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Fabian Paul commented on FLINK-35749: ------------------------------------- [~zjmean] I can assign the ticket to you. Do you have a root cause for what is causing the issue? >From the information in the ticket, it's hard to find the reason since it >misses critical information. * How did you configure your Flink job e.g. checkpointing, boundedness? * Which Flink version do you use? * Are you using the KafkaSink with exactly once semantics? * How do you count the messages in the output topic, e.g., only committed records? > Kafka sink component will lose data when kafka cluster is unavailable for a > while > --------------------------------------------------------------------------------- > > Key: FLINK-35749 > URL: https://issues.apache.org/jira/browse/FLINK-35749 > Project: Flink > Issue Type: Bug > Components: Connectors / Kafka > Affects Versions: 1.16.2, 1.17.1, 1.20.0 > Reporter: Jimmy Zhao > Priority: Blocker > > As the title described, here is the procedure to reproduce the problem: > 1. develop a simple flink stream job to consume from one kafka topic and sink > to anthoer kafka sever and topic > 2. make amount of kafka message and produce to the source kafka topic, record > the message number > 3. start the flink stream job, and config to cosume from earliest source > topic offset > 4. during the job cosuming the source topic, restart the kafka cluster(we use > aws MSK) > 5. the flink job will not throw any Exception like nothing happened, but only > print error log like : [kafka-producer-network-thread | producer-2] INFO > org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-2] Node > 2 disconnected. > 6. wait for the kafka cluster finished restarting and all the source kafka > message consumed > 7. count the target kafka topic message number, compare to the source, there > is a high probability of data loss(more than 50%) -- This message was sent by Atlassian Jira (v8.20.10#820010)