HDFS-9838. Refactor the excessReplicateMap to a class.

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

@@ -228,6 +228,8 @@ Trunk (Unreleased)
     HDFS-9829. Erasure Coding: Improve few exception handling logic of
     ErasureCodingWorker. (Rakesh R via jing9)
 
+    HDFS-9838. Refactor the excessReplicateMap to a class.  (szetszwo)
+
   OPTIMIZATIONS
 
   BUG FIXES

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

@@ -155,7 +155,6 @@ public class BlockManager implements BlockStatsMXBean {
   /** flag indicating whether replication queues have been initialized */
   private boolean initializedReplQueues;
 
-  private final AtomicLong excessBlocksCount = new AtomicLong(0L);
   private final AtomicLong postponedMisreplicatedBlocksCount = new AtomicLong(0L);
   private final long startupDelayBlockDeletionInMs;
   private final BlockReportLeaseManager blockReportLeaseManager;
@@ -187,7 +186,7 @@ public class BlockManager implements BlockStatsMXBean {
   }
   /** Used by metrics */
   public long getExcessBlocksCount() {
-    return excessBlocksCount.get();
+    return excessReplicas.size();
   }
   /** Used by metrics */
   public long getPostponedMisreplicatedBlocksCount() {
@@ -247,8 +246,7 @@ public class BlockManager implements BlockStatsMXBean {
    * Maps a StorageID to the set of blocks that are "extra" for this
    * DataNode. We'll eventually remove these extras.
    */
-  public final Map<String, LightWeightHashSet<BlockInfo>> excessReplicateMap =
-    new HashMap<>();
+  private final ExcessReplicaMap excessReplicas = new ExcessReplicaMap();
 
   /**
    * Store set of Blocks that need to be replicated 1 or more times.
@@ -1832,13 +1830,17 @@ public class BlockManager implements BlockStatsMXBean {
       }
       containingNodes.add(node);
 
-      // do not select corrupted replica as src. also do not select the block
-      // that is already in excess map
+      // do not select the replica if it is corrupt or excess
       if (state == StoredReplicaState.CORRUPT ||
           state == StoredReplicaState.EXCESS) {
         continue;
       }
 
+      // never use already decommissioned nodes or unknown state replicas
+      if (state == null || state == StoredReplicaState.DECOMMISSIONED) {
+        continue;
+      }
+
       if(priority != UnderReplicatedBlocks.QUEUE_HIGHEST_PRIORITY 
           && !node.isDecommissionInProgress() 
           && node.getNumberOfBlocksToBeReplicated() >= maxReplicationStreams) {
@@ -1847,10 +1849,6 @@ public class BlockManager implements BlockStatsMXBean {
       if (node.getNumberOfBlocksToBeReplicated() >= replicationStreamsHardLimit) {
         continue;
       }
-      // never use already decommissioned nodes
-      if (node.isDecommissioned()) {
-        continue;
-      }
 
       if(isStriped || srcNodes.isEmpty()) {
         srcNodes.add(node);
@@ -3194,9 +3192,7 @@ public class BlockManager implements BlockStatsMXBean {
         postponeBlock(block);
         return;
       }
-      LightWeightHashSet<BlockInfo> excessBlocks = excessReplicateMap.get(
-          cur.getDatanodeUuid());
-      if (excessBlocks == null || !excessBlocks.contains(block)) {
+      if (!isExcess(cur, block)) {
         if (!cur.isDecommissionInProgress() && !cur.isDecommissioned()) {
           // exclude corrupt replicas
           if (corruptNodes == null || !corruptNodes.contains(cur)) {
@@ -3335,7 +3331,7 @@ public class BlockManager implements BlockStatsMXBean {
       final Collection<DatanodeStorageInfo> nonExcess,
       final DatanodeStorageInfo chosen, BlockInfo storedBlock) {
     nonExcess.remove(chosen);
-    addToExcessReplicate(chosen.getDatanodeDescriptor(), storedBlock);
+    excessReplicas.add(chosen.getDatanodeDescriptor(), storedBlock);
     //
     // The 'excessblocks' tracks blocks until we get confirmation
     // that the datanode has deleted them; the only way we remove them
@@ -3351,21 +3347,6 @@ public class BlockManager implements BlockStatsMXBean {
         + "({}, {}) is added to invalidated blocks set", chosen, storedBlock);
   }
 
-  private void addToExcessReplicate(DatanodeInfo dn, BlockInfo storedBlock) {
-    assert namesystem.hasWriteLock();
-    LightWeightHashSet<BlockInfo> excessBlocks = excessReplicateMap.get(
-        dn.getDatanodeUuid());
-    if (excessBlocks == null) {
-      excessBlocks = new LightWeightHashSet<>();
-      excessReplicateMap.put(dn.getDatanodeUuid(), excessBlocks);
-    }
-    if (excessBlocks.add(storedBlock)) {
-      excessBlocksCount.incrementAndGet();
-      blockLog.debug("BLOCK* addToExcessReplicate: ({}, {}) is added to"
-          + " excessReplicateMap", dn, storedBlock);
-    }
-  }
-
   private void removeStoredBlock(DatanodeStorageInfo storageInfo, Block block,
       DatanodeDescriptor node) {
     if (shouldPostponeBlocksFromFuture && isGenStampInFuture(block)) {
@@ -3414,24 +3395,7 @@ public class BlockManager implements BlockStatsMXBean {
         updateNeededReplications(storedBlock, -1, 0);
       }
 
-      //
-      // We've removed a block from a node, so it's definitely no longer
-      // in "excess" there.
-      //
-      LightWeightHashSet<BlockInfo> excessBlocks = excessReplicateMap.get(
-          node.getDatanodeUuid());
-      if (excessBlocks != null) {
-        if (excessBlocks.remove(storedBlock)) {
-          excessBlocksCount.decrementAndGet();
-          blockLog.debug("BLOCK* removeStoredBlock: {} is removed from " +
-              "excessBlocks", storedBlock);
-          if (excessBlocks.size() == 0) {
-            excessReplicateMap.remove(node.getDatanodeUuid());
-          }
-        }
-      }
-
-      // Remove the replica from corruptReplicas
+      excessReplicas.remove(node, storedBlock);
       corruptReplicas.removeFromCorruptReplicasMap(storedBlock, node);
     }
   }
@@ -3745,10 +3709,13 @@ public class BlockManager implements BlockStatsMXBean {
     }
   }
 
-  private boolean isExcess(DatanodeDescriptor node, BlockInfo block) {
-    LightWeightHashSet<BlockInfo> blocksExcess = excessReplicateMap.get(
-        node.getDatanodeUuid());
-    return blocksExcess != null && blocksExcess.contains(block);
+  @VisibleForTesting
+  int getExcessSize4Testing(String dnUuid) {
+    return excessReplicas.getSize4Testing(dnUuid);
+  }
+
+  public boolean isExcess(DatanodeDescriptor dn, BlockInfo blk) {
+    return excessReplicas.contains(dn, blk);
   }
 
   /** 
@@ -4053,31 +4020,15 @@ public class BlockManager implements BlockStatsMXBean {
   }
 
   public void removeBlockFromMap(BlockInfo block) {
-    removeFromExcessReplicateMap(block);
+    for(DatanodeStorageInfo info : blocksMap.getStorages(block)) {
+      excessReplicas.remove(info.getDatanodeDescriptor(), block);
+    }
+
     blocksMap.removeBlock(block);
     // If block is removed from blocksMap remove it from corruptReplicasMap
     corruptReplicas.removeFromCorruptReplicasMap(block);
   }
 
-  /**
-   * If a block is removed from blocksMap, remove it from excessReplicateMap.
-   */
-  private void removeFromExcessReplicateMap(BlockInfo block) {
-    for (DatanodeStorageInfo info : blocksMap.getStorages(block)) {
-      String uuid = info.getDatanodeDescriptor().getDatanodeUuid();
-      LightWeightHashSet<BlockInfo> excessReplicas =
-          excessReplicateMap.get(uuid);
-      if (excessReplicas != null) {
-        if (excessReplicas.remove(block)) {
-          excessBlocksCount.decrementAndGet();
-          if (excessReplicas.isEmpty()) {
-            excessReplicateMap.remove(uuid);
-          }
-        }
-      }
-    }
-  }
-
   public int getCapacity() {
     return blocksMap.getCapacity();
   }
@@ -4270,7 +4221,7 @@ public class BlockManager implements BlockStatsMXBean {
   public void clearQueues() {
     neededReplications.clear();
     pendingReplications.clear();
-    excessReplicateMap.clear();
+    excessReplicas.clear();
     invalidateBlocks.clear();
     datanodeManager.clearPendingQueues();
     postponedMisreplicatedBlocks.clear();

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

@@ -0,0 +1,106 @@
+/**
+ * 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.hdfs.server.blockmanagement;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicLong;
+
+import org.apache.hadoop.hdfs.server.namenode.NameNode;
+import org.apache.hadoop.hdfs.util.LightWeightHashSet;
+import org.slf4j.Logger;
+
+import com.google.common.annotations.VisibleForTesting;
+
+/**
+ * Maps a datnode to the set of excess replicas.
+ *
+ * This class is thread safe.
+ */
+class ExcessReplicaMap {
+  public static final Logger blockLog = NameNode.blockStateChangeLog;
+
+  private final Map<String, LightWeightHashSet<BlockInfo>> map =new HashMap<>();
+  private final AtomicLong size = new AtomicLong(0L);
+
+  /** @return the number of replicas in this map. */
+  long size() {
+    return size.get();
+  }
+
+  /** @return the number of replicas corresponding to the given datanode. */
+  @VisibleForTesting
+  synchronized int getSize4Testing(String dnUuid) {
+    final LightWeightHashSet<BlockInfo> set = map.get(dnUuid);
+    return set == null? 0: set.size();
+  }
+
+  synchronized void clear() {
+    map.clear();
+    size.set(0L);
+  }
+
+  /**
+   * @return does this map contains a replica corresponding to the given
+   *         datanode and the given block?
+   */
+  synchronized boolean contains(DatanodeDescriptor dn, BlockInfo blk) {
+    final LightWeightHashSet<BlockInfo> set = map.get(dn.getDatanodeUuid());
+    return set != null && set.contains(blk);
+  }
+
+  /**
+   * Add the replica of the given block stored in the given datanode to the map.
+   * @return true if the block is added.
+   */
+  synchronized boolean add(DatanodeDescriptor dn, BlockInfo blk) {
+    LightWeightHashSet<BlockInfo> set = map.get(dn.getDatanodeUuid());
+    if (set == null) {
+      set = new LightWeightHashSet<>();
+      map.put(dn.getDatanodeUuid(), set);
+    }
+    final boolean added = set.add(blk);
+    if (added) {
+      size.incrementAndGet();
+      blockLog.debug("BLOCK* ExcessReplicaMap.add({}, {})", dn, blk);
+    }
+    return added;
+  }
+
+  /**
+   * Remove the replica corresponding to the given datanode and the given block.
+   * @return true if the block is removed.
+   */
+  synchronized boolean remove(DatanodeDescriptor dn, BlockInfo blk) {
+    final LightWeightHashSet<BlockInfo> set = map.get(dn.getDatanodeUuid());
+    if (set == null) {
+      return false;
+    }
+
+    final boolean removed = set.remove(blk);
+    if (removed) {
+      size.decrementAndGet();
+      blockLog.debug("BLOCK* ExcessReplicaMap.remove({}, {})", dn, blk);
+
+      if (set.isEmpty()) {
+        map.remove(dn.getDatanodeUuid());
+      }
+    }
+    return removed;
+  }
+}

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

@@ -73,7 +73,6 @@ import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeStorageInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.NumberReplicas;
 import org.apache.hadoop.hdfs.server.datanode.CachingStrategy;
-import org.apache.hadoop.hdfs.util.LightWeightHashSet;
 import org.apache.hadoop.net.NetUtils;
 import org.apache.hadoop.net.NetworkTopology;
 import org.apache.hadoop.net.NodeBase;
@@ -570,8 +569,6 @@ public class NamenodeFsck implements DataEncryptionKeyFactory {
             storage.getStorageType()));
       }
       if (showReplicaDetails) {
-        LightWeightHashSet<BlockInfo> blocksExcess =
-            blockManager.excessReplicateMap.get(dnDesc.getDatanodeUuid());
         Collection<DatanodeDescriptor> corruptReplicas =
             blockManager.getCorruptReplicas(storedBlock);
         sb.append("(");
@@ -582,8 +579,7 @@ public class NamenodeFsck implements DataEncryptionKeyFactory {
         } else if (corruptReplicas != null
             && corruptReplicas.contains(dnDesc)) {
           sb.append("CORRUPT)");
-        } else if (blocksExcess != null
-            && blocksExcess.contains(storedBlock)) {
+        } else if (blockManager.isExcess(dnDesc, storedBlock)) {
           sb.append("EXCESS)");
         } else if (dnDesc.isStale(this.staleInterval)) {
           sb.append("STALE_NODE)");

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestNodeCount.java

@@ -19,7 +19,6 @@ package org.apache.hadoop.hdfs.server.blockmanagement;
 
 import static org.junit.Assert.assertTrue;
 
-import java.util.Collection;
 import java.util.concurrent.TimeoutException;
 
 import org.apache.hadoop.conf.Configuration;
@@ -105,10 +104,12 @@ public class TestNodeCount {
       
       // find out a non-excess node
       DatanodeDescriptor nonExcessDN = null;
+
       for(DatanodeStorageInfo storage : bm.blocksMap.getStorages(block.getLocalBlock())) {
         final DatanodeDescriptor dn = storage.getDatanodeDescriptor();
-        Collection<BlockInfo> blocks = bm.excessReplicateMap.get(dn.getDatanodeUuid());
-        if (blocks == null || !blocks.contains(block.getLocalBlock()) ) {
+        final BlockInfo info = new BlockInfoContiguous(
+            block.getLocalBlock(), (short)0);
+        if (!bm.isExcess(dn, info)) {
           nonExcessDN = dn;
           break;
         }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestOverReplicatedBlocks.java

@@ -22,7 +22,6 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
-import java.util.Collection;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.BlockLocation;
@@ -153,6 +152,7 @@ public class TestOverReplicatedBlocks {
       cluster = new MiniDFSCluster.Builder(conf).numDataNodes(3).build();
       fs = cluster.getFileSystem();
       final FSNamesystem namesystem = cluster.getNamesystem();
+      final BlockManager bm = namesystem.getBlockManager();
 
       conf.setLong(DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_KEY, 300);
       cluster.startDataNodes(conf, 1, true, null, null, null);
@@ -171,8 +171,7 @@ public class TestOverReplicatedBlocks {
       long waitTime = DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_DEFAULT * 1000 *
         (DFSConfigKeys.DFS_NAMENODE_TOLERATE_HEARTBEAT_MULTIPLIER_DEFAULT + 1);
       do {
-        nodeInfo = namesystem.getBlockManager().getDatanodeManager()
-            .getDatanode(dnReg);
+        nodeInfo = bm.getDatanodeManager().getDatanode(dnReg);
         lastHeartbeat = nodeInfo.getLastUpdateMonotonic();
       } while (monotonicNow() - lastHeartbeat < waitTime);
       fs.setReplication(fileName, (short)3);
@@ -183,10 +182,9 @@ public class TestOverReplicatedBlocks {
       // All replicas for deletion should be scheduled on lastDN.
       // And should not actually be deleted, because lastDN does not heartbeat.
       namesystem.readLock();
-      Collection<BlockInfo> dnBlocks =
-        namesystem.getBlockManager().excessReplicateMap.get(lastDNid);
+      final int dnBlocks = bm.getExcessSize4Testing(dnReg.getDatanodeUuid());
       assertEquals("Replicas on node " + lastDNid + " should have been deleted",
-          SMALL_FILE_LENGTH / SMALL_BLOCK_SIZE, dnBlocks.size());
+          SMALL_FILE_LENGTH / SMALL_BLOCK_SIZE, dnBlocks);
       namesystem.readUnlock();
       for(BlockLocation location : locs)
         assertEquals("Block should still have 4 replicas",

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/metrics/TestNameNodeMetrics.java

@@ -289,7 +289,7 @@ public class TestNameNodeMetrics {
     fs.delete(file, true);
     rb = getMetrics(NS_METRICS);
     assertGauge("ExcessBlocks", 0L, rb);
-    assertTrue(bm.excessReplicateMap.isEmpty());
+    assertEquals(0L, bm.getExcessBlocksCount());
   }
   
   /** Test to ensure metrics reflects missing blocks */