Github user srowen commented on a diff in the pull request:
https://github.com/apache/spark/pull/10023#discussion_r46079471
--- Diff:
core/src/main/scala/org/apache/spark/util/random/SamplingUtils.scala ---
@@ -52,16 +52,21 @@ private[spark] object SamplingUtils {
(trimReservoir, i)
} else {
// If input size > k, continue the sampling process.
+ var l = i.toLong
val rand = new XORShiftRandom(seed)
while (input.hasNext) {
val item = input.next()
- val replacementIndex = rand.nextInt(i)
+ val replacementIndex = if (l < Int.MaxValue) {
+ rand.nextInt(l.toInt)
+ } else {
+ rand.nextLong()
--- End diff --
This isn't valid, because it chooses a value from (negative)
`Long.MIN_VALUE` to `Long.MAX_VALUE`. You need to choose a number in `[0, l)`.
Rather than even special case it, just use
```
val replacementIndex = (random.nextDouble() * l).toLong
```
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
