blob: b1becf1c70e2f8d566a2e45266bf557d67186644 [file] [log] [blame]
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "hadoop/Pipes.hh"
#include "hadoop/TemplateFactory.hh"
class SortMap: public HadoopPipes::Mapper {
private:
/* the fraction 0.0 to 1.0 of records to keep */
float keepFraction;
/* the number of records kept so far */
long long keptRecords;
/* the total number of records */
long long totalRecords;
static const std::string MAP_KEEP_PERCENT;
public:
/*
* Look in the config to find the fraction of records to keep.
*/
SortMap(HadoopPipes::TaskContext& context){
const HadoopPipes::JobConf* conf = context.getJobConf();
if (conf->hasKey(MAP_KEEP_PERCENT)) {
keepFraction = conf->getFloat(MAP_KEEP_PERCENT) / 100.0;
} else {
keepFraction = 1.0;
}
keptRecords = 0;
totalRecords = 0;
}
void map(HadoopPipes::MapContext& context) {
totalRecords += 1;
while ((float) keptRecords / totalRecords < keepFraction) {
keptRecords += 1;
context.emit(context.getInputKey(), context.getInputValue());
}
}
};
const std::string SortMap::MAP_KEEP_PERCENT("hadoop.sort.map.keep.percent");
class SortReduce: public HadoopPipes::Reducer {
private:
/* the fraction 0.0 to 1.0 of records to keep */
float keepFraction;
/* the number of records kept so far */
long long keptRecords;
/* the total number of records */
long long totalRecords;
static const std::string REDUCE_KEEP_PERCENT;
public:
SortReduce(HadoopPipes::TaskContext& context){
const HadoopPipes::JobConf* conf = context.getJobConf();
if (conf->hasKey(REDUCE_KEEP_PERCENT)) {
keepFraction = conf->getFloat(REDUCE_KEEP_PERCENT) / 100.0;
} else {
keepFraction = 1.0;
}
keptRecords = 0;
totalRecords = 0;
}
void reduce(HadoopPipes::ReduceContext& context) {
while (context.nextValue()) {
totalRecords += 1;
while ((float) keptRecords / totalRecords < keepFraction) {
keptRecords += 1;
context.emit(context.getInputKey(), context.getInputValue());
}
}
}
};
const std::string
SortReduce::REDUCE_KEEP_PERCENT("hadoop.sort.reduce.keep.percent");
int main(int argc, char *argv[]) {
return HadoopPipes::runTask(HadoopPipes::TemplateFactory<SortMap,
SortReduce>());
}