Hi Gerard, I second to what Zhijiang wrote. Please check GC pauses, either via GC logging, 3rd party tool like jconsole (or some memory profiler) or via enabling resource logging in Flink.
After confirming that this is not the issue next time this happens, instead of cancelling the job, please collect thread dumps on a process that is stuck. Piotrek > On 16 Jul 2018, at 13:53, Fabian Hueske <fhue...@gmail.com> wrote: > > Hi Gerard, > > Thanks for reporting this issue. I'm pulling in Nico and Piotr who have been > working on the networking stack lately and might have some ideas regarding > your issue. > > Best, Fabian > > 2018-07-13 13:00 GMT+02:00 Zhijiang(wangzhijiang999) > <wangzhijiang...@aliyun.com <mailto:wangzhijiang...@aliyun.com>>: > Hi Gerard, > > I thought the failed task triggers cancel process before, now I am clear that > you cancel the task when it stops processing data. > I think you can jstack the process to find where task thread is blocked > instead of canceling it, then we may find some hints. > > In addition, the following stack "DataOutputSerializer.resize" indicates the > task is serializing the record and there will be overhead byte buffers in the > serializer for copying data temporarily. And if your record is too large, it > may cause OOM in this process and this overhead memory is not managed by > flink framework. Also you can monitor the gc status to check the full gc > delay. > > Best, > Zhijiang > ------------------------------------------------------------------ > 发件人：Gerard Garcia <ger...@talaia.io <mailto:ger...@talaia.io>> > 发送时间：2018年7月13日(星期五) 16:22 > 收件人：wangzhijiang999 <wangzhijiang...@aliyun.com > <mailto:wangzhijiang...@aliyun.com>> > 抄 送：user <user@flink.apache.org <mailto:user@flink.apache.org>> > 主 题：Re: Flink job hangs/deadlocks (possibly related to out of memory) > > Hi Zhijiang, > > The problem is that no other task failed first. We have a task that sometimes > just stops processing data, and when we cancel it, we see the logs messages > saying: > > " Task (...) did not react to cancelling signal for 30 seconds, but is stuck > in method: > org.apache.flink.core.memory.DataOutputSerializer.resize(DataOutputSerializer.java:305) > > org.apache.flink.core.memory.DataOutputSerializer.write(DataOutputSerializer.java:133) > org.apache.flink.types.StringValue.writeString(StringValue.java:802) > (...)" > > That is why we suspect that it hangs forever at that point and that is why it > stops processing data. I don;t see any increase in memory use in the heap (I > guess because these buffers are managed by Flink) so I'm not sure if that is > really the problem. > > Gerard > > On Tue, Jul 3, 2018 at 6:15 AM Zhijiang(wangzhijiang999) > <wangzhijiang...@aliyun.com <mailto:wangzhijiang...@aliyun.com>> wrote: > Hi Gerard, > > I think you can check the job manager log to find which task failed at first, > and then trace the task manager log containing the failed task to find the > initial reason. > The failed task will trigger canceling all the other tasks, and during > canceling process, the blocked task that is waiting for output buffer can not > be interrupted by the > canceler thread which is shown in your description. So I think the cancel > process is not the key point and is in expectation. Maybe it did not cause > OOM at all. > If the taskduring canceling, the task manager process will be exited finally > to trigger restarting the job. > > Zhijiang > ------------------------------------------------------------------ > 发件人：Gerard Garcia <ger...@talaia.io <mailto:ger...@talaia.io>> > 发送时间：2018年7月2日(星期一) 18:29 > 收件人：wangzhijiang999 <wangzhijiang...@aliyun.com > <mailto:wangzhijiang...@aliyun.com>> > 抄 送：user <user@flink.apache.org <mailto:user@flink.apache.org>> > 主 题：Re: Flink job hangs/deadlocks (possibly related to out of memory) > > Thanks Zhijiang, > > We haven't found any other relevant log messages anywhere. These traces > belong to the unresponsive task, that is why we suspect that at some point it > did not have enough memory to serialize the message and it blocked. I've also > found that when it hanged several output buffers were full (see attached > image buffers.outPoolUsage.png) so I guess the traces just reflect that. > > Probably the task hanged for some other reason and that is what filled the > output buffers previous to the blocked operator. I'll have to continue > investigating to find the real cause. > > Gerard > > > > > On Mon, Jul 2, 2018 at 9:50 AM Zhijiang(wangzhijiang999) > <wangzhijiang...@aliyun.com <mailto:wangzhijiang...@aliyun.com>> wrote: > Hi Gerard, > > From the below stack, it can only indicate the task is canceled that may > be triggered by job manager becuase of other task failure. If the task can > not be interrupted within timeout config, the task managerprocess will be > exited. Do you see any OutOfMemory messages from the task manager log? > Normally the ouput serialization buffer is managed by task manager framework > and will not cause OOM, and on the input desearialization side, there will be > a temp bytes array on each channel for holding partial records which is not > managed by framework. I think you can confirm whether and where caused the > OOM. Maybe check the task failure logs. > > Zhijiang > > ------------------------------------------------------------------ > 发件人：gerardg <ger...@talaia.io <mailto:ger...@talaia.io>> > 发送时间：2018年6月30日(星期六) 00:12 > 收件人：user <user@flink.apache.org <mailto:user@flink.apache.org>> > 主 题：Re: Flink job hangs/deadlocks (possibly related to out of memory) > > (fixed formatting) > > Hello, > > We have experienced some problems where a task just hangs without showing any > kind of log error while other tasks running in the same task manager continue > without problems. When these tasks are restarted the task manager gets killed > and shows several errors similar to these ones: > > [Canceler/Interrupts for (...)' did not react to cancelling signal for 30 > seconds, but is stuck in method: > java.nio.ByteBuffer.wrap(ByteBuffer.java:373) > java.nio.ByteBuffer.wrap(ByteBuffer.java:396) > org.apache.flink.core.memory.DataOutputSerializer.resize(DataOutputSerializer.java:330) > > org.apache.flink.core.memory.DataOutputSerializer.writeInt(DataOutputSerializer.java:212) > > org.apache.flink.api.common.typeutils.base.IntSerializer.serialize(IntSerializer.java:63) > > org.apache.flink.api.common.typeutils.base.IntSerializer.serialize(IntSerializer.java:27) > > org.apache.flink.api.scala.typeutils.CaseClassSerializer.serialize(CaseClassSerializer.scala:113) > > org.apache.flink.api.scala.typeutils.CaseClassSerializer.serialize(CaseClassSerializer.scala:32) > > org.apache.flink.api.scala.typeutils.TraversableSerializer$$anonfun$serialize$1.apply(TraversableSerializer.scala:98) > > org.apache.flink.api.scala.typeutils.TraversableSerializer$$anonfun$serialize$1.apply(TraversableSerializer.scala:93) > scala.collection.immutable.List.foreach(List.scala:392) > org.apache.flink.api.scala.typeutils.TraversableSerializer.serialize(TraversableSerializer.scala:93) > > org.apache.flink.api.scala.typeutils.TraversableSerializer.serialize(TraversableSerializer.scala:33) > > org.apache.flink.api.scala.typeutils.CaseClassSerializer.serialize(CaseClassSerializer.scala:113) > > org.apache.flink.api.scala.typeutils.CaseClassSerializer.serialize(CaseClassSerializer.scala:32) > > org.apache.flink.streaming.runtime.streamrecord.StreamElementSerializer.serialize(StreamElementSerializer.java:177) > > org.apache.flink.streaming.runtime.streamrecord.StreamElementSerializer.serialize(StreamElementSerializer.java:49) > > org.apache.flink.runtime.plugable.SerializationDelegate.write(SerializationDelegate.java:54) > org.apache.flink.runtime.io > <http://org.apache.flink.runtime.io/>.network.api.serialization.SpanningRecordSerializer.addRecord(SpanningRecordSerializer.java:88) > org.apache.flink.runtime.io > <http://org.apache.flink.runtime.io/>.network.api.writer.RecordWriter.sendToTarget(RecordWriter.java:129) > org.apache.flink.runtime.io > <http://org.apache.flink.runtime.io/>.network.api.writer.RecordWriter.emit(RecordWriter.java:105) > > org.apache.flink.streaming.runtime.io.StreamRecordWriter.emit(StreamRecordWriter.java:81) > > org.apache.flink.streaming.runtime.io.RecordWriterOutput.pushToRecordWriter(RecordWriterOutput.java:107) > > org.apache.flink.streaming.runtime.io.RecordWriterOutput.collect(RecordWriterOutput.java:89) > > org.apache.flink.streaming.runtime.io.RecordWriterOutput.collect(RecordWriterOutput.java:45) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingBroadcastingOutputCollector.collect(OperatorChain.java:667) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingBroadcastingOutputCollector.collect(OperatorChain.java:653) > > org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:679) > > org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:657) > > org.apache.flink.streaming.api.operators.TimestampedCollector.collect(TimestampedCollector.java:51) > (...) > org.apache.flink.streaming.api.operators.StreamFlatMap.processElement(StreamFlatMap.java:50) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$ChainingOutput.pushToOperator(OperatorChain.java:469) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$ChainingOutput.collect(OperatorChain.java:446) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$ChainingOutput.collect(OperatorChain.java:405) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingBroadcastingOutputCollector.collect(OperatorChain.java:672) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingBroadcastingOutputCollector.collect(OperatorChain.java:653) > > org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:679) > > org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:657) > > org.apache.flink.streaming.api.operators.TimestampedCollector.collect(TimestampedCollector.java:51) > (...) > org.apache.flink.streaming.api.scala.function.util.ScalaProcessWindowFunctionWrapper.process(ScalaProcessWindowFunctionWrapper.scala:63) > > org.apache.flink.streaming.runtime.operators.windowing.functions.InternalIterableProcessWindowFunction.process(InternalIterableProcessWindowFunction.java:50) > > org.apache.flink.streaming.runtime.operators.windowing.functions.InternalIterableProcessWindowFunction.process(InternalIterableProcessWindowFunction.java:32) > > org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.emitWindowContents(WindowOperator.java:550) > > org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.processElement(WindowOperator.java:403) > org.apache.flink.streaming.runtime.io > <http://runtime.io/>.StreamInputProcessor.processInput(StreamInputProcessor.java:202) > > org.apache.flink.streaming.runtime.tasks.OneInputStreamTask.run(OneInputStreamTask.java:103) > > org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:306) > org.apache.flink.runtime.taskmanager.Task.run(Task.java:703) > java.lang.Thread.run(Thread.java:748) > > [Canceler/Interrupts for (...)' did not react to cancelling signal for 30 > seconds, but is stuck in method: > org.apache.flink.core.memory.DataOutputSerializer.resize(DataOutputSerializer.java:305) > > org.apache.flink.core.memory.DataOutputSerializer.writeInt(DataOutputSerializer.java:212) > > org.apache.flink.api.common.typeutils.base.IntSerializer.serialize(IntSerializer.java:63) > > org.apache.flink.api.common.typeutils.base.IntSerializer.serialize(IntSerializer.java:27) > > org.apache.flink.api.scala.typeutils.CaseClassSerializer.serialize(CaseClassSerializer.scala:113) > > org.apache.flink.api.scala.typeutils.CaseClassSerializer.serialize(CaseClassSerializer.scala:32) > > org.apache.flink.api.scala.typeutils.CaseClassSerializer.serialize(CaseClassSerializer.scala:113) > > org.apache.flink.api.scala.typeutils.CaseClassSerializer.serialize(CaseClassSerializer.scala:32) > > org.apache.flink.api.scala.typeutils.TraversableSerializer$$anonfun$serialize$1.apply(TraversableSerializer.scala:98) > > org.apache.flink.api.scala.typeutils.TraversableSerializer$$anonfun$serialize$1.apply(TraversableSerializer.scala:93) > scala.collection.immutable.List.foreach(List.scala:392) > org.apache.flink.api.scala.typeutils.TraversableSerializer.serialize(TraversableSerializer.scala:93) > > org.apache.flink.api.scala.typeutils.TraversableSerializer.serialize(TraversableSerializer.scala:33) > > org.apache.flink.api.scala.typeutils.CaseClassSerializer.serialize(CaseClassSerializer.scala:113) > > org.apache.flink.api.scala.typeutils.CaseClassSerializer.serialize(CaseClassSerializer.scala:32) > > org.apache.flink.streaming.runtime.streamrecord.StreamElementSerializer.serialize(StreamElementSerializer.java:177) > > org.apache.flink.streaming.runtime.streamrecord.StreamElementSerializer.serialize(StreamElementSerializer.java:49) > > org.apache.flink.runtime.plugable.SerializationDelegate.write(SerializationDelegate.java:54) > org.apache.flink.runtime.io > <http://org.apache.flink.runtime.io/>.network.api.serialization.SpanningRecordSerializer.addRecord(SpanningRecordSerializer.java:88) > org.apache.flink.runtime.io > <http://org.apache.flink.runtime.io/>.network.api.writer.RecordWriter.sendToTarget(RecordWriter.java:129) > org.apache.flink.runtime.io > <http://org.apache.flink.runtime.io/>.network.api.writer.RecordWriter.emit(RecordWriter.java:105) > > org.apache.flink.streaming.runtime.io.StreamRecordWriter.emit(StreamRecordWriter.java:81) > > org.apache.flink.streaming.runtime.io.RecordWriterOutput.pushToRecordWriter(RecordWriterOutput.java:107) > > org.apache.flink.streaming.runtime.io.RecordWriterOutput.collect(RecordWriterOutput.java:89) > > org.apache.flink.streaming.runtime.io.RecordWriterOutput.collect(RecordWriterOutput.java:45) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingBroadcastingOutputCollector.collect(OperatorChain.java:667) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingBroadcastingOutputCollector.collect(OperatorChain.java:653) > > org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:679) > > org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:657) > > org.apache.flink.streaming.api.operators.TimestampedCollector.collect(TimestampedCollector.java:51) > (...) > org.apache.flink.streaming.api.operators.StreamFlatMap.processElement(StreamFlatMap.java:50) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$ChainingOutput.pushToOperator(OperatorChain.java:469) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$ChainingOutput.collect(OperatorChain.java:446) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$ChainingOutput.collect(OperatorChain.java:405) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingBroadcastingOutputCollector.collect(OperatorChain.java:672) > > org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingBroadcastingOutputCollector.collect(OperatorChain.java:653) > > org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:679) > > org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:657) > > org.apache.flink.streaming.api.operators.TimestampedCollector.collect(TimestampedCollector.java:51) > (...) > org.apache.flink.streaming.api.scala.function.util.ScalaProcessWindowFunctionWrapper.process(ScalaProcessWindowFunctionWrapper.scala:63) > > org.apache.flink.streaming.runtime.operators.windowing.functions.InternalIterableProcessWindowFunction.process(InternalIterableProcessWindowFunction.java:50) > > org.apache.flink.streaming.runtime.operators.windowing.functions.InternalIterableProcessWindowFunction.process(InternalIterableProcessWindowFunction.java:32) > > org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.emitWindowContents(WindowOperator.java:550) > > org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.processElement(WindowOperator.java:403) > org.apache.flink.streaming.runtime.io > <http://runtime.io/>.StreamInputProcessor.processInput(StreamInputProcessor.java:202) > > org.apache.flink.streaming.runtime.tasks.OneInputStreamTask.run(OneInputStreamTask.java:103) > > org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:306) > org.apache.flink.runtime.taskmanager.Task.run(Task.java:703) > java.lang.Thread.run(Thread.java:748) > > Our task bundles several thousand of messages together so it creates some big > single messages which could explain why the operator hangs trying to > serialize the message. Our problem is that when a task hangs is very > difficult to detect and we have to manually cancel and restart it. > > Is there any way to make the task manager fail or to increase the memory > required by the allocation? > > Thanks, Gerard > Sent from the Apache Flink User Mailing List archive. mailing list archive > <http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/> at > Nabble.com. > > > >
