden by setting the startOffset binding property. There will be no committed offset(s) the first time the binding is started with a particular group. The other condition where no committed offset exists is if the offset has been expired. With modern brokers (since 2.1), and default broker properties, the offsets are expired 7 days after the last member leaves the group. See the offsets.retention.minutes broker property for more information.

When resetOffsets is true, the binder applies similar semantics to those that apply when there is no committed offset on the broker, as if this binding has never consumed from the topic; i.e. any current committed offset is ignored.

Following are two use cases when this might be used.

  1. Consuming from a compacted topic containing key/value pairs. Set resetOffsets to true and startOffset to earliest; the binding will perform a seekToBeginning on all newly assigned partitions.

  2. Consuming from a topic containing events, where you are only interested in events that occur while this binding is running. Set resetOffsets to true and startOffset to latest; the binding will perform a seekToEnd on all newly assigned partitions.

If a rebalance occurs after the initial assignment, the seeks will only be performed on any newly assigned partitions that were not assigned during the initial assignment.

For more control over topic offsets, see rebalance listener; when a listener is provided, resetOffsets should not be set to true, otherwise, that will cause an error.