[KAFKA-14545] MirrorCheckpointTask throws NullPointerException when group hasn't consumed from some partitions

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3.0, 3.4.0
• Fix Version/s: 3.5.0, 3.4.1, 3.3.3
• Component/s: mirrormaker
• Assignee: Chris Solidum
• Reporter: Chris Solidum
• Created: 21/Dec/22 21:48
• Updated: 23/Feb/23 14:26
• Resolved: 04/Jan/23 11:04

Description

MirrorTaskConnector looks like it's throwing a NullPointerException when a consumer group hasn't consumed from all topics from a partition. This blocks the syncing of consumer group offsets to the target cluster. The stacktrace and error message is as follows:

WARN Failure polling consumer state for checkpoints. (org.apache.kafka.connect.mirror.MirrorCheckpointTask)
at java.base/java.lang.Thread.run(Thread.java:829)Dec 20
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
at org.apache.kafka.connect.runtime.AbstractWorkerSourceTask.run(AbstractWorkerSourceTask.java:72)
at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:244)
at org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:189)
at org.apache.kafka.connect.runtime.AbstractWorkerSourceTask.execute(AbstractWorkerSourceTask.java:346)
at org.apache.kafka.connect.runtime.AbstractWorkerSourceTask.poll(AbstractWorkerSourceTask.java:452)
at org.apache.kafka.connect.mirror.MirrorCheckpointTask.poll(MirrorCheckpointTask.java:142)
at org.apache.kafka.connect.mirror.MirrorCheckpointTask.sourceRecordsForGroup(MirrorCheckpointTask.java:160)
at org.apache.kafka.connect.mirror.MirrorCheckpointTask.checkpointsForGroup(MirrorCheckpointTask.java:177)
at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578)
at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913)
at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
at java.base/java.util.HashMap$EntrySpliterator.forEachRemaining(HashMap.java:1764)
at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
at org.apache.kafka.connect.mirror.MirrorCheckpointTask.lambda$checkpointsForGroup$2(MirrorCheckpointTask.java:174)
at org.apache.kafka.connect.mirror.MirrorCheckpointTask.checkpoint(MirrorCheckpointTask.java:191)
java.lang.NullPointerException
 

This seems to happen if the OffsetFetch call returns a OffsetFetchPartitionResponsePartition with a negative commitedOffset. Mirrormaker should handle this case more gracefully and still be sync over consumer offsets for non negative partitions.

TRACE [AdminClient clientId=adminclient-55] Call(callName=offsetFetch(api=OFFSET_FETCH), deadlineMs=1671657869539, tries=0, nextAllowedTryMs=0) got response OffsetFetchResponseData(throttleTimeMs=0, topics=[OffsetFetchResponseTopic(name='XXX', partitions=[OffsetFetchResponsePartition(partitionIndex=1, committedOffset=866, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=0, committedOffset=865, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=9, committedOffset=868, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=14, committedOffset=870, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=5, committedOffset=803, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=8, committedOffset=881, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=11, committedOffset=-1, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=4, committedOffset=872, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=7, committedOffset=863, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=10, committedOffset=835, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=13, committedOffset=860, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=12, committedOffset=885, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=3, committedOffset=771, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=6, committedOffset=859, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=2, committedOffset=820, committedLeaderEpoch=-1, metadata='', errorCode=0), OffsetFetchResponsePartition(partitionIndex=15, committedOffset=826, committedLeaderEpoch=-1, metadata='', errorCode=0)])], errorCode=0, groups=[]) (org.apache.kafka.clients.admin.KafkaAdminClient) 

Issue Links

• is duplicated by: KAFKA-14072 Crashed MirrorCheckpointConnector appears as running in REST API
• links to: GitHub Pull Request #13052
• links to: GitHub Pull Request #13077