Github user SaintBacchus commented on the pull request:
https://github.com/apache/spark/pull/2874#issuecomment-69496171
Sorry for forgetting explain why there must be `Int.MaxValue -1` instead
of `Int.MaxValue` .
As the SparkPi using the `parallelize` to generator the RDD so it has a
limit of input seq, and go through the implement of this:
```scala
def positions(length: Long, numSlices: Int): Iterator[(Int, Int)] = {
(0 until numSlices).iterator.map(i => {
val start = ((i * length) / numSlices).toInt
val end = (((i + 1) * length) / numSlices).toInt
(start, end)
})
}
```
in line 122 at `ParallelCollectionRDD.scala`
The max size of the input seq was `Int.MaxValue - 1`, otherwise the `end =
(((i + 1) * length) / numSlices).toInt` will overflow and lead an uncorrect
reslut.
I tested this:
```scala
sc.makeRDD(1 to (Int.MaxValue)).count // result = 0
sc.makeRDD(1 to (Int.MaxValue - 1)).count // result = 2147483646 =
Int.MaxValue - 1
sc.makeRDD(1 until (Int.MaxValue)).count // result = 2147483646 =
Int.MaxValue - 1
```
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