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 | package org.apache.hadoop.record; |
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20 | |
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21 | import org.apache.hadoop.mapred.*; |
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22 | import org.apache.hadoop.fs.*; |
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23 | import org.apache.hadoop.io.*; |
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24 | import org.apache.hadoop.io.SequenceFile.CompressionType; |
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25 | import org.apache.hadoop.conf.*; |
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26 | import junit.framework.TestCase; |
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27 | import java.io.*; |
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28 | import java.util.*; |
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29 | |
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30 | |
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31 | /********************************************************** |
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32 | * MapredLoadTest generates a bunch of work that exercises |
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33 | * a Hadoop Map-Reduce system (and DFS, too). It goes through |
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34 | * the following steps: |
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35 | * |
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36 | * 1) Take inputs 'range' and 'counts'. |
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37 | * 2) Generate 'counts' random integers between 0 and range-1. |
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38 | * 3) Create a file that lists each integer between 0 and range-1, |
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39 | * and lists the number of times that integer was generated. |
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40 | * 4) Emit a (very large) file that contains all the integers |
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41 | * in the order generated. |
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42 | * 5) After the file has been generated, read it back and count |
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43 | * how many times each int was generated. |
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44 | * 6) Compare this big count-map against the original one. If |
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45 | * they match, then SUCCESS! Otherwise, FAILURE! |
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46 | * |
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47 | * OK, that's how we can think about it. What are the map-reduce |
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48 | * steps that get the job done? |
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49 | * |
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50 | * 1) In a non-mapred thread, take the inputs 'range' and 'counts'. |
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51 | * 2) In a non-mapread thread, generate the answer-key and write to disk. |
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52 | * 3) In a mapred job, divide the answer key into K jobs. |
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53 | * 4) A mapred 'generator' task consists of K map jobs. Each reads |
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54 | * an individual "sub-key", and generates integers according to |
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55 | * to it (though with a random ordering). |
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56 | * 5) The generator's reduce task agglomerates all of those files |
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57 | * into a single one. |
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58 | * 6) A mapred 'reader' task consists of M map jobs. The output |
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59 | * file is cut into M pieces. Each of the M jobs counts the |
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60 | * individual ints in its chunk and creates a map of all seen ints. |
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61 | * 7) A mapred job integrates all the count files into a single one. |
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62 | * |
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63 | **********************************************************/ |
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64 | public class TestRecordMR extends TestCase { |
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65 | /** |
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66 | * Modified to make it a junit test. |
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67 | * The RandomGen Job does the actual work of creating |
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68 | * a huge file of assorted numbers. It receives instructions |
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69 | * as to how many times each number should be counted. Then |
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70 | * it emits those numbers in a crazy order. |
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71 | * |
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72 | * The map() function takes a key/val pair that describes |
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73 | * a value-to-be-emitted (the key) and how many times it |
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74 | * should be emitted (the value), aka "numtimes". map() then |
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75 | * emits a series of intermediate key/val pairs. It emits |
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76 | * 'numtimes' of these. The key is a random number and the |
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77 | * value is the 'value-to-be-emitted'. |
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78 | * |
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79 | * The system collates and merges these pairs according to |
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80 | * the random number. reduce() function takes in a key/value |
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81 | * pair that consists of a crazy random number and a series |
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82 | * of values that should be emitted. The random number key |
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83 | * is now dropped, and reduce() emits a pair for every intermediate value. |
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84 | * The emitted key is an intermediate value. The emitted value |
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85 | * is just a blank string. Thus, we've created a huge file |
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86 | * of numbers in random order, but where each number appears |
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87 | * as many times as we were instructed. |
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88 | */ |
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89 | static public class RandomGenMapper implements Mapper<RecInt, RecInt, |
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90 | RecInt, RecString> { |
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91 | Random r = new Random(); |
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92 | public void configure(JobConf job) { |
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93 | } |
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94 | |
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95 | public void map(RecInt key, |
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96 | RecInt val, |
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97 | OutputCollector<RecInt, RecString> out, |
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98 | Reporter reporter) throws IOException { |
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99 | int randomVal = key.getData(); |
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100 | int randomCount = val.getData(); |
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101 | |
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102 | for (int i = 0; i < randomCount; i++) { |
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103 | out.collect(new RecInt(Math.abs(r.nextInt())), |
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104 | new RecString(Integer.toString(randomVal))); |
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105 | } |
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106 | } |
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107 | public void close() { |
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108 | } |
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109 | } |
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110 | /** |
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111 | */ |
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112 | static public class RandomGenReducer implements Reducer<RecInt, RecString, |
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113 | RecInt, RecString> { |
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114 | public void configure(JobConf job) { |
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115 | } |
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116 | |
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117 | public void reduce(RecInt key, |
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118 | Iterator<RecString> it, |
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119 | OutputCollector<RecInt, RecString> out, |
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120 | Reporter reporter) throws IOException { |
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121 | int keyint = key.getData(); |
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122 | while (it.hasNext()) { |
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123 | String val = it.next().getData(); |
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124 | out.collect(new RecInt(Integer.parseInt(val)), |
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125 | new RecString("")); |
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126 | } |
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127 | } |
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128 | public void close() { |
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129 | } |
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130 | } |
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131 | |
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132 | /** |
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133 | * The RandomCheck Job does a lot of our work. It takes |
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134 | * in a num/string keyspace, and transforms it into a |
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135 | * key/count(int) keyspace. |
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136 | * |
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137 | * The map() function just emits a num/1 pair for every |
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138 | * num/string input pair. |
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139 | * |
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140 | * The reduce() function sums up all the 1s that were |
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141 | * emitted for a single key. It then emits the key/total |
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142 | * pair. |
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143 | * |
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144 | * This is used to regenerate the random number "answer key". |
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145 | * Each key here is a random number, and the count is the |
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146 | * number of times the number was emitted. |
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147 | */ |
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148 | static public class RandomCheckMapper implements Mapper<RecInt, RecString, |
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149 | RecInt, RecString> { |
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150 | public void configure(JobConf job) { |
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151 | } |
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152 | |
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153 | public void map(RecInt key, |
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154 | RecString val, |
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155 | OutputCollector<RecInt, RecString> out, |
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156 | Reporter reporter) throws IOException { |
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157 | int pos = key.getData(); |
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158 | String str = val.getData(); |
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159 | out.collect(new RecInt(pos), new RecString("1")); |
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160 | } |
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161 | public void close() { |
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162 | } |
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163 | } |
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164 | /** |
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165 | */ |
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166 | static public class RandomCheckReducer implements Reducer<RecInt, RecString, |
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167 | RecInt, RecString> { |
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168 | public void configure(JobConf job) { |
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169 | } |
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170 | |
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171 | public void reduce(RecInt key, |
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172 | Iterator<RecString> it, |
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173 | OutputCollector<RecInt, RecString> out, |
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174 | Reporter reporter) throws IOException { |
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175 | int keyint = key.getData(); |
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176 | int count = 0; |
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177 | while (it.hasNext()) { |
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178 | it.next(); |
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179 | count++; |
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180 | } |
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181 | out.collect(new RecInt(keyint), new RecString(Integer.toString(count))); |
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182 | } |
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183 | public void close() { |
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184 | } |
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185 | } |
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186 | |
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187 | /** |
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188 | * The Merge Job is a really simple one. It takes in |
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189 | * an int/int key-value set, and emits the same set. |
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190 | * But it merges identical keys by adding their values. |
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191 | * |
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192 | * Thus, the map() function is just the identity function |
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193 | * and reduce() just sums. Nothing to see here! |
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194 | */ |
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195 | static public class MergeMapper implements Mapper<RecInt, RecString, |
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196 | RecInt, RecInt> { |
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197 | public void configure(JobConf job) { |
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198 | } |
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199 | |
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200 | public void map(RecInt key, |
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201 | RecString val, |
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202 | OutputCollector<RecInt, RecInt> out, |
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203 | Reporter reporter) throws IOException { |
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204 | int keyint = key.getData(); |
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205 | String valstr = val.getData(); |
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206 | out.collect(new RecInt(keyint), new RecInt(Integer.parseInt(valstr))); |
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207 | } |
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208 | public void close() { |
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209 | } |
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210 | } |
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211 | static public class MergeReducer implements Reducer<RecInt, RecInt, |
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212 | RecInt, RecInt> { |
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213 | public void configure(JobConf job) { |
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214 | } |
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215 | |
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216 | public void reduce(RecInt key, |
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217 | Iterator<RecInt> it, |
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218 | OutputCollector<RecInt, RecInt> out, |
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219 | Reporter reporter) throws IOException { |
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220 | int keyint = key.getData(); |
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221 | int total = 0; |
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222 | while (it.hasNext()) { |
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223 | total += it.next().getData(); |
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224 | } |
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225 | out.collect(new RecInt(keyint), new RecInt(total)); |
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226 | } |
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227 | public void close() { |
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228 | } |
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229 | } |
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230 | |
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231 | private static int range = 10; |
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232 | private static int counts = 100; |
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233 | private static Random r = new Random(); |
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234 | private static Configuration conf = new Configuration(); |
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235 | |
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236 | public void testMapred() throws Exception { |
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237 | launch(); |
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238 | } |
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239 | |
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240 | /** |
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241 | * |
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242 | */ |
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243 | public static void launch() throws Exception { |
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244 | // |
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245 | // Generate distribution of ints. This is the answer key. |
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246 | // |
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247 | int countsToGo = counts; |
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248 | int dist[] = new int[range]; |
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249 | for (int i = 0; i < range; i++) { |
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250 | double avgInts = (1.0 * countsToGo) / (range - i); |
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251 | dist[i] = (int) Math.max(0, Math.round(avgInts + (Math.sqrt(avgInts) * r.nextGaussian()))); |
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252 | countsToGo -= dist[i]; |
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253 | } |
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254 | if (countsToGo > 0) { |
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255 | dist[dist.length-1] += countsToGo; |
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256 | } |
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257 | |
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258 | // |
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259 | // Write the answer key to a file. |
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260 | // |
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261 | FileSystem fs = FileSystem.get(conf); |
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262 | Path testdir = new Path("mapred.loadtest"); |
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263 | if (!fs.mkdirs(testdir)) { |
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264 | throw new IOException("Mkdirs failed to create directory " + testdir.toString()); |
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265 | } |
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266 | |
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267 | Path randomIns = new Path(testdir, "genins"); |
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268 | if (!fs.mkdirs(randomIns)) { |
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269 | throw new IOException("Mkdirs failed to create directory " + randomIns.toString()); |
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270 | } |
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271 | |
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272 | Path answerkey = new Path(randomIns, "answer.key"); |
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273 | SequenceFile.Writer out = SequenceFile.createWriter(fs, conf, |
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274 | answerkey, RecInt.class, RecInt.class, |
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275 | CompressionType.NONE); |
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276 | try { |
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277 | for (int i = 0; i < range; i++) { |
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278 | RecInt k = new RecInt(); |
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279 | RecInt v = new RecInt(); |
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280 | k.setData(i); |
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281 | v.setData(dist[i]); |
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282 | out.append(k, v); |
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283 | } |
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284 | } finally { |
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285 | out.close(); |
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286 | } |
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287 | |
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288 | // |
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289 | // Now we need to generate the random numbers according to |
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290 | // the above distribution. |
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291 | // |
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292 | // We create a lot of map tasks, each of which takes at least |
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293 | // one "line" of the distribution. (That is, a certain number |
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294 | // X is to be generated Y number of times.) |
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295 | // |
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296 | // A map task emits Y key/val pairs. The val is X. The key |
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297 | // is a randomly-generated number. |
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298 | // |
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299 | // The reduce task gets its input sorted by key. That is, sorted |
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300 | // in random order. It then emits a single line of text that |
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301 | // for the given values. It does not emit the key. |
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302 | // |
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303 | // Because there's just one reduce task, we emit a single big |
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304 | // file of random numbers. |
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305 | // |
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306 | Path randomOuts = new Path(testdir, "genouts"); |
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307 | fs.delete(randomOuts, true); |
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308 | |
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309 | |
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310 | JobConf genJob = new JobConf(conf, TestRecordMR.class); |
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311 | FileInputFormat.setInputPaths(genJob, randomIns); |
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312 | genJob.setInputFormat(SequenceFileInputFormat.class); |
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313 | genJob.setMapperClass(RandomGenMapper.class); |
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314 | |
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315 | FileOutputFormat.setOutputPath(genJob, randomOuts); |
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316 | genJob.setOutputKeyClass(RecInt.class); |
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317 | genJob.setOutputValueClass(RecString.class); |
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318 | genJob.setOutputFormat(SequenceFileOutputFormat.class); |
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319 | genJob.setReducerClass(RandomGenReducer.class); |
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320 | genJob.setNumReduceTasks(1); |
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321 | |
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322 | JobClient.runJob(genJob); |
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323 | |
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324 | // |
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325 | // Next, we read the big file in and regenerate the |
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326 | // original map. It's split into a number of parts. |
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327 | // (That number is 'intermediateReduces'.) |
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328 | // |
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329 | // We have many map tasks, each of which read at least one |
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330 | // of the output numbers. For each number read in, the |
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331 | // map task emits a key/value pair where the key is the |
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332 | // number and the value is "1". |
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333 | // |
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334 | // We have a single reduce task, which receives its input |
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335 | // sorted by the key emitted above. For each key, there will |
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336 | // be a certain number of "1" values. The reduce task sums |
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337 | // these values to compute how many times the given key was |
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338 | // emitted. |
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339 | // |
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340 | // The reduce task then emits a key/val pair where the key |
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341 | // is the number in question, and the value is the number of |
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342 | // times the key was emitted. This is the same format as the |
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343 | // original answer key (except that numbers emitted zero times |
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344 | // will not appear in the regenerated key.) The answer set |
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345 | // is split into a number of pieces. A final MapReduce job |
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346 | // will merge them. |
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347 | // |
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348 | // There's not really a need to go to 10 reduces here |
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349 | // instead of 1. But we want to test what happens when |
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350 | // you have multiple reduces at once. |
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351 | // |
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352 | int intermediateReduces = 10; |
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353 | Path intermediateOuts = new Path(testdir, "intermediateouts"); |
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354 | fs.delete(intermediateOuts, true); |
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355 | JobConf checkJob = new JobConf(conf, TestRecordMR.class); |
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356 | FileInputFormat.setInputPaths(checkJob, randomOuts); |
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357 | checkJob.setInputFormat(SequenceFileInputFormat.class); |
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358 | checkJob.setMapperClass(RandomCheckMapper.class); |
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359 | |
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360 | FileOutputFormat.setOutputPath(checkJob, intermediateOuts); |
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361 | checkJob.setOutputKeyClass(RecInt.class); |
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362 | checkJob.setOutputValueClass(RecString.class); |
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363 | checkJob.setOutputFormat(SequenceFileOutputFormat.class); |
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364 | checkJob.setReducerClass(RandomCheckReducer.class); |
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365 | checkJob.setNumReduceTasks(intermediateReduces); |
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366 | |
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367 | JobClient.runJob(checkJob); |
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368 | |
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369 | // |
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370 | // OK, now we take the output from the last job and |
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371 | // merge it down to a single file. The map() and reduce() |
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372 | // functions don't really do anything except reemit tuples. |
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373 | // But by having a single reduce task here, we end up merging |
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374 | // all the files. |
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375 | // |
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376 | Path finalOuts = new Path(testdir, "finalouts"); |
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377 | fs.delete(finalOuts, true); |
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378 | JobConf mergeJob = new JobConf(conf, TestRecordMR.class); |
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379 | FileInputFormat.setInputPaths(mergeJob, intermediateOuts); |
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380 | mergeJob.setInputFormat(SequenceFileInputFormat.class); |
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381 | mergeJob.setMapperClass(MergeMapper.class); |
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382 | |
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383 | FileOutputFormat.setOutputPath(mergeJob, finalOuts); |
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384 | mergeJob.setOutputKeyClass(RecInt.class); |
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385 | mergeJob.setOutputValueClass(RecInt.class); |
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386 | mergeJob.setOutputFormat(SequenceFileOutputFormat.class); |
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387 | mergeJob.setReducerClass(MergeReducer.class); |
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388 | mergeJob.setNumReduceTasks(1); |
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389 | |
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390 | JobClient.runJob(mergeJob); |
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391 | |
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392 | |
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393 | // |
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394 | // Finally, we compare the reconstructed answer key with the |
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395 | // original one. Remember, we need to ignore zero-count items |
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396 | // in the original key. |
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397 | // |
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398 | boolean success = true; |
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399 | Path recomputedkey = new Path(finalOuts, "part-00000"); |
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400 | SequenceFile.Reader in = new SequenceFile.Reader(fs, recomputedkey, conf); |
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401 | int totalseen = 0; |
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402 | try { |
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403 | RecInt key = new RecInt(); |
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404 | RecInt val = new RecInt(); |
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405 | for (int i = 0; i < range; i++) { |
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406 | if (dist[i] == 0) { |
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407 | continue; |
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408 | } |
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409 | if (!in.next(key, val)) { |
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410 | System.err.println("Cannot read entry " + i); |
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411 | success = false; |
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412 | break; |
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413 | } else { |
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414 | if (!((key.getData() == i) && (val.getData() == dist[i]))) { |
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415 | System.err.println("Mismatch! Pos=" + key.getData() + ", i=" + i + ", val=" + val.getData() + ", dist[i]=" + dist[i]); |
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416 | success = false; |
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417 | } |
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418 | totalseen += val.getData(); |
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419 | } |
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420 | } |
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421 | if (success) { |
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422 | if (in.next(key, val)) { |
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423 | System.err.println("Unnecessary lines in recomputed key!"); |
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424 | success = false; |
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425 | } |
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426 | } |
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427 | } finally { |
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428 | in.close(); |
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429 | } |
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430 | int originalTotal = 0; |
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431 | for (int i = 0; i < dist.length; i++) { |
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432 | originalTotal += dist[i]; |
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433 | } |
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434 | System.out.println("Original sum: " + originalTotal); |
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435 | System.out.println("Recomputed sum: " + totalseen); |
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436 | |
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437 | // |
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438 | // Write to "results" whether the test succeeded or not. |
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439 | // |
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440 | Path resultFile = new Path(testdir, "results"); |
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441 | BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fs.create(resultFile))); |
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442 | try { |
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443 | bw.write("Success=" + success + "\n"); |
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444 | System.out.println("Success=" + success); |
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445 | } finally { |
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446 | bw.close(); |
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447 | } |
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448 | fs.delete(testdir, true); |
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449 | } |
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450 | |
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451 | /** |
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452 | * Launches all the tasks in order. |
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453 | */ |
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454 | public static void main(String[] argv) throws Exception { |
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455 | if (argv.length < 2) { |
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456 | System.err.println("Usage: TestRecordMR <range> <counts>"); |
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457 | System.err.println(); |
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458 | System.err.println("Note: a good test will have a <counts> value that is substantially larger than the <range>"); |
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459 | return; |
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460 | } |
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461 | |
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462 | int i = 0; |
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463 | int range = Integer.parseInt(argv[i++]); |
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464 | int counts = Integer.parseInt(argv[i++]); |
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465 | launch(); |
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466 | } |
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467 | } |
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