Moved to [email protected] On Wed, Aug 16, 2017 at 9:22 AM, Pawel Bartoszek <[email protected] > wrote:
> When flink performs a checkpoint I get randomly > ConcurrentModificationException. > > From my investigation it looks like the method > > public boolean advance() throws IOException > > <http://goog_859136059> > from > > https://github.com/apache/beam/blob/release-2.0.0/sdks/ > java/io/kinesis/src/main/java/org/apache/beam/sdk/io/ > kinesis/KinesisReader.java > > is called in another thread while checkpoint is being performed. > > The exception is caused because the method > > public UnboundedSource.CheckpointMark getCheckpointMark() > > from the KinesisReader.java > <https://github.com/apache/beam/blob/release-2.0.0/sdks/java/io/kinesis/src/main/java/org/apache/beam/sdk/io/kinesis/KinesisReader.java> > is iterating over iterator returned by > RoundRobin<ShardRecordsIterator>.iterator() while a > > public boolean advance() throws IOException is calling RoundRobin< > ShardRecordsIterator>.moveForward() from another thread which is causing > java.util.ConcurrentModificationException to be thrown. > > > RoundRobin<ShardRecordsIterator> class is using java.util.Deque queue > which doesn't allow adding/removal of element while it's being iterated. > > Is some locking missing? > > I am using Beam 2.0.0, Flink 1.2.1, 20 slots and 32 kinesis shards. > > I created a bug for it as well > https://issues.apache.org/jira/browse/BEAM-2752 > > Stacktrace: > > java.lang.Exception: Error while triggering checkpoint 59 for Source: > Read(KinesisSource) -> Flat Map -> ParMultiDo(KinesisExtractor) -> Flat Map > -> ParMultiDo(StringToRecord) -> Flat Map -> ParMultiDo(Anonymous) -> Flat > Map -> ParMultiDo(ToRRecord) -> Flat Map -> ParMultiDo(AddTimestamps) -> Flat > Map -> xxxx.yyyy.GroupByOneMinuteWindow GROUP RDOTRECORDS BY ONE MINUTE > WINDOWS/Window.Assign.out -> (ParMultiDo(Anonymous) -> Flat Map -> > ParMultiDo(ToSomeKey) -> Flat Map -> ToKeyedWorkItem, > ParMultiDo(ToCompositeKey) -> Flat Map -> ParMultiDo(Anonymous) -> Flat Map > -> ToKeyedWorkItem, ParMultiDo(Anonymous) -> Flat Map -> > ParMultiDo(ApplyShardingKey) -> Flat Map -> ToKeyedWorkItem) (1/20) > at org.apache.flink.runtime.taskmanager.Task$3.run(Task.java:1136) > at > java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) > at java.util.concurrent.FutureTask.run(FutureTask.java:266) > at > java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) > at > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) > at java.lang.Thread.run(Thread.java:748) > Caused by: java.lang.Exception: Could not perform checkpoint 59 for operator > Source: Read(KinesisSource) -> Flat Map -> ParMultiDo(KinesisExtractor) -> > Flat Map -> ParMultiDo(StringToRecord) -> Flat Map -> ParMultiDo(Anonymous) > -> Flat Map -> ParMultiDo(ToRRecord) -> Flat Map -> ParMultiDo(AddTimestamps) > -> Flat Map -> xxxx.yyyy.GroupByOneMinuteWindow GROUP RDOTRECORDS BY ONE > MINUTE WINDOWS/Window.Assign.out -> (ParMultiDo(Anonymous) -> Flat Map -> > ParMultiDo(ToSomeKey) -> Flat Map -> ToKeyedWorkItem, > ParMultiDo(ToCompositeKey) -> Flat Map -> ParMultiDo(Anonymous) -> Flat Map > -> ToKeyedWorkItem, ParMultiDo(Anonymous) -> Flat Map -> > ParMultiDo(ApplyShardingKey) -> Flat Map -> ToKeyedWorkItem) (1/20). > at > org.apache.flink.streaming.runtime.tasks.StreamTask.triggerCheckpoint(StreamTask.java:524) > at org.apache.flink.runtime.taskmanager.Task$3.run(Task.java:1125) > ... 5 more > Caused by: java.lang.Exception: Could not complete snapshot 59 for operator > Source: Read(KinesisSource) -> Flat Map -> ParMultiDo(KinesisExtractor) -> > Flat Map -> ParMultiDo(StringToRecord) -> Flat Map -> ParMultiDo(Anonymous) > -> Flat Map -> ParMultiDo(ToRRecord) -> Flat Map -> ParMultiDo(AddTimestamps) > -> Flat Map -> xxxx.yyyy.GroupByOneMinuteWindow GROUP RDOTRECORDS BY ONE > MINUTE WINDOWS/Window.Assign.out -> (ParMultiDo(Anonymous) -> Flat Map -> > ParMultiDo(ToSomeKey) -> Flat Map -> ToKeyedWorkItem, > ParMultiDo(ToCompositeKey) -> Flat Map -> ParMultiDo(Anonymous) -> Flat Map > -> ToKeyedWorkItem, ParMultiDo(Anonymous) -> Flat Map -> > ParMultiDo(ApplyShardingKey) -> Flat Map -> ToKeyedWorkItem) (1/20). > at > org.apache.flink.streaming.api.operators.AbstractStreamOperator.snapshotState(AbstractStreamOperator.java:379) > at > org.apache.flink.streaming.runtime.tasks.StreamTask$CheckpointingOperation.checkpointStreamOperator(StreamTask.java:1157) > at > org.apache.flink.streaming.runtime.tasks.StreamTask$CheckpointingOperation.executeCheckpointing(StreamTask.java:1090) > at > org.apache.flink.streaming.runtime.tasks.StreamTask.checkpointState(StreamTask.java:630) > at > org.apache.flink.streaming.runtime.tasks.StreamTask.performCheckpoint(StreamTask.java:575) > at > org.apache.flink.streaming.runtime.tasks.StreamTask.triggerCheckpoint(StreamTask.java:518) > ... 6 more > Caused by: java.util.ConcurrentModificationException > at java.util.ArrayDeque$DeqIterator.next(ArrayDeque.java:643) > at > org.apache.beam.sdks.java.io.kinesis.repackaged.com.google.common.collect.TransformedIterator.next(TransformedIterator.java:47) > at > org.apache.beam.sdks.java.io.kinesis.repackaged.com.google.common.collect.ImmutableCollection$Builder.addAll(ImmutableCollection.java:409) > at > org.apache.beam.sdks.java.io.kinesis.repackaged.com.google.common.collect.ImmutableList$Builder.addAll(ImmutableList.java:699) > at > org.apache.beam.sdks.java.io.kinesis.repackaged.com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:256) > at > org.apache.beam.sdks.java.io.kinesis.repackaged.com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:209) > at > org.apache.beam.sdk.io.kinesis.KinesisReaderCheckpoint.<init>(KinesisReaderCheckpoint.java:44) > at > org.apache.beam.sdk.io.kinesis.KinesisReaderCheckpoint.asCurrentStateOf(KinesisReaderCheckpoint.java:49) > at > org.apache.beam.sdk.io.kinesis.KinesisReader.getCheckpointMark(KinesisReader.java:137) > at > org.apache.beam.runners.flink.translation.wrappers.streaming.io.UnboundedSourceWrapper.snapshotState(UnboundedSourceWrapper.java:379) > at > org.apache.flink.streaming.api.functions.util.StreamingFunctionUtils.trySnapshotFunctionState(StreamingFunctionUtils.java:118) > at > org.apache.flink.streaming.api.functions.util.StreamingFunctionUtils.snapshotFunctionState(StreamingFunctionUtils.java:99) > at > org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.snapshotState(AbstractUdfStreamOperator.java:100) > at > org.apache.flink.streaming.api.operators.AbstractStreamOperator.snapshotState(AbstractStreamOperator.java:357) > ... 11 more > > >
