There actually exists this deadlock for special scenarios. Before fixing the bug, we can avoid this issue by not deploying the map and sink tasks in the same task manager to work around. Krishna, do you share the slot for these two tasks? If so, you can set disable slot sharing for this job.
Or I guess we can set the ExecutionMode#PIPELINED_FORCED to not generate blocking result partition to avoid this issue temporarily. Best, Zhijiang ------------------------------------------------------------------ 发件人：Piotr Nowojski <pi...@data-artisans.com> 发送时间：2018年10月4日(星期四) 21:54 收件人：Aljoscha Krettek <aljos...@apache.org> 抄 送："Narayanaswamy, Krishna" <krishna.narayanasw...@gs.com>; Nico Kruber <n...@data-artisans.com>; user@flink.apache.org <user@flink.apache.org> 主 题：Re: Memory Allocate/Deallocate related Thread Deadlock encountered when running a large job > 10k tasks Hi, Thanks for reporting the problem. This bug was previously unknown to us. I have created a jira ticket for this bug: https://issues.apache.org/jira/browse/FLINK-10491 Unfortunately I’m not familiar with running batch jobs in Flink, so I don’t know if there is some hot fix or anything that can at least mitigate/decrease the probability of the bug for you until we fix it properly. Piotrek On 4 Oct 2018, at 13:55, Aljoscha Krettek <aljos...@apache.org> wrote: Hi, this looks like a potential Flink bug. Looping in Nico and Piotr who have looked into that in the past. Could you please comment on that? Best, Aljoscha On 3. Oct 2018, at 12:12, Narayanaswamy, Krishna <krishna.narayanasw...@gs.com> wrote: Hi, I am trying to run one large single job graph which has > 10k tasks. The form of the graph is something like DataSource -> Filter -> Map [...multiple] Sink1 Sink2 I am using a parallelism of 10 with 1 slot per task manager and a memory allocation of 32G per TM. The JM is running with 8G. Everything starts up and runs fine with close to 6-7k tasks (this is variable and is mostly the source /filter/map portions) completing and then the graph just hangs. I managed to connect to the task managers and get a thread dump just in time and found the following deadlock on one of the TMs which apparently seems to be holding up everything else. Please could someone take a look and advise if there is something I could do or try out to fix this. Marked below are the 2 isolated thread stacks marking the deadlock - Thread-1 "DataSink (DATA#HadoopFileOutputFormat ) (1/2)@11002" prio=5 tid=0x3e2 nid=NA waiting for monitor entry waiting for Map (Key Extractor) (1/10)@9967 to release lock on <0x2dfb> (a java.util.ArrayDeque) at org.apache.flink.runtime.io.network.partition.SpillableSubpartition.releaseMemory(SpillableSubpartition.java:223) at org.apache.flink.runtime.io.network.partition.ResultPartition.releaseMemory(ResultPartition.java:373) at org.apache.flink.runtime.io.network.buffer.LocalBufferPool.setNumBuffers(LocalBufferPool.java:355) - locked <0x2dfd> (a java.util.ArrayDeque) at org.apache.flink.runtime.io.network.buffer.NetworkBufferPool.redistributeBuffers(NetworkBufferPool.java:402) at org.apache.flink.runtime.io.network.buffer.NetworkBufferPool.recycleMemorySegments(NetworkBufferPool.java:203) - locked <0x2da5> (a java.lang.Object) at org.apache.flink.runtime.io.network.buffer.NetworkBufferPool.recycleMemorySegments(NetworkBufferPool.java:193) at org.apache.flink.runtime.io.network.partition.consumer.SingleInputGate.returnExclusiveSegments(SingleInputGate.java:318) at org.apache.flink.runtime.io.network.partition.consumer.RemoteInputChannel.releaseAllResources(RemoteInputChannel.java:259) at org.apache.flink.runtime.io.network.partition.consumer.SingleInputGate.getNextBufferOrEvent(SingleInputGate.java:578) at org.apache.flink.runtime.io.network.partition.consumer.SingleInputGate.pollNextBufferOrEvent(SingleInputGate.java:507) at org.apache.flink.runtime.io.network.partition.consumer.UnionInputGate.waitAndGetNextInputGate(UnionInputGate.java:213) at org.apache.flink.runtime.io.network.partition.consumer.UnionInputGate.getNextBufferOrEvent(UnionInputGate.java:163) at org.apache.flink.runtime.io.network.api.reader.AbstractRecordReader.getNextRecord(AbstractRecordReader.java:86) at org.apache.flink.runtime.io.network.api.reader.MutableRecordReader.next(MutableRecordReader.java:47) at org.apache.flink.runtime.operators.util.ReaderIterator.next(ReaderIterator.java:73) at org.apache.flink.runtime.operators.DataSinkTask.invoke(DataSinkTask.java:216) at org.apache.flink.runtime.taskmanager.Task.run(Task.java:703) at java.lang.Thread.run(Thread.java:745) Thread-2 "Map (Key Extractor) (1/10)@9967" prio=5 tid=0xaab nid=NA waiting for monitor entry java.lang.Thread.State: BLOCKED blocks DataSink (DATA#HadoopFileOutputFormat ) (1/2)@11002 waiting for DataSink (DATA#HadoopFileOutputFormat ) (1/2)@11002 to release lock on <0x2dfd> (a java.util.ArrayDeque) at org.apache.flink.runtime.io.network.buffer.LocalBufferPool.recycle(LocalBufferPool.java:261) at org.apache.flink.runtime.io.network.buffer.NetworkBuffer.deallocate(NetworkBuffer.java:171) at org.apache.flink.shaded.netty4.io.netty.buffer.AbstractReferenceCountedByteBuf.release(AbstractReferenceCountedByteBuf.java:106) at org.apache.flink.runtime.io.network.buffer.NetworkBuffer.recycleBuffer(NetworkBuffer.java:146) at org.apache.flink.runtime.io.network.buffer.BufferConsumer.close(BufferConsumer.java:110) at org.apache.flink.runtime.io.network.partition.SpillableSubpartition.spillFinishedBufferConsumers(SpillableSubpartition.java:271) at org.apache.flink.runtime.io.network.partition.SpillableSubpartition.add(SpillableSubpartition.java:117) - locked <0x2dfb> (a java.util.ArrayDeque) at org.apache.flink.runtime.io.network.partition.SpillableSubpartition.add(SpillableSubpartition.java:96) - locked <0x2dfc> (a org.apache.flink.runtime.io.network.partition.SpillableSubpartition) at org.apache.flink.runtime.io.network.partition.ResultPartition.addBufferConsumer(ResultPartition.java:255) at org.apache.flink.runtime.io.network.api.writer.RecordWriter.requestNewBufferBuilder(RecordWriter.java:211) at org.apache.flink.runtime.io.network.api.writer.RecordWriter.sendToTarget(RecordWriter.java:142) at org.apache.flink.runtime.io.network.api.writer.RecordWriter.emit(RecordWriter.java:105) at org.apache.flink.runtime.operators.shipping.OutputCollector.collect(OutputCollector.java:65) at org.apache.flink.runtime.operators.util.metrics.CountingCollector.collect(CountingCollector.java:35) at org.apache.flink.runtime.operators.MapDriver.run(MapDriver.java:103) at org.apache.flink.runtime.operators.BatchTask.run(BatchTask.java:503) at org.apache.flink.runtime.operators.BatchTask.invoke(BatchTask.java:368) at org.apache.flink.runtime.taskmanager.Task.run(Task.java:703) at java.lang.Thread.run(Thread.java:745) Thanks, Krishna. ________________________________ Your Personal Data: We may collect and process information about you that may be subject to data protection laws. 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