Hello,
I am running Flink job which reads topics from Kafka and write results
to Redis. I use FsStatebackend with HDFS.
I noticed that taking checkpoint takes serveral minutes and sometimes expires.
---
2016-06-14 17:25:40,734 INFO
org.apache.flink.runtime.checkpoint.CheckpointCoordinator -
Completed checkpoint 1456 (in 257956 ms)
2016-06-14 17:25:40,735 INFO
org.apache.flink.runtime.checkpoint.CheckpointCoordinator -
Triggering checkpoint 1457 @ 1465892740734
2016-06-14 17:35:40,735 INFO
org.apache.flink.runtime.checkpoint.CheckpointCoordinator -
Checkpoint 1457 expired before completing.
2016-06-14 17:35:40,736 INFO
org.apache.flink.runtime.checkpoint.CheckpointCoordinator -
Triggering checkpoint 1458 @ 1465893340735
2016-06-14 17:45:40,736 INFO
org.apache.flink.runtime.checkpoint.CheckpointCoordinator -
Checkpoint 1458 expired before completing.
2016-06-14 17:45:40,737 INFO
org.apache.flink.runtime.checkpoint.CheckpointCoordinator -
Triggering checkpoint 1459 @ 1465893940736
2016-06-14 17:55:40,738 INFO
org.apache.flink.runtime.checkpoint.CheckpointCoordinator -
Checkpoint 1459 expired before completing.
2016-06-14 17:55:40,739 INFO
org.apache.flink.runtime.checkpoint.CheckpointCoordinator -
Triggering checkpoint 1460 @ 1465894540738
---
According to WebUI, checkpoint size is just 1MB. Why checkpointing
takes so long?
I took jstack during checkpointing. It looks that checkpointing thread
is blocked in commitOffsets.
----
"Async calls on Source: Custom Source -> Flat Map (2/3)" daemon
prio=10 tid=0x00007f2b14010800 nid=0x1b89a waiting for monitor entry
[0x00007f2b3ddfc000]
java.lang.Thread.State: BLOCKED (on object monitor)
at
org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer09.commitOffsets(FlinkKafkaConsumer09.java:392)
- waiting to lock <0x0000000659111b58> (a
org.apache.kafka.clients.consumer.KafkaConsumer)
at
org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.notifyCheckpointComplete(FlinkKafkaConsumerBase.java:169)
at
org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.notifyOfCompletedCheckpoint(AbstractUdfStreamOperator.java:179)
at
org.apache.flink.streaming.runtime.tasks.StreamTask.notifyCheckpointComplete(StreamTask.java:596)
- locked <0x0000000659111cc8> (a java.lang.Object)
at org.apache.flink.runtime.taskmanager.Task$3.run(Task.java:945)
at
java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
---
Blocker is this.
---
"Thread-9" daemon prio=10 tid=0x00007f2b2440d000 nid=0x1b838 runnable
[0x00007f2b3dbfa000]
java.lang.Thread.State: RUNNABLE
at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)
at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)
at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:79)
at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:87)
- locked <0x0000000659457dc8> (a sun.nio.ch.Util$2)
- locked <0x0000000659457db8> (a java.util.Collections$UnmodifiableSet)
- locked <0x0000000659457108> (a sun.nio.ch.EPollSelectorImpl)
at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:98)
at org.apache.kafka.common.network.Selector.select(Selector.java:425)
at org.apache.kafka.common.network.Selector.poll(Selector.java:254)
at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:256)
at
org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.clientPoll(ConsumerNetworkClient.java:320)
at
org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:213)
at
org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:193)
at
org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:908)
at
org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:853)
at
org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer09$ConsumerThread.run(FlinkKafkaConsumer09.java:449)
- locked <0x0000000659111b58> (a
org.apache.kafka.clients.consumer.KafkaConsumer)
---
If someone could advise me of the cause or the way to investigate
further, that would be appreciated.
Thanks,
Hironori
