How to convert InternalRow to Row.

[Jason Jun]

Hi dev,

i'm working on generating custom pipeline on the fly, which means I
generate SparkPlan along with each node in my pipeline.

So, my pipeline end up with PipeLineRelation extending BaseRelation like:

case class PipeLineRelation(schema: StructType, pipeLinePlan:
LogicalPlan)(@transient override val sqlContext: SQLContext) extends
BaseRelation with PrunedFilteredScan {
  override def needConversion: Boolean = true
  override def unhandledFilters(filters: Array[Filter]): Array[Filter] =
filters

  override def buildScan(requiredColumns: Array[String], filters:
Array[Filter]): RDD[Row] = {
    ...
    val sparkPlan =
sqlContext.sparkSession.sessionState.planner.plan(pipeLinePlan).next()
    *sparkPlan.execute().mapPartitions* { itr =>
      itr.map { internalRow =>
        val values = prunedColumnWithIndex.map { case (index, columnType) =>
          internalRow.get(index, columnType)
        }
*        Row.fromSeq(values) // Line 46*
      }
    }
  }
}

I'm getting InternalRow by executing subsequent Spark Plan, and converting
it into Row using Row.fromSeq(). i saw values at Line 46 are what i exactly
want :
------
values = {Object[5]@14277}
 0 = {UTF8String@14280} "Thin"
 1 = {UTF8String@14281} "Cell phone"
 2 = {Integer@14282} 6000
 3 = {Integer@14283} 2
 4 = {Integer@14284} 12000

but execution of Line 46 ended up with this error :
------
Job aborted due to stage failure: Task 0 in stage 0.0 failed 1 times, most
recent failure: Lost task 0.0 in stage 0.0 (TID 0, localhost, executor
driver): java.lang.IllegalArgumentException: The value (2) of the type
(java.lang.Integer) cannot be converted to the string type
at
org.apache.spark.sql.catalyst.CatalystTypeConverters$StringConverter$.toCatalystImpl(CatalystTypeConverters.scala:290)
at
org.apache.spark.sql.catalyst.CatalystTypeConverters$StringConverter$.toCatalystImpl(CatalystTypeConverters.scala:285)
at
org.apache.spark.sql.catalyst.CatalystTypeConverters$CatalystTypeConverter.toCatalyst(CatalystTypeConverters.scala:103)
at
org.apache.spark.sql.catalyst.CatalystTypeConverters$$anonfun$createToCatalystConverter$2.apply(CatalystTypeConverters.scala:396)
at
org.apache.spark.sql.execution.RDDConversions$$anonfun$rowToRowRdd$1$$anonfun$apply$3.apply(ExistingRDD.scala:60)
at
org.apache.spark.sql.execution.RDDConversions$$anonfun$rowToRowRdd$1$$anonfun$apply$3.apply(ExistingRDD.scala:57)
at scala.collection.Iterator$$anon$11.next(Iterator.scala:370)
at
org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIteratorForCodegenStage1.processNext(Unknown
Source)
at
org.apache.spark.sql.execution.BufferedRowIterator.hasNext(BufferedRowIterator.java:43)
at
org.apache.spark.sql.execution.WholeStageCodegenExec$$anonfun$11$$anon$1.hasNext(WholeStageCodegenExec.scala:619)
at
org.apache.spark.sql.execution.SparkPlan$$anonfun$2.apply(SparkPlan.scala:255)
at
org.apache.spark.sql.execution.SparkPlan$$anonfun$2.apply(SparkPlan.scala:247)
at
org.apache.spark.rdd.RDD$$anonfun$mapPartitionsInternal$1$$anonfun$apply$24.apply(RDD.scala:836)
at
org.apache.spark.rdd.RDD$$anonfun$mapPartitionsInternal$1$$anonfun$apply$24.apply(RDD.scala:836)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:90)
at org.apache.spark.scheduler.Task.run(Task.scala:121)
at
org.apache.spark.executor.Executor$TaskRunner$$anonfun$10.apply(Executor.scala:402)
at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1360)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:408)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:748)
----

Is it existing bug? otherwise how do I convert InternalRow to Row?

Thanks in advance.
Jason