Commit

Commit is the operation that records, for a Consumer Group, up to which offset of a partition has already been successfully processed. It can be automatic (enable.auto.commit=true, the client commits periodically in the background) or manual (the application decides exactly when to commit, typically after confirming that processing of the message has finished). The choice between auto commit and manual commit defines the consumer's behavior in the face of a failure: whatever was processed but not yet committed gets reprocessed from scratch after a restart or rebalance.