What is the difference between kafka earliest and latest offset values

Question

producer sends messages 1, 2, 3, 4

consumer receives messages 1, 2, 3, 4

consumer crashes/disconnects

producer sends messages 5, 6, 7

consumer comes back up and should receive messages starting from 5 instead of 7

For this kind of result, which offset value I have to use and what are the other changes/configurations need to do

Answer 1

When a consumer joins a consumer group it will fetch the last committed offset so it will restart to read from 5, 6, 7 if before crashing it committed the latest offset (so 4). The earliest and latest values for the auto.offset.reset property is used when a consumer starts but there is no committed offset for the assigned partition. In this case you can chose if you want to re-read all the messages from the beginning (earliest) or just after the last one (latest).