lindong28 commented on a change in pull request #15161: URL: https://github.com/apache/flink/pull/15161#discussion_r600205574
########## File path: flink-connectors/flink-connector-kafka/src/main/java/org/apache/flink/connector/kafka/source/KafkaSourceBuilder.java ########## @@ -435,6 +435,7 @@ private void parseAndSetRequiredProperties() { true); maybeOverride( ConsumerConfig.GROUP_ID_CONFIG, "KafkaSource-" + new Random().nextLong(), false); + maybeOverride(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "false", false); Review comment: Hmm... from what I can tell, old Kafka Source (i.e. `FlinkKafkaConsumer`) actually allows `enable.auto.commit` to be set to `true`. This is because the `FlinkKafkaConsumer` [constructor](https://github.com/apache/flink/blob/master/flink-connectors/flink-connector-kafka/src/main/java/org/apache/flink/streaming/connectors/kafka/FlinkKafkaConsumer.java#L210) allows users to specify `enable.auto.commit` in `Properties` which is used to instantiated Kafka consumer. And it is mentioned in [here](https://github.com/apache/flink/blob/master/flink-connectors/flink-connector-kafka/src/main/java/org/apache/flink/streaming/connectors/kafka/FlinkKafkaConsumer.java#L251) that we will overwrite the "enable.auto.commit" in the properties if our offset commit mode is ON_CHECKPOINTS. From what I learned from @becketqin, the use-case here is that, by enabling auto offset commit (when the Flink job does not do checkpoint), we allow third-party Kafka tools to track the progress of the Kafka consumer. Does this make sense? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org