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Posted to issues@spark.apache.org by "Hyukjin Kwon (Jira)" <ji...@apache.org> on 2020/09/07 06:48:00 UTC
[jira] [Commented] (SPARK-32809) RDD different partitions cause
didderent results
[ https://issues.apache.org/jira/browse/SPARK-32809?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17191485#comment-17191485 ]
Hyukjin Kwon commented on SPARK-32809:
--------------------------------------
The results is correct. For {{local[1]}}, there's a single partition. So {{seqOp}} will be used for {{("apple", 10), ("apple", 15)}}. When {{local[3]}} the partitions are three. {{combOp}} will be used to combine each partition.
> RDD different partitions cause didderent results
> --------------------------------------------------
>
> Key: SPARK-32809
> URL: https://issues.apache.org/jira/browse/SPARK-32809
> Project: Spark
> Issue Type: Bug
> Components: Spark Core
> Affects Versions: 2.2.0
> Environment: spark2.2.0 ,scala 2.11.8 , hadoop-client2.6.0
> Reporter: zhangchenglong
> Priority: Major
> Original Estimate: 12h
> Remaining Estimate: 12h
>
> {code}
> class Exec3 {
> private val exec: SparkConf = new SparkConf().setMaster("local[1]").setAppName("exec3")
> private val context = new SparkContext(exec)
> context.setCheckpointDir("checkPoint")
>
> /**
> * get total number by key
> * in this project desired results are ("apple",25) ("huwei",20)
> * but in fact i get ("apple",150) ("huawei",20)
> * when i change it to local[3] the result is correct
> * i want to know which cause it and how to slove it
> */
> @Test
> def testError(): Unit ={
> val rdd = context.parallelize(Seq(("apple", 10), ("apple", 15), ("huawei", 20)))
> rdd.aggregateByKey(1.0)(
> seqOp = (zero, price) => price * zero,
> combOp = (curr, agg) => curr + agg).collect().foreach(println(_))
> context.stop()
> }
> }
> {code}
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