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考虑下面的代码片段(Python的2.7运行星火2.1):数据分布,而在星火重新分区RDD
nums = range(0, 10)
with SparkContext("local[2]") as sc:
rdd = sc.parallelize(nums)
print("Number of partitions: {}".format(rdd.getNumPartitions()))
print("Partitions structure: {}".format(rdd.glom().collect()))
rdd2 = rdd.repartition(5)
print("Number of partitions: {}".format(rdd2.getNumPartitions()))
print("Partitions structure: {}".format(rdd2.glom().collect()))
输出是:
Number of partitions: 2
Partitions structure: [[0, 1, 2, 3, 4], [5, 6, 7, 8, 9]]
Number of partitions: 5
Partitions structure: [[], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [], [], []]
为什么重新划分数据后未在所有分布式分区?
感谢您的评论。我不认为情况会如此。此方法在使用DataFrame时有效(请参阅https://hackernoon.com/managing-spark-partitions-with-coalesce-and-repartition-4050c57ad5c4),但在纯RDD上失败 – Khozzy