Chris Egerton created KAFKA-10240:
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Summary: Sink tasks should not throw WakeupException on shutdown
Key: KAFKA-10240
URL: https://issues.apache.org/jira/browse/KAFKA-10240
Project: Kafka
Issue Type: Bug
Components: KafkaConnect
Affects Versions: 2.4.1, 2.5.0, 2.3.1, 2.4.0, 2.2.2, 2.2.1, 2.3.0, 2.1.1,
2.2.0, 2.1.0, 2.0.1, 2.0.0, 2.6.0
Reporter: Chris Egerton
Assignee: Chris Egerton
* When a task is scheduled for shutdown, the framework [wakes up the
consumer|https://github.com/apache/kafka/blob/8a24da376b801c6eb6522ad4861b83f5beb5826c/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/WorkerSinkTask.java#L159]
for that task.
* As is noted in the [Javadocs for that
method|https://github.com/apache/kafka/blob/8a24da376b801c6eb6522ad4861b83f5beb5826c/clients/src/main/java/org/apache/kafka/clients/consumer/KafkaConsumer.java#L2348],
“If no thread is blocking in a method which can throw
{{org.apache.kafka.common.errors.WakeupException}}, the next call to such a
method will raise it instead.”
* It just so happens that, if the framework isn’t in the middle of a call to
the consumer and then the task gets stopped, the next call the framework will
make on the consumer may be to commit offsets, which will immediately throw a
{{WakeupException}}.
* Currently, the framework handles this by [immediately retrying the offset
commit|https://github.com/apache/kafka/blob/8a24da376b801c6eb6522ad4861b83f5beb5826c/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/WorkerSinkTask.java#L337-L339]
until it either throws a different exception or succeeds, and then throwing
the original {{WakeupException}}. Since this synchronous commit of offsets only
occurs during task shutdown, it's unnecessary to throw the {{WakeupException}}
back to the caller, and can cause alarming {{ERROR}}-level messages to get
logged by the worker.
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