MAPREDUCE-6780. Add support for HDFS directory with erasure code policy to TeraGen and TeraSort. Contributed by Sammi Chen

hadoop-mapreduce-project/hadoop-mapreduce-examples/src/main/java/org/apache/hadoop/examples/terasort/TeraGen.java

@@ -246,6 +246,9 @@ public class TeraGen extends Configured implements Tool {
 
   private static void usage() throws IOException {
     System.err.println("teragen <num rows> <output dir>");
+    System.err.println("If you want to generate data and store them as " +
+        "erasure code striping file, just make sure that the parent dir " +
+        "of <output dir> has erasure code policy set");
   }
 
   /**

hadoop-mapreduce-project/hadoop-mapreduce-examples/src/main/java/org/apache/hadoop/examples/terasort/TeraOutputFormat.java

@@ -20,6 +20,8 @@ package org.apache.hadoop.examples.terasort;
 
 import java.io.IOException;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileStatus;
@@ -40,6 +42,7 @@ import org.apache.hadoop.mapreduce.security.TokenCache;
  * An output format that writes the key and value appended together.
  */
 public class TeraOutputFormat extends FileOutputFormat<Text,Text> {
+  private static final Log LOG = LogFactory.getLog(TeraOutputFormat.class);
   private OutputCommitter committer = null;
 
   /**
@@ -74,10 +77,22 @@ public class TeraOutputFormat extends FileOutputFormat<Text,Text> {
       out.write(key.getBytes(), 0, key.getLength());
       out.write(value.getBytes(), 0, value.getLength());
     }
-    
+
     public void close(TaskAttemptContext context) throws IOException {
       if (finalSync) {
-        out.hsync();
+        try {
+          out.hsync();
+        } catch (UnsupportedOperationException e) {
+          /*
+           * Currently, hsync operation on striping file with erasure code
+           * policy is not supported yet. So this is a workaround to make
+           * teragen and terasort to support directory with striping files. In
+           * future, if the hsync operation is supported on striping file, this
+           * workaround should be removed.
+           */
+          LOG.info("Operation hsync is not supported so far on path with " +
+                  "erasure code policy set");
+        }
       }
       out.close();
     }
@@ -135,5 +150,4 @@ public class TeraOutputFormat extends FileOutputFormat<Text,Text> {
     }
     return committer;
   }
-
 }

hadoop-mapreduce-project/hadoop-mapreduce-examples/src/main/java/org/apache/hadoop/examples/terasort/TeraSort.java

@@ -287,6 +287,9 @@ public class TeraSort extends Configured implements Tool {
     for (TeraSortConfigKeys teraSortConfigKeys : TeraSortConfigKeys.values()) {
       System.err.println(teraSortConfigKeys.toString());
     }
+    System.err.println("If you want to store the output data as " +
+        "erasure code striping file, just make sure that the parent dir " +
+        "of <out> has erasure code policy set");
   }
 
   public int run(String[] args) throws Exception {