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MAPREDUCE-3685. Fix bugs in MergeManager to ensure compression codec is appropriately used and that on-disk segments are correctly sorted on file-size. Contributed by Anty Rao and Ravi Prakash.

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git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1453365 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Arun Murthy 2013-03-06 15:02:45 +00:00
parent e1062b8b78
commit df68c56267
5 changed files with 103 additions and 11 deletions
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4
hadoop-mapreduce-project/CHANGES.txt
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@ -201,6 +201,10 @@ Release 2.0.4-beta - UNRELEASED
MAPREDUCE-4896. mapred queue -info spits out ugly exception when queue does
not exist. (sandyr via tucu)
MAPREDUCE-3685. Fix bugs in MergeManager to ensure compression codec is
appropriately used and that on-disk segments are correctly sorted on
file-size. (Anty Rao and Ravi Prakash via acmurthy)
Release 2.0.3-alpha - 2013-02-06
INCOMPATIBLE CHANGES

2
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/Merger.java
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@ -169,7 +169,7 @@ RawKeyValueIterator merge(Configuration conf, FileSystem fs,
}
static <K extends Object, V extends Object>
public static <K extends Object, V extends Object>
RawKeyValueIterator merge(Configuration conf, FileSystem fs,
Class<K> keyClass, Class<V> valueClass,
CompressionCodec codec,

33
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/task/reduce/MergeManagerImpl.java
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@ -477,7 +477,7 @@ public void merge(List<InMemoryMapOutput<K,V>> inputs) throws IOException {
}
writer.close();
compressAwarePath = new CompressAwarePath(outputPath,
writer.getRawLength());
writer.getRawLength(), writer.getCompressedLength());
LOG.info(reduceId +
" Merge of the " + noInMemorySegments +
@ -500,7 +500,7 @@ public void merge(List<InMemoryMapOutput<K,V>> inputs) throws IOException {
private class OnDiskMerger extends MergeThread<CompressAwarePath,K,V> {
public OnDiskMerger(MergeManagerImpl<K, V> manager) {
super(manager, Integer.MAX_VALUE, exceptionReporter);
super(manager, ioSortFactor, exceptionReporter);
setName("OnDiskMerger - Thread to merge on-disk map-outputs");
setDaemon(true);
}
@ -554,7 +554,7 @@ public void merge(List<CompressAwarePath> inputs) throws IOException {
Merger.writeFile(iter, writer, reporter, jobConf);
writer.close();
compressAwarePath = new CompressAwarePath(outputPath,
writer.getRawLength());
writer.getRawLength(), writer.getCompressedLength());
} catch (IOException e) {
localFS.delete(outputPath, true);
throw e;
@ -719,7 +719,7 @@ private RawKeyValueIterator finalMerge(JobConf job, FileSystem fs,
Merger.writeFile(rIter, writer, reporter, job);
writer.close();
onDiskMapOutputs.add(new CompressAwarePath(outputPath,
writer.getRawLength()));
writer.getRawLength(), writer.getCompressedLength()));
writer = null;
// add to list of final disk outputs.
} catch (IOException e) {
@ -791,7 +791,7 @@ public int compare(Segment<K, V> o1, Segment<K, V> o2) {
// merges. See comment where mergePhaseFinished is being set
Progress thisPhase = (mergePhaseFinished) ? null : mergePhase;
RawKeyValueIterator diskMerge = Merger.merge(
job, fs, keyClass, valueClass, diskSegments,
job, fs, keyClass, valueClass, codec, diskSegments,
ioSortFactor, numInMemSegments, tmpDir, comparator,
reporter, false, spilledRecordsCounter, null, thisPhase);
diskSegments.clear();
@ -810,16 +810,22 @@ public int compare(Segment<K, V> o1, Segment<K, V> o2) {
static class CompressAwarePath extends Path {
private long rawDataLength;
private long compressedSize;
public CompressAwarePath(Path path, long rawDataLength) {
public CompressAwarePath(Path path, long rawDataLength, long compressSize) {
super(path.toUri());
this.rawDataLength = rawDataLength;
this.compressedSize = compressSize;
}
public long getRawDataLength() {
return rawDataLength;
}
public long getCompressedSize() {
return compressedSize;
}
@Override
public boolean equals(Object other) {
return super.equals(other);
@ -829,5 +835,20 @@ public boolean equals(Object other) {
public int hashCode() {
return super.hashCode();
}
@Override
public int compareTo(Object obj) {
if(obj instanceof CompressAwarePath) {
CompressAwarePath compPath = (CompressAwarePath) obj;
if(this.compressedSize < compPath.getCompressedSize()) {
return -1;
} else if (this.getCompressedSize() > compPath.getCompressedSize()) {
return 1;
}
// Not returning 0 here so that objects with the same size (but
// different paths) are still added to the TreeSet.
}
return super.compareTo(obj);
}
}
}

4
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/task/reduce/OnDiskMapOutput.java
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@ -48,6 +48,7 @@ class OnDiskMapOutput<K, V> extends MapOutput<K, V> {
private final Path outputPath;
private final MergeManagerImpl<K, V> merger;
private final OutputStream disk;
private long compressedSize;
public OnDiskMapOutput(TaskAttemptID mapId, TaskAttemptID reduceId,
MergeManagerImpl<K, V> merger, long size,
@ -108,13 +109,14 @@ public void shuffle(MapHost host, InputStream input,
bytesLeft + " bytes missing of " +
compressedLength + ")");
}
this.compressedSize = compressedLength;
}
@Override
public void commit() throws IOException {
localFS.rename(tmpOutputPath, outputPath);
CompressAwarePath compressAwarePath = new CompressAwarePath(outputPath,
getSize());
getSize(), this.compressedSize);
merger.closeOnDiskFile(compressAwarePath);
}

67
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/test/java/org/apache/hadoop/mapreduce/task/reduce/TestMergeManager.java
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@ -17,28 +17,38 @@
*/
package org.apache.hadoop.mapreduce.task.reduce;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.mockito.Mockito.mock;
import java.io.IOException;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocalFileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.BoundedByteArrayOutputStream;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MROutputFiles;
import org.apache.hadoop.mapred.MapOutputFile;
import org.apache.hadoop.mapreduce.MRJobConfig;
import org.apache.hadoop.mapreduce.task.reduce.MergeManagerImpl.CompressAwarePath;
import org.junit.Assert;
import org.junit.Test;
import org.mockito.internal.util.reflection.Whitebox;
public class TestMergeManager {
@Test(timeout=10000)
@SuppressWarnings("unchecked")
public void testMemoryMerge() throws Exception {
final int TOTAL_MEM_BYTES = 10000;
final int OUTPUT_SIZE = 7950;
@ -195,4 +205,59 @@ public int getNumExceptions() {
return exceptions.size();
}
}
@SuppressWarnings({ "unchecked", "deprecation" })
@Test(timeout=10000)
public void testOnDiskMerger() throws IOException, URISyntaxException,
InterruptedException {
JobConf jobConf = new JobConf();
final int SORT_FACTOR = 5;
jobConf.setInt(MRJobConfig.IO_SORT_FACTOR, SORT_FACTOR);
MapOutputFile mapOutputFile = new MROutputFiles();
FileSystem fs = FileSystem.getLocal(jobConf);
MergeManagerImpl<IntWritable, IntWritable> manager =
new MergeManagerImpl<IntWritable, IntWritable>(null, jobConf, fs, null
, null, null, null, null, null, null, null, null, null, mapOutputFile);
MergeThread<MapOutput<IntWritable, IntWritable>, IntWritable, IntWritable>
onDiskMerger = (MergeThread<MapOutput<IntWritable, IntWritable>,
IntWritable, IntWritable>) Whitebox.getInternalState(manager,
"onDiskMerger");
int mergeFactor = (Integer) Whitebox.getInternalState(onDiskMerger,
"mergeFactor");
// make sure the io.sort.factor is set properly
assertEquals(mergeFactor, SORT_FACTOR);
// Stop the onDiskMerger thread so that we can intercept the list of files
// waiting to be merged.
onDiskMerger.suspend();
//Send the list of fake files waiting to be merged
Random rand = new Random();
for(int i = 0; i < 2*SORT_FACTOR; ++i) {
Path path = new Path("somePath");
CompressAwarePath cap = new CompressAwarePath(path, 1l, rand.nextInt());
manager.closeOnDiskFile(cap);
}
//Check that the files pending to be merged are in sorted order.
LinkedList<List<CompressAwarePath>> pendingToBeMerged =
(LinkedList<List<CompressAwarePath>>) Whitebox.getInternalState(
onDiskMerger, "pendingToBeMerged");
assertTrue("No inputs were added to list pending to merge",
pendingToBeMerged.size() > 0);
for(int i = 0; i < pendingToBeMerged.size(); ++i) {
List<CompressAwarePath> inputs = pendingToBeMerged.get(i);
for(int j = 1; j < inputs.size(); ++j) {
assertTrue("Not enough / too many inputs were going to be merged",
inputs.size() > 0 && inputs.size() <= SORT_FACTOR);
assertTrue("Inputs to be merged were not sorted according to size: ",
inputs.get(j).getCompressedSize()
>= inputs.get(j-1).getCompressedSize());
}
}
}
}