Hi, We are using Kafka Streams 2.2.1 and Kafka 2.2.0, and we noticed that the end offset number is larger than the numbers of events sent to a topic if we set *processing guarantee* as *exactly once* in a Kafka Streams app.
For example, if we send 2615 events to an empty topic, we expect the end of the topic to be offset 2616. However, if we set *processing guarantee* as *exactly once,* the end of the topic is offset 2619 instead. Key: 5-****5 offset: 0 Key: 5-****-5 offset: 1 Key: 5-****-5 offset: 2 Key: 5-****-5 offset: 3 Key: 5-****-5 offset: 4 Key: 25-****-f offset: 6 Key: 25-****-f offset: 7 Key: 25-****-f offset: 8 ..... % Reached end of topic tracking_events[0] at offset 2619: exiting In addition, there are "missing offsets" in the topic. There seems to be nothing inside message offset 5, but it still counts as a message...I used Kafkacat to print out that message, and I have specified -Z (Print NULL messages and keys as "NULL"(instead of empty)), but it didn't print out anything either... Has anyone encountered the same issue before? Are there any other methods to calculate the number of messages inside a topic efficiently? Thanks for the help :) Trinity
