Major Description
this is a bug in the branch-2.1, but i don't think it was in 2.1.0-rc1
code (contrived, but based on real code we run):
case class Holder(i: Int)
val agg1 = new Aggregator[Int, Tuple1[Option[Holder]], Seq[(String, Int, Int)]] {
def zero: Tuple1[Option[Holder]] = {
val x = Tuple1(None)
println(s"zero ${x}")
x
}
def reduce(b: Tuple1[Option[Holder]], a: Int): Tuple1[Option[Holder]] = {
println(s"reduce ${b} ${a}")
Tuple1(Some(Holder(b._1.map(_.i + a).getOrElse(a))))
}
def merge(b1: Tuple1[Option[Holder]], b2: Tuple1[Option[Holder]]): Tuple1[Option[Holder]] = {
println(s"merge ${b1} ${b2}")
(b1._1, b2._1) match {
case (Some(Holder(i1)), Some(Holder(i2))) => Tuple1(Some(Holder(i1 + i2)))
case (Some(Holder(i1)), _) => Tuple1(Some(Holder(i1)))
case (_, Some(Holder(i2))) => Tuple1(Some(Holder(i2)))
case _ => Tuple1(None)
}
}
def finish(reduction: Tuple1[Option[Holder]]): Seq[(String, Int, Int)] = {
println(s"finish ${reduction}")
Seq(("ha", reduction._1.get.i, 0))
}
def bufferEncoder: Encoder[Tuple1[Option[Holder]]] = ExpressionEncoder[Tuple1[Option[Holder]]]()
def outputEncoder: Encoder[Seq[(String, Int, Int)]] = ExpressionEncoder[Seq[(String, Int, Int)]]()
}
val x = Seq(("a", 1), ("a", 2))
.toDS
.groupByKey(_._1)
.mapValues(_._2)
.agg(agg1.toColumn)
x.printSchema
x.show
result is:
org.apache.spark.executor.Executor: Exception in task 1.0 in stage 146.0 (TID 423) java.lang.NullPointerException at org.apache.spark.sql.catalyst.expressions.GeneratedClass$SpecificMutableProjection.apply_0$(Unknown Source) at org.apache.spark.sql.catalyst.expressions.GeneratedClass$SpecificMutableProjection.apply(Unknown Source) at org.apache.spark.sql.execution.aggregate.AggregationIterator$$anonfun$generateResultProjection$1.apply(AggregationIterator.scala:223) at org.apache.spark.sql.execution.aggregate.AggregationIterator$$anonfun$generateResultProjection$1.apply(AggregationIterator.scala:221) at org.apache.spark.sql.execution.aggregate.SortBasedAggregationIterator.next(SortBasedAggregationIterator.scala:159) at org.apache.spark.sql.execution.aggregate.SortBasedAggregationIterator.next(SortBasedAggregationIterator.scala:29) at org.apache.spark.sql.execution.SparkPlan$$anonfun$2.apply(SparkPlan.scala:232) at org.apache.spark.sql.execution.SparkPlan$$anonfun$2.apply(SparkPlan.scala:225) at org.apache.spark.rdd.RDD$$anonfun$mapPartitionsInternal$1$$anonfun$apply$25.apply(RDD.scala:826) at org.apache.spark.rdd.RDD$$anonfun$mapPartitionsInternal$1$$anonfun$apply$25.apply(RDD.scala:826) at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323) at org.apache.spark.rdd.RDD.iterator(RDD.scala:287) at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:87) at org.apache.spark.scheduler.Task.run(Task.scala:99) at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:282) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:745)
the error seems to be in the code generation for the aggregator result.
