MAPREDUCE-2632. Avoid calling the partitioner when the numReduceTasks is 1. (Ravi Teja Ch N V and Sunil G via kasha)

This commit is contained in:
Karthik Kambatla 2015-05-08 10:18:29 -07:00
parent a0fae8dcae
commit bdbd10fde1
7 changed files with 161 additions and 5 deletions

View File

@ -109,6 +109,9 @@ Trunk (Unreleased)
MAPREDUCE-6057. Remove obsolete entries from mapred-default.xml MAPREDUCE-6057. Remove obsolete entries from mapred-default.xml
(Ray Chiang via aw) (Ray Chiang via aw)
MAPREDUCE-2632. Avoid calling the partitioner when the numReduceTasks is 1.
(Ravi Teja Ch N V and Sunil G via kasha)
BUG FIXES BUG FIXES
MAPREDUCE-6191. Improve clearing stale state of Java serialization MAPREDUCE-6191. Improve clearing stale state of Java serialization

View File

@ -95,7 +95,13 @@ Writable getEntry(MapFile.Reader[] readers,
Partitioner<K, V> partitioner, Partitioner<K, V> partitioner,
K key, K key,
V value) throws IOException { V value) throws IOException {
int part = partitioner.getPartition(key, value, readers.length); int readerLength = readers.length;
int part;
if (readerLength <= 1) {
part = 0;
} else {
part = partitioner.getPartition(key, value, readers.length);
}
return readers[part].get(key, value); return readers[part].get(key, value);
} }

View File

@ -30,6 +30,9 @@
* is the same as the number of reduce tasks for the job. Hence this controls * is the same as the number of reduce tasks for the job. Hence this controls
* which of the <code>m</code> reduce tasks the intermediate key (and hence the * which of the <code>m</code> reduce tasks the intermediate key (and hence the
* record) is sent for reduction.</p> * record) is sent for reduction.</p>
*
* <p>Note: A <code>Partitioner</code> is created only when there are multiple
* reducers.</p>
* *
* @see Reducer * @see Reducer
*/ */

View File

@ -31,9 +31,12 @@
* is the same as the number of reduce tasks for the job. Hence this controls * is the same as the number of reduce tasks for the job. Hence this controls
* which of the <code>m</code> reduce tasks the intermediate key (and hence the * which of the <code>m</code> reduce tasks the intermediate key (and hence the
* record) is sent for reduction.</p> * record) is sent for reduction.</p>
* *
* Note: If you require your Partitioner class to obtain the Job's configuration * <p>Note: A <code>Partitioner</code> is created only when there are multiple
* object, implement the {@link Configurable} interface. * reducers.</p>
*
* <p>Note: If you require your Partitioner class to obtain the Job's
* configuration object, implement the {@link Configurable} interface.</p>
* *
* @see Reducer * @see Reducer
*/ */

View File

@ -114,7 +114,13 @@ public boolean accept(Path path) {
public static <K extends WritableComparable<?>, V extends Writable> public static <K extends WritableComparable<?>, V extends Writable>
Writable getEntry(MapFile.Reader[] readers, Writable getEntry(MapFile.Reader[] readers,
Partitioner<K, V> partitioner, K key, V value) throws IOException { Partitioner<K, V> partitioner, K key, V value) throws IOException {
int part = partitioner.getPartition(key, value, readers.length); int readerLength = readers.length;
int part;
if (readerLength <= 1) {
part = 0;
} else {
part = partitioner.getPartition(key, value, readers.length);
}
return readers[part].get(key, value); return readers[part].get(key, value);
} }
} }

View File

@ -0,0 +1,70 @@
/**
* 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 static org.junit.Assert.assertTrue;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.MapFile.Reader;
import org.junit.Test;
import org.mockito.Mockito;
public class TestMapFileOutputFormat {
@SuppressWarnings("static-access")
@Test
public void testPartitionerShouldNotBeCalledWhenOneReducerIsPresent()
throws Exception {
MapFileOutputFormat outputFormat = new MapFileOutputFormat();
Reader reader = Mockito.mock(Reader.class);
Reader[] readers = new Reader[]{reader};
outputFormat.getEntry(readers, new MyPartitioner(), new Text(), new Text());
assertTrue(!MyPartitioner.isGetPartitionCalled());
}
protected void tearDown() throws Exception {
MyPartitioner.setGetPartitionCalled(false);
};
private static class MyPartitioner
implements
Partitioner<WritableComparable, Writable> {
private static boolean getPartitionCalled = false;
@Override
public int getPartition(WritableComparable key, Writable value,
int numPartitions) {
setGetPartitionCalled(true);
return -1;
}
public static boolean isGetPartitionCalled() {
return getPartitionCalled;
}
@Override
public void configure(JobConf job) {
}
public static void setGetPartitionCalled(boolean getPartitionCalled) {
MyPartitioner.getPartitionCalled = getPartitionCalled;
}
}
}

View File

@ -0,0 +1,65 @@
/**
* 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.mapreduce.lib.output;
import static org.junit.Assert.assertTrue;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.MapFile.Reader;
import org.apache.hadoop.mapreduce.Partitioner;
import org.junit.Test;
import org.mockito.Mockito;
public class TestMapFileOutputFormat {
@SuppressWarnings("static-access")
@Test
public void testPartitionerShouldNotBeCalledWhenOneReducerIsPresent()
throws Exception {
MapFileOutputFormat outputFormat = new MapFileOutputFormat();
Reader reader = Mockito.mock(Reader.class);
Reader[] readers = new Reader[]{reader};
outputFormat.getEntry(readers, new MyPartitioner(), new Text(), new Text());
assertTrue(!MyPartitioner.isGetPartitionCalled());
}
public void tearDown() throws Exception {
MyPartitioner.setGetPartitionCalled(false);
}
private static class MyPartitioner
extends
Partitioner<WritableComparable, Writable> {
private static boolean getPartitionCalled = false;
public static boolean isGetPartitionCalled() {
return getPartitionCalled;
}
@Override
public int getPartition(WritableComparable key, Writable value,
int numPartitions) {
setGetPartitionCalled(true);
return -1;
}
public static void setGetPartitionCalled(boolean getPartitionCalled) {
MyPartitioner.getPartitionCalled = getPartitionCalled;
}
}
}