MAPREDUCE-5168. Reducer can OOM during shuffle because on-disk outputstream not released. Contributed by Jason Lowe

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1482463 13f79535-47bb-0310-9956-ffa450edef68

hadoop-mapreduce-project/CHANGES.txt

@@ -27,6 +27,9 @@ Release 0.23.8 - UNRELEASED
     MAPREDUCE-5211. Reducer intermediate files can collide during merge
     (jlowe)
 
+    MAPREDUCE-5168. Reducer can OOM during shuffle because on-disk output
+    stream not released (jlowe)
+
 Release 0.23.7 - 2013-04-18
 
   INCOMPATIBLE CHANGES

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/task/reduce/MapOutput.java

@@ -24,7 +24,6 @@ import java.util.concurrent.atomic.AtomicInteger;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.LocalDirAllocator;
 import org.apache.hadoop.fs.Path;
@@ -56,7 +55,7 @@ class MapOutput<K,V> {
   private final FileSystem localFS;
   private final Path tmpOutputPath;
   private final Path outputPath;
-  private final OutputStream disk; 
+  private OutputStream disk; 
   
   private final Type type;
   
@@ -193,6 +192,7 @@ class MapOutput<K,V> {
     } else if (type == Type.DISK) {
       localFS.rename(tmpOutputPath, outputPath);
       merger.closeOnDiskFile(this);
+      disk = null;
     } else {
       throw new IOException("Cannot commit MapOutput of type WAIT!");
     }
@@ -207,6 +207,7 @@ class MapOutput<K,V> {
       } catch (IOException ie) {
         LOG.info("failure to clean up " + tmpOutputPath, ie);
       }
+      disk = null;
     } else {
       throw new IllegalArgumentException
                    ("Cannot commit MapOutput with of type WAIT!");

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/test/java/org/apache/hadoop/mapreduce/task/reduce/TestMapOutput.java

@@ -0,0 +1,85 @@
+/**
+ * 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.task.reduce;
+
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyLong;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.io.IOException;
+
+import org.apache.hadoop.fs.FileContext;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.UnsupportedFileSystemException;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapred.JobConf;
+import org.apache.hadoop.mapred.MapOutputFile;
+import org.apache.hadoop.mapreduce.TaskAttemptID;
+import org.apache.hadoop.mapreduce.TaskID;
+import org.apache.hadoop.mapreduce.TaskType;
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class TestMapOutput {
+
+  private static final FileContext lfs = getLfs();
+  private static final FileContext getLfs() {
+    try {
+      return FileContext.getLocalFSFileContext();
+    } catch (UnsupportedFileSystemException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  private static final Path base =
+    lfs.makeQualified(new Path("target", TestMapOutput.class.getName()));
+
+  @BeforeClass
+  public static void createBase() throws IOException {
+    lfs.mkdir(base,  null, true);
+  }
+
+  @AfterClass
+  public static void removeBase() throws IOException {
+    lfs.delete(base, true);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Test
+  public void testDiskOutputBufferLeak() throws IOException {
+    MapOutputFile mof = mock(MapOutputFile.class);
+    when(mof.getInputFileForWrite(any(TaskID.class), anyLong())).thenReturn(
+        new Path(base, "mapoutputfile"));
+    TaskAttemptID mtid = new TaskAttemptID("0", 1, TaskType.MAP, 1, 1);
+    MergeManager<Text,Text> merger = mock(MergeManager.class);
+    MapOutput<Text,Text> odmo = new MapOutput<Text,Text>(
+        mtid, merger, 0, new JobConf(), null, 0, true, mof);
+    Assert.assertNotNull(odmo.getDisk());
+    odmo.commit();
+    Assert.assertNull(odmo.getDisk());
+
+    odmo = new MapOutput<Text,Text>(
+        mtid, merger, 0, new JobConf(), null, 0, true, mof);
+    Assert.assertNotNull(odmo.getDisk());
+    odmo.abort();
+    Assert.assertNull(odmo.getDisk());
+  }
+}