Null writer class, that discards all Row/InternalRow passed to it. The class, however, does some accounting.

AtrOutputWriter.scala

package org.apache.spark.sql.execution.datasources.atr

import org.apache.hadoop.mapreduce.TaskAttemptContext
import org.apache.spark.sql.Row
import org.apache.spark.sql.catalyst.InternalRow
import org.apache.spark.sql.execution.datasources.OutputWriter

import scala.tools.jline_embedded.internal.Log

/**
  * Created by atr on 16.12.16.
  */
class AtrOutputWriter(path: String, context: TaskAttemptContext) extends OutputWriter {
  private val init = System.nanoTime()
  private var start = 0L
  private var itemsInternalRow:Long = 0L

  override def close(): Unit = {
    val end = System.nanoTime()
    val tx = (end - start)
    val str = "closing Atr(Null)OutputWriter. " +
      "initPause: " + (start - init).toFloat/1000 + " usec " +
      " RunTimes: " + tx.toFloat/1000 + " usec " +
      " InternalRow: " + this.itemsInternalRow +
      " time/row: " + tx/this.itemsInternalRow + " nsec"
    Log.info(str)
  }

  override def write(row: Row): Unit = throw new UnsupportedOperationException("call writeInternal")

  override def writeInternal(row: InternalRow): Unit = {
    if(this.itemsInternalRow == 0) {
      start = System.nanoTime()
    }
    this.itemsInternalRow+=1
  }
}