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Jimmy Zhao commented on FLINK-35749: ------------------------------------ [~fpaul] another important point about the root cause: In WriterCallback#onCompletion, using mailboxExecutor.submit to throw the Exception is not effected, because we know submit function of Executor will swallow Exceptions inside without getting the future result like: future.get(). This point will cause the job be silent(only print some disconnected log) even if flushing messages to kafka throws Exception > 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 > Assignee: 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)