Github user shivaram commented on a diff in the pull request:
https://github.com/apache/spark/pull/7461#discussion_r38497048
--- Diff: core/src/main/scala/org/apache/spark/rdd/RDD.scala ---
@@ -1080,6 +1080,21 @@ abstract class RDD[T: ClassTag](
var partiallyAggregated = mapPartitions(it =>
Iterator(aggregatePartition(it)))
var numPartitions = partiallyAggregated.partitions.length
val scale = math.max(math.ceil(math.pow(numPartitions, 1.0 /
depth)).toInt, 2)
+
+ // Do one level of aggregation based on executorId before starting
the tree
+ // NOTE: exclude the driver from list of executors
+ val numExecutors = math.max(context.getExecutorStorageStatus.length
- 1, 1)
+ partiallyAggregated = partiallyAggregated.mapPartitionsWithIndex {
case (idx, iter) =>
+ def isAllDigits(x: String) = x forall Character.isDigit
+ val execId = SparkEnv.get.executorId
+ if (isAllDigits(execId)) {
+ iter.map((execId.toInt, _))
+ } else {
+ iter.map((execId.hashCode, _))
--- End diff --
Hmm it looks like the reason I added this in an earlier version was to
avoid some hashCollisions[1]. Not sure what was exactly the problem as I can't
reproduce any collisions with all digit strings -- so going with `hashCode` for
now seems fine.
[1]
https://github.com/amplab/ml-matrix/commit/5d7e00e136f8bbc2233adca6d495507d446815bf
---
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]
