From 29a076e862864f2242eb9cc272c8154d3389cdb0 Mon Sep 17 00:00:00 2001 From: Ariel Rabkin Date: Thu, 12 Jun 2014 12:17:01 -0400 Subject: [PATCH] doc fix --- .../main/scala/org/apache/spark/SparkContext.scala | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/core/src/main/scala/org/apache/spark/SparkContext.scala b/core/src/main/scala/org/apache/spark/SparkContext.scala index 8bdaf0bf76e85..1ffde59f8bc6a 100644 --- a/core/src/main/scala/org/apache/spark/SparkContext.scala +++ b/core/src/main/scala/org/apache/spark/SparkContext.scala @@ -431,12 +431,21 @@ class SparkContext(config: SparkConf) extends Logging { // Methods for creating RDDs - /** Distribute a local Scala collection to form an RDD. */ + /** Distribute a local Scala collection to form an RDD. + * + * @note Parallelize acts lazily. If `seq` is a mutable collection and is + * altered after the call to parallelize and before the first action on the + * RDD, the resultant RDD will reflect the modified collection. Pass a copy of + * the argument to avoid this. + */ def parallelize[T: ClassTag](seq: Seq[T], numSlices: Int = defaultParallelism): RDD[T] = { new ParallelCollectionRDD[T](this, seq, numSlices, Map[Int, Seq[String]]()) } - /** Distribute a local Scala collection to form an RDD. */ + /** Distribute a local Scala collection to form an RDD. + * + * This method is identical to `parallelize`. + */ def makeRDD[T: ClassTag](seq: Seq[T], numSlices: Int = defaultParallelism): RDD[T] = { parallelize(seq, numSlices) }