This is a crazy cases that has a few millions of files, the scheduler will run
out of memory. Be default, each file will become a partition, so you will
have more than 1M partitions, also 1M tasks. With coalesce(), it will reduce
the number of tasks, but can not reduce the number of partitions of original
RDD.
Could you pack the small files int bigger ones? Spark works much better than
small files.
On Mon, Nov 3, 2014 at 11:46 AM, <jan.zi...@centrum.cz> wrote:
> I have 3 datasets in all the datasets the average file size is 10-12Kb.
> I am able to run my code on the dataset with 70K files, but I am not able to
> run it on datasets with 1.1M and 3.8M files.
>
> ______________________________________________________________
>
> On Sun, Nov 2, 2014 at 1:35 AM, <jan.zi...@centrum.cz> wrote:
>> Hi,
>>
>> I am using Spark on Yarn, particularly Spark in Python. I am trying to
>> run:
>>
>> myrdd = sc.textFile("s3n://mybucket/files/*/*/*.json")
>
> How many files do you have? and the average size of each file?
>
>> myrdd.getNumPartitions()
>>
>> Unfortunately it seems that Spark tries to load everything to RAM, or at
>> least after while of running this everything slows down and then I am
>> getting errors with log below. Everything works fine for datasets smaller
>> than RAM, but I would expect Spark doing this without storing everything
>> to
>> RAM. So I would like to ask if I'm not missing some settings in Spark on
>> Yarn?
>>
>>
>> Thank you in advance for any help.
>>
>>
>> 14/11/01 22:06:57 ERROR actor.ActorSystemImpl: Uncaught fatal error from
>> thread [sparkDriver-akka.actor.default-dispatcher-375] shutting down
>> ActorSystem [sparkDriver]
>>
>> java.lang.OutOfMemoryError: GC overhead limit exceeded
>>
>> 14/11/01 22:06:57 ERROR actor.ActorSystemImpl: Uncaught fatal error from
>> thread [sparkDriver-akka.actor.default-dispatcher-381] shutting down
>> ActorSystem [sparkDriver]
>>
>> java.lang.OutOfMemoryError: GC overhead limit exceeded
>>
>> 11744,575: [Full GC 1194515K->1192839K(1365504K), 2,2367150 secs]
>>
>> 11746,814: [Full GC 1194507K->1193186K(1365504K), 2,1788150 secs]
>>
>> 11748,995: [Full GC 1194507K->1193278K(1365504K), 1,3511480 secs]
>>
>> 11750,347: [Full GC 1194507K->1193263K(1365504K), 2,2735350 secs]
>>
>> 11752,622: [Full GC 1194506K->1193192K(1365504K), 1,2700110 secs]
>>
>> Traceback (most recent call last):
>>
>> File "<stdin>", line 1, in <module>
>>
>> File "/home/hadoop/spark/python/pyspark/rdd.py", line 391, in
>> getNumPartitions
>>
>> return self._jrdd.partitions().size()
>>
>> File
>> "/home/hadoop/spark/python/lib/py4j-0.8.2.1-src.zip/py4j/java_gateway.py",
>> line 538, in __call__
>>
>> File
>> "/home/hadoop/spark/python/lib/py4j-0.8.2.1-src.zip/py4j/protocol.py",
>> line
>> 300, in get_return_value
>>
>> py4j.protocol.Py4JJavaError14/11/01 22:07:07 INFO scheduler.DAGScheduler:
>> Failed to run saveAsTextFile at NativeMethodAccessorImpl.java:-2
>>
>> : An error occurred while calling o112.partitions.
>>
>> : java.lang.OutOfMemoryError: GC overhead limit exceeded
>>
>>
>>
>>>>> 11753,896: [Full GC 1194506K->947839K(1365504K), 2,1483780 secs]
>>
>> 14/11/01 22:07:09 INFO remote.RemoteActorRefProvider$RemotingTerminator:
>> Shutting down remote daemon.
>>
>> 14/11/01 22:07:09 ERROR actor.ActorSystemImpl: Uncaught fatal error from
>> thread [sparkDriver-akka.actor.default-dispatcher-381] shutting down
>> ActorSystem [sparkDriver]
>>
>> java.lang.OutOfMemoryError: GC overhead limit exceeded
>>
>> 14/11/01 22:07:09 ERROR actor.ActorSystemImpl: Uncaught fatal error from
>> thread [sparkDriver-akka.actor.default-dispatcher-309] shutting down
>> ActorSystem [sparkDriver]
>>
>> java.lang.OutOfMemoryError: GC overhead limit exceeded
>>
>> 14/11/01 22:07:09 INFO remote.RemoteActorRefProvider$RemotingTerminator:
>> Remote daemon shut down; proceeding with flushing remote transports.
>>
>> 14/11/01 22:07:09 INFO Remoting: Remoting shut down
>>
>> 14/11/01 22:07:09 INFO remote.RemoteActorRefProvider$RemotingTerminator:
>> Remoting shut down.
>>
>> 14/11/01 22:07:09 INFO network.ConnectionManager: Removing
>> ReceivingConnection to
>> ConnectionManagerId(ip-172-31-18-35.us-west-2.compute.internal,55871)
>>
>> 14/11/01 22:07:09 INFO network.ConnectionManager: Removing
>> SendingConnection
>> to ConnectionManagerId(ip-172-31-18-35.us-west-2.compute.internal,55871)
>>
>> 14/11/01 22:07:09 INFO network.ConnectionManager: Removing
>> SendingConnection
>> to ConnectionManagerId(ip-172-31-18-35.us-west-2.compute.internal,55871)
>>
>> 14/11/01 22:07:09 INFO network.ConnectionManager: Key not valid ?
>> sun.nio.ch.SelectionKeyImpl@5ca1c790
>>
>> 14/11/01 22:07:09 INFO network.ConnectionManager: key already cancelled ?
>> sun.nio.ch.SelectionKeyImpl@5ca1c790
>>
>> java.nio.channels.CancelledKeyException
>>
>> at
>>
>> org.apache.spark.network.ConnectionManager.run(ConnectionManager.scala:386)
>>
>> at
>>
>> org.apache.spark.network.ConnectionManager$$anon$4.run(ConnectionManager.scala:139)
>>
>> 14/11/01 22:07:09 INFO network.ConnectionManager: Removing
>> SendingConnection
>> to ConnectionManagerId(ip-172-31-18-35.us-west-2.compute.internal,52768)
>>
>> 14/11/01 22:07:09 INFO network.ConnectionManager: Removing
>> ReceivingConnection to
>> ConnectionManagerId(ip-172-31-18-35.us-west-2.compute.internal,52768)
>>
>> 14/11/01 22:07:09 ERROR network.ConnectionManager: Corresponding
>> SendingConnection to
>> ConnectionManagerId(ip-172-31-18-35.us-west-2.compute.internal,52768) not
>> found
>>
>> 14/11/01 22:07:10 ERROR cluster.YarnClientSchedulerBackend: Yarn
>> application
>> already ended: FINISHED
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/metrics/json,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/stages/stage/kill,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/static,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/executors/json,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/executors,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/environment/json,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/environment,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/storage/rdd/json,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/storage/rdd,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/storage/json,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/storage,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/stages/pool/json,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/stages/pool,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/stages/stage/json,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/stages/stage,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/stages/json,null}
>>
>> 14/11/01 22:07:10 INFO handler.ContextHandler: stopped
>> o.e.j.s.ServletContextHandler{/stages,null}
>>
>> 14/11/01 22:07:10 INFO ui.SparkUI: Stopped Spark web UI at
>> http://ip-172-31-20-69.us-west-2.compute.internal:4040
>>
>> 14/11/01 22:07:10 INFO scheduler.DAGScheduler: Stopping DAGScheduler
>>
>> 14/11/01 22:07:10 INFO cluster.YarnClientSchedulerBackend: Shutting down
>> all
>> executors
>>
>> 14/11/01 22:07:10 INFO cluster.YarnClientSchedulerBackend: Stopped
>>
>> 14/11/01 22:07:11 ERROR spark.MapOutputTrackerMaster: Error communicating
>> with MapOutputTracker
>>
>> akka.pattern.AskTimeoutException:
>> Recipient[Actor[akka://sparkDriver/user/MapOutputTracker#132167931]] had
>> already been terminated.
>>
>> at akka.pattern.AskableActorRef$.ask$extension(AskSupport.scala:134)
>>
>> at
>> org.apache.spark.MapOutputTracker.askTracker(MapOutputTracker.scala:106)
>>
>> at
>> org.apache.spark.MapOutputTracker.sendTracker(MapOutputTracker.scala:117)
>>
>> at
>> org.apache.spark.MapOutputTrackerMaster.stop(MapOutputTracker.scala:324)
>>
>> at org.apache.spark.SparkEnv.stop(SparkEnv.scala:80)
>>
>> at org.apache.spark.SparkContext.stop(SparkContext.scala:1024)
>>
>> at
>>
>> org.apache.spark.scheduler.cluster.YarnClientSchedulerBackend$$anon$1.run(YarnClientSchedulerBackend.scala:131)
>>
>> Exception in thread "Yarn Application State Checker"
>> org.apache.spark.SparkException: Error communicating with MapOutputTracker
>>
>> at
>> org.apache.spark.MapOutputTracker.askTracker(MapOutputTracker.scala:111)
>>
>> at
>> org.apache.spark.MapOutputTracker.sendTracker(MapOutputTracker.scala:117)
>>
>> at
>> org.apache.spark.MapOutputTrackerMaster.stop(MapOutputTracker.scala:324)
>>
>> at org.apache.spark.SparkEnv.stop(SparkEnv.scala:80)
>>
>> at org.apache.spark.SparkContext.stop(SparkContext.scala:1024)
>>
>> at
>>
>> org.apache.spark.scheduler.cluster.YarnClientSchedulerBackend$$anon$1.run(YarnClientSchedulerBackend.scala:131)
>>
>> Caused by: akka.pattern.AskTimeoutException:
>> Recipient[Actor[akka://sparkDriver/user/MapOutputTracker#132167931]] had
>> already been terminated.
>>
>> at akka.pattern.AskableActorRef$.ask$extension(AskSupport.scala:134)
>>
>> at
>> org.apache.spark.MapOutputTracker.askTracker(MapOutputTracker.scala:106)
>>
>> ... 5 more
>>
>>
>>
>>
>>
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