Author: tucu
Date: Mon Jan 6 18:46:17 2014
New Revision: 1555972
URL: http://svn.apache.org/r1555972
Log:
MAPREDUCE-3310. Custom grouping comparator cannot be set for Combiners (tucu)
Added:
hadoop/common/branches/branch-1/src/test/org/apache/hadoop/mapred/TestOldCombinerGrouping.java
hadoop/common/branches/branch-1/src/test/org/apache/hadoop/mapreduce/TestNewCombinerGrouping.java
Modified:
hadoop/common/branches/branch-1/CHANGES.txt
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapred/JobConf.java
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapred/Task.java
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapreduce/Job.java
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapreduce/JobContext.java
Modified: hadoop/common/branches/branch-1/CHANGES.txt
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-1/CHANGES.txt?rev=1555972&r1=1555971&r2=1555972&view=diff
==============================================================================
--- hadoop/common/branches/branch-1/CHANGES.txt (original)
+++ hadoop/common/branches/branch-1/CHANGES.txt Mon Jan 6 18:46:17 2014
@@ -49,6 +49,9 @@ Release 1.3.0 - unreleased
MAPREDUCE-5609. Add debug log message when sending job end notification.
(rkanter via tucu)
+ MAPREDUCE-3310. Custom grouping comparator cannot be set for Combiners
+ (tucu)
+
BUG FIXES
HADOOP-9863. Backport HADOOP-8686 to support BigEndian on ppc64.
Modified:
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapred/JobConf.java
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapred/JobConf.java?rev=1555972&r1=1555971&r2=1555972&view=diff
==============================================================================
---
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapred/JobConf.java
(original)
+++
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapred/JobConf.java
Mon Jan 6 18:46:17 2014
@@ -21,10 +21,6 @@ package org.apache.hadoop.mapred;
import java.io.IOException;
-import java.net.URL;
-import java.net.URLDecoder;
-import java.util.Enumeration;
-
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.filecache.DistributedCache;
@@ -883,6 +879,24 @@ public class JobConf extends Configurati
return get("mapred.text.key.partitioner.options");
}
+ /**
+ * Get the user defined {@link WritableComparable} comparator for
+ * grouping keys of inputs to the combiner.
+ *
+ * @return comparator set by the user for grouping values.
+ * @see #setCombinerKeyGroupingComparator(Class) for details.
+ */
+ public RawComparator getCombinerKeyGroupingComparator() {
+ Class<? extends RawComparator> theClass = getClass(
+ "mapred.combiner.groupfn.class", null, RawComparator.class);
+ if (theClass == null) {
+ return getOutputKeyComparator();
+ }
+
+ return ReflectionUtils.newInstance(theClass, this);
+ }
+
+
/**
* Get the user defined {@link WritableComparable} comparator for
* grouping keys of inputs to the reduce.
@@ -900,6 +914,37 @@ public class JobConf extends Configurati
return ReflectionUtils.newInstance(theClass, this);
}
+
+ /**
+ * Set the user defined {@link RawComparator} comparator for
+ * grouping keys in the input to the combiner.
+ * <p/>
+ * <p>This comparator should be provided if the equivalence rules for keys
+ * for sorting the intermediates are different from those for grouping keys
+ * before each call to
+ * {@link Reducer#reduce(Object, java.util.Iterator, OutputCollector,
Reporter)}.</p>
+ * <p/>
+ * <p>For key-value pairs (K1,V1) and (K2,V2), the values (V1, V2) are passed
+ * in a single call to the reduce function if K1 and K2 compare as equal.</p>
+ * <p/>
+ * <p>Since {@link #setOutputKeyComparatorClass(Class)} can be used to
control
+ * how keys are sorted, this can be used in conjunction to simulate
+ * <i>secondary sort on values</i>.</p>
+ * <p/>
+ * <p><i>Note</i>: This is not a guarantee of the combiner sort being
+ * <i>stable</i> in any sense. (In any case, with the order of available
+ * map-outputs to the combiner being non-deterministic, it wouldn't make
+ * that much sense.)</p>
+ *
+ * @param theClass the comparator class to be used for grouping keys for the
+ * combiner. It should implement <code>RawComparator</code>.
+ * @see #setOutputKeyComparatorClass(Class)
+ */
+ public void setCombinerKeyGroupingComparator(
+ Class<? extends RawComparator> theClass) {
+ setClass("mapred.combiner.groupfn.class", theClass, RawComparator.class);
+ }
+
/**
* Set the user defined {@link RawComparator} comparator for
* grouping keys in the input to the reduce.
@@ -923,7 +968,9 @@ public class JobConf extends Configurati
*
* @param theClass the comparator class to be used for grouping keys.
* It should implement <code>RawComparator</code>.
- * @see #setOutputKeyComparatorClass(Class)
+ * @see #setOutputKeyComparatorClass(Class)
+ * @see {@link #setCombinerKeyGroupingComparator(Class)} for setting a
+ * comparator for the combiner.
*/
public void setOutputValueGroupingComparator(
Class<? extends RawComparator> theClass) {
Modified:
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapred/Task.java
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapred/Task.java?rev=1555972&r1=1555971&r2=1555972&view=diff
==============================================================================
---
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapred/Task.java
(original)
+++
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapred/Task.java
Mon Jan 6 18:46:17 2014
@@ -56,7 +56,6 @@ import org.apache.hadoop.util.Reflection
import org.apache.hadoop.util.ResourceCalculatorPlugin;
import org.apache.hadoop.util.ResourceCalculatorPlugin.ProcResourceValues;
import org.apache.hadoop.util.StringUtils;
-import org.apache.hadoop.fs.FSDataInputStream;
/**
* Base class for tasks.
@@ -1425,7 +1424,8 @@ abstract public class Task implements Wr
combinerClass = cls;
keyClass = (Class<K>) job.getMapOutputKeyClass();
valueClass = (Class<V>) job.getMapOutputValueClass();
- comparator = (RawComparator<K>) job.getOutputKeyComparator();
+ comparator = (RawComparator<K>)
+ job.getCombinerKeyGroupingComparator();
}
@SuppressWarnings("unchecked")
@@ -1472,7 +1472,7 @@ abstract public class Task implements Wr
this.taskId = taskId;
keyClass = (Class<K>) context.getMapOutputKeyClass();
valueClass = (Class<V>) context.getMapOutputValueClass();
- comparator = (RawComparator<K>) context.getSortComparator();
+ comparator = (RawComparator<K>)
context.getCombinerKeyGroupingComparator();
this.committer = committer;
}
Modified:
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapreduce/Job.java
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapreduce/Job.java?rev=1555972&r1=1555971&r2=1555972&view=diff
==============================================================================
---
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapreduce/Job.java
(original)
+++
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapreduce/Job.java
Mon Jan 6 18:46:17 2014
@@ -24,7 +24,6 @@ import java.security.PrivilegedException
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.RawComparator;
-import org.apache.hadoop.mapreduce.TaskAttemptID;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.RunningJob;
@@ -290,11 +289,28 @@ public class Job extends JobContext {
/**
* Define the comparator that controls which keys are grouped together
+ * for a single call to combiner,
+ * {@link Reducer#reduce(Object, Iterable,
+ * org.apache.hadoop.mapreduce.Reducer.Context)}
+ *
+ * @param cls the raw comparator to use
+ * @throws IllegalStateException if the job is submitted
+ */
+ public void setCombinerKeyGroupingComparatorClass(
+ Class<? extends RawComparator> cls) throws IllegalStateException {
+ ensureState(JobState.DEFINE);
+ conf.setCombinerKeyGroupingComparator(cls);
+ }
+
+ /**
+ * Define the comparator that controls which keys are grouped together
* for a single call to
* {@link Reducer#reduce(Object, Iterable,
* org.apache.hadoop.mapreduce.Reducer.Context)}
* @param cls the raw comparator to use
* @throws IllegalStateException if the job is submitted
+ * @see {@link #setCombinerKeyGroupingComparatorClass(Class)} for setting a
+ * comparator for the combiner.
*/
public void setGroupingComparatorClass(Class<? extends RawComparator> cls
) throws IllegalStateException {
Modified:
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapreduce/JobContext.java
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapreduce/JobContext.java?rev=1555972&r1=1555971&r2=1555972&view=diff
==============================================================================
---
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapreduce/JobContext.java
(original)
+++
hadoop/common/branches/branch-1/src/mapred/org/apache/hadoop/mapreduce/JobContext.java
Mon Jan 6 18:46:17 2014
@@ -23,7 +23,6 @@ import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.RawComparator;
-import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.mapreduce.lib.partition.HashPartitioner;
@@ -268,12 +267,25 @@ public class JobContext {
return conf.getJar();
}
+ /**
+ * Get the user defined {@link RawComparator} comparator for
+ * grouping keys of inputs to the combiner.
+ *
+ * @return comparator set by the user for grouping values.
+ * @see Job#setCombinerKeyGroupingComparatorClass(Class) for details.
+ */
+ public RawComparator<?> getCombinerKeyGroupingComparator() {
+ return conf.getCombinerKeyGroupingComparator();
+ }
+
/**
* Get the user defined {@link RawComparator} comparator for
* grouping keys of inputs to the reduce.
*
* @return comparator set by the user for grouping values.
* @see Job#setGroupingComparatorClass(Class) for details.
+ * @see {@link #getCombinerKeyGroupingComparator()} for setting a
+ * comparator for the combiner.
*/
public RawComparator<?> getGroupingComparator() {
return conf.getOutputValueGroupingComparator();
Added:
hadoop/common/branches/branch-1/src/test/org/apache/hadoop/mapred/TestOldCombinerGrouping.java
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-1/src/test/org/apache/hadoop/mapred/TestOldCombinerGrouping.java?rev=1555972&view=auto
==============================================================================
---
hadoop/common/branches/branch-1/src/test/org/apache/hadoop/mapred/TestOldCombinerGrouping.java
(added)
+++
hadoop/common/branches/branch-1/src/test/org/apache/hadoop/mapred/TestOldCombinerGrouping.java
Mon Jan 6 18:46:17 2014
@@ -0,0 +1,189 @@
+/**
+ * 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 junit.framework.Assert;
+import junit.framework.TestCase;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.RawComparator;
+import org.apache.hadoop.io.Text;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Set;
+import java.util.UUID;
+
+public class TestOldCombinerGrouping extends TestCase {
+ private static String TEST_ROOT_DIR =
+ new File("build", UUID.randomUUID().toString()).getAbsolutePath();
+
+ public static class Map implements
+ Mapper<LongWritable, Text, Text, LongWritable> {
+ @Override
+ public void map(LongWritable key, Text value,
+ OutputCollector<Text, LongWritable> output, Reporter reporter)
+ throws IOException {
+ String v = value.toString();
+ String k = v.substring(0, v.indexOf(","));
+ v = v.substring(v.indexOf(",") + 1);
+ output.collect(new Text(k), new LongWritable(Long.parseLong(v)));
+ }
+
+ @Override
+ public void close() throws IOException {
+ }
+
+ @Override
+ public void configure(JobConf job) {
+ }
+ }
+
+ public static class Reduce implements
+ Reducer<Text, LongWritable, Text, LongWritable> {
+
+ @Override
+ public void reduce(Text key, Iterator<LongWritable> values,
+ OutputCollector<Text, LongWritable> output, Reporter reporter)
+ throws IOException {
+ LongWritable maxValue = null;
+ while (values.hasNext()) {
+ LongWritable value = values.next();
+ if (maxValue == null) {
+ maxValue = value;
+ } else if (value.compareTo(maxValue) > 0) {
+ maxValue = value;
+ }
+ }
+ output.collect(key, maxValue);
+ }
+
+ @Override
+ public void close() throws IOException {
+ }
+
+ @Override
+ public void configure(JobConf job) {
+ }
+ }
+
+ public static class Combiner extends Reduce {
+ }
+
+ public static class GroupComparator implements RawComparator<Text> {
+ @Override
+ public int compare(byte[] bytes, int i, int i2, byte[] bytes2, int i3,
+ int i4) {
+ byte[] b1 = new byte[i2];
+ System.arraycopy(bytes, i, b1, 0, i2);
+
+ byte[] b2 = new byte[i4];
+ System.arraycopy(bytes2, i3, b2, 0, i4);
+
+ return compare(new Text(new String(b1)), new Text(new String(b2)));
+ }
+
+ @Override
+ public int compare(Text o1, Text o2) {
+ String s1 = o1.toString();
+ String s2 = o2.toString();
+ s1 = s1.substring(0, s1.indexOf("|"));
+ s2 = s2.substring(0, s2.indexOf("|"));
+ return s1.compareTo(s2);
+ }
+
+ }
+
+ public void testCombiner() throws Exception {
+ if (!new File(TEST_ROOT_DIR).mkdirs()) {
+ throw new RuntimeException("Could not create test dir: " +
TEST_ROOT_DIR);
+ }
+ File in = new File(TEST_ROOT_DIR, "input");
+ if (!in.mkdirs()) {
+ throw new RuntimeException("Could not create test dir: " + in);
+ }
+ File out = new File(TEST_ROOT_DIR, "output");
+ PrintWriter pw = new PrintWriter(new FileWriter(new File(in, "data.txt")));
+ pw.println("A|a,1");
+ pw.println("A|b,2");
+ pw.println("B|a,3");
+ pw.println("B|b,4");
+ pw.println("B|c,5");
+ pw.close();
+ JobConf job = new JobConf();
+ TextInputFormat.setInputPaths(job, new Path(in.getPath()));
+ TextOutputFormat.setOutputPath(job, new Path(out.getPath()));
+ job.setMapperClass(Map.class);
+ job.setReducerClass(Reduce.class);
+ job.setInputFormat(TextInputFormat.class);
+ job.setMapOutputKeyClass(Text.class);
+ job.setMapOutputValueClass(LongWritable.class);
+ job.setOutputFormat(TextOutputFormat.class);
+ job.setOutputValueGroupingComparator(GroupComparator.class);
+
+ job.setCombinerClass(Combiner.class);
+ job.setCombinerKeyGroupingComparator(GroupComparator.class);
+ job.setInt("min.num.spills.for.combine", 0);
+
+ JobClient client = new JobClient(job);
+ RunningJob runningJob = client.submitJob(job);
+ runningJob.waitForCompletion();
+ if (runningJob.isSuccessful()) {
+ Counters counters = runningJob.getCounters();
+
+ long combinerInputRecords = counters.getGroup(
+ "org.apache.hadoop.mapred.Task$Counter").
+ getCounterForName("COMBINE_INPUT_RECORDS").getValue();
+ long combinerOutputRecords = counters.getGroup(
+ "org.apache.hadoop.mapred.Task$Counter").
+ getCounterForName("COMBINE_OUTPUT_RECORDS").getValue();
+ Assert.assertTrue(combinerInputRecords > 0);
+ Assert.assertTrue(combinerInputRecords > combinerOutputRecords);
+
+ BufferedReader br = new BufferedReader(new FileReader(
+ new File(out, "part-00000")));
+ Set<String> output = new HashSet<String>();
+ String line = br.readLine();
+ Assert.assertNotNull(line);
+ output.add(line.substring(0, 1) + line.substring(4, 5));
+ line = br.readLine();
+ Assert.assertNotNull(line);
+ output.add(line.substring(0, 1) + line.substring(4, 5));
+ line = br.readLine();
+ Assert.assertNull(line);
+ br.close();
+
+ Set<String> expected = new HashSet<String>();
+ expected.add("A2");
+ expected.add("B5");
+
+ Assert.assertEquals(expected, output);
+
+ } else {
+ Assert.fail("Job failed");
+ }
+ }
+
+}
Added:
hadoop/common/branches/branch-1/src/test/org/apache/hadoop/mapreduce/TestNewCombinerGrouping.java
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-1/src/test/org/apache/hadoop/mapreduce/TestNewCombinerGrouping.java?rev=1555972&view=auto
==============================================================================
---
hadoop/common/branches/branch-1/src/test/org/apache/hadoop/mapreduce/TestNewCombinerGrouping.java
(added)
+++
hadoop/common/branches/branch-1/src/test/org/apache/hadoop/mapreduce/TestNewCombinerGrouping.java
Mon Jan 6 18:46:17 2014
@@ -0,0 +1,174 @@
+/**
+ * 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;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.RawComparator;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
+import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.UUID;
+
+public class TestNewCombinerGrouping extends TestCase {
+ private static String TEST_ROOT_DIR =
+ new File("build", UUID.randomUUID().toString()).getAbsolutePath();
+
+ public static class Map extends
+ Mapper<LongWritable, Text, Text, LongWritable> {
+
+ @Override
+ protected void map(LongWritable key, Text value,
+ Context context)
+ throws IOException, InterruptedException {
+ String v = value.toString();
+ String k = v.substring(0, v.indexOf(","));
+ v = v.substring(v.indexOf(",") + 1);
+ context.write(new Text(k), new LongWritable(Long.parseLong(v)));
+ }
+ }
+
+ public static class Reduce extends
+ Reducer<Text, LongWritable, Text, LongWritable> {
+
+ @Override
+ protected void reduce(Text key, Iterable<LongWritable> values,
+ Context context)
+ throws IOException, InterruptedException {
+ LongWritable maxValue = null;
+ for (LongWritable value : values) {
+ if (maxValue == null) {
+ maxValue = value;
+ } else if (value.compareTo(maxValue) > 0) {
+ maxValue = value;
+ }
+ }
+ context.write(key, maxValue);
+ }
+ }
+
+ public static class Combiner extends Reduce {
+ }
+
+ public static class GroupComparator implements RawComparator<Text> {
+ @Override
+ public int compare(byte[] bytes, int i, int i2, byte[] bytes2, int i3,
+ int i4) {
+ byte[] b1 = new byte[i2];
+ System.arraycopy(bytes, i, b1, 0, i2);
+
+ byte[] b2 = new byte[i4];
+ System.arraycopy(bytes2, i3, b2, 0, i4);
+
+ return compare(new Text(new String(b1)), new Text(new String(b2)));
+ }
+
+ @Override
+ public int compare(Text o1, Text o2) {
+ String s1 = o1.toString();
+ String s2 = o2.toString();
+ s1 = s1.substring(0, s1.indexOf("|"));
+ s2 = s2.substring(0, s2.indexOf("|"));
+ return s1.compareTo(s2);
+ }
+
+ }
+
+ public void testCombiner() throws Exception {
+ if (!new File(TEST_ROOT_DIR).mkdirs()) {
+ throw new RuntimeException("Could not create test dir: " +
TEST_ROOT_DIR);
+ }
+ File in = new File(TEST_ROOT_DIR, "input");
+ if (!in.mkdirs()) {
+ throw new RuntimeException("Could not create test dir: " + in);
+ }
+ File out = new File(TEST_ROOT_DIR, "output");
+ PrintWriter pw = new PrintWriter(new FileWriter(new File(in, "data.txt")));
+ pw.println("A|a,1");
+ pw.println("A|b,2");
+ pw.println("B|a,3");
+ pw.println("B|b,4");
+ pw.println("B|c,5");
+ pw.close();
+ Job job = new Job();
+ TextInputFormat.setInputPaths(job, new Path(in.getPath()));
+ TextOutputFormat.setOutputPath(job, new Path(out.getPath()));
+
+ job.setMapperClass(Map.class);
+ job.setReducerClass(Reduce.class);
+ job.setInputFormatClass(TextInputFormat.class);
+ job.setMapOutputKeyClass(Text.class);
+ job.setMapOutputValueClass(LongWritable.class);
+ job.setOutputFormatClass(TextOutputFormat.class);
+ job.setGroupingComparatorClass(GroupComparator.class);
+
+ job.setCombinerKeyGroupingComparatorClass(GroupComparator.class);
+ job.setCombinerClass(Combiner.class);
+ job.getConfiguration().setInt("min.num.spills.for.combine", 0);
+
+ job.submit();
+ job.waitForCompletion(false);
+ if (job.isSuccessful()) {
+ Counters counters = job.getCounters();
+
+ long combinerInputRecords = counters.findCounter(
+ "org.apache.hadoop.mapred.Task$Counter",
+ "COMBINE_INPUT_RECORDS").getValue();
+ long combinerOutputRecords = counters.findCounter(
+ "org.apache.hadoop.mapred.Task$Counter",
+ "COMBINE_OUTPUT_RECORDS").getValue();
+ Assert.assertTrue(combinerInputRecords > 0);
+ Assert.assertTrue(combinerInputRecords > combinerOutputRecords);
+
+ BufferedReader br = new BufferedReader(new FileReader(
+ new File(out, "part-r-00000")));
+ Set<String> output = new HashSet<String>();
+ String line = br.readLine();
+ Assert.assertNotNull(line);
+ output.add(line.substring(0,1) + line.substring(4, 5));
+ line = br.readLine();
+ Assert.assertNotNull(line);
+ output.add(line.substring(0, 1) + line.substring(4, 5));
+ line = br.readLine();
+ Assert.assertNull(line);
+ br.close();
+
+ Set<String> expected = new HashSet<String>();
+ expected.add("A2");
+ expected.add("B5");
+
+ Assert.assertEquals(expected, output);
+
+ } else {
+ Assert.fail("Job failed");
+ }
+ }
+
+}
