2

I am using spark's scala api and trying to union 3000 RDDs.

I am doing a for loop iterating over 3000 text files, creating an RDD and making a union out of the old RDD and the new RDD that was just created from the text file.

Here is my code:

var tempRDD = sc.textFile(s"" + fileNameArray(ind)).filter(_.split(",",-1).length == cols).filter(line => line.split(",").filter(cell => cell.length > 0).length == cols).
    map{line => 
        val parts = line.split(",",-1);
        val relaventFeatures = Array(parts(ind0),parts(ind1),parts(ind2));
        val vector = Vectors.dense(relaventFeatures.map(_.toDouble));
        val fileName = fileNameArray(ind);
        (fileName, (parts(0), vector))};
    if ( !tempRDD.isEmpty){
        allRDD = sc.union(allRDD, tempRDD);
    }

I saw a question that asked about getting a stack overfow when using RDD.union and the answer said that if you use SparkContext.union a stack overflow can't happen- but I am getting one:

java.lang.StackOverflowError at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at org.apache.spark.rdd.UnionRDD$$anonfun$1.apply(UnionRDD.scala:66) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.immutable.List.foreach(List.scala:318) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.AbstractTraversable.map(Traversable.scala:105) at org.apache.spark.rdd.UnionRDD.getPartitions(UnionRDD.scala:66) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) at scala.Option.getOrElse(Option.scala:120)

Anyone know what I'm doing wrong?

Community
  • 1
  • 1
user3494047
  • 1,643
  • 4
  • 31
  • 61
  • 2
    Possible duplicate of [Stackoverflow due to long RDD Lineage](http://stackoverflow.com/questions/34461804/stackoverflow-due-to-long-rdd-lineage) – zero323 Jun 16 '16 at 16:28

1 Answers1

3

First of all. It seems like your allRdd is a var. Try to avoid that; you can do something like:

val allRdd = fileNameArray.map(name => {
  val rdd = sc.textFile(s"" + name).filter(...)
}).reduce(_ + _)

Now... Joining 3000 RDDs sounds a bit crazy. Union method makes this:

new UnionRDD(sc, Array(this, other))

If you make a join of 3000 RDDs you will get:

new UnionRDD(sc, Array(this, new UnionRDD(sc, Array(this2, new UnionRDD(sc, Array(this3, new UnionRDD(sc, Array(this4, (........)))))))))

That's the reason of your StackOverflow

You can use wildcards and read them from a directory...

val allRdds = sc.textFile("filesDir/*.txt"). // or whatever
filter(...)

Or if you prefer read the list of files:

val allRdds = sc.textFile(fileNameArray.mkString(",")).filter(...)

Update:

Since you need the filename, you can use wholeTextFiles function:

val files: RDD[(String, String)] = sc.wholeTextFiles(fileNameArray.mkString(",")).
  flatMap(f => f._2.split("\n").map(l => (f._1, l) ) )
files.filter(...).mapValues(...)
rhernando
  • 1,051
  • 7
  • 18
  • the reason i'm not just reading them from a directory is because I need to have an RDD composed of many files in a directory where every element of the RDD is a tuple with the name of the file and the line of text from that file. – user3494047 Jun 17 '16 at 09:19
  • You can use then wholeTextFiles. I updated the answer – rhernando Jun 19 '16 at 20:04