scala - How to find spark RDD/Dataframe size?

Question

I know how to find the file size in scala.But how to find a RDD/dataframe size in spark?

Scala:

object Main extends App {
  val file = new java.io.File("hdfs://localhost:9000/samplefile.txt").toString()
  println(file.length)
}

Spark:

val distFile = sc.textFile(file)
println(distFile.length)

but if i process it not getting file size. How to find the RDD size?

Answer 1

If you are simply looking to count the number of rows in the rdd, do:

val distFile = sc.textFile(file)
println(distFile.count)

If you are interested in the bytes, you can use the SizeEstimator:

import org.apache.spark.util.SizeEstimator
println(SizeEstimator.estimate(distFile))

https://spark.apache.org/docs/latest/api/java/org/apache/spark/util/SizeEstimator.html