HDFS-6268. Better sorting in NetworkTopology#pseudoSortByDistance when no local node is found. (wang)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1599842 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -147,6 +147,9 @@ Release 2.5.0 - UNRELEASED
     HDFS-6109 let sync_file_range() system call run in background
     (Liang Xie via stack)
 
+    HDFS-6268. Better sorting in NetworkTopology#pseudoSortByDistance when
+    no local node is found. (wang)
+
   OPTIMIZATIONS
 
     HDFS-6214. Webhdfs has poor throughput for files >2GB (daryn)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeManager.java

@@ -351,7 +351,8 @@ public class DatanodeManager {
         DFSUtil.DECOM_COMPARATOR;
         
     for (LocatedBlock b : locatedblocks) {
-      networktopology.pseudoSortByDistance(client, b.getLocations());
+      networktopology.sortByDistance(client, b.getLocations(), b
+          .getBlock().getBlockId());
       // Move decommissioned/stale datanodes to the bottom
       Arrays.sort(b.getLocations(), comparator);
     }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -1618,9 +1618,11 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       blockManager.getDatanodeManager().sortLocatedBlocks(
           clientMachine, blocks.getLocatedBlocks());
       
+      // lastBlock is not part of getLocatedBlocks(), might need to sort it too
       LocatedBlock lastBlock = blocks.getLastLocatedBlock();
       if (lastBlock != null) {
-        ArrayList<LocatedBlock> lastBlockList = new ArrayList<LocatedBlock>();
+        ArrayList<LocatedBlock> lastBlockList =
+            Lists.newArrayListWithCapacity(1);
         lastBlockList.add(lastBlock);
         blockManager.getDatanodeManager().sortLocatedBlocks(
                               clientMachine, lastBlockList);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestGetBlocks.java

@@ -169,6 +169,9 @@ public class TestGetBlocks {
       if (stm != null) {
         stm.close();
       }
+      if (client != null) {
+        client.close();
+      }
       cluster.shutdown();
     }
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshotFileLength.java

@@ -143,10 +143,10 @@ public class TestSnapshotFileLength {
 
     // Make sure we can read the entire file via its non-snapshot path.
     fileStatus = hdfs.getFileStatus(file1);
-    assertEquals(fileStatus.getLen(), BLOCKSIZE * 2);
+    assertEquals("Unexpected file length", BLOCKSIZE * 2, fileStatus.getLen());
     fis = hdfs.open(file1);
     bytesRead = fis.read(buffer, 0, buffer.length);
-    assertEquals(bytesRead, BLOCKSIZE * 2);
+    assertEquals("Unexpected # bytes read", BLOCKSIZE * 2, bytesRead);
     fis.close();
 
     Path file1snap1 =
@@ -156,21 +156,23 @@ public class TestSnapshotFileLength {
     assertEquals(fileStatus.getLen(), BLOCKSIZE);
     // Make sure we can only read up to the snapshot length.
     bytesRead = fis.read(buffer, 0, buffer.length);
-    assertEquals(bytesRead, BLOCKSIZE);
+    assertEquals("Unexpected # bytes read", BLOCKSIZE, bytesRead);
     fis.close();
 
-    PrintStream psBackup = System.out;
+    PrintStream outBackup = System.out;
+    PrintStream errBackup = System.err;
     ByteArrayOutputStream bao = new ByteArrayOutputStream();
     System.setOut(new PrintStream(bao));
     System.setErr(new PrintStream(bao));
     // Make sure we can cat the file upto to snapshot length
     FsShell shell = new FsShell();
-    try{
+    try {
       ToolRunner.run(conf, shell, new String[] { "-cat",
       "/TestSnapshotFileLength/sub1/.snapshot/snapshot1/file1" });
-      assertEquals(bao.size(), BLOCKSIZE);
-    }finally{
-      System.setOut(psBackup);
+      assertEquals("Unexpected # bytes from -cat", BLOCKSIZE, bao.size());
+    } finally {
+      System.setOut(outBackup);
+      System.setErr(errBackup);
     }
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/net/TestHdfsNetworkTopologyWithNodeGroup.java

@@ -86,7 +86,7 @@ public class TestHdfsNetworkTopologyWithNodeGroup extends TestCase {
     assertEquals(cluster.getDistance(dataNodes[0], dataNodes[6]), 8);
   }
 
-  public void testPseudoSortByDistance() throws Exception {
+  public void testSortByDistance() throws Exception {
     DatanodeDescriptor[] testNodes = new DatanodeDescriptor[4];
 
     // array contains both local node, local node group & local rack node
@@ -94,7 +94,7 @@ public class TestHdfsNetworkTopologyWithNodeGroup extends TestCase {
     testNodes[1] = dataNodes[2];
     testNodes[2] = dataNodes[3];
     testNodes[3] = dataNodes[0];
-    cluster.pseudoSortByDistance(dataNodes[0], testNodes );
+    cluster.sortByDistance(dataNodes[0], testNodes, 0xDEADBEEF);
     assertTrue(testNodes[0] == dataNodes[0]);
     assertTrue(testNodes[1] == dataNodes[1]);
     assertTrue(testNodes[2] == dataNodes[2]);
@@ -105,7 +105,7 @@ public class TestHdfsNetworkTopologyWithNodeGroup extends TestCase {
     testNodes[1] = dataNodes[4];
     testNodes[2] = dataNodes[1];
     testNodes[3] = dataNodes[0];
-    cluster.pseudoSortByDistance(dataNodes[0], testNodes );
+    cluster.sortByDistance(dataNodes[0], testNodes, 0xDEADBEEF);
     assertTrue(testNodes[0] == dataNodes[0]);
     assertTrue(testNodes[1] == dataNodes[1]);
 
@@ -114,7 +114,7 @@ public class TestHdfsNetworkTopologyWithNodeGroup extends TestCase {
     testNodes[1] = dataNodes[3];
     testNodes[2] = dataNodes[2];
     testNodes[3] = dataNodes[0];
-    cluster.pseudoSortByDistance(dataNodes[0], testNodes );
+    cluster.sortByDistance(dataNodes[0], testNodes, 0xDEADBEEF);
     assertTrue(testNodes[0] == dataNodes[0]);
     assertTrue(testNodes[1] == dataNodes[2]);
 
@@ -123,7 +123,7 @@ public class TestHdfsNetworkTopologyWithNodeGroup extends TestCase {
     testNodes[1] = dataNodes[7];
     testNodes[2] = dataNodes[2];
     testNodes[3] = dataNodes[0];
-    cluster.pseudoSortByDistance(computeNode, testNodes );
+    cluster.sortByDistance(computeNode, testNodes, 0xDEADBEEF);
     assertTrue(testNodes[0] == dataNodes[0]);
     assertTrue(testNodes[1] == dataNodes[2]);
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/net/TestNetworkTopology.java

@@ -54,7 +54,8 @@ public class TestNetworkTopology {
         DFSTestUtil.getDatanodeDescriptor("4.4.4.4", "/d1/r2"),
         DFSTestUtil.getDatanodeDescriptor("5.5.5.5", "/d1/r2"),
         DFSTestUtil.getDatanodeDescriptor("6.6.6.6", "/d2/r3"),
-        DFSTestUtil.getDatanodeDescriptor("7.7.7.7", "/d2/r3")
+        DFSTestUtil.getDatanodeDescriptor("7.7.7.7", "/d2/r3"),
+        DFSTestUtil.getDatanodeDescriptor("8.8.8.8", "/d2/r3")
     };
     for (int i = 0; i < dataNodes.length; i++) {
       cluster.add(dataNodes[i]);
@@ -117,14 +118,14 @@ public class TestNetworkTopology {
   }
 
   @Test
-  public void testPseudoSortByDistance() throws Exception {
+  public void testSortByDistance() throws Exception {
     DatanodeDescriptor[] testNodes = new DatanodeDescriptor[3];
     
     // array contains both local node & local rack node
     testNodes[0] = dataNodes[1];
     testNodes[1] = dataNodes[2];
     testNodes[2] = dataNodes[0];
-    cluster.pseudoSortByDistance(dataNodes[0], testNodes );
+    cluster.sortByDistance(dataNodes[0], testNodes, 0xDEADBEEF);
     assertTrue(testNodes[0] == dataNodes[0]);
     assertTrue(testNodes[1] == dataNodes[1]);
     assertTrue(testNodes[2] == dataNodes[2]);
@@ -133,7 +134,7 @@ public class TestNetworkTopology {
     testNodes[0] = dataNodes[1];
     testNodes[1] = dataNodes[3];
     testNodes[2] = dataNodes[0];
-    cluster.pseudoSortByDistance(dataNodes[0], testNodes );
+    cluster.sortByDistance(dataNodes[0], testNodes, 0xDEADBEEF);
     assertTrue(testNodes[0] == dataNodes[0]);
     assertTrue(testNodes[1] == dataNodes[1]);
     assertTrue(testNodes[2] == dataNodes[3]);
@@ -142,21 +143,50 @@ public class TestNetworkTopology {
     testNodes[0] = dataNodes[5];
     testNodes[1] = dataNodes[3];
     testNodes[2] = dataNodes[1];
-    cluster.pseudoSortByDistance(dataNodes[0], testNodes );
+    cluster.sortByDistance(dataNodes[0], testNodes, 0xDEADBEEF);
     assertTrue(testNodes[0] == dataNodes[1]);
     assertTrue(testNodes[1] == dataNodes[3]);
     assertTrue(testNodes[2] == dataNodes[5]);
-    
+
     // array contains local rack node which happens to be in position 0
     testNodes[0] = dataNodes[1];
     testNodes[1] = dataNodes[5];
     testNodes[2] = dataNodes[3];
-    cluster.pseudoSortByDistance(dataNodes[0], testNodes );
-    // peudoSortByDistance does not take the "data center" layer into consideration 
+    cluster.sortByDistance(dataNodes[0], testNodes, 0xDEADBEEF);
+    assertTrue(testNodes[0] == dataNodes[1]);
+    assertTrue(testNodes[1] == dataNodes[3]);
+    assertTrue(testNodes[2] == dataNodes[5]);
+
+    // Same as previous, but with a different random seed to test randomization
+    testNodes[0] = dataNodes[1];
+    testNodes[1] = dataNodes[5];
+    testNodes[2] = dataNodes[3];
+    cluster.sortByDistance(dataNodes[0], testNodes, 0xDEAD);
+    // sortByDistance does not take the "data center" layer into consideration
     // and it doesn't sort by getDistance, so 1, 5, 3 is also valid here
     assertTrue(testNodes[0] == dataNodes[1]);
     assertTrue(testNodes[1] == dataNodes[5]);
     assertTrue(testNodes[2] == dataNodes[3]);
+
+    // Array is just local rack nodes
+    // Expect a random first node depending on the seed (normally the block ID).
+    DatanodeDescriptor first = null;
+    boolean foundRandom = false;
+    for (int i=5; i<=7; i++) {
+      testNodes[0] = dataNodes[5];
+      testNodes[1] = dataNodes[6];
+      testNodes[2] = dataNodes[7];
+      cluster.sortByDistance(dataNodes[i], testNodes, 0xBEADED+i);
+      if (first == null) {
+        first = testNodes[0];
+      } else {
+        if (first != testNodes[0]) {
+          foundRandom = true;
+          break;
+        }
+      }
+    }
+    assertTrue("Expected to find a different first location", foundRandom);
   }
   
   @Test