spark sql數據框加入與循環中的重命名

Question

我試圖做一個傳遞閉包數據框。幾次迭代後，我得到一些內部火花異常。關於什麼原因以及如何解決它的任何想法。下面是我的程序：

val e = Seq((1, 2), (1, 3), (2, 4), (4, 5), (5, 6), (6, 7), (7, 8), (8, 9), (9, 10), (10, 11), (11, 12), (12, 13), (13, 14), (14, 15), (15, 16), (16, 17), (17, 18), (18, 19)) 
var edges = e.map(p => Edge(p._1, p._2)).toDF() 
var filtered = edges 
    .filter("start = 1") 
    .distinct() 
    .withColumnRenamed("start", "fStart") 
    .withColumnRenamed("end", "fEnd") 

var i = 0 
while (i < 30) { 
    i = i + 1 
    println("\n i = " + i) 
    filtered = filtered 
    .join(edges, filtered("fEnd") === edges("start")) 
    .select(filtered("fStart"), edges("end")) 
    .withColumnRenamed("start", "fStart") 
    .withColumnRenamed("end", "fEnd").distinct 
    filtered.show 
} 

它需要在頂層中定義一個簡單的例子類：

case class Edge(start: Int, end: Int) 

，這裏是與異常輸出之後，火花掛了一會兒，然後退出時出現錯誤Executor heartbeat timed out。

i = 1 
+------+----+ 
|fStart|fEnd| 
+------+----+ 
|  1| 4| 
+------+----+ 


i = 2 
+------+----+ 
|fStart|fEnd| 
+------+----+ 
|  1| 5| 
+------+----+ 


i = 3 
+------+----+ 
|fStart|fEnd| 
+------+----+ 
|  1| 6| 
+------+----+ 
... 

i = 10 
+------+----+ 
|fStart|fEnd| 
+------+----+ 
|  1| 13| 
+------+----+ 


i = 11 
16/01/29 00:28:59 ERROR Utils: Uncaught exception in thread driver-heartbeater 
java.io.IOException: java.lang.ClassCastException: cannot assign instance of scala.collection.immutable.HashMap$SerializationProxy to field org.apache.spark.executor.TaskMetrics._accumulatorUpdates of type scala.collection.immutable.Map in instance of org.apache.spark.executor.TaskMetrics 
at org.apache.spark.util.Utils$.tryOrIOException(Utils.scala:1207) 
at org.apache.spark.executor.TaskMetrics.readObject(TaskMetrics.scala:219) 
at sun.reflect.GeneratedMethodAccessor20.invoke(Unknown Source) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
at java.lang.reflect.Method.invoke(Method.java:498) 
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1058) 
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1900) 
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) 
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) 
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) 
at org.apache.spark.util.Utils$.deserialize(Utils.scala:92) 
at org.apache.spark.executor.Executor$$anonfun$org$apache$spark$executor$Executor$$reportHeartBeat$1$$anonfun$apply$6.apply(Executor.scala:436) 
at org.apache.spark.executor.Executor$$anonfun$org$apache$spark$executor$Executor$$reportHeartBeat$1$$anonfun$apply$6.apply(Executor.scala:426) 
at scala.Option.foreach(Option.scala:236) 
at org.apache.spark.executor.Executor$$anonfun$org$apache$spark$executor$Executor$$reportHeartBeat$1.apply(Executor.scala:426) 
at org.apache.spark.executor.Executor$$anonfun$org$apache$spark$executor$Executor$$reportHeartBeat$1.apply(Executor.scala:424) 
at scala.collection.Iterator$class.foreach(Iterator.scala:727) 
at scala.collection.AbstractIterator.foreach(Iterator.scala:1157) 
at scala.collection.IterableLike$class.foreach(IterableLike.scala:72) 
at scala.collection.AbstractIterable.foreach(Iterable.scala:54) 
at org.apache.spark.executor.Executor.org$apache$spark$executor$Executor$$reportHeartBeat(Executor.scala:424) 
at org.apache.spark.executor.Executor$$anon$1$$anonfun$run$1.apply$mcV$sp(Executor.scala:468) 
at org.apache.spark.executor.Executor$$anon$1$$anonfun$run$1.apply(Executor.scala:468) 
at org.apache.spark.executor.Executor$$anon$1$$anonfun$run$1.apply(Executor.scala:468) 
at org.apache.spark.util.Utils$.logUncaughtExceptions(Utils.scala:1741) 
at org.apache.spark.executor.Executor$$anon$1.run(Executor.scala:468) 
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) 
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) 
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) 
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) 
at java.lang.Thread.run(Thread.java:745) 
Caused by: java.lang.ClassCastException: cannot assign instance of scala.collection.immutable.HashMap$SerializationProxy to field org.apache.spark.executor.TaskMetrics._accumulatorUpdates of type scala.collection.immutable.Map in instance of org.apache.spark.executor.TaskMetrics 
at java.io.ObjectStreamClass$FieldReflector.setObjFieldValues(ObjectStreamClass.java:2133) 
at java.io.ObjectStreamClass.setObjFieldValues(ObjectStreamClass.java:1305) 
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2006) 
at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:501) 
at org.apache.spark.executor.TaskMetrics$$anonfun$readObject$1.apply$mcV$sp(TaskMetrics.scala:220) 
at org.apache.spark.util.Utils$.tryOrIOException(Utils.scala:1204) 
... 32 more 
+------+----+ 
|fStart|fEnd| 
+------+----+ 
|  1| 14| 
+------+----+ 
... 

PS1。如何在沒有列重命名的情況下完成這種連接？ PS2。還有一些關於如何使用數據幀的文檔？ API文檔非常簡約。

Answer 1

這些錯誤似乎只在集羣資源不足以滿足請求並且積壓正在增加並且一段時間後出現這些類型錯誤時纔會出現。

要解決您的問題，請在filtered.show之前加filtered.cache。

第16次迭代後也不會有結果，因爲沒有匹配的filtered.fEnd === edges.start。