Spark中产生shuffle的算子
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作用 |
算子名 |
能否替换，由谁替换 |
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去重 |
distinct() |
不能 |
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聚合 |
reduceByKey() |
groupByKey |
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groupBy() |
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groupByKey() |
reduceByKey |
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aggregateByKey() |
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combineByKey() |
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排序 |
sortByKey() |
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sortBy() |
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重分区 |
coalesce() |
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repartition() |
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集合或者表操作 |
Intersection() |
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Substract() |
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SubstractByKey() |
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Join() |
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LeftOutJoin() |
https://www.cnblogs.com/Alex-zqzy/p/9949117.html
去重
def distinct() def distinct(numPartitions: Int)
聚合
def reduceByKey(func: (V, V) => V, numPartitions: Int): RDD[(K, V)] def reduceByKey(partitioner: Partitioner, func: (V, V) => V): RDD[(K, V)] def groupBy[K](f: T => K, p: Partitioner):RDD[(K, Iterable[V])] def groupByKey(partitioner: Partitioner):RDD[(K, Iterable[V])] def aggregateByKey[U: ClassTag](zeroValue: U, partitioner: Partitioner): RDD[(K, U)] def aggregateByKey[U: ClassTag](zeroValue: U, numPartitions: Int): RDD[(K, U)] def combineByKey[C](createCombiner: V => C, mergeValue: (C, V) => C, mergeCombiners: (C, C) => C): RDD[(K, C)] def combineByKey[C](createCombiner: V => C, mergeValue: (C, V) => C, mergeCombiners: (C, C) => C, numPartitions: Int): RDD[(K, C)] def combineByKey[C](createCombiner: V => C, mergeValue: (C, V) => C, mergeCombiners: (C, C) => C, partitioner: Partitioner, mapSideCombine: Boolean = true, serializer: Serializer = null): RDD[(K, C)]
排序
def sortByKey(ascending: Boolean = true, numPartitions: Int = self.partitions.length): RDD[(K, V)] def sortBy[K](f: (T) => K, ascending: Boolean = true, numPartitions: Int = this.partitions.length)(implicit ord: Ordering[K], ctag: ClassTag[K]): RDD[T]
重分区
def coalesce(numPartitions: Int, shuffle: Boolean = false, partitionCoalescer: Option[PartitionCoalescer] = Option.empty) def repartition(numPartitions: Int)(implicit ord: Ordering[T] = null)
集合或者表操作
def intersection(other: RDD[T]): RDD[T] def intersection(other: RDD[T], partitioner: Partitioner)(implicit ord: Ordering[T] = null): RDD[T] def intersection(other: RDD[T], numPartitions: Int): RDD[T] def subtract(other: RDD[T], numPartitions: Int): RDD[T] def subtract(other: RDD[T], p: Partitioner)(implicit ord: Ordering[T] = null): RDD[T] def subtractByKey[W: ClassTag](other: RDD[(K, W)]): RDD[(K, V)] def subtractByKey[W: ClassTag](other: RDD[(K, W)], numPartitions: Int): RDD[(K, V)] def subtractByKey[W: ClassTag](other: RDD[(K, W)], p: Partitioner): RDD[(K, V)] def join[W](other: RDD[(K, W)], partitioner: Partitioner): RDD[(K, (V, W))] def join[W](other: RDD[(K, W)]): RDD[(K, (V, W))] def join[W](other: RDD[(K, W)], numPartitions: Int): RDD[(K, (V, W))] def leftOuterJoin[W](other: RDD[(K, W)]): RDD[(K, (V, Option[W]))]