/**
* 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.
*/
package org.apache.hadoop.mapred;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.examples.RandomWriter;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.mapred.lib.IdentityReducer;
import org.apache.hadoop.util.ToolRunner;
import junit.framework.TestCase;
/**
* A JUnit test to test the Map-Reduce framework's sort in presence of
* null intermediate map-outputs, when compression is enabled for intermediate
* map-outputs.
*/
public class TestCompressedEmptyMapOutputs extends TestCase {
// Input/Output paths for sort
private static final Path SORT_INPUT_PATH = new Path("/sort/input");
private static final Path SORT_OUTPUT_PATH = new Path("/sort/output");
// Knobs to control randomwriter; and hence sort
private static final int NUM_HADOOP_SLAVES = 3;
private static final int RW_BYTES_PER_MAP = 50000;
private static final int RW_MAPS_PER_HOST = 5;
private static void runRandomWriter(JobConf job, Path sortInput)
throws Exception {
// Scale down the default settings for RandomWriter for the test-case
// Generates NUM_HADOOP_SLAVES * RW_MAPS_PER_HOST * RW_BYTES_PER_MAP -> 1MB
job.setInt("test.randomwrite.bytes_per_map", RW_BYTES_PER_MAP);
job.setInt("test.randomwriter.maps_per_host", RW_MAPS_PER_HOST);
String[] rwArgs = {sortInput.toString()};
// Run RandomWriter
assertEquals(ToolRunner.run(job, new RandomWriter(), rwArgs), 0);
}
static class SinkMapper<K, V>
extends MapReduceBase implements Mapper<K, V, K, V> {
public void map(K key, V val,
OutputCollector<K, V> output, Reporter reporter)
throws IOException {
// Don't output anything!
if (false) output.collect(key, val);
}
}
private static void runSort(JobConf jobConf, Path sortInput, Path sortOutput)
throws Exception {
// Set up the job
jobConf.setJobName("null-sorter");
jobConf.setMapperClass(SinkMapper.class);
jobConf.setReducerClass(IdentityReducer.class);
jobConf.setNumReduceTasks(2);
jobConf.setInputFormat(SequenceFileInputFormat.class);
jobConf.setOutputFormat(SequenceFileOutputFormat.class);
jobConf.setOutputKeyClass(BytesWritable.class);
jobConf.setOutputValueClass(BytesWritable.class);
FileInputFormat.setInputPaths(jobConf, sortInput);
FileOutputFormat.setOutputPath(jobConf, sortOutput);
// Compress the intermediate map-outputs!
jobConf.setCompressMapOutput(true);
// Run the job
JobClient.runJob(jobConf);
}
public void testMapReduceSortWithCompressedEmptyMapOutputs()
throws Exception {
MiniDFSCluster dfs = null;
MiniMRCluster mr = null;
FileSystem fileSys = null;
try {
Configuration conf = new Configuration();
// Start the mini-MR and mini-DFS clusters
dfs = new MiniDFSCluster(conf, NUM_HADOOP_SLAVES, true, null);
fileSys = dfs.getFileSystem();
mr = new MiniMRCluster(NUM_HADOOP_SLAVES, fileSys.getUri().toString(), 1);
// Run randomwriter to generate input for 'sort'
runRandomWriter(mr.createJobConf(), SORT_INPUT_PATH);
// Run sort
runSort(mr.createJobConf(), SORT_INPUT_PATH, SORT_OUTPUT_PATH);
} finally {
if (dfs != null) { dfs.shutdown(); }
if (mr != null) { mr.shutdown();
}
}
}
}