Any reason why do you broadcast such large variable ? It doesn't make sense to me
On Tue, Mar 8, 2016 at 7:29 AM, Arash <aras...@gmail.com> wrote: > Hello all, > > I'm trying to broadcast a variable of size ~1G to a cluster of 20 nodes > but haven't been able to make it work so far. > > It looks like the executors start to run out of memory during > deserialization. This behavior only shows itself when the number of > partitions is above a few 10s, the broadcast does work for 10 or 20 > partitions. > > I'm using the following setup to observe the problem: > > val tuples: Array[((String, String), (String, String))] // ~ 10M > tuples > val tuplesBc = sc.broadcast(tuples) > val numsRdd = sc.parallelize(1 to 5000, 100) > numsRdd.map(n => tuplesBc.value.head).count() > > If I set the number of partitions for numsRDD to 20, the count goes > through successfully, but at 100, I'll start to get errors such as: > > 16/03/07 19:35:32 WARN scheduler.TaskSetManager: Lost task 77.0 in stage > 1.0 (TID 1677, xxx.ec2.internal): java.lang.OutOfMemoryError: Java heap > space > at > java.io.ObjectInputStream$HandleTable.grow(ObjectInputStream.java:3472) > at > java.io.ObjectInputStream$HandleTable.assign(ObjectInputStream.java:3278) > at > java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1789) > at > java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350) > at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370) > at > scala.collection.immutable.HashMap$SerializationProxy.readObject(HashMap.scala:516) > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at > sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) > at java.lang.reflect.Method.invoke(Method.java:606) > at > java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1058) > at > java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1897) > at > java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798) > at > java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350) > at > java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1997) > at > java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1921) > at > java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798) > at > java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350) > at > java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1997) > at > java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1921) > at > java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798) > at > java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350) > at > java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1997) > at > java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1921) > at > java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798) > at > java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350) > at > java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1997) > at > java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1921) > at > java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798) > at > java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350) > at > java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1997) > at > java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1921) > > > I'm using spark 1.5.2. Cluster nodes are amazon r3.2xlarge. The spark > property maximizeResourceAllocation is set to true (executor.memory = 48G > according to spark ui environment). We're also using kryo serialization and > Yarn is the resource manager. > > Any ideas as what might be going wrong and how to debug this? > > Thanks, > Arash > > -- Best Regards Jeff Zhang
