[120] | 1 | /** |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
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| 3 | * or more contributor license agreements. See the NOTICE file |
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| 4 | * distributed with this work for additional information |
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| 5 | * regarding copyright ownership. The ASF licenses this file |
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| 6 | * to you under the Apache License, Version 2.0 (the |
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| 7 | * "License"); you may not use this file except in compliance |
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| 8 | * with the License. You may obtain a copy of the License at |
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| 9 | * |
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| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 11 | * |
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| 12 | * Unless required by applicable law or agreed to in writing, software |
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| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 15 | * See the License for the specific language governing permissions and |
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| 16 | * limitations under the License. |
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| 17 | */ |
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| 18 | |
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| 19 | #include "hadoop/Pipes.hh" |
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| 20 | #include "hadoop/TemplateFactory.hh" |
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| 21 | |
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| 22 | class SortMap: public HadoopPipes::Mapper { |
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| 23 | private: |
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| 24 | /* the fraction 0.0 to 1.0 of records to keep */ |
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| 25 | float keepFraction; |
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| 26 | /* the number of records kept so far */ |
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| 27 | long long keptRecords; |
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| 28 | /* the total number of records */ |
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| 29 | long long totalRecords; |
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| 30 | static const std::string MAP_KEEP_PERCENT; |
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| 31 | public: |
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| 32 | /* |
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| 33 | * Look in the config to find the fraction of records to keep. |
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| 34 | */ |
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| 35 | SortMap(HadoopPipes::TaskContext& context){ |
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| 36 | const HadoopPipes::JobConf* conf = context.getJobConf(); |
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| 37 | if (conf->hasKey(MAP_KEEP_PERCENT)) { |
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| 38 | keepFraction = conf->getFloat(MAP_KEEP_PERCENT) / 100.0; |
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| 39 | } else { |
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| 40 | keepFraction = 1.0; |
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| 41 | } |
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| 42 | keptRecords = 0; |
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| 43 | totalRecords = 0; |
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| 44 | } |
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| 45 | |
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| 46 | void map(HadoopPipes::MapContext& context) { |
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| 47 | totalRecords += 1; |
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| 48 | while ((float) keptRecords / totalRecords < keepFraction) { |
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| 49 | keptRecords += 1; |
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| 50 | context.emit(context.getInputKey(), context.getInputValue()); |
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| 51 | } |
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| 52 | } |
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| 53 | }; |
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| 54 | |
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| 55 | const std::string SortMap::MAP_KEEP_PERCENT("hadoop.sort.map.keep.percent"); |
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| 56 | |
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| 57 | class SortReduce: public HadoopPipes::Reducer { |
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| 58 | private: |
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| 59 | /* the fraction 0.0 to 1.0 of records to keep */ |
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| 60 | float keepFraction; |
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| 61 | /* the number of records kept so far */ |
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| 62 | long long keptRecords; |
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| 63 | /* the total number of records */ |
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| 64 | long long totalRecords; |
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| 65 | static const std::string REDUCE_KEEP_PERCENT; |
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| 66 | public: |
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| 67 | SortReduce(HadoopPipes::TaskContext& context){ |
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| 68 | const HadoopPipes::JobConf* conf = context.getJobConf(); |
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| 69 | if (conf->hasKey(REDUCE_KEEP_PERCENT)) { |
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| 70 | keepFraction = conf->getFloat(REDUCE_KEEP_PERCENT) / 100.0; |
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| 71 | } else { |
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| 72 | keepFraction = 1.0; |
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| 73 | } |
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| 74 | keptRecords = 0; |
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| 75 | totalRecords = 0; |
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| 76 | } |
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| 77 | |
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| 78 | void reduce(HadoopPipes::ReduceContext& context) { |
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| 79 | while (context.nextValue()) { |
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| 80 | totalRecords += 1; |
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| 81 | while ((float) keptRecords / totalRecords < keepFraction) { |
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| 82 | keptRecords += 1; |
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| 83 | context.emit(context.getInputKey(), context.getInputValue()); |
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| 84 | } |
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| 85 | } |
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| 86 | } |
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| 87 | }; |
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| 88 | |
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| 89 | const std::string |
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| 90 | SortReduce::REDUCE_KEEP_PERCENT("hadoop.sort.reduce.keep.percent"); |
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| 91 | |
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| 92 | int main(int argc, char *argv[]) { |
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| 93 | return HadoopPipes::runTask(HadoopPipes::TemplateFactory<SortMap, |
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| 94 | SortReduce>()); |
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| 95 | } |
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| 96 | |
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