No, what did you have in mind? I assumed they’d work from the docs and it does using local[4] but not sure if the broadcast does any actual serializing in that case.
I certainly could be off base about my suspicions since I’m just learning to interpret Spark error messages. On Jun 26, 2014, at 1:54 PM, Muttineni, Vinay <vmuttin...@ebay.com> wrote: Hi Pat, Did you try accessing the broadcast variable value outside the Map? https://google-collections.googlecode.com/svn/trunk/javadoc/com/google/common/collect/HashBiMap.html As per the document in the link above, it looks like HashBitMap can indeed be serialized. -----Original Message----- From: Pat Ferrel [mailto:p...@occamsmachete.com] Sent: Thursday, June 26, 2014 12:13 PM To: user@spark.apache.org Subject: Running new code on a Spark Cluster I've created a CLI driver for a Spark version of a Mahout job called "item similarity" with several tests that all work fine on local[4] Spark standalone. The code even reads and writes to clustered HDFS. But switching to clustered Spark has a problem that seems tied to a broadcast and/or serialization. The code uses HashBiMap, which is a Guava Java thing. There are two of these created for every Mahout drm (a distributed matrix), for bi-directional row and column ID lookup. They are created once and then broadcast for access everywhere. When I run this on clustered Spark I get the following error. At one point we were using HashMaps and they seemed to work on the cluster. So I suspect something about the HashBiMap is causing the problem. I'm also suspicious that it may have to do with serialization in the broadcast. Here is a snippet of code and the error. Any ideas? // create BiMaps for bi-directional lookup of ID by either Mahout ID or external ID // broadcast them for access in distributed processes, so they are not recalculated in every task. // rowIDDictionary is a HashBiMap[String, Int] val rowIDDictionary = asOrderedDictionary(rowIDs) // this creates the HashBiMap in a non-dsitributed manner val rowIDDictionary_bcast = mc.broadcast(rowIDDictionary) val columnIDDictionary = asOrderedDictionary(columnIDs)) // this creates the HashBiMap in a non-dsitributed manner val columnIDDictionary_bcast = mc.broadcast(columnIDDictionary) val indexedInteractions = interactions.map { case (rowID, columnID) => //<<<<<<<<<<< this is the stage being submitted before the error val rowIndex = rowIDDictionary_bcast.value.get(rowID).get val columnIndex = columnIDDictionary_bcast.value.get(columnID).get rowIndex -> columnIndex } The error seems to happen in executing interactions.map when accessing the _bcast vals. Any idea where to start looking for this? 14/06/26 11:23:36 INFO scheduler.DAGScheduler: Submitting Stage 9 (MappedRDD[17] at map at TextDelimitedReaderWriter.scala:83), which has no missing parents 14/06/26 11:23:36 INFO scheduler.DAGScheduler: Submitting 2 missing tasks from Stage 9 (MappedRDD[17] at map at TextDelimitedReaderWriter.scala:83) 14/06/26 11:23:36 INFO scheduler.TaskSchedulerImpl: Adding task set 9.0 with 2 tasks 14/06/26 11:23:36 INFO scheduler.TaskSetManager: Starting task 9.0:0 as TID 16 on executor 0: occam4 (PROCESS_LOCAL) 14/06/26 11:23:36 INFO scheduler.TaskSetManager: Serialized task 9.0:0 as 2418 bytes in 0 ms 14/06/26 11:23:36 INFO scheduler.TaskSetManager: Starting task 9.0:1 as TID 17 on executor 0: occam4 (PROCESS_LOCAL) 14/06/26 11:23:36 INFO scheduler.TaskSetManager: Serialized task 9.0:1 as 2440 bytes in 0 ms 14/06/26 11:23:36 WARN scheduler.TaskSetManager: Lost TID 16 (task 9.0:0) 14/06/26 11:23:36 WARN scheduler.TaskSetManager: Loss was due to java.lang.NullPointerException java.lang.NullPointerException at com.google.common.collect.HashBiMap.seekByKey(HashBiMap.java:180) at com.google.common.collect.HashBiMap.put(HashBiMap.java:230) at com.google.common.collect.HashBiMap.put(HashBiMap.java:218) at com.esotericsoftware.kryo.serializers.MapSerializer.read(MapSerializer.java:135) at com.esotericsoftware.kryo.serializers.MapSerializer.read(MapSerializer.java:17) at com.esotericsoftware.kryo.Kryo.readClassAndObject(Kryo.java:729) at org.apache.spark.serializer.KryoDeserializationStream.readObject(KryoSerializer.scala:102) at org.apache.spark.broadcast.HttpBroadcast$.read(HttpBroadcast.scala:165) at org.apache.spark.broadcast.HttpBroadcast.readObject(HttpBroadcast.scala:56) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:969) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1775) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1327) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1969) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1775) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1327) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1969) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1775) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1327) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:349) at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:40) at org.apache.spark.scheduler.ShuffleMapTask$.deserializeInfo(ShuffleMapTask.scala:69) at org.apache.spark.scheduler.ShuffleMapTask.readExternal(ShuffleMapTask.scala:138) at java.io.ObjectInputStream.readExternalData(ObjectInputStream.java:1814) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1773) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1327) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:349) at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:40) at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:62) at org.apache.spark.executor.Executor$TaskRunner$$anonfun$run$1.apply$mcV$sp(Executor.scala:193) at org.apache.spark.deploy.SparkHadoopUtil$$anon$1.run(SparkHadoopUtil.scala:42) at org.apache.spark.deploy.SparkHadoopUtil$$anon$1.run(SparkHadoopUtil.scala:41) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:396) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1190) at org.apache.spark.deploy.SparkHadoopUtil.runAsUser(SparkHadoopUtil.scala:41) at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:176) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918) at java.lang.Thread.run(Thread.java:662)