[FLINK-27041] KafkaSource in batch mode failing if any topic partition is empty

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.14.4
• Fix Version/s: 1.15.1, 1.14.6
• Component/s: Connectors / Kafka
• Labels: pull-request-available

Environment

Kafka cluster version: 3.1.0

Flink version 1.14.4

• Flags: Important
• Assignee: Qingsheng Ren
• Reporter: Terxor
• Created: 03/Apr/22 19:59
• Updated: 17/Jun/22 12:58
• Resolved: 17/Jun/22 02:48

Description

First let's take the case of consuming from a Kafka topic with a single partition having 0 messages. Execution in batch mode, with bounded offsets set to latest, is expected to finish gracefully. However, it fails with an exception.

Consider this minimal working example (assume that test_topic exists with 1 partition and 0 messages):

		final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
		env.setRuntimeMode(RuntimeExecutionMode.BATCH);

		KafkaSource<String> kafkaSource = KafkaSource
				.<String>builder()
				.setBootstrapServers("localhost:9092")
				.setTopics("test_topic")
				.setValueOnlyDeserializer(new SimpleStringSchema())
				.setBounded(OffsetsInitializer.latest())
				.build();

		DataStream<String> stream = env.fromSource(
				kafkaSource,
				WatermarkStrategy.noWatermarks(),
				"Kafka Source"
		);
		stream.print();

		env.execute("Flink KafkaSource test job");

This produces exception:

Exception in thread "main" org.apache.flink.runtime.client.JobExecutionException: Job execution failed.
	at org.apache.flink.runtime.jobmaster.JobResult.toJobExecutionResult(JobResult.java:144)
  ... [omitted for readability]
Caused by: org.apache.flink.runtime.JobException: Recovery is suppressed by NoRestartBackoffTimeStrategy
	at org.apache.flink.runtime.executiongraph.failover.flip1.ExecutionFailureHandler.handleFailure(ExecutionFailureHandler.java:138)
  ... [omitted for readability]
Caused by: java.lang.RuntimeException: One or more fetchers have encountered exception
	at org.apache.flink.connector.base.source.reader.fetcher.SplitFetcherManager.checkErrors(SplitFetcherManager.java:225)
	at org.apache.flink.connector.base.source.reader.SourceReaderBase.getNextFetch(SourceReaderBase.java:169)
	at org.apache.flink.connector.base.source.reader.SourceReaderBase.pollNext(SourceReaderBase.java:130)
	at org.apache.flink.streaming.api.operators.SourceOperator.emitNext(SourceOperator.java:351)
	at org.apache.flink.streaming.runtime.io.StreamTaskSourceInput.emitNext(StreamTaskSourceInput.java:68)
	at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processInput(StreamOneInputProcessor.java:65)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.processInput(StreamTask.java:496)
	at org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.runMailboxLoop(MailboxProcessor.java:203)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.runMailboxLoop(StreamTask.java:809)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:761)
	at org.apache.flink.runtime.taskmanager.Task.runWithSystemExitMonitoring(Task.java:958)
	at org.apache.flink.runtime.taskmanager.Task.restoreAndInvoke(Task.java:937)
	at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:766)
	at org.apache.flink.runtime.taskmanager.Task.run(Task.java:575)
	at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: java.lang.RuntimeException: SplitFetcher thread 0 received unexpected exception while polling the records
	at org.apache.flink.connector.base.source.reader.fetcher.SplitFetcher.runOnce(SplitFetcher.java:150)
	at org.apache.flink.connector.base.source.reader.fetcher.SplitFetcher.run(SplitFetcher.java:105)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	... 1 more
Caused by: java.lang.IllegalStateException: Consumer is not subscribed to any topics or assigned any partitions
	at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1223)
	at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1211)
	at org.apache.flink.connector.kafka.source.reader.KafkaPartitionSplitReader.fetch(KafkaPartitionSplitReader.java:97)
	at org.apache.flink.connector.base.source.reader.fetcher.FetchTask.run(FetchTask.java:58)
	at org.apache.flink.connector.base.source.reader.fetcher.SplitFetcher.runOnce(SplitFetcher.java:142)
	... 6 more

In our actual use case, we have a Kafka topic with many partitions. Some of them have no messages. This causes our batch job to fail.

Issue Links

• links to: GitHub Pull Request #19456