Flink version is 1.5.3/Hadoop 27
_____________________________________________
From: Narayanaswamy, Krishna [Tech]
Sent: Wednesday, October 03, 2018 3:42 PM
To: 'user@flink.apache.org' <user@flink.apache.org>
Subject: Memory Allocate/Deallocate related Thread Deadlock encountered when
running a large job > 10k tasks
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.
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