Github user mengxr commented on a diff in the pull request:
https://github.com/apache/spark/pull/916#discussion_r13691153
--- Diff: core/src/main/scala/org/apache/spark/rdd/RDD.scala ---
@@ -394,20 +401,22 @@ abstract class RDD[T: ClassTag](
return new Array[T](0)
}
- if (initialCount > Integer.MAX_VALUE - 1) {
- maxSelected = Integer.MAX_VALUE - 1
- } else {
- maxSelected = initialCount.toInt
+ if (!withReplacement && num > initialCount) {
+ throw new IllegalArgumentException("Cannot create sample larger than
the original when " +
+ "sampling without replacement")
}
- if (num > initialCount && !withReplacement) {
- total = maxSelected
- fraction = multiplier * (maxSelected + 1) / initialCount
- } else {
- fraction = multiplier * (num + 1) / initialCount
- total = num
+ if (initialCount > Integer.MAX_VALUE - 1) {
+ val maxSelected = Integer.MAX_VALUE - (5.0 *
math.sqrt(Integer.MAX_VALUE)).toInt
+ if (num > maxSelected) {
+ throw new IllegalArgumentException("Cannot support a sample size >
Integer.MAX_VALUE - " +
+ "5.0 * math.sqrt(Integer.MAX_VALUE)")
+ }
}
+ fraction = SamplingUtils.computeFraction(num, initialCount,
withReplacement)
--- End diff --
`fraction` could be a `val`.
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