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Sean Owen commented on SPARK-10493: ----------------------------------- Maybe union() tides you over; CDH 5.5 = Spark 1.5 is coming in ~2 months. > reduceByKey not returning distinct results > ------------------------------------------ > > Key: SPARK-10493 > URL: https://issues.apache.org/jira/browse/SPARK-10493 > Project: Spark > Issue Type: Bug > Components: Spark Core > Reporter: Glenn Strycker > Attachments: reduceByKey_example_001.scala > > > I am running Spark 1.3.0 and creating an RDD by unioning several earlier RDDs > (using zipPartitions), partitioning by a hash partitioner, and then applying > a reduceByKey to summarize statistics by key. > Since my set before the reduceByKey consists of records such as (K, V1), (K, > V2), (K, V3), I expect the results after reduceByKey to be just (K, > f(V1,V2,V3)), where the function f is appropriately associative, commutative, > etc. Therefore, the results after reduceByKey ought to be distinct, correct? > I am running counts of my RDD and finding that adding an additional > .distinct after my .reduceByKey is changing the final count!! > Here is some example code: > rdd3 = tempRDD1. > zipPartitions(tempRDD2, true)((iter, iter2) => iter++iter2). > partitionBy(new HashPartitioner(numPartitions)). > reduceByKey((a,b) => (math.Ordering.String.min(a._1, b._1), a._2 + b._2, > math.max(a._3, b._3), math.max(a._4, b._4), math.max(a._5, b._5))) > println(rdd3.count) > rdd4 = rdd3.distinct > println(rdd4.count) > I am using persistence, checkpointing, and other stuff in my actual code that > I did not paste here, so I can paste my actual code if it would be helpful. > This issue may be related to SPARK-2620, except I am not using case classes, > to my knowledge. > See also > http://stackoverflow.com/questions/32466176/apache-spark-rdd-reducebykey-operation-not-returning-correct-distinct-results -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org