我正在使用Spark的Scala API并尝试结合3000 rdds。
我正在做一个用于循环迭代3000多个文本文件，创建rdd并通过刚刚从文本文件创建的旧RDD和新的RDD。
这是我的代码：
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);
}
我看到了一个问题，该问题在使用rdd.union时询问堆栈过高，答案说，如果您使用SparkContext.Union。
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)
有人知道我做错了什么？
首先。似乎您的 allrdd 是 var 。尝试避免这种情况；您可以做类似的事情：
val allRdd = fileNameArray.map(name => {
val rdd = sc.textFile(s"" + name).filter(...)
}).reduce(_ + _)
现在...加入3000 RDD的声音听起来有些疯狂。联合方法使它：
new UnionRDD(sc, Array(this, other))
如果您加入了3000个RDD的加入，您将获得：
new UnionRDD(sc, Array(this, new UnionRDD(sc, Array(this2, new UnionRDD(sc, Array(this3, new UnionRDD(sc, Array(this4, (........)))))))))
这就是您的 stackoverflow
的原因您可以使用通配符并从目录中阅读它们...
val allRdds = sc.textFile("filesDir/*.txt"). // or whatever
filter(...)
，或者如果您喜欢阅读文件列表：
val allRdds = sc.textFile(fileNameArray.mkString(",")).filter(...)
更新：
由于您需要文件名，因此可以使用 wholetextfiles 函数：
val files: RDD[(String, String)] = sc.wholeTextFiles(fileNameArray.mkString(",")).
flatMap(f => f._2.split("n").map(l => (f._1, l) ) )
files.filter(...).mapValues(...)