spark下统计单词频次

写了一个简单的语句，还没有优化：

scala> sc.     | textFile("/etc/profile").     | flatMap((s:String)=>s.split("\\s")).     | map(_.toUpperCase).     | map((s:String)=>(s, 1)).     | filter((pair)=>pair._1.forall((ch)=>ch>'A'&&ch<'Z')).     | reduceByKey(_+_).     | sortByKey().     | foreach(println)

注意这代码还可以优化：

scala> sc.     | textFile("/etc/profile").     | flatMap(_.split("\\s")).     | map(_.toUpperCase).     | map((_, 1)).     | filter(_._1.forall((ch)=>ch>'A'&&ch<'Z')).     | reduceByKey(_+_).     | sortByKey().     | foreach(println)

输出结果如下：

15/03/06 08:50:44 INFO MemoryStore: ensureFreeSpace(75904) called with curMem=259812, maxMem=27784249315/03/06 08:50:44 INFO MemoryStore: Block broadcast_10 stored as values in memory (estimated size 74.1 KB, free 264.7 MB)15/03/06 08:50:44 INFO FileInputFormat: Total input paths to process : 115/03/06 08:50:44 INFO SparkContext: Starting job: sortByKey at <console>:2015/03/06 08:50:44 INFO DAGScheduler: Registering RDD 25 (filter at <console>:18)15/03/06 08:50:44 INFO DAGScheduler: Got job 4 (sortByKey at <console>:20) with 2 output partitions (allowLocal=false)15/03/06 08:50:44 INFO DAGScheduler: Final stage: Stage 10(sortByKey at <console>:20)15/03/06 08:50:44 INFO DAGScheduler: Parents of final stage: List(Stage 11)15/03/06 08:50:44 INFO DAGScheduler: Missing parents: List(Stage 11)15/03/06 08:50:44 INFO DAGScheduler: Submitting Stage 11 (FilteredRDD[25] at filter at <console>:18), which has no missing parents15/03/06 08:50:44 INFO MemoryStore: ensureFreeSpace(3736) called with curMem=335716, maxMem=27784249315/03/06 08:50:44 INFO MemoryStore: Block broadcast_11 stored as values in memory (estimated size 3.6 KB, free 264.6 MB)15/03/06 08:50:44 INFO DAGScheduler: Submitting 2 missing tasks from Stage 11 (FilteredRDD[25] at filter at <console>:18)15/03/06 08:50:44 INFO TaskSchedulerImpl: Adding task set 11.0 with 2 tasks15/03/06 08:50:44 INFO TaskSetManager: Starting task 0.0 in stage 11.0 (TID 16, localhost, PROCESS_LOCAL, 1162 bytes)15/03/06 08:50:44 INFO TaskSetManager: Starting task 1.0 in stage 11.0 (TID 17, localhost, PROCESS_LOCAL, 1162 bytes)15/03/06 08:50:44 INFO Executor: Running task 1.0 in stage 11.0 (TID 17)15/03/06 08:50:44 INFO Executor: Running task 0.0 in stage 11.0 (TID 16)15/03/06 08:50:44 INFO HadoopRDD: Input split: file:/etc/profile:1189+118915/03/06 08:50:44 INFO HadoopRDD: Input split: file:/etc/profile:0+118915/03/06 08:50:44 INFO Executor: Finished task 1.0 in stage 11.0 (TID 17). 1863 bytes result sent to driver15/03/06 08:50:44 INFO TaskSetManager: Finished task 1.0 in stage 11.0 (TID 17) in 43 ms on localhost (1/2)15/03/06 08:50:44 INFO Executor: Finished task 0.0 in stage 11.0 (TID 16). 1863 bytes result sent to driver15/03/06 08:50:44 INFO TaskSetManager: Finished task 0.0 in stage 11.0 (TID 16) in 51 ms on localhost (2/2)15/03/06 08:50:44 INFO DAGScheduler: Stage 11 (filter at <console>:18) finished in 0.054 s15/03/06 08:50:44 INFO DAGScheduler: looking for newly runnable stages15/03/06 08:50:44 INFO DAGScheduler: running: Set()15/03/06 08:50:44 INFO DAGScheduler: waiting: Set(Stage 10)15/03/06 08:50:44 INFO DAGScheduler: failed: Set()15/03/06 08:50:44 INFO TaskSchedulerImpl: Removed TaskSet 11.0, whose tasks have all completed, from pool 15/03/06 08:50:44 INFO DAGScheduler: Missing parents for Stage 10: List()15/03/06 08:50:44 INFO DAGScheduler: Submitting Stage 10 (MapPartitionsRDD[28] at sortByKey at <console>:20), which is now runnable15/03/06 08:50:44 INFO MemoryStore: ensureFreeSpace(2856) called with curMem=339452, maxMem=27784249315/03/06 08:50:44 INFO MemoryStore: Block broadcast_12 stored as values in memory (estimated size 2.8 KB, free 264.6 MB)15/03/06 08:50:44 INFO DAGScheduler: Submitting 2 missing tasks from Stage 10 (MapPartitionsRDD[28] at sortByKey at <console>:20)15/03/06 08:50:44 INFO TaskSchedulerImpl: Adding task set 10.0 with 2 tasks15/03/06 08:50:44 INFO TaskSetManager: Starting task 0.0 in stage 10.0 (TID 18, localhost, PROCESS_LOCAL, 948 bytes)15/03/06 08:50:44 INFO TaskSetManager: Starting task 1.0 in stage 10.0 (TID 19, localhost, PROCESS_LOCAL, 948 bytes)15/03/06 08:50:44 INFO Executor: Running task 0.0 in stage 10.0 (TID 18)15/03/06 08:50:44 INFO Executor: Running task 1.0 in stage 10.0 (TID 19)15/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: maxBytesInFlight: 50331648, targetRequestSize: 1006632915/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Getting 2 non-empty blocks out of 2 blocks15/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Started 0 remote fetches in 0 ms15/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: maxBytesInFlight: 50331648, targetRequestSize: 1006632915/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Getting 2 non-empty blocks out of 2 blocks15/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Started 0 remote fetches in 0 ms15/03/06 08:50:44 INFO Executor: Finished task 0.0 in stage 10.0 (TID 18). 1165 bytes result sent to driver15/03/06 08:50:44 INFO TaskSetManager: Finished task 0.0 in stage 10.0 (TID 18) in 18 ms on localhost (1/2)15/03/06 08:50:44 INFO Executor: Finished task 1.0 in stage 10.0 (TID 19). 1293 bytes result sent to driver15/03/06 08:50:44 INFO TaskSetManager: Finished task 1.0 in stage 10.0 (TID 19) in 28 ms on localhost (2/2)15/03/06 08:50:44 INFO DAGScheduler: Stage 10 (sortByKey at <console>:20) finished in 0.031 s15/03/06 08:50:44 INFO TaskSchedulerImpl: Removed TaskSet 10.0, whose tasks have all completed, from pool 15/03/06 08:50:44 INFO SparkContext: Job finished: sortByKey at <console>:20, took 0.107864348 s15/03/06 08:50:44 INFO SparkContext: Starting job: foreach at <console>:2115/03/06 08:50:44 INFO MapOutputTrackerMaster: Size of output statuses for shuffle 4 is 144 bytes15/03/06 08:50:44 INFO DAGScheduler: Registering RDD 26 (reduceByKey at <console>:19)15/03/06 08:50:44 INFO DAGScheduler: Got job 5 (foreach at <console>:21) with 2 output partitions (allowLocal=false)15/03/06 08:50:44 INFO DAGScheduler: Final stage: Stage 12(foreach at <console>:21)15/03/06 08:50:44 INFO DAGScheduler: Parents of final stage: List(Stage 14)15/03/06 08:50:44 INFO DAGScheduler: Missing parents: List(Stage 14)15/03/06 08:50:44 INFO DAGScheduler: Submitting Stage 14 (ShuffledRDD[26] at reduceByKey at <console>:19), which has no missing parents15/03/06 08:50:44 INFO MemoryStore: ensureFreeSpace(2472) called with curMem=342308, maxMem=27784249315/03/06 08:50:44 INFO MemoryStore: Block broadcast_13 stored as values in memory (estimated size 2.4 KB, free 264.6 MB)15/03/06 08:50:44 INFO DAGScheduler: Submitting 2 missing tasks from Stage 14 (ShuffledRDD[26] at reduceByKey at <console>:19)15/03/06 08:50:44 INFO TaskSchedulerImpl: Adding task set 14.0 with 2 tasks15/03/06 08:50:44 INFO TaskSetManager: Starting task 0.0 in stage 14.0 (TID 20, localhost, PROCESS_LOCAL, 937 bytes)15/03/06 08:50:44 INFO TaskSetManager: Starting task 1.0 in stage 14.0 (TID 21, localhost, PROCESS_LOCAL, 937 bytes)15/03/06 08:50:44 INFO Executor: Running task 1.0 in stage 14.0 (TID 21)15/03/06 08:50:44 INFO Executor: Running task 0.0 in stage 14.0 (TID 20)15/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: maxBytesInFlight: 50331648, targetRequestSize: 1006632915/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Getting 2 non-empty blocks out of 2 blocks15/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Started 0 remote fetches in 0 ms15/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: maxBytesInFlight: 50331648, targetRequestSize: 1006632915/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Getting 2 non-empty blocks out of 2 blocks15/03/06 08:50:44 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Started 0 remote fetches in 1 ms15/03/06 08:50:44 INFO Executor: Finished task 1.0 in stage 14.0 (TID 21). 996 bytes result sent to driver15/03/06 08:50:44 INFO TaskSetManager: Finished task 1.0 in stage 14.0 (TID 21) in 14 ms on localhost (1/2)15/03/06 08:50:44 INFO Executor: Finished task 0.0 in stage 14.0 (TID 20). 996 bytes result sent to driver15/03/06 08:50:44 INFO TaskSetManager: Finished task 0.0 in stage 14.0 (TID 20) in 21 ms on localhost (2/2)15/03/06 08:50:44 INFO TaskSchedulerImpl: Removed TaskSet 14.0, whose tasks have all completed, from pool 15/03/06 08:50:44 INFO DAGScheduler: Stage 14 (reduceByKey at <console>:19) finished in 0.022 s15/03/06 08:50:44 INFO DAGScheduler: looking for newly runnable stages15/03/06 08:50:44 INFO DAGScheduler: running: Set()15/03/06 08:50:44 INFO DAGScheduler: waiting: Set(Stage 12)15/03/06 08:50:44 INFO DAGScheduler: failed: Set()15/03/06 08:50:44 INFO DAGScheduler: Missing parents for Stage 12: List()15/03/06 08:50:44 INFO DAGScheduler: Submitting Stage 12 (ShuffledRDD[29] at sortByKey at <console>:20), which is now runnable15/03/06 08:50:44 INFO MemoryStore: ensureFreeSpace(2304) called with curMem=344780, maxMem=27784249315/03/06 08:50:44 INFO MemoryStore: Block broadcast_14 stored as values in memory (estimated size 2.3 KB, free 264.6 MB)15/03/06 08:50:44 INFO DAGScheduler: Submitting 2 missing tasks from Stage 12 (ShuffledRDD[29] at sortByKey at <console>:20)15/03/06 08:50:44 INFO TaskSchedulerImpl: Adding task set 12.0 with 2 tasks15/03/06 08:50:44 INFO TaskSetManager: Starting task 0.0 in stage 12.0 (TID 22, localhost, PROCESS_LOCAL, 948 bytes)15/03/06 08:50:44 INFO TaskSetManager: Starting task 1.0 in stage 12.0 (TID 23, localhost, PROCESS_LOCAL, 948 bytes)15/03/06 08:50:45 INFO Executor: Running task 1.0 in stage 12.0 (TID 23)15/03/06 08:50:45 INFO Executor: Running task 0.0 in stage 12.0 (TID 22)15/03/06 08:50:45 INFO BlockFetcherIterator$BasicBlockFetcherIterator: maxBytesInFlight: 50331648, targetRequestSize: 1006632915/03/06 08:50:45 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Getting 2 non-empty blocks out of 2 blocks15/03/06 08:50:45 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Started 0 remote fetches in 0 ms15/03/06 08:50:45 INFO BlockFetcherIterator$BasicBlockFetcherIterator: maxBytesInFlight: 50331648, targetRequestSize: 1006632915/03/06 08:50:45 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Getting 2 non-empty blocks out of 2 blocks15/03/06 08:50:45 INFO BlockFetcherIterator$BasicBlockFetcherIterator: Started 0 remote fetches in 0 ms(LOGIN,2)(MERGING,1)(MUCH,1)(NEED,1)(NOT,1)(PREVENT,1)(RESERVED,1)(SCRIPT,1)(SETS,1)(SETUP,1)(SHELL,2)(SYSTEM,2)(THE,1)(THEN,8)(THIS,3)(THRESHOLD,1)(TO,5)(UIDGID,1)(UNLESS,1)(UNSET,2)(USER,1)(WE,1)(WIDE,1)(WILL,1)(YOU,3)(YOUR,1)15/03/06 08:50:45 INFO Executor: Finished task 1.0 in stage 12.0 (TID 23). 826 bytes result sent to driver15/03/06 08:50:45 INFO TaskSetManager: Finished task 1.0 in stage 12.0 (TID 23) in 13 ms on localhost (1/2)(,260)(BETTER,1)(BY,1)(CHECK,1)(COULD,1)(CURRENT,1)(CUSTOM,1)(DO,1)(DONE,1)(ELSE,5)(ENVIRONMENT,1)(EXPORT,15)(FI,8)(FILE,2)(FOR,5)(FUNCTIONS,1)(FUTURE,1)(GET,1)(GO,1)(GOOD,1)(HISTCONTROL,1)(I,2)(IF,8)(IN,6)(IS,1)(IT,1)(KNOW,1)(KSH,1)15/03/06 08:50:45 INFO Executor: Finished task 0.0 in stage 12.0 (TID 22). 826 bytes result sent to driver15/03/06 08:50:45 INFO TaskSetManager: Finished task 0.0 in stage 12.0 (TID 22) in 27 ms on localhost (2/2)15/03/06 08:50:45 INFO TaskSchedulerImpl: Removed TaskSet 12.0, whose tasks have all completed, from pool 15/03/06 08:50:45 INFO DAGScheduler: Stage 12 (foreach at <console>:21) finished in 0.025 s15/03/06 08:50:45 INFO SparkContext: Job finished: foreach at <console>:21, took 0.07397057 s

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通过如下代码，可以输出参与计算的节点名称，注意start-all并指定shell的–master参数：

spark-shell --master spark://bluejoe0:7077

代码如下：

rdd.mapPartitions(_=>Array[String](("hostname" !!).trim).iterator, false).collectres28: Array[String] = Array(bluejoe4, bluejoe5)