[jira] [Created] (SPARK-8892) Column.cast(LongType) does not work for large values

["Jason Moore (JIRA)" <ji...@apache.org>]

Jason Moore created SPARK-8892:
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             Summary: Column.cast(LongType) does not work for large values
                 Key: SPARK-8892
                 URL: https://issues.apache.org/jira/browse/SPARK-8892
             Project: Spark
          Issue Type: Bug
          Components: SQL
    Affects Versions: 1.4.0
            Reporter: Jason Moore


It seems that casting a column from String to Long seems to go through an intermediate step of being cast to a Double (hits Cast.scala line 328 in castToDecimal).  The result is that for large values, the wrong value is returned.

This test reveals this bug:

{code:java}
import org.apache.spark.sql.types._
import org.apache.spark.sql.{Row, SQLContext}
import org.apache.spark.{SparkConf, SparkContext}
import org.scalatest.FlatSpec

import scala.util.Random

class DataFrameCastBug extends FlatSpec {

  "DataFrame" should "cast StringType to LongType correctly" in {
    val sc = new SparkContext(new SparkConf().setMaster("local").setAppName("app"))
    val qc = new SQLContext(sc)

    val values = Seq.fill(100000)(Random.nextLong)
    val source = qc.createDataFrame(
      sc.parallelize(values.map(v => Row(v))),
      StructType(Seq(StructField("value", LongType))))

    val result = source.select(source("value"), source("value").cast(StringType).cast(LongType).as("castValue"))

    assert(result.where(result("value") !== result("castValue")).count() === 0)
  }
}
{code}



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