HBASE-3787 Increment is non-idempotent but client retries RPC

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1542168 13f79535-47bb-0310-9956-ffa450edef68

hbase-client/src/main/java/org/apache/hadoop/hbase/client/Action.java

@@ -19,9 +19,10 @@
 package org.apache.hadoop.hbase.client;
 
 import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.hbase.HConstants;
 
 /**
- * A Get, Put or Delete associated with it's region.  Used internally by  
+ * A Get, Put, Increment, Append, or Delete associated with it's region.  Used internally by  
  * {@link HTable#batch} to associate the action with it's region and maintain
  * the index from the original request. 
  */
@@ -30,6 +31,7 @@ public class Action<R> implements Comparable<R> {
   // TODO: This class should not be visible outside of the client package.
   private Row action;
   private int originalIndex;
+  private long nonce = HConstants.NO_NONCE;
 
   public Action(Row action, int originalIndex) {
     super();
@@ -37,6 +39,13 @@ public class Action<R> implements Comparable<R> {
     this.originalIndex = originalIndex;    
   }
 
+  public void setNonce(long nonce) {
+    this.nonce = nonce;
+  }
+
+  public boolean hasNonce() {
+    return nonce != HConstants.NO_NONCE;
+  }
 
   public Row getAction() {
     return action;
@@ -64,4 +73,8 @@ public class Action<R> implements Comparable<R> {
     Action<?> other = (Action<?>) obj;
     return compareTo(other) == 0;
   }
+
+  public long getNonce() {
+    return nonce;
+  }
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncProcess.java

@@ -275,6 +275,7 @@ class AsyncProcess<CResult> {
     long currentTaskCnt = tasksDone.get();
     boolean alreadyLooped = false;
 
+    NonceGenerator ng = this.hConnection.getNonceGenerator();
     do {
       if (alreadyLooped){
         // if, for whatever reason, we looped, we want to be sure that something has changed.
@@ -302,12 +303,12 @@ class AsyncProcess<CResult> {
           it.remove();
         } else if (canTakeOperation(loc, regionIncluded, serverIncluded)) {
           Action<Row> action = new Action<Row>(r, ++posInList);
+          setNonce(ng, r, action);
           retainedActions.add(action);
-          addAction(loc, action, actionsByServer);
+          addAction(loc, action, actionsByServer, ng);
           it.remove();
         }
       }
-
     } while (retainedActions.isEmpty() && atLeastOne && !hasError());
 
     HConnectionManager.ServerErrorTracker errorsByServer = createServerErrorTracker();
@@ -320,15 +321,21 @@ class AsyncProcess<CResult> {
    * @param loc - the destination. Must not be null.
    * @param action - the action to add to the multiaction
    * @param actionsByServer the multiaction per server
+   * @param ng Nonce generator, or null if no nonces are needed.
    */
   private void addAction(HRegionLocation loc, Action<Row> action, Map<HRegionLocation,
-      MultiAction<Row>> actionsByServer) {
+      MultiAction<Row>> actionsByServer, NonceGenerator ng) {
     final byte[] regionName = loc.getRegionInfo().getRegionName();
     MultiAction<Row> multiAction = actionsByServer.get(loc);
     if (multiAction == null) {
       multiAction = new MultiAction<Row>();
       actionsByServer.put(loc, multiAction);
     }
+    if (action.hasNonce() && !multiAction.hasNonceGroup()) {
+      // TODO: this code executes for every (re)try, and calls getNonceGroup again
+      //       for the same action. It must return the same value across calls.
+      multiAction.setNonceGroup(ng.getNonceGroup());
+    }
 
     multiAction.add(regionName, action);
   }
@@ -443,15 +450,22 @@ class AsyncProcess<CResult> {
 
     // The position will be used by the processBatch to match the object array returned.
     int posInList = -1;
+    NonceGenerator ng = this.hConnection.getNonceGenerator();
     for (Row r : rows) {
       posInList++;
       Action<Row> action = new Action<Row>(r, posInList);
+      setNonce(ng, r, action);
       actions.add(action);
     }
     HConnectionManager.ServerErrorTracker errorsByServer = createServerErrorTracker();
     submit(actions, actions, 1, errorsByServer);
   }
 
+  private void setNonce(NonceGenerator ng, Row r, Action<Row> action) {
+    if (!(r instanceof Append) && !(r instanceof Increment)) return;
+    action.setNonce(ng.newNonce()); // Action handles NO_NONCE, so it's ok if ng is disabled.
+  }
+
 
   /**
    * Group a list of actions per region servers, and send them. The created MultiActions are
@@ -473,10 +487,11 @@ class AsyncProcess<CResult> {
     final Map<HRegionLocation, MultiAction<Row>> actionsByServer =
         new HashMap<HRegionLocation, MultiAction<Row>>();
 
+    NonceGenerator ng = this.hConnection.getNonceGenerator();
     for (Action<Row> action : currentActions) {
       HRegionLocation loc = findDestLocation(action.getAction(), action.getOriginalIndex());
       if (loc != null) {
-        addAction(loc, action, actionsByServer);
+        addAction(loc, action, actionsByServer, ng);
       }
     }
 

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientIdGenerator.java

@@ -0,0 +1,108 @@
+/**
+ *
+ * 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.hbase.client;
+
+import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.net.Inet4Address;
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.util.Enumeration;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.hbase.util.Bytes;
+
+/**
+ * The class that is able to determine some unique strings for the client,
+ * such as an IP address, PID, and composite deterministic ID.
+ */
+@InterfaceAudience.Private
+class ClientIdGenerator {
+  static final Log LOG = LogFactory.getLog(ClientIdGenerator.class);
+
+  /**
+   * @return a unique ID incorporating IP address, PID, TID and timer. Might be an overkill...
+   * Note though that new UUID in java by default is just a random number.
+   */
+  public static byte[] generateClientId() {
+    byte[] selfBytes = getIpAddressBytes();
+    Long pid = getPid();
+    long tid = Thread.currentThread().getId();
+    long ts = System.currentTimeMillis();
+
+    byte[] id = new byte[selfBytes.length + ((pid != null ? 1 : 0) + 2) * Bytes.SIZEOF_LONG];
+    int offset = Bytes.putBytes(id, 0, selfBytes, 0, selfBytes.length);
+    if (pid != null) {
+      offset = Bytes.putLong(id, offset, pid);
+    }
+    offset = Bytes.putLong(id, offset, tid);
+    offset = Bytes.putLong(id, offset, ts);
+    assert offset == id.length;
+    return id;
+  }
+
+  /**
+   * @return PID of the current process, if it can be extracted from JVM name, or null.
+   */
+  public static Long getPid() {
+    String name = ManagementFactory.getRuntimeMXBean().getName();
+    String[] nameParts = name.split("@");
+    if (nameParts.length == 2) { // 12345@somewhere
+      try {
+        return Long.parseLong(nameParts[0]);
+      } catch (NumberFormatException ex) {
+        LOG.warn("Failed to get PID from [" + name + "]", ex);
+      }
+    } else {
+      LOG.warn("Don't know how to get PID from [" + name + "]");
+    }
+    return null;
+  }
+
+  /**
+   * @return Some IPv4/IPv6 address available on the current machine that is up, not virtual
+   *         and not a loopback address. Empty array if none can be found or error occured.
+   */
+  public static byte[] getIpAddressBytes() {
+    try {
+      // Before we connect somewhere, we cannot be sure about what we'd be bound to; however,
+      // we only connect when the message where client ID is, is long constructed. Thus,
+      // just use whichever IP address we can find.
+      Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
+      while (interfaces.hasMoreElements()) {
+        NetworkInterface current = interfaces.nextElement();
+        if (!current.isUp() || current.isLoopback() || current.isVirtual()) continue;
+        Enumeration<InetAddress> addresses = current.getInetAddresses();
+        while (addresses.hasMoreElements()) {
+          InetAddress addr = addresses.nextElement();
+          if (addr.isLoopbackAddress()) continue;
+          if (addr instanceof Inet4Address || addr instanceof Inet6Address) {
+            return addr.getAddress();
+          }
+        }
+      }
+    } catch (IOException ex) {
+      LOG.warn("Failed to get IP address bytes", ex);
+    }
+    return new byte[0];
+  }
+}

hbase-client/src/main/java/org/apache/hadoop/hbase/client/HConnection.java

@@ -515,4 +515,9 @@ public interface HConnection extends Abortable, Closeable {
    * @return true if the server is known as dead, false otherwise.
    */
   boolean isDeadServer(ServerName serverName);
+
+  /**
+   * @return Nonce generator for this HConnection; may be null if disabled in configuration.
+   */
+  public NonceGenerator getNonceGenerator();
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java

@@ -124,6 +124,7 @@ import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
 import org.apache.hadoop.ipc.RemoteException;
 import org.apache.zookeeper.KeeperException;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.protobuf.BlockingRpcChannel;
 import com.google.protobuf.RpcController;
 import com.google.protobuf.ServiceException;
@@ -197,6 +198,7 @@ public class HConnectionManager {
   static final Log LOG = LogFactory.getLog(HConnectionManager.class);
 
   public static final String RETRIES_BY_SERVER_KEY = "hbase.client.retries.by.server";
+  private static final String CLIENT_NONCES_ENABLED_KEY = "hbase.client.nonces.enabled";
 
   // An LRU Map of HConnectionKey -> HConnection (TableServer).  All
   // access must be synchronized.  This map is not private because tests
@@ -205,6 +207,14 @@ public class HConnectionManager {
 
   public static final int MAX_CACHED_CONNECTION_INSTANCES;
 
+  /**
+   * Global nonceGenerator shared per client.Currently there's no reason to limit its scope.
+   * Once it's set under nonceGeneratorCreateLock, it is never unset or changed.
+   */
+  private static volatile NonceGenerator nonceGenerator = null;
+  /** The nonce generator lock. Only taken when creating HConnection, which gets a private copy. */
+  private static Object nonceGeneratorCreateLock = new Object();
+
   static {
     // We set instances to one more than the value specified for {@link
     // HConstants#ZOOKEEPER_MAX_CLIENT_CNXNS}. By default, the zk default max
@@ -229,6 +239,20 @@ public class HConnectionManager {
     super();
   }
 
+  /**
+   * @param conn The connection for which to replace the generator.
+   * @param cnm Replaces the nonce generator used, for testing.
+   * @return old nonce generator.
+   */
+  @VisibleForTesting
+  public static NonceGenerator injectNonceGeneratorForTesting(
+      HConnection conn, NonceGenerator cnm) {
+    NonceGenerator ng = conn.getNonceGenerator();
+    LOG.warn("Nonce generator is being replaced by test code for " + cnm.getClass().getName());
+    ((HConnectionImplementation)conn).nonceGenerator = cnm;
+    return ng;
+  }
+
   /**
    * Get the connection that goes with the passed <code>conf</code> configuration instance.
    * If no current connection exists, method creates a new connection and keys it using
@@ -547,6 +571,7 @@ public class HConnectionManager {
     private final long pause;
     private final int numTries;
     final int rpcTimeout;
+    private NonceGenerator nonceGenerator = null;
     private final int prefetchRegionLimit;
 
     private volatile boolean closed;
@@ -661,6 +686,17 @@ public class HConnectionManager {
       }
     }
 
+    /** Dummy nonce generator for disabled nonces. */
+    private static class NoNonceGenerator implements NonceGenerator {
+      @Override
+      public long getNonceGroup() {
+        return HConstants.NO_NONCE;
+      }
+      @Override
+      public long newNonce() {
+        return HConstants.NO_NONCE;
+      }
+    }
 
     /**
      * For tests.
@@ -675,6 +711,17 @@ public class HConnectionManager {
       this.rpcTimeout = conf.getInt(
           HConstants.HBASE_RPC_TIMEOUT_KEY,
           HConstants.DEFAULT_HBASE_RPC_TIMEOUT);
+      if (conf.getBoolean(CLIENT_NONCES_ENABLED_KEY, true)) {
+        synchronized (HConnectionManager.nonceGeneratorCreateLock) {
+          if (HConnectionManager.nonceGenerator == null) {
+            HConnectionManager.nonceGenerator = new PerClientRandomNonceGenerator();
+          }
+          this.nonceGenerator = HConnectionManager.nonceGenerator;
+        }
+      } else {
+        this.nonceGenerator = new NoNonceGenerator();
+      }
+
       this.prefetchRegionLimit = conf.getInt(
           HConstants.HBASE_CLIENT_PREFETCH_LIMIT,
           HConstants.DEFAULT_HBASE_CLIENT_PREFETCH_LIMIT);
@@ -2617,6 +2664,11 @@ public class HConnectionManager {
       return getHTableDescriptorsByTableName(tableNames);
     }
 
+    @Override
+    public NonceGenerator getNonceGenerator() {
+      return this.nonceGenerator;
+    }
+
     /**
      * Connects to the master to get the table descriptor.
      * @param tableName table name

hbase-client/src/main/java/org/apache/hadoop/hbase/client/HTable.java

@@ -986,12 +986,15 @@ public class HTable implements HTableInterface {
       throw new IOException(
           "Invalid arguments to append, no columns specified");
     }
+
+    NonceGenerator ng = this.connection.getNonceGenerator();
+    final long nonceGroup = ng.getNonceGroup(), nonce = ng.newNonce();
     RegionServerCallable<Result> callable =
       new RegionServerCallable<Result>(this.connection, getName(), append.getRow()) {
         public Result call() throws IOException {
           try {
             MutateRequest request = RequestConverter.buildMutateRequest(
-              getLocation().getRegionInfo().getRegionName(), append);
+              getLocation().getRegionInfo().getRegionName(), append, nonceGroup, nonce);
             PayloadCarryingRpcController rpcController = new PayloadCarryingRpcController();
             rpcController.setPriority(getTableName());
             MutateResponse response = getStub().mutate(rpcController, request);
@@ -1014,12 +1017,14 @@ public class HTable implements HTableInterface {
       throw new IOException(
           "Invalid arguments to increment, no columns specified");
     }
+    NonceGenerator ng = this.connection.getNonceGenerator();
+    final long nonceGroup = ng.getNonceGroup(), nonce = ng.newNonce();
     RegionServerCallable<Result> callable = new RegionServerCallable<Result>(this.connection,
         getName(), increment.getRow()) {
       public Result call() throws IOException {
         try {
           MutateRequest request = RequestConverter.buildMutateRequest(
-            getLocation().getRegionInfo().getRegionName(), increment);
+            getLocation().getRegionInfo().getRegionName(), increment, nonceGroup, nonce);
           PayloadCarryingRpcController rpcController = new PayloadCarryingRpcController();
           rpcController.setPriority(getTableName());
           MutateResponse response = getStub().mutate(rpcController, request);
@@ -1074,13 +1079,15 @@ public class HTable implements HTableInterface {
           "Invalid arguments to incrementColumnValue", npe);
     }
 
+    NonceGenerator ng = this.connection.getNonceGenerator();
+    final long nonceGroup = ng.getNonceGroup(), nonce = ng.newNonce();
     RegionServerCallable<Long> callable =
       new RegionServerCallable<Long>(connection, getName(), row) {
         public Long call() throws IOException {
           try {
-            MutateRequest request = RequestConverter.buildMutateRequest(
+            MutateRequest request = RequestConverter.buildIncrementRequest(
               getLocation().getRegionInfo().getRegionName(), row, family,
-              qualifier, amount, durability);
+              qualifier, amount, durability, nonceGroup, nonce);
             PayloadCarryingRpcController rpcController = new PayloadCarryingRpcController();
             rpcController.setPriority(getTableName());
             MutateResponse response = getStub().mutate(rpcController, request);

hbase-client/src/main/java/org/apache/hadoop/hbase/client/MultiAction.java

@@ -25,6 +25,7 @@ import java.util.Set;
 import java.util.TreeMap;
 
 import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.util.Bytes;
 
 /**
@@ -39,6 +40,8 @@ public final class MultiAction<R> {
   public Map<byte[], List<Action<R>>> actions =
     new TreeMap<byte[], List<Action<R>>>(Bytes.BYTES_COMPARATOR);
 
+  private long nonceGroup = HConstants.NO_NONCE;
+
   public MultiAction() {
     super();
   }
@@ -73,6 +76,10 @@ public final class MultiAction<R> {
     rsActions.add(a);
   }
 
+  public void setNonceGroup(long nonceGroup) {
+    this.nonceGroup = nonceGroup;
+  }
+
   public Set<byte[]> getRegions() {
     return actions.keySet();
   }
@@ -87,4 +94,12 @@ public final class MultiAction<R> {
     }
     return res;
   }
+
+  public boolean hasNonceGroup() {
+    return nonceGroup != HConstants.NO_NONCE;
+  }
+
+  public long getNonceGroup() {
+    return this.nonceGroup;
+  }
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/MultiServerCallable.java

@@ -19,12 +19,14 @@ package org.apache.hadoop.hbase.client;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.CellScannable;
 import org.apache.hadoop.hbase.DoNotRetryIOException;
+import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.HRegionLocation;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.ipc.PayloadCarryingRpcController;
@@ -71,6 +73,10 @@ class MultiServerCallable<R> extends RegionServerCallable<MultiResponse> {
     MutationProto.Builder mutationBuilder = MutationProto.newBuilder();
     List<CellScannable> cells = null;
     // The multi object is a list of Actions by region.  Iterate by region.
+    long nonceGroup = multiAction.getNonceGroup();
+    if (nonceGroup != HConstants.NO_NONCE) {
+      multiRequestBuilder.setNonceGroup(nonceGroup);
+    }
     for (Map.Entry<byte[], List<Action<R>>> e: this.multiAction.actions.entrySet()) {
       final byte [] regionName = e.getKey();
       final List<Action<R>> actions = e.getValue();
@@ -92,6 +98,7 @@ class MultiServerCallable<R> extends RegionServerCallable<MultiResponse> {
       }
       multiRequestBuilder.addRegionAction(regionActionBuilder.build());
     }
+
     // Controller optionally carries cell data over the proxy/service boundary and also
     // optionally ferries cell response data back out again.
     PayloadCarryingRpcController controller = new PayloadCarryingRpcController(cells);

hbase-client/src/main/java/org/apache/hadoop/hbase/client/NonceGenerator.java

@@ -0,0 +1,37 @@
+/**
+ *
+ * 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.hbase.client;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+
+/**
+ * NonceGenerator interface.
+ * In general, nonce group is an ID (one per client, or region+client, or whatever) that
+ * could be used to reduce collision potential, or be used by compatible server nonce manager
+ * to optimize nonce storage and removal. See HBASE-3787.
+ */
+@InterfaceAudience.Private
+public interface NonceGenerator {
+
+  /** @return the nonce group (client ID) of this client manager. */
+  public long getNonceGroup();
+
+  /** @return New nonce. */
+  public long newNonce();
+}

hbase-client/src/main/java/org/apache/hadoop/hbase/client/PerClientRandomNonceGenerator.java

@@ -0,0 +1,34 @@
+package org.apache.hadoop.hbase.client;
+
+import java.util.Arrays;
+import java.util.Random;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.hbase.HConstants;
+
+/**
+ * NonceGenerator implementation that uses client ID hash + random int as nonce group,
+ * and random numbers as nonces.
+ */
+@InterfaceAudience.Private
+public class PerClientRandomNonceGenerator implements NonceGenerator {
+  private final Random rdm = new Random();
+  private final long clientId;
+
+  public PerClientRandomNonceGenerator() {
+    byte[] clientIdBase = ClientIdGenerator.generateClientId();
+    this.clientId = (((long)Arrays.hashCode(clientIdBase)) << 32) + rdm.nextInt();
+  }
+
+  public long getNonceGroup() {
+    return this.clientId;
+  }
+
+  public long newNonce() {
+    long result = HConstants.NO_NONCE;
+    do {
+      result = rdm.nextLong();
+    } while (result == HConstants.NO_NONCE);
+    return result;
+  }
+}

hbase-client/src/main/java/org/apache/hadoop/hbase/exceptions/OperationConflictException.java

@@ -0,0 +1,49 @@
+/**
+ *
+ * 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.hbase.exceptions;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.hbase.DoNotRetryIOException;
+
+/**
+ * The exception that is thrown if there's duplicate execution of non-idempotent operation.
+ * Client should not retry; may use "get" to get the desired value.
+ */
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public class OperationConflictException extends DoNotRetryIOException {
+  private static final long serialVersionUID = -8930333627489862872L;
+
+  public OperationConflictException() {
+    super();
+  }
+
+  public OperationConflictException(String message) {
+    super(message);
+  }
+
+  public OperationConflictException(Throwable cause) {
+    super(cause);
+  }
+
+  public OperationConflictException(String message, Throwable cause) {
+    super(message, cause);
+  }
+}

hbase-client/src/main/java/org/apache/hadoop/hbase/protobuf/ProtobufUtil.java

@@ -988,11 +988,14 @@ public final class ProtobufUtil {
    * @param increment
    * @return the converted mutate
    */
-  public static MutationProto toMutation(final Increment increment,
+  public static MutationProto toMutation(
-      final MutationProto.Builder builder) {
+    final Increment increment, final MutationProto.Builder builder, long nonce) {
     builder.setRow(ZeroCopyLiteralByteString.wrap(increment.getRow()));
     builder.setMutateType(MutationType.INCREMENT);
     builder.setDurability(toDurability(increment.getDurability()));
+    if (nonce != HConstants.NO_NONCE) {
+      builder.setNonce(nonce);
+    }
     TimeRange timeRange = increment.getTimeRange();
     if (!timeRange.isAllTime()) {
       HBaseProtos.TimeRange.Builder timeRangeBuilder =
@@ -1035,6 +1038,11 @@ public final class ProtobufUtil {
     return builder.build();
   }
 
+  public static MutationProto toMutation(final MutationType type, final Mutation mutation)
+    throws IOException {
+    return toMutation(type, mutation, HConstants.NO_NONCE);
+  }
+
   /**
    * Create a protocol buffer Mutate based on a client Mutation
    *
@@ -1043,15 +1051,23 @@ public final class ProtobufUtil {
    * @return a protobuf'd Mutation
    * @throws IOException
    */
-  public static MutationProto toMutation(final MutationType type, final Mutation mutation)
+  public static MutationProto toMutation(final MutationType type, final Mutation mutation,
-  throws IOException {
+    final long nonce) throws IOException {
-    return toMutation(type, mutation, MutationProto.newBuilder());
+    return toMutation(type, mutation, MutationProto.newBuilder(), nonce);
   }
 
   public static MutationProto toMutation(final MutationType type, final Mutation mutation,
-      MutationProto.Builder builder)
+      MutationProto.Builder builder) throws IOException {
+    return toMutation(type, mutation, builder, HConstants.NO_NONCE);
+  }
+
+  public static MutationProto toMutation(final MutationType type, final Mutation mutation,
+      MutationProto.Builder builder, long nonce)
   throws IOException {
     builder = getMutationBuilderAndSetCommonFields(type, mutation, builder);
+    if (nonce != HConstants.NO_NONCE) {
+      builder.setNonce(nonce);
+    }
     ColumnValue.Builder columnBuilder = ColumnValue.newBuilder();
     QualifierValue.Builder valueBuilder = QualifierValue.newBuilder();
     for (Map.Entry<byte[],List<Cell>> family: mutation.getFamilyCellMap().entrySet()) {
@@ -1078,6 +1094,11 @@ public final class ProtobufUtil {
     return builder.build();
   }
 
+  public static MutationProto toMutationNoData(final MutationType type, final Mutation mutation,
+      final MutationProto.Builder builder)  throws IOException {
+    return toMutationNoData(type, mutation, builder, HConstants.NO_NONCE);
+  }
+
   /**
    * Create a protocol buffer MutationProto based on a client Mutation.  Does NOT include data.
    * Understanding is that the Cell will be transported other than via protobuf.
@@ -1087,10 +1108,12 @@ public final class ProtobufUtil {
    * @throws IOException
    */
   public static MutationProto toMutationNoData(final MutationType type, final Mutation mutation,
-      final MutationProto.Builder builder)
+      final MutationProto.Builder builder, long nonce) throws IOException {
-  throws IOException {
     getMutationBuilderAndSetCommonFields(type, mutation, builder);
     builder.setAssociatedCellCount(mutation.size());
+    if (nonce != HConstants.NO_NONCE) {
+      builder.setNonce(nonce);
+    }
     return builder.build();
   }
 

hbase-client/src/main/java/org/apache/hadoop/hbase/protobuf/RequestConverter.java

@@ -22,6 +22,8 @@ import java.util.List;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.CellScannable;
+import org.apache.hadoop.hbase.HConstants;
+import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.DoNotRetryIOException;
 import org.apache.hadoop.hbase.HColumnDescriptor;
 import org.apache.hadoop.hbase.HRegionInfo;
@@ -172,9 +174,9 @@ public final class RequestConverter {
    * @param durability
    * @return a mutate request
    */
-  public static MutateRequest buildMutateRequest(
+  public static MutateRequest buildIncrementRequest(
-      final byte[] regionName, final byte[] row, final byte[] family,
+      final byte[] regionName, final byte[] row, final byte[] family, final byte[] qualifier,
-      final byte [] qualifier, final long amount, final Durability durability) {
+      final long amount, final Durability durability, long nonceGroup, long nonce) {
     MutateRequest.Builder builder = MutateRequest.newBuilder();
     RegionSpecifier region = buildRegionSpecifier(
       RegionSpecifierType.REGION_NAME, regionName);
@@ -191,7 +193,13 @@ public final class RequestConverter {
     valueBuilder.setQualifier(ZeroCopyLiteralByteString.wrap(qualifier));
     columnBuilder.addQualifierValue(valueBuilder.build());
     mutateBuilder.addColumnValue(columnBuilder.build());
+    if (nonce != HConstants.NO_NONCE) {
+      mutateBuilder.setNonce(nonce);
+    }
     builder.setMutation(mutateBuilder.build());
+    if (nonceGroup != HConstants.NO_NONCE) {
+      builder.setNonceGroup(nonceGroup);
+    }
     return builder.build();
   }
 
@@ -278,14 +286,17 @@ public final class RequestConverter {
    * @return a mutate request
    * @throws IOException
    */
-  public static MutateRequest buildMutateRequest(
+  public static MutateRequest buildMutateRequest(final byte[] regionName,
-      final byte[] regionName, final Append append) throws IOException {
+      final Append append, long nonceGroup, long nonce) throws IOException {
     MutateRequest.Builder builder = MutateRequest.newBuilder();
     RegionSpecifier region = buildRegionSpecifier(
       RegionSpecifierType.REGION_NAME, regionName);
     builder.setRegion(region);
+    if (nonce != HConstants.NO_NONCE && nonceGroup != HConstants.NO_NONCE) {
+      builder.setNonceGroup(nonceGroup);
+    }
     builder.setMutation(ProtobufUtil.toMutation(MutationType.APPEND, append,
-      MutationProto.newBuilder()));
+      MutationProto.newBuilder(), nonce));
     return builder.build();
   }
 
@@ -296,13 +307,16 @@ public final class RequestConverter {
    * @param increment
    * @return a mutate request
    */
-  public static MutateRequest buildMutateRequest(
+  public static MutateRequest buildMutateRequest(final byte[] regionName,
-      final byte[] regionName, final Increment increment) {
+      final Increment increment, final long nonceGroup, final long nonce) {
     MutateRequest.Builder builder = MutateRequest.newBuilder();
     RegionSpecifier region = buildRegionSpecifier(
       RegionSpecifierType.REGION_NAME, regionName);
     builder.setRegion(region);
-    builder.setMutation(ProtobufUtil.toMutation(increment, MutationProto.newBuilder()));
+    if (nonce != HConstants.NO_NONCE && nonceGroup != HConstants.NO_NONCE) {
+      builder.setNonceGroup(nonceGroup);
+    }
+    builder.setMutation(ProtobufUtil.toMutation(increment, MutationProto.newBuilder(), nonce));
     return builder.build();
   }
 
@@ -499,8 +513,7 @@ public final class RequestConverter {
   public static <R> RegionAction.Builder buildRegionAction(final byte[] regionName,
       final List<Action<R>> actions, final RegionAction.Builder regionActionBuilder,
       final ClientProtos.Action.Builder actionBuilder,
-      final MutationProto.Builder mutationBuilder)
+      final MutationProto.Builder mutationBuilder) throws IOException {
-  throws IOException {
     for (Action<R> action: actions) {
       Row row = action.getAction();
       actionBuilder.clear();
@@ -516,11 +529,11 @@ public final class RequestConverter {
         regionActionBuilder.addAction(actionBuilder.
           setMutation(ProtobufUtil.toMutation(MutationType.DELETE, (Delete)row, mutationBuilder)));
       } else if (row instanceof Append) {
-        regionActionBuilder.addAction(actionBuilder.
+        regionActionBuilder.addAction(actionBuilder.setMutation(ProtobufUtil.toMutation(
-          setMutation(ProtobufUtil.toMutation(MutationType.APPEND, (Append)row, mutationBuilder)));
+            MutationType.APPEND, (Append)row, mutationBuilder, action.getNonce())));
       } else if (row instanceof Increment) {
-        regionActionBuilder.addAction(actionBuilder.
+        regionActionBuilder.addAction(actionBuilder.setMutation(
-          setMutation(ProtobufUtil.toMutation((Increment)row, mutationBuilder)));
+            ProtobufUtil.toMutation((Increment)row, mutationBuilder, action.getNonce())));
       } else if (row instanceof RowMutations) {
         throw new UnsupportedOperationException("No RowMutations in multi calls; use mutateRow");
       } else {
@@ -550,10 +563,9 @@ public final class RequestConverter {
       final List<Action<R>> actions, final List<CellScannable> cells,
       final RegionAction.Builder regionActionBuilder,
       final ClientProtos.Action.Builder actionBuilder,
-      final MutationProto.Builder mutationBuilder)
+      final MutationProto.Builder mutationBuilder) throws IOException {
-  throws IOException {
+    RegionAction.Builder builder = getRegionActionBuilderWithRegion(
-    RegionAction.Builder builder =
+      RegionAction.newBuilder(), regionName);
-      getRegionActionBuilderWithRegion(RegionAction.newBuilder(), regionName);
     for (Action<R> action: actions) {
       Row row = action.getAction();
       actionBuilder.clear();
@@ -586,13 +598,13 @@ public final class RequestConverter {
       } else if (row instanceof Append) {
         Append a = (Append)row;
         cells.add(a);
-        builder.addAction(actionBuilder.
+        builder.addAction(actionBuilder.setMutation(ProtobufUtil.toMutationNoData(
-          setMutation(ProtobufUtil.toMutationNoData(MutationType.APPEND, a, mutationBuilder)));
+          MutationType.APPEND, a, mutationBuilder, action.getNonce())));
       } else if (row instanceof Increment) {
         Increment i = (Increment)row;
         cells.add(i);
-        builder.addAction(actionBuilder.
+        builder.addAction(actionBuilder.setMutation(ProtobufUtil.toMutationNoData(
-          setMutation(ProtobufUtil.toMutationNoData(MutationType.INCREMENT, i, mutationBuilder)));
+          MutationType.INCREMENT, i, mutationBuilder, action.getNonce())));
       } else if (row instanceof RowMutations) {
         continue; // ignore RowMutations
       } else {

hbase-common/src/main/java/org/apache/hadoop/hbase/HConstants.java

@@ -743,6 +743,9 @@ public final class HConstants {
   public static final String HBASE_REGION_SPLIT_POLICY_KEY =
     "hbase.regionserver.region.split.policy";
 
+  /** Whether nonces are enabled; default is true. */
+  public static String HBASE_RS_NONCES_ENABLED = "hbase.regionserver.nonces.enabled";
+
   /**
    * Configuration key for the size of the block cache
    */
@@ -934,6 +937,8 @@ public final class HConstants {
   public static final String STATUS_MULTICAST_PORT = "hbase.status.multicast.port";
   public static final int DEFAULT_STATUS_MULTICAST_PORT = 60100;
 
+  public static final long NO_NONCE = 0;
+
   private HConstants() {
     // Can't be instantiated with this ctor.
   }

hbase-common/src/main/java/org/apache/hadoop/hbase/util/Triple.java

@@ -35,6 +35,11 @@ public class Triple<A, B, C> {
     this.third = third;
   }
 
+  // ctor cannot infer types w/o warning but a method can.
+  public static <A, B, C> Triple<A, B, C> create(A first, B second, C third) {
+    return new Triple<A, B, C>(first, second, third);
+  }
+
   public int hashCode() {
     int hashFirst = (first != null ? first.hashCode() : 0);
     int hashSecond = (second != null ? second.hashCode() : 0);

hbase-protocol/src/main/java/org/apache/hadoop/hbase/protobuf/generated/ClientProtos.java

@@ -6487,6 +6487,16 @@ public final class ClientProtos {
      * </pre>
      */
     int getAssociatedCellCount();
+
+    // optional uint64 nonce = 9;
+    /**
+     * <code>optional uint64 nonce = 9;</code>
+     */
+    boolean hasNonce();
+    /**
+     * <code>optional uint64 nonce = 9;</code>
+     */
+    long getNonce();
   }
   /**
    * Protobuf type {@code MutationProto}
@@ -6614,6 +6624,11 @@ public final class ClientProtos {
               associatedCellCount_ = input.readInt32();
               break;
             }
+            case 72: {
+              bitField0_ |= 0x00000040;
+              nonce_ = input.readUInt64();
+              break;
+            }
           }
         }
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
@@ -8801,6 +8816,22 @@ public final class ClientProtos {
       return associatedCellCount_;
     }
 
+    // optional uint64 nonce = 9;
+    public static final int NONCE_FIELD_NUMBER = 9;
+    private long nonce_;
+    /**
+     * <code>optional uint64 nonce = 9;</code>
+     */
+    public boolean hasNonce() {
+      return ((bitField0_ & 0x00000040) == 0x00000040);
+    }
+    /**
+     * <code>optional uint64 nonce = 9;</code>
+     */
+    public long getNonce() {
+      return nonce_;
+    }
+
     private void initFields() {
       row_ = com.google.protobuf.ByteString.EMPTY;
       mutateType_ = org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MutationProto.MutationType.APPEND;
@@ -8810,6 +8841,7 @@ public final class ClientProtos {
       durability_ = org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MutationProto.Durability.USE_DEFAULT;
       timeRange_ = org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.TimeRange.getDefaultInstance();
       associatedCellCount_ = 0;
+      nonce_ = 0L;
     }
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
@@ -8859,6 +8891,9 @@ public final class ClientProtos {
       if (((bitField0_ & 0x00000020) == 0x00000020)) {
         output.writeInt32(8, associatedCellCount_);
       }
+      if (((bitField0_ & 0x00000040) == 0x00000040)) {
+        output.writeUInt64(9, nonce_);
+      }
       getUnknownFields().writeTo(output);
     }
 
@@ -8900,6 +8935,10 @@ public final class ClientProtos {
         size += com.google.protobuf.CodedOutputStream
           .computeInt32Size(8, associatedCellCount_);
       }
+      if (((bitField0_ & 0x00000040) == 0x00000040)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeUInt64Size(9, nonce_);
+      }
       size += getUnknownFields().getSerializedSize();
       memoizedSerializedSize = size;
       return size;
@@ -8957,6 +8996,11 @@ public final class ClientProtos {
         result = result && (getAssociatedCellCount()
             == other.getAssociatedCellCount());
       }
+      result = result && (hasNonce() == other.hasNonce());
+      if (hasNonce()) {
+        result = result && (getNonce()
+            == other.getNonce());
+      }
       result = result &&
           getUnknownFields().equals(other.getUnknownFields());
       return result;
@@ -9002,6 +9046,10 @@ public final class ClientProtos {
         hash = (37 * hash) + ASSOCIATED_CELL_COUNT_FIELD_NUMBER;
         hash = (53 * hash) + getAssociatedCellCount();
       }
+      if (hasNonce()) {
+        hash = (37 * hash) + NONCE_FIELD_NUMBER;
+        hash = (53 * hash) + hashLong(getNonce());
+      }
       hash = (29 * hash) + getUnknownFields().hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -9151,6 +9199,8 @@ public final class ClientProtos {
         bitField0_ = (bitField0_ & ~0x00000040);
         associatedCellCount_ = 0;
         bitField0_ = (bitField0_ & ~0x00000080);
+        nonce_ = 0L;
+        bitField0_ = (bitField0_ & ~0x00000100);
         return this;
       }
 
@@ -9225,6 +9275,10 @@ public final class ClientProtos {
           to_bitField0_ |= 0x00000020;
         }
         result.associatedCellCount_ = associatedCellCount_;
+        if (((from_bitField0_ & 0x00000100) == 0x00000100)) {
+          to_bitField0_ |= 0x00000040;
+        }
+        result.nonce_ = nonce_;
         result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
@@ -9311,6 +9365,9 @@ public final class ClientProtos {
         if (other.hasAssociatedCellCount()) {
           setAssociatedCellCount(other.getAssociatedCellCount());
         }
+        if (other.hasNonce()) {
+          setNonce(other.getNonce());
+        }
         this.mergeUnknownFields(other.getUnknownFields());
         return this;
       }
@@ -10202,6 +10259,39 @@ public final class ClientProtos {
         return this;
       }
 
+      // optional uint64 nonce = 9;
+      private long nonce_ ;
+      /**
+       * <code>optional uint64 nonce = 9;</code>
+       */
+      public boolean hasNonce() {
+        return ((bitField0_ & 0x00000100) == 0x00000100);
+      }
+      /**
+       * <code>optional uint64 nonce = 9;</code>
+       */
+      public long getNonce() {
+        return nonce_;
+      }
+      /**
+       * <code>optional uint64 nonce = 9;</code>
+       */
+      public Builder setNonce(long value) {
+        bitField0_ |= 0x00000100;
+        nonce_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * <code>optional uint64 nonce = 9;</code>
+       */
+      public Builder clearNonce() {
+        bitField0_ = (bitField0_ & ~0x00000100);
+        nonce_ = 0L;
+        onChanged();
+        return this;
+      }
+
       // @@protoc_insertion_point(builder_scope:MutationProto)
     }
 
@@ -10257,6 +10347,16 @@ public final class ClientProtos {
      * <code>optional .Condition condition = 3;</code>
      */
     org.apache.hadoop.hbase.protobuf.generated.ClientProtos.ConditionOrBuilder getConditionOrBuilder();
+
+    // optional uint64 nonce_group = 4;
+    /**
+     * <code>optional uint64 nonce_group = 4;</code>
+     */
+    boolean hasNonceGroup();
+    /**
+     * <code>optional uint64 nonce_group = 4;</code>
+     */
+    long getNonceGroup();
   }
   /**
    * Protobuf type {@code MutateRequest}
@@ -10359,6 +10459,11 @@ public final class ClientProtos {
               bitField0_ |= 0x00000004;
               break;
             }
+            case 32: {
+              bitField0_ |= 0x00000008;
+              nonceGroup_ = input.readUInt64();
+              break;
+            }
           }
         }
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
@@ -10465,10 +10570,27 @@ public final class ClientProtos {
       return condition_;
     }
 
+    // optional uint64 nonce_group = 4;
+    public static final int NONCE_GROUP_FIELD_NUMBER = 4;
+    private long nonceGroup_;
+    /**
+     * <code>optional uint64 nonce_group = 4;</code>
+     */
+    public boolean hasNonceGroup() {
+      return ((bitField0_ & 0x00000008) == 0x00000008);
+    }
+    /**
+     * <code>optional uint64 nonce_group = 4;</code>
+     */
+    public long getNonceGroup() {
+      return nonceGroup_;
+    }
+
     private void initFields() {
       region_ = org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.RegionSpecifier.getDefaultInstance();
       mutation_ = org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MutationProto.getDefaultInstance();
       condition_ = org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Condition.getDefaultInstance();
+      nonceGroup_ = 0L;
     }
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
@@ -10513,6 +10635,9 @@ public final class ClientProtos {
       if (((bitField0_ & 0x00000004) == 0x00000004)) {
         output.writeMessage(3, condition_);
       }
+      if (((bitField0_ & 0x00000008) == 0x00000008)) {
+        output.writeUInt64(4, nonceGroup_);
+      }
       getUnknownFields().writeTo(output);
     }
 
@@ -10534,6 +10659,10 @@ public final class ClientProtos {
         size += com.google.protobuf.CodedOutputStream
           .computeMessageSize(3, condition_);
       }
+      if (((bitField0_ & 0x00000008) == 0x00000008)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeUInt64Size(4, nonceGroup_);
+      }
       size += getUnknownFields().getSerializedSize();
       memoizedSerializedSize = size;
       return size;
@@ -10572,6 +10701,11 @@ public final class ClientProtos {
         result = result && getCondition()
             .equals(other.getCondition());
       }
+      result = result && (hasNonceGroup() == other.hasNonceGroup());
+      if (hasNonceGroup()) {
+        result = result && (getNonceGroup()
+            == other.getNonceGroup());
+      }
       result = result &&
           getUnknownFields().equals(other.getUnknownFields());
       return result;
@@ -10597,6 +10731,10 @@ public final class ClientProtos {
         hash = (37 * hash) + CONDITION_FIELD_NUMBER;
         hash = (53 * hash) + getCondition().hashCode();
       }
+      if (hasNonceGroup()) {
+        hash = (37 * hash) + NONCE_GROUP_FIELD_NUMBER;
+        hash = (53 * hash) + hashLong(getNonceGroup());
+      }
       hash = (29 * hash) + getUnknownFields().hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -10738,6 +10876,8 @@ public final class ClientProtos {
           conditionBuilder_.clear();
         }
         bitField0_ = (bitField0_ & ~0x00000004);
+        nonceGroup_ = 0L;
+        bitField0_ = (bitField0_ & ~0x00000008);
         return this;
       }
 
@@ -10790,6 +10930,10 @@ public final class ClientProtos {
         } else {
           result.condition_ = conditionBuilder_.build();
         }
+        if (((from_bitField0_ & 0x00000008) == 0x00000008)) {
+          to_bitField0_ |= 0x00000008;
+        }
+        result.nonceGroup_ = nonceGroup_;
         result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
@@ -10815,6 +10959,9 @@ public final class ClientProtos {
         if (other.hasCondition()) {
           mergeCondition(other.getCondition());
         }
+        if (other.hasNonceGroup()) {
+          setNonceGroup(other.getNonceGroup());
+        }
         this.mergeUnknownFields(other.getUnknownFields());
         return this;
       }
@@ -11215,6 +11362,39 @@ public final class ClientProtos {
         return conditionBuilder_;
       }
 
+      // optional uint64 nonce_group = 4;
+      private long nonceGroup_ ;
+      /**
+       * <code>optional uint64 nonce_group = 4;</code>
+       */
+      public boolean hasNonceGroup() {
+        return ((bitField0_ & 0x00000008) == 0x00000008);
+      }
+      /**
+       * <code>optional uint64 nonce_group = 4;</code>
+       */
+      public long getNonceGroup() {
+        return nonceGroup_;
+      }
+      /**
+       * <code>optional uint64 nonce_group = 4;</code>
+       */
+      public Builder setNonceGroup(long value) {
+        bitField0_ |= 0x00000008;
+        nonceGroup_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * <code>optional uint64 nonce_group = 4;</code>
+       */
+      public Builder clearNonceGroup() {
+        bitField0_ = (bitField0_ & ~0x00000008);
+        nonceGroup_ = 0L;
+        onChanged();
+        return this;
+      }
+
       // @@protoc_insertion_point(builder_scope:MutateRequest)
     }
 
@@ -25450,6 +25630,16 @@ public final class ClientProtos {
      */
     org.apache.hadoop.hbase.protobuf.generated.ClientProtos.RegionActionOrBuilder getRegionActionOrBuilder(
         int index);
+
+    // optional uint64 nonceGroup = 2;
+    /**
+     * <code>optional uint64 nonceGroup = 2;</code>
+     */
+    boolean hasNonceGroup();
+    /**
+     * <code>optional uint64 nonceGroup = 2;</code>
+     */
+    long getNonceGroup();
   }
   /**
    * Protobuf type {@code MultiRequest}
@@ -25519,6 +25709,11 @@ public final class ClientProtos {
               regionAction_.add(input.readMessage(org.apache.hadoop.hbase.protobuf.generated.ClientProtos.RegionAction.PARSER, extensionRegistry));
               break;
             }
+            case 16: {
+              bitField0_ |= 0x00000001;
+              nonceGroup_ = input.readUInt64();
+              break;
+            }
           }
         }
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
@@ -25561,6 +25756,7 @@ public final class ClientProtos {
       return PARSER;
     }
 
+    private int bitField0_;
     // repeated .RegionAction regionAction = 1;
     public static final int REGIONACTION_FIELD_NUMBER = 1;
     private java.util.List<org.apache.hadoop.hbase.protobuf.generated.ClientProtos.RegionAction> regionAction_;
@@ -25597,8 +25793,25 @@ public final class ClientProtos {
       return regionAction_.get(index);
     }
 
+    // optional uint64 nonceGroup = 2;
+    public static final int NONCEGROUP_FIELD_NUMBER = 2;
+    private long nonceGroup_;
+    /**
+     * <code>optional uint64 nonceGroup = 2;</code>
+     */
+    public boolean hasNonceGroup() {
+      return ((bitField0_ & 0x00000001) == 0x00000001);
+    }
+    /**
+     * <code>optional uint64 nonceGroup = 2;</code>
+     */
+    public long getNonceGroup() {
+      return nonceGroup_;
+    }
+
     private void initFields() {
       regionAction_ = java.util.Collections.emptyList();
+      nonceGroup_ = 0L;
     }
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
@@ -25621,6 +25834,9 @@ public final class ClientProtos {
       for (int i = 0; i < regionAction_.size(); i++) {
         output.writeMessage(1, regionAction_.get(i));
       }
+      if (((bitField0_ & 0x00000001) == 0x00000001)) {
+        output.writeUInt64(2, nonceGroup_);
+      }
       getUnknownFields().writeTo(output);
     }
 
@@ -25634,6 +25850,10 @@ public final class ClientProtos {
         size += com.google.protobuf.CodedOutputStream
           .computeMessageSize(1, regionAction_.get(i));
       }
+      if (((bitField0_ & 0x00000001) == 0x00000001)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeUInt64Size(2, nonceGroup_);
+      }
       size += getUnknownFields().getSerializedSize();
       memoizedSerializedSize = size;
       return size;
@@ -25659,6 +25879,11 @@ public final class ClientProtos {
       boolean result = true;
       result = result && getRegionActionList()
           .equals(other.getRegionActionList());
+      result = result && (hasNonceGroup() == other.hasNonceGroup());
+      if (hasNonceGroup()) {
+        result = result && (getNonceGroup()
+            == other.getNonceGroup());
+      }
       result = result &&
           getUnknownFields().equals(other.getUnknownFields());
       return result;
@@ -25676,6 +25901,10 @@ public final class ClientProtos {
         hash = (37 * hash) + REGIONACTION_FIELD_NUMBER;
         hash = (53 * hash) + getRegionActionList().hashCode();
       }
+      if (hasNonceGroup()) {
+        hash = (37 * hash) + NONCEGROUP_FIELD_NUMBER;
+        hash = (53 * hash) + hashLong(getNonceGroup());
+      }
       hash = (29 * hash) + getUnknownFields().hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -25801,6 +26030,8 @@ public final class ClientProtos {
         } else {
           regionActionBuilder_.clear();
         }
+        nonceGroup_ = 0L;
+        bitField0_ = (bitField0_ & ~0x00000002);
         return this;
       }
 
@@ -25828,6 +26059,7 @@ public final class ClientProtos {
       public org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MultiRequest buildPartial() {
         org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MultiRequest result = new org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MultiRequest(this);
         int from_bitField0_ = bitField0_;
+        int to_bitField0_ = 0;
         if (regionActionBuilder_ == null) {
           if (((bitField0_ & 0x00000001) == 0x00000001)) {
             regionAction_ = java.util.Collections.unmodifiableList(regionAction_);
@@ -25837,6 +26069,11 @@ public final class ClientProtos {
         } else {
           result.regionAction_ = regionActionBuilder_.build();
         }
+        if (((from_bitField0_ & 0x00000002) == 0x00000002)) {
+          to_bitField0_ |= 0x00000001;
+        }
+        result.nonceGroup_ = nonceGroup_;
+        result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
       }
@@ -25878,6 +26115,9 @@ public final class ClientProtos {
             }
           }
         }
+        if (other.hasNonceGroup()) {
+          setNonceGroup(other.getNonceGroup());
+        }
         this.mergeUnknownFields(other.getUnknownFields());
         return this;
       }
@@ -26151,6 +26391,39 @@ public final class ClientProtos {
         return regionActionBuilder_;
       }
 
+      // optional uint64 nonceGroup = 2;
+      private long nonceGroup_ ;
+      /**
+       * <code>optional uint64 nonceGroup = 2;</code>
+       */
+      public boolean hasNonceGroup() {
+        return ((bitField0_ & 0x00000002) == 0x00000002);
+      }
+      /**
+       * <code>optional uint64 nonceGroup = 2;</code>
+       */
+      public long getNonceGroup() {
+        return nonceGroup_;
+      }
+      /**
+       * <code>optional uint64 nonceGroup = 2;</code>
+       */
+      public Builder setNonceGroup(long value) {
+        bitField0_ |= 0x00000002;
+        nonceGroup_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * <code>optional uint64 nonceGroup = 2;</code>
+       */
+      public Builder clearNonceGroup() {
+        bitField0_ = (bitField0_ & ~0x00000002);
+        nonceGroup_ = 0L;
+        onChanged();
+        return this;
+      }
+
       // @@protoc_insertion_point(builder_scope:MultiRequest)
     }
 
@@ -27627,7 +27900,7 @@ public final class ClientProtos {
       "t\"\200\001\n\tCondition\022\013\n\003row\030\001 \002(\014\022\016\n\006family\030\002" +
       " \002(\014\022\021\n\tqualifier\030\003 \002(\014\022\"\n\014compare_type\030" +
       "\004 \002(\0162\014.CompareType\022\037\n\ncomparator\030\005 \002(\0132" +
-      "\013.Comparator\"\246\006\n\rMutationProto\022\013\n\003row\030\001 " +
+      "\013.Comparator\"\265\006\n\rMutationProto\022\013\n\003row\030\001 " +
       "\001(\014\0220\n\013mutate_type\030\002 \001(\0162\033.MutationProto",
       ".MutationType\0220\n\014column_value\030\003 \003(\0132\032.Mu" +
       "tationProto.ColumnValue\022\021\n\ttimestamp\030\004 \001" +
@@ -27635,74 +27908,76 @@ public final class ClientProtos {
       "\ndurability\030\006 \001(\0162\031.MutationProto.Durabi" +
       "lity:\013USE_DEFAULT\022\036\n\ntime_range\030\007 \001(\0132\n." +
       "TimeRange\022\035\n\025associated_cell_count\030\010 \001(\005" +
-      "\032\347\001\n\013ColumnValue\022\016\n\006family\030\001 \002(\014\022B\n\017qual" +
+      "\022\r\n\005nonce\030\t \001(\004\032\347\001\n\013ColumnValue\022\016\n\006famil" +
-      "ifier_value\030\002 \003(\0132).MutationProto.Column" +
+      "y\030\001 \002(\014\022B\n\017qualifier_value\030\002 \003(\0132).Mutat" +
-      "Value.QualifierValue\032\203\001\n\016QualifierValue\022" +
+      "ionProto.ColumnValue.QualifierValue\032\203\001\n\016" +
-      "\021\n\tqualifier\030\001 \001(\014\022\r\n\005value\030\002 \001(\014\022\021\n\ttim",
+      "QualifierValue\022\021\n\tqualifier\030\001 \001(\014\022\r\n\005val",
-      "estamp\030\003 \001(\004\022.\n\013delete_type\030\004 \001(\0162\031.Muta" +
+      "ue\030\002 \001(\014\022\021\n\ttimestamp\030\003 \001(\004\022.\n\013delete_ty" +
-      "tionProto.DeleteType\022\014\n\004tags\030\005 \001(\014\"W\n\nDu" +
+      "pe\030\004 \001(\0162\031.MutationProto.DeleteType\022\014\n\004t" +
-      "rability\022\017\n\013USE_DEFAULT\020\000\022\014\n\010SKIP_WAL\020\001\022" +
+      "ags\030\005 \001(\014\"W\n\nDurability\022\017\n\013USE_DEFAULT\020\000" +
-      "\r\n\tASYNC_WAL\020\002\022\014\n\010SYNC_WAL\020\003\022\r\n\tFSYNC_WA" +
+      "\022\014\n\010SKIP_WAL\020\001\022\r\n\tASYNC_WAL\020\002\022\014\n\010SYNC_WA" +
-      "L\020\004\">\n\014MutationType\022\n\n\006APPEND\020\000\022\r\n\tINCRE" +
+      "L\020\003\022\r\n\tFSYNC_WAL\020\004\">\n\014MutationType\022\n\n\006AP" +
-      "MENT\020\001\022\007\n\003PUT\020\002\022\n\n\006DELETE\020\003\"p\n\nDeleteTyp" +
+      "PEND\020\000\022\r\n\tINCREMENT\020\001\022\007\n\003PUT\020\002\022\n\n\006DELETE" +
-      "e\022\026\n\022DELETE_ONE_VERSION\020\000\022\034\n\030DELETE_MULT" +
+      "\020\003\"p\n\nDeleteType\022\026\n\022DELETE_ONE_VERSION\020\000" +
-      "IPLE_VERSIONS\020\001\022\021\n\rDELETE_FAMILY\020\002\022\031\n\025DE" +
+      "\022\034\n\030DELETE_MULTIPLE_VERSIONS\020\001\022\021\n\rDELETE" +
-      "LETE_FAMILY_VERSION\020\003\"r\n\rMutateRequest\022 " +
+      "_FAMILY\020\002\022\031\n\025DELETE_FAMILY_VERSION\020\003\"\207\001\n" +
-      "\n\006region\030\001 \002(\0132\020.RegionSpecifier\022 \n\010muta",
+      "\rMutateRequest\022 \n\006region\030\001 \002(\0132\020.RegionS",
-      "tion\030\002 \002(\0132\016.MutationProto\022\035\n\tcondition\030" +
+      "pecifier\022 \n\010mutation\030\002 \002(\0132\016.MutationPro" +
-      "\003 \001(\0132\n.Condition\"<\n\016MutateResponse\022\027\n\006r" +
+      "to\022\035\n\tcondition\030\003 \001(\0132\n.Condition\022\023\n\013non" +
-      "esult\030\001 \001(\0132\007.Result\022\021\n\tprocessed\030\002 \001(\010\"" +
+      "ce_group\030\004 \001(\004\"<\n\016MutateResponse\022\027\n\006resu" +
-      "\344\002\n\004Scan\022\027\n\006column\030\001 \003(\0132\007.Column\022!\n\tatt" +
+      "lt\030\001 \001(\0132\007.Result\022\021\n\tprocessed\030\002 \001(\010\"\344\002\n" +
-      "ribute\030\002 \003(\0132\016.NameBytesPair\022\021\n\tstart_ro" +
+      "\004Scan\022\027\n\006column\030\001 \003(\0132\007.Column\022!\n\tattrib" +
-      "w\030\003 \001(\014\022\020\n\010stop_row\030\004 \001(\014\022\027\n\006filter\030\005 \001(" +
+      "ute\030\002 \003(\0132\016.NameBytesPair\022\021\n\tstart_row\030\003" +
-      "\0132\007.Filter\022\036\n\ntime_range\030\006 \001(\0132\n.TimeRan" +
+      " \001(\014\022\020\n\010stop_row\030\004 \001(\014\022\027\n\006filter\030\005 \001(\0132\007" +
-      "ge\022\027\n\014max_versions\030\007 \001(\r:\0011\022\032\n\014cache_blo" +
+      ".Filter\022\036\n\ntime_range\030\006 \001(\0132\n.TimeRange\022" +
-      "cks\030\010 \001(\010:\004true\022\022\n\nbatch_size\030\t \001(\r\022\027\n\017m" +
+      "\027\n\014max_versions\030\007 \001(\r:\0011\022\032\n\014cache_blocks" +
-      "ax_result_size\030\n \001(\004\022\023\n\013store_limit\030\013 \001(",
+      "\030\010 \001(\010:\004true\022\022\n\nbatch_size\030\t \001(\r\022\027\n\017max_",
-      "\r\022\024\n\014store_offset\030\014 \001(\r\022&\n\036load_column_f" +
+      "result_size\030\n \001(\004\022\023\n\013store_limit\030\013 \001(\r\022\024" +
-      "amilies_on_demand\030\r \001(\010\022\r\n\005small\030\016 \001(\010\"\236" +
+      "\n\014store_offset\030\014 \001(\r\022&\n\036load_column_fami" +
-      "\001\n\013ScanRequest\022 \n\006region\030\001 \001(\0132\020.RegionS" +
+      "lies_on_demand\030\r \001(\010\022\r\n\005small\030\016 \001(\010\"\236\001\n\013" +
-      "pecifier\022\023\n\004scan\030\002 \001(\0132\005.Scan\022\022\n\nscanner" +
+      "ScanRequest\022 \n\006region\030\001 \001(\0132\020.RegionSpec" +
-      "_id\030\003 \001(\004\022\026\n\016number_of_rows\030\004 \001(\r\022\025\n\rclo" +
+      "ifier\022\023\n\004scan\030\002 \001(\0132\005.Scan\022\022\n\nscanner_id" +
-      "se_scanner\030\005 \001(\010\022\025\n\rnext_call_seq\030\006 \001(\004\"" +
+      "\030\003 \001(\004\022\026\n\016number_of_rows\030\004 \001(\r\022\025\n\rclose_" +
-      "y\n\014ScanResponse\022\030\n\020cells_per_result\030\001 \003(" +
+      "scanner\030\005 \001(\010\022\025\n\rnext_call_seq\030\006 \001(\004\"y\n\014" +
-      "\r\022\022\n\nscanner_id\030\002 \001(\004\022\024\n\014more_results\030\003 " +
+      "ScanResponse\022\030\n\020cells_per_result\030\001 \003(\r\022\022" +
-      "\001(\010\022\013\n\003ttl\030\004 \001(\r\022\030\n\007results\030\005 \003(\0132\007.Resu" +
+      "\n\nscanner_id\030\002 \001(\004\022\024\n\014more_results\030\003 \001(\010" +
-      "lt\"\263\001\n\024BulkLoadHFileRequest\022 \n\006region\030\001 ",
+      "\022\013\n\003ttl\030\004 \001(\r\022\030\n\007results\030\005 \003(\0132\007.Result\"",
-      "\002(\0132\020.RegionSpecifier\0225\n\013family_path\030\002 \003" +
+      "\263\001\n\024BulkLoadHFileRequest\022 \n\006region\030\001 \002(\013" +
-      "(\0132 .BulkLoadHFileRequest.FamilyPath\022\026\n\016" +
+      "2\020.RegionSpecifier\0225\n\013family_path\030\002 \003(\0132" +
-      "assign_seq_num\030\003 \001(\010\032*\n\nFamilyPath\022\016\n\006fa" +
+      " .BulkLoadHFileRequest.FamilyPath\022\026\n\016ass" +
-      "mily\030\001 \002(\014\022\014\n\004path\030\002 \002(\t\"\'\n\025BulkLoadHFil" +
+      "ign_seq_num\030\003 \001(\010\032*\n\nFamilyPath\022\016\n\006famil" +
-      "eResponse\022\016\n\006loaded\030\001 \002(\010\"a\n\026Coprocessor" +
+      "y\030\001 \002(\014\022\014\n\004path\030\002 \002(\t\"\'\n\025BulkLoadHFileRe" +
-      "ServiceCall\022\013\n\003row\030\001 \002(\014\022\024\n\014service_name" +
+      "sponse\022\016\n\006loaded\030\001 \002(\010\"a\n\026CoprocessorSer" +
-      "\030\002 \002(\t\022\023\n\013method_name\030\003 \002(\t\022\017\n\007request\030\004" +
+      "viceCall\022\013\n\003row\030\001 \002(\014\022\024\n\014service_name\030\002 " +
-      " \002(\014\"d\n\031CoprocessorServiceRequest\022 \n\006reg" +
+      "\002(\t\022\023\n\013method_name\030\003 \002(\t\022\017\n\007request\030\004 \002(" +
-      "ion\030\001 \002(\0132\020.RegionSpecifier\022%\n\004call\030\002 \002(" +
+      "\014\"d\n\031CoprocessorServiceRequest\022 \n\006region" +
-      "\0132\027.CoprocessorServiceCall\"]\n\032Coprocesso",
+      "\030\001 \002(\0132\020.RegionSpecifier\022%\n\004call\030\002 \002(\0132\027",
-      "rServiceResponse\022 \n\006region\030\001 \002(\0132\020.Regio" +
+      ".CoprocessorServiceCall\"]\n\032CoprocessorSe" +
-      "nSpecifier\022\035\n\005value\030\002 \002(\0132\016.NameBytesPai" +
+      "rviceResponse\022 \n\006region\030\001 \002(\0132\020.RegionSp" +
-      "r\"L\n\006Action\022\r\n\005index\030\001 \001(\r\022 \n\010mutation\030\002" +
+      "ecifier\022\035\n\005value\030\002 \002(\0132\016.NameBytesPair\"L" +
-      " \001(\0132\016.MutationProto\022\021\n\003get\030\003 \001(\0132\004.Get\"" +
+      "\n\006Action\022\r\n\005index\030\001 \001(\r\022 \n\010mutation\030\002 \001(" +
-      "Y\n\014RegionAction\022 \n\006region\030\001 \002(\0132\020.Region" +
+      "\0132\016.MutationProto\022\021\n\003get\030\003 \001(\0132\004.Get\"Y\n\014" +
-      "Specifier\022\016\n\006atomic\030\002 \001(\010\022\027\n\006action\030\003 \003(" +
+      "RegionAction\022 \n\006region\030\001 \002(\0132\020.RegionSpe" +
-      "\0132\007.Action\"^\n\021ResultOrException\022\r\n\005index" +
+      "cifier\022\016\n\006atomic\030\002 \001(\010\022\027\n\006action\030\003 \003(\0132\007" +
-      "\030\001 \001(\r\022\027\n\006result\030\002 \001(\0132\007.Result\022!\n\texcep" +
+      ".Action\"^\n\021ResultOrException\022\r\n\005index\030\001 " +
-      "tion\030\003 \001(\0132\016.NameBytesPair\"f\n\022RegionActi" +
+      "\001(\r\022\027\n\006result\030\002 \001(\0132\007.Result\022!\n\texceptio" +
-      "onResult\022-\n\021resultOrException\030\001 \003(\0132\022.Re",
+      "n\030\003 \001(\0132\016.NameBytesPair\"f\n\022RegionActionR",
-      "sultOrException\022!\n\texception\030\002 \001(\0132\016.Nam" +
+      "esult\022-\n\021resultOrException\030\001 \003(\0132\022.Resul" +
-      "eBytesPair\"3\n\014MultiRequest\022#\n\014regionActi" +
+      "tOrException\022!\n\texception\030\002 \001(\0132\016.NameBy" +
-      "on\030\001 \003(\0132\r.RegionAction\"@\n\rMultiResponse" +
+      "tesPair\"G\n\014MultiRequest\022#\n\014regionAction\030" +
-      "\022/\n\022regionActionResult\030\001 \003(\0132\023.RegionAct" +
+      "\001 \003(\0132\r.RegionAction\022\022\n\nnonceGroup\030\002 \001(\004" +
-      "ionResult2\261\002\n\rClientService\022 \n\003Get\022\013.Get" +
+      "\"@\n\rMultiResponse\022/\n\022regionActionResult\030" +
-      "Request\032\014.GetResponse\022)\n\006Mutate\022\016.Mutate" +
+      "\001 \003(\0132\023.RegionActionResult2\261\002\n\rClientSer" +
-      "Request\032\017.MutateResponse\022#\n\004Scan\022\014.ScanR" +
+      "vice\022 \n\003Get\022\013.GetRequest\032\014.GetResponse\022)" +
-      "equest\032\r.ScanResponse\022>\n\rBulkLoadHFile\022\025" +
+      "\n\006Mutate\022\016.MutateRequest\032\017.MutateRespons" +
-      ".BulkLoadHFileRequest\032\026.BulkLoadHFileRes" +
+      "e\022#\n\004Scan\022\014.ScanRequest\032\r.ScanResponse\022>" +
-      "ponse\022F\n\013ExecService\022\032.CoprocessorServic",
+      "\n\rBulkLoadHFile\022\025.BulkLoadHFileRequest\032\026",
-      "eRequest\032\033.CoprocessorServiceResponse\022&\n" +
+      ".BulkLoadHFileResponse\022F\n\013ExecService\022\032." +
-      "\005Multi\022\r.MultiRequest\032\016.MultiResponseBB\n" +
+      "CoprocessorServiceRequest\032\033.CoprocessorS" +
-      "*org.apache.hadoop.hbase.protobuf.genera" +
+      "erviceResponse\022&\n\005Multi\022\r.MultiRequest\032\016" +
-      "tedB\014ClientProtosH\001\210\001\001\240\001\001"
+      ".MultiResponseBB\n*org.apache.hadoop.hbas" +
+      "e.protobuf.generatedB\014ClientProtosH\001\210\001\001\240" +
+      "\001\001"
     };
     com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner assigner =
       new com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner() {
@@ -27750,7 +28025,7 @@ public final class ClientProtos {
           internal_static_MutationProto_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_MutationProto_descriptor,
-              new java.lang.String[] { "Row", "MutateType", "ColumnValue", "Timestamp", "Attribute", "Durability", "TimeRange", "AssociatedCellCount", });
+              new java.lang.String[] { "Row", "MutateType", "ColumnValue", "Timestamp", "Attribute", "Durability", "TimeRange", "AssociatedCellCount", "Nonce", });
           internal_static_MutationProto_ColumnValue_descriptor =
             internal_static_MutationProto_descriptor.getNestedTypes().get(0);
           internal_static_MutationProto_ColumnValue_fieldAccessorTable = new
@@ -27768,7 +28043,7 @@ public final class ClientProtos {
           internal_static_MutateRequest_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_MutateRequest_descriptor,
-              new java.lang.String[] { "Region", "Mutation", "Condition", });
+              new java.lang.String[] { "Region", "Mutation", "Condition", "NonceGroup", });
           internal_static_MutateResponse_descriptor =
             getDescriptor().getMessageTypes().get(8);
           internal_static_MutateResponse_fieldAccessorTable = new
@@ -27858,7 +28133,7 @@ public final class ClientProtos {
           internal_static_MultiRequest_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_MultiRequest_descriptor,
-              new java.lang.String[] { "RegionAction", });
+              new java.lang.String[] { "RegionAction", "NonceGroup", });
           internal_static_MultiResponse_descriptor =
             getDescriptor().getMessageTypes().get(22);
           internal_static_MultiResponse_fieldAccessorTable = new

hbase-protocol/src/main/java/org/apache/hadoop/hbase/protobuf/generated/MultiRowMutationProtos.java

@@ -711,6 +711,26 @@ public final class MultiRowMutationProtos {
      */
     org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MutationProtoOrBuilder getMutationRequestOrBuilder(
         int index);
+
+    // optional uint64 nonce_group = 2;
+    /**
+     * <code>optional uint64 nonce_group = 2;</code>
+     */
+    boolean hasNonceGroup();
+    /**
+     * <code>optional uint64 nonce_group = 2;</code>
+     */
+    long getNonceGroup();
+
+    // optional uint64 nonce = 3;
+    /**
+     * <code>optional uint64 nonce = 3;</code>
+     */
+    boolean hasNonce();
+    /**
+     * <code>optional uint64 nonce = 3;</code>
+     */
+    long getNonce();
   }
   /**
    * Protobuf type {@code MutateRowsRequest}
@@ -771,6 +791,16 @@ public final class MultiRowMutationProtos {
               mutationRequest_.add(input.readMessage(org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MutationProto.PARSER, extensionRegistry));
               break;
             }
+            case 16: {
+              bitField0_ |= 0x00000001;
+              nonceGroup_ = input.readUInt64();
+              break;
+            }
+            case 24: {
+              bitField0_ |= 0x00000002;
+              nonce_ = input.readUInt64();
+              break;
+            }
           }
         }
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
@@ -813,6 +843,7 @@ public final class MultiRowMutationProtos {
       return PARSER;
     }
 
+    private int bitField0_;
     // repeated .MutationProto mutation_request = 1;
     public static final int MUTATION_REQUEST_FIELD_NUMBER = 1;
     private java.util.List<org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MutationProto> mutationRequest_;
@@ -849,8 +880,42 @@ public final class MultiRowMutationProtos {
       return mutationRequest_.get(index);
     }
 
+    // optional uint64 nonce_group = 2;
+    public static final int NONCE_GROUP_FIELD_NUMBER = 2;
+    private long nonceGroup_;
+    /**
+     * <code>optional uint64 nonce_group = 2;</code>
+     */
+    public boolean hasNonceGroup() {
+      return ((bitField0_ & 0x00000001) == 0x00000001);
+    }
+    /**
+     * <code>optional uint64 nonce_group = 2;</code>
+     */
+    public long getNonceGroup() {
+      return nonceGroup_;
+    }
+
+    // optional uint64 nonce = 3;
+    public static final int NONCE_FIELD_NUMBER = 3;
+    private long nonce_;
+    /**
+     * <code>optional uint64 nonce = 3;</code>
+     */
+    public boolean hasNonce() {
+      return ((bitField0_ & 0x00000002) == 0x00000002);
+    }
+    /**
+     * <code>optional uint64 nonce = 3;</code>
+     */
+    public long getNonce() {
+      return nonce_;
+    }
+
     private void initFields() {
       mutationRequest_ = java.util.Collections.emptyList();
+      nonceGroup_ = 0L;
+      nonce_ = 0L;
     }
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
@@ -873,6 +938,12 @@ public final class MultiRowMutationProtos {
       for (int i = 0; i < mutationRequest_.size(); i++) {
         output.writeMessage(1, mutationRequest_.get(i));
       }
+      if (((bitField0_ & 0x00000001) == 0x00000001)) {
+        output.writeUInt64(2, nonceGroup_);
+      }
+      if (((bitField0_ & 0x00000002) == 0x00000002)) {
+        output.writeUInt64(3, nonce_);
+      }
       getUnknownFields().writeTo(output);
     }
 
@@ -886,6 +957,14 @@ public final class MultiRowMutationProtos {
         size += com.google.protobuf.CodedOutputStream
           .computeMessageSize(1, mutationRequest_.get(i));
       }
+      if (((bitField0_ & 0x00000001) == 0x00000001)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeUInt64Size(2, nonceGroup_);
+      }
+      if (((bitField0_ & 0x00000002) == 0x00000002)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeUInt64Size(3, nonce_);
+      }
       size += getUnknownFields().getSerializedSize();
       memoizedSerializedSize = size;
       return size;
@@ -911,6 +990,16 @@ public final class MultiRowMutationProtos {
       boolean result = true;
       result = result && getMutationRequestList()
           .equals(other.getMutationRequestList());
+      result = result && (hasNonceGroup() == other.hasNonceGroup());
+      if (hasNonceGroup()) {
+        result = result && (getNonceGroup()
+            == other.getNonceGroup());
+      }
+      result = result && (hasNonce() == other.hasNonce());
+      if (hasNonce()) {
+        result = result && (getNonce()
+            == other.getNonce());
+      }
       result = result &&
           getUnknownFields().equals(other.getUnknownFields());
       return result;
@@ -928,6 +1017,14 @@ public final class MultiRowMutationProtos {
         hash = (37 * hash) + MUTATION_REQUEST_FIELD_NUMBER;
         hash = (53 * hash) + getMutationRequestList().hashCode();
       }
+      if (hasNonceGroup()) {
+        hash = (37 * hash) + NONCE_GROUP_FIELD_NUMBER;
+        hash = (53 * hash) + hashLong(getNonceGroup());
+      }
+      if (hasNonce()) {
+        hash = (37 * hash) + NONCE_FIELD_NUMBER;
+        hash = (53 * hash) + hashLong(getNonce());
+      }
       hash = (29 * hash) + getUnknownFields().hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -1044,6 +1141,10 @@ public final class MultiRowMutationProtos {
         } else {
           mutationRequestBuilder_.clear();
         }
+        nonceGroup_ = 0L;
+        bitField0_ = (bitField0_ & ~0x00000002);
+        nonce_ = 0L;
+        bitField0_ = (bitField0_ & ~0x00000004);
         return this;
       }
 
@@ -1071,6 +1172,7 @@ public final class MultiRowMutationProtos {
       public org.apache.hadoop.hbase.protobuf.generated.MultiRowMutationProtos.MutateRowsRequest buildPartial() {
         org.apache.hadoop.hbase.protobuf.generated.MultiRowMutationProtos.MutateRowsRequest result = new org.apache.hadoop.hbase.protobuf.generated.MultiRowMutationProtos.MutateRowsRequest(this);
         int from_bitField0_ = bitField0_;
+        int to_bitField0_ = 0;
         if (mutationRequestBuilder_ == null) {
           if (((bitField0_ & 0x00000001) == 0x00000001)) {
             mutationRequest_ = java.util.Collections.unmodifiableList(mutationRequest_);
@@ -1080,6 +1182,15 @@ public final class MultiRowMutationProtos {
         } else {
           result.mutationRequest_ = mutationRequestBuilder_.build();
         }
+        if (((from_bitField0_ & 0x00000002) == 0x00000002)) {
+          to_bitField0_ |= 0x00000001;
+        }
+        result.nonceGroup_ = nonceGroup_;
+        if (((from_bitField0_ & 0x00000004) == 0x00000004)) {
+          to_bitField0_ |= 0x00000002;
+        }
+        result.nonce_ = nonce_;
+        result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
       }
@@ -1121,6 +1232,12 @@ public final class MultiRowMutationProtos {
             }
           }
         }
+        if (other.hasNonceGroup()) {
+          setNonceGroup(other.getNonceGroup());
+        }
+        if (other.hasNonce()) {
+          setNonce(other.getNonce());
+        }
         this.mergeUnknownFields(other.getUnknownFields());
         return this;
       }
@@ -1394,6 +1511,72 @@ public final class MultiRowMutationProtos {
         return mutationRequestBuilder_;
       }
 
+      // optional uint64 nonce_group = 2;
+      private long nonceGroup_ ;
+      /**
+       * <code>optional uint64 nonce_group = 2;</code>
+       */
+      public boolean hasNonceGroup() {
+        return ((bitField0_ & 0x00000002) == 0x00000002);
+      }
+      /**
+       * <code>optional uint64 nonce_group = 2;</code>
+       */
+      public long getNonceGroup() {
+        return nonceGroup_;
+      }
+      /**
+       * <code>optional uint64 nonce_group = 2;</code>
+       */
+      public Builder setNonceGroup(long value) {
+        bitField0_ |= 0x00000002;
+        nonceGroup_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * <code>optional uint64 nonce_group = 2;</code>
+       */
+      public Builder clearNonceGroup() {
+        bitField0_ = (bitField0_ & ~0x00000002);
+        nonceGroup_ = 0L;
+        onChanged();
+        return this;
+      }
+
+      // optional uint64 nonce = 3;
+      private long nonce_ ;
+      /**
+       * <code>optional uint64 nonce = 3;</code>
+       */
+      public boolean hasNonce() {
+        return ((bitField0_ & 0x00000004) == 0x00000004);
+      }
+      /**
+       * <code>optional uint64 nonce = 3;</code>
+       */
+      public long getNonce() {
+        return nonce_;
+      }
+      /**
+       * <code>optional uint64 nonce = 3;</code>
+       */
+      public Builder setNonce(long value) {
+        bitField0_ |= 0x00000004;
+        nonce_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * <code>optional uint64 nonce = 3;</code>
+       */
+      public Builder clearNonce() {
+        bitField0_ = (bitField0_ & ~0x00000004);
+        nonce_ = 0L;
+        onChanged();
+        return this;
+      }
+
       // @@protoc_insertion_point(builder_scope:MutateRowsRequest)
     }
 
@@ -2006,13 +2189,14 @@ public final class MultiRowMutationProtos {
     java.lang.String[] descriptorData = {
       "\n\026MultiRowMutation.proto\032\014Client.proto\"\"" +
       "\n MultiRowMutationProcessorRequest\"#\n!Mu" +
-      "ltiRowMutationProcessorResponse\"=\n\021Mutat" +
+      "ltiRowMutationProcessorResponse\"a\n\021Mutat" +
       "eRowsRequest\022(\n\020mutation_request\030\001 \003(\0132\016" +
-      ".MutationProto\"\024\n\022MutateRowsResponse2P\n\027" +
+      ".MutationProto\022\023\n\013nonce_group\030\002 \001(\004\022\r\n\005n" +
-      "MultiRowMutationService\0225\n\nMutateRows\022\022." +
+      "once\030\003 \001(\004\"\024\n\022MutateRowsResponse2P\n\027Mult" +
-      "MutateRowsRequest\032\023.MutateRowsResponseBL" +
+      "iRowMutationService\0225\n\nMutateRows\022\022.Muta" +
-      "\n*org.apache.hadoop.hbase.protobuf.gener" +
+      "teRowsRequest\032\023.MutateRowsResponseBL\n*or" +
-      "atedB\026MultiRowMutationProtosH\001\210\001\001\240\001\001"
+      "g.apache.hadoop.hbase.protobuf.generated" +
+      "B\026MultiRowMutationProtosH\001\210\001\001\240\001\001"
     };
     com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner assigner =
       new com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner() {
@@ -2036,7 +2220,7 @@ public final class MultiRowMutationProtos {
           internal_static_MutateRowsRequest_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_MutateRowsRequest_descriptor,
-              new java.lang.String[] { "MutationRequest", });
+              new java.lang.String[] { "MutationRequest", "NonceGroup", "Nonce", });
           internal_static_MutateRowsResponse_descriptor =
             getDescriptor().getMessageTypes().get(3);
           internal_static_MutateRowsResponse_fieldAccessorTable = new

hbase-protocol/src/main/java/org/apache/hadoop/hbase/protobuf/generated/RowProcessorProtos.java

@@ -50,6 +50,26 @@ public final class RowProcessorProtos {
      * <code>optional bytes row_processor_initializer_message = 3;</code>
      */
     com.google.protobuf.ByteString getRowProcessorInitializerMessage();
+
+    // optional uint64 nonce_group = 4;
+    /**
+     * <code>optional uint64 nonce_group = 4;</code>
+     */
+    boolean hasNonceGroup();
+    /**
+     * <code>optional uint64 nonce_group = 4;</code>
+     */
+    long getNonceGroup();
+
+    // optional uint64 nonce = 5;
+    /**
+     * <code>optional uint64 nonce = 5;</code>
+     */
+    boolean hasNonce();
+    /**
+     * <code>optional uint64 nonce = 5;</code>
+     */
+    long getNonce();
   }
   /**
    * Protobuf type {@code ProcessRequest}
@@ -117,6 +137,16 @@ public final class RowProcessorProtos {
               rowProcessorInitializerMessage_ = input.readBytes();
               break;
             }
+            case 32: {
+              bitField0_ |= 0x00000008;
+              nonceGroup_ = input.readUInt64();
+              break;
+            }
+            case 40: {
+              bitField0_ |= 0x00000010;
+              nonce_ = input.readUInt64();
+              break;
+            }
           }
         }
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
@@ -259,10 +289,44 @@ public final class RowProcessorProtos {
       return rowProcessorInitializerMessage_;
     }
 
+    // optional uint64 nonce_group = 4;
+    public static final int NONCE_GROUP_FIELD_NUMBER = 4;
+    private long nonceGroup_;
+    /**
+     * <code>optional uint64 nonce_group = 4;</code>
+     */
+    public boolean hasNonceGroup() {
+      return ((bitField0_ & 0x00000008) == 0x00000008);
+    }
+    /**
+     * <code>optional uint64 nonce_group = 4;</code>
+     */
+    public long getNonceGroup() {
+      return nonceGroup_;
+    }
+
+    // optional uint64 nonce = 5;
+    public static final int NONCE_FIELD_NUMBER = 5;
+    private long nonce_;
+    /**
+     * <code>optional uint64 nonce = 5;</code>
+     */
+    public boolean hasNonce() {
+      return ((bitField0_ & 0x00000010) == 0x00000010);
+    }
+    /**
+     * <code>optional uint64 nonce = 5;</code>
+     */
+    public long getNonce() {
+      return nonce_;
+    }
+
     private void initFields() {
       rowProcessorClassName_ = "";
       rowProcessorInitializerMessageName_ = "";
       rowProcessorInitializerMessage_ = com.google.protobuf.ByteString.EMPTY;
+      nonceGroup_ = 0L;
+      nonce_ = 0L;
     }
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
@@ -289,6 +353,12 @@ public final class RowProcessorProtos {
       if (((bitField0_ & 0x00000004) == 0x00000004)) {
         output.writeBytes(3, rowProcessorInitializerMessage_);
       }
+      if (((bitField0_ & 0x00000008) == 0x00000008)) {
+        output.writeUInt64(4, nonceGroup_);
+      }
+      if (((bitField0_ & 0x00000010) == 0x00000010)) {
+        output.writeUInt64(5, nonce_);
+      }
       getUnknownFields().writeTo(output);
     }
 
@@ -310,6 +380,14 @@ public final class RowProcessorProtos {
         size += com.google.protobuf.CodedOutputStream
           .computeBytesSize(3, rowProcessorInitializerMessage_);
       }
+      if (((bitField0_ & 0x00000008) == 0x00000008)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeUInt64Size(4, nonceGroup_);
+      }
+      if (((bitField0_ & 0x00000010) == 0x00000010)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeUInt64Size(5, nonce_);
+      }
       size += getUnknownFields().getSerializedSize();
       memoizedSerializedSize = size;
       return size;
@@ -348,6 +426,16 @@ public final class RowProcessorProtos {
         result = result && getRowProcessorInitializerMessage()
             .equals(other.getRowProcessorInitializerMessage());
       }
+      result = result && (hasNonceGroup() == other.hasNonceGroup());
+      if (hasNonceGroup()) {
+        result = result && (getNonceGroup()
+            == other.getNonceGroup());
+      }
+      result = result && (hasNonce() == other.hasNonce());
+      if (hasNonce()) {
+        result = result && (getNonce()
+            == other.getNonce());
+      }
       result = result &&
           getUnknownFields().equals(other.getUnknownFields());
       return result;
@@ -373,6 +461,14 @@ public final class RowProcessorProtos {
         hash = (37 * hash) + ROW_PROCESSOR_INITIALIZER_MESSAGE_FIELD_NUMBER;
         hash = (53 * hash) + getRowProcessorInitializerMessage().hashCode();
       }
+      if (hasNonceGroup()) {
+        hash = (37 * hash) + NONCE_GROUP_FIELD_NUMBER;
+        hash = (53 * hash) + hashLong(getNonceGroup());
+      }
+      if (hasNonce()) {
+        hash = (37 * hash) + NONCE_FIELD_NUMBER;
+        hash = (53 * hash) + hashLong(getNonce());
+      }
       hash = (29 * hash) + getUnknownFields().hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -488,6 +584,10 @@ public final class RowProcessorProtos {
         bitField0_ = (bitField0_ & ~0x00000002);
         rowProcessorInitializerMessage_ = com.google.protobuf.ByteString.EMPTY;
         bitField0_ = (bitField0_ & ~0x00000004);
+        nonceGroup_ = 0L;
+        bitField0_ = (bitField0_ & ~0x00000008);
+        nonce_ = 0L;
+        bitField0_ = (bitField0_ & ~0x00000010);
         return this;
       }
 
@@ -528,6 +628,14 @@ public final class RowProcessorProtos {
           to_bitField0_ |= 0x00000004;
         }
         result.rowProcessorInitializerMessage_ = rowProcessorInitializerMessage_;
+        if (((from_bitField0_ & 0x00000008) == 0x00000008)) {
+          to_bitField0_ |= 0x00000008;
+        }
+        result.nonceGroup_ = nonceGroup_;
+        if (((from_bitField0_ & 0x00000010) == 0x00000010)) {
+          to_bitField0_ |= 0x00000010;
+        }
+        result.nonce_ = nonce_;
         result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
@@ -557,6 +665,12 @@ public final class RowProcessorProtos {
         if (other.hasRowProcessorInitializerMessage()) {
           setRowProcessorInitializerMessage(other.getRowProcessorInitializerMessage());
         }
+        if (other.hasNonceGroup()) {
+          setNonceGroup(other.getNonceGroup());
+        }
+        if (other.hasNonce()) {
+          setNonce(other.getNonce());
+        }
         this.mergeUnknownFields(other.getUnknownFields());
         return this;
       }
@@ -772,6 +886,72 @@ public final class RowProcessorProtos {
         return this;
       }
 
+      // optional uint64 nonce_group = 4;
+      private long nonceGroup_ ;
+      /**
+       * <code>optional uint64 nonce_group = 4;</code>
+       */
+      public boolean hasNonceGroup() {
+        return ((bitField0_ & 0x00000008) == 0x00000008);
+      }
+      /**
+       * <code>optional uint64 nonce_group = 4;</code>
+       */
+      public long getNonceGroup() {
+        return nonceGroup_;
+      }
+      /**
+       * <code>optional uint64 nonce_group = 4;</code>
+       */
+      public Builder setNonceGroup(long value) {
+        bitField0_ |= 0x00000008;
+        nonceGroup_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * <code>optional uint64 nonce_group = 4;</code>
+       */
+      public Builder clearNonceGroup() {
+        bitField0_ = (bitField0_ & ~0x00000008);
+        nonceGroup_ = 0L;
+        onChanged();
+        return this;
+      }
+
+      // optional uint64 nonce = 5;
+      private long nonce_ ;
+      /**
+       * <code>optional uint64 nonce = 5;</code>
+       */
+      public boolean hasNonce() {
+        return ((bitField0_ & 0x00000010) == 0x00000010);
+      }
+      /**
+       * <code>optional uint64 nonce = 5;</code>
+       */
+      public long getNonce() {
+        return nonce_;
+      }
+      /**
+       * <code>optional uint64 nonce = 5;</code>
+       */
+      public Builder setNonce(long value) {
+        bitField0_ |= 0x00000010;
+        nonce_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * <code>optional uint64 nonce = 5;</code>
+       */
+      public Builder clearNonce() {
+        bitField0_ = (bitField0_ & ~0x00000010);
+        nonce_ = 0L;
+        onChanged();
+        return this;
+      }
+
       // @@protoc_insertion_point(builder_scope:ProcessRequest)
     }
 
@@ -1479,15 +1659,16 @@ public final class RowProcessorProtos {
       descriptor;
   static {
     java.lang.String[] descriptorData = {
-      "\n\022RowProcessor.proto\"\215\001\n\016ProcessRequest\022" +
+      "\n\022RowProcessor.proto\"\261\001\n\016ProcessRequest\022" +
       " \n\030row_processor_class_name\030\001 \002(\t\022.\n&row" +
       "_processor_initializer_message_name\030\002 \001(" +
       "\t\022)\n!row_processor_initializer_message\030\003" +
-      " \001(\014\"/\n\017ProcessResponse\022\034\n\024row_processor" +
+      " \001(\014\022\023\n\013nonce_group\030\004 \001(\004\022\r\n\005nonce\030\005 \001(\004" +
-      "_result\030\001 \002(\0142C\n\023RowProcessorService\022,\n\007" +
+      "\"/\n\017ProcessResponse\022\034\n\024row_processor_res" +
-      "Process\022\017.ProcessRequest\032\020.ProcessRespon" +
+      "ult\030\001 \002(\0142C\n\023RowProcessorService\022,\n\007Proc" +
-      "seBH\n*org.apache.hadoop.hbase.protobuf.g" +
+      "ess\022\017.ProcessRequest\032\020.ProcessResponseBH" +
-      "eneratedB\022RowProcessorProtosH\001\210\001\001\240\001\001"
+      "\n*org.apache.hadoop.hbase.protobuf.gener" +
+      "atedB\022RowProcessorProtosH\001\210\001\001\240\001\001"
     };
     com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner assigner =
       new com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner() {
@@ -1499,7 +1680,7 @@ public final class RowProcessorProtos {
           internal_static_ProcessRequest_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_ProcessRequest_descriptor,
-              new java.lang.String[] { "RowProcessorClassName", "RowProcessorInitializerMessageName", "RowProcessorInitializerMessage", });
+              new java.lang.String[] { "RowProcessorClassName", "RowProcessorInitializerMessageName", "RowProcessorInitializerMessage", "NonceGroup", "Nonce", });
           internal_static_ProcessResponse_descriptor =
             getDescriptor().getMessageTypes().get(1);
           internal_static_ProcessResponse_fieldAccessorTable = new

hbase-protocol/src/main/java/org/apache/hadoop/hbase/protobuf/generated/WALProtos.java

@@ -694,6 +694,26 @@ public final class WALProtos {
      */
     org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.UUIDOrBuilder getClusterIdsOrBuilder(
         int index);
+
+    // optional uint64 nonceGroup = 9;
+    /**
+     * <code>optional uint64 nonceGroup = 9;</code>
+     */
+    boolean hasNonceGroup();
+    /**
+     * <code>optional uint64 nonceGroup = 9;</code>
+     */
+    long getNonceGroup();
+
+    // optional uint64 nonce = 10;
+    /**
+     * <code>optional uint64 nonce = 10;</code>
+     */
+    boolean hasNonce();
+    /**
+     * <code>optional uint64 nonce = 10;</code>
+     */
+    long getNonce();
   }
   /**
    * Protobuf type {@code WALKey}
@@ -804,6 +824,16 @@ public final class WALProtos {
               clusterIds_.add(input.readMessage(org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.UUID.PARSER, extensionRegistry));
               break;
             }
+            case 72: {
+              bitField0_ |= 0x00000040;
+              nonceGroup_ = input.readUInt64();
+              break;
+            }
+            case 80: {
+              bitField0_ |= 0x00000080;
+              nonce_ = input.readUInt64();
+              break;
+            }
           }
         }
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
@@ -1078,6 +1108,38 @@ public final class WALProtos {
       return clusterIds_.get(index);
     }
 
+    // optional uint64 nonceGroup = 9;
+    public static final int NONCEGROUP_FIELD_NUMBER = 9;
+    private long nonceGroup_;
+    /**
+     * <code>optional uint64 nonceGroup = 9;</code>
+     */
+    public boolean hasNonceGroup() {
+      return ((bitField0_ & 0x00000040) == 0x00000040);
+    }
+    /**
+     * <code>optional uint64 nonceGroup = 9;</code>
+     */
+    public long getNonceGroup() {
+      return nonceGroup_;
+    }
+
+    // optional uint64 nonce = 10;
+    public static final int NONCE_FIELD_NUMBER = 10;
+    private long nonce_;
+    /**
+     * <code>optional uint64 nonce = 10;</code>
+     */
+    public boolean hasNonce() {
+      return ((bitField0_ & 0x00000080) == 0x00000080);
+    }
+    /**
+     * <code>optional uint64 nonce = 10;</code>
+     */
+    public long getNonce() {
+      return nonce_;
+    }
+
     private void initFields() {
       encodedRegionName_ = com.google.protobuf.ByteString.EMPTY;
       tableName_ = com.google.protobuf.ByteString.EMPTY;
@@ -1087,6 +1149,8 @@ public final class WALProtos {
       scopes_ = java.util.Collections.emptyList();
       followingKvCount_ = 0;
       clusterIds_ = java.util.Collections.emptyList();
+      nonceGroup_ = 0L;
+      nonce_ = 0L;
     }
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
@@ -1158,6 +1222,12 @@ public final class WALProtos {
       for (int i = 0; i < clusterIds_.size(); i++) {
         output.writeMessage(8, clusterIds_.get(i));
       }
+      if (((bitField0_ & 0x00000040) == 0x00000040)) {
+        output.writeUInt64(9, nonceGroup_);
+      }
+      if (((bitField0_ & 0x00000080) == 0x00000080)) {
+        output.writeUInt64(10, nonce_);
+      }
       getUnknownFields().writeTo(output);
     }
 
@@ -1199,6 +1269,14 @@ public final class WALProtos {
         size += com.google.protobuf.CodedOutputStream
           .computeMessageSize(8, clusterIds_.get(i));
       }
+      if (((bitField0_ & 0x00000040) == 0x00000040)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeUInt64Size(9, nonceGroup_);
+      }
+      if (((bitField0_ & 0x00000080) == 0x00000080)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeUInt64Size(10, nonce_);
+      }
       size += getUnknownFields().getSerializedSize();
       memoizedSerializedSize = size;
       return size;
@@ -1256,6 +1334,16 @@ public final class WALProtos {
       }
       result = result && getClusterIdsList()
           .equals(other.getClusterIdsList());
+      result = result && (hasNonceGroup() == other.hasNonceGroup());
+      if (hasNonceGroup()) {
+        result = result && (getNonceGroup()
+            == other.getNonceGroup());
+      }
+      result = result && (hasNonce() == other.hasNonce());
+      if (hasNonce()) {
+        result = result && (getNonce()
+            == other.getNonce());
+      }
       result = result &&
           getUnknownFields().equals(other.getUnknownFields());
       return result;
@@ -1301,6 +1389,14 @@ public final class WALProtos {
         hash = (37 * hash) + CLUSTER_IDS_FIELD_NUMBER;
         hash = (53 * hash) + getClusterIdsList().hashCode();
       }
+      if (hasNonceGroup()) {
+        hash = (37 * hash) + NONCEGROUP_FIELD_NUMBER;
+        hash = (53 * hash) + hashLong(getNonceGroup());
+      }
+      if (hasNonce()) {
+        hash = (37 * hash) + NONCE_FIELD_NUMBER;
+        hash = (53 * hash) + hashLong(getNonce());
+      }
       hash = (29 * hash) + getUnknownFields().hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -1445,6 +1541,10 @@ public final class WALProtos {
         } else {
           clusterIdsBuilder_.clear();
         }
+        nonceGroup_ = 0L;
+        bitField0_ = (bitField0_ & ~0x00000100);
+        nonce_ = 0L;
+        bitField0_ = (bitField0_ & ~0x00000200);
         return this;
       }
 
@@ -1519,6 +1619,14 @@ public final class WALProtos {
         } else {
           result.clusterIds_ = clusterIdsBuilder_.build();
         }
+        if (((from_bitField0_ & 0x00000100) == 0x00000100)) {
+          to_bitField0_ |= 0x00000040;
+        }
+        result.nonceGroup_ = nonceGroup_;
+        if (((from_bitField0_ & 0x00000200) == 0x00000200)) {
+          to_bitField0_ |= 0x00000080;
+        }
+        result.nonce_ = nonce_;
         result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
@@ -1605,6 +1713,12 @@ public final class WALProtos {
             }
           }
         }
+        if (other.hasNonceGroup()) {
+          setNonceGroup(other.getNonceGroup());
+        }
+        if (other.hasNonce()) {
+          setNonce(other.getNonce());
+        }
         this.mergeUnknownFields(other.getUnknownFields());
         return this;
       }
@@ -2614,6 +2728,72 @@ public final class WALProtos {
         return clusterIdsBuilder_;
       }
 
+      // optional uint64 nonceGroup = 9;
+      private long nonceGroup_ ;
+      /**
+       * <code>optional uint64 nonceGroup = 9;</code>
+       */
+      public boolean hasNonceGroup() {
+        return ((bitField0_ & 0x00000100) == 0x00000100);
+      }
+      /**
+       * <code>optional uint64 nonceGroup = 9;</code>
+       */
+      public long getNonceGroup() {
+        return nonceGroup_;
+      }
+      /**
+       * <code>optional uint64 nonceGroup = 9;</code>
+       */
+      public Builder setNonceGroup(long value) {
+        bitField0_ |= 0x00000100;
+        nonceGroup_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * <code>optional uint64 nonceGroup = 9;</code>
+       */
+      public Builder clearNonceGroup() {
+        bitField0_ = (bitField0_ & ~0x00000100);
+        nonceGroup_ = 0L;
+        onChanged();
+        return this;
+      }
+
+      // optional uint64 nonce = 10;
+      private long nonce_ ;
+      /**
+       * <code>optional uint64 nonce = 10;</code>
+       */
+      public boolean hasNonce() {
+        return ((bitField0_ & 0x00000200) == 0x00000200);
+      }
+      /**
+       * <code>optional uint64 nonce = 10;</code>
+       */
+      public long getNonce() {
+        return nonce_;
+      }
+      /**
+       * <code>optional uint64 nonce = 10;</code>
+       */
+      public Builder setNonce(long value) {
+        bitField0_ |= 0x00000200;
+        nonce_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * <code>optional uint64 nonce = 10;</code>
+       */
+      public Builder clearNonce() {
+        bitField0_ = (bitField0_ & ~0x00000200);
+        nonce_ = 0L;
+        onChanged();
+        return this;
+      }
+
       // @@protoc_insertion_point(builder_scope:WALKey)
     }
 
@@ -4812,22 +4992,23 @@ public final class WALProtos {
   static {
     java.lang.String[] descriptorData = {
       "\n\tWAL.proto\032\013HBase.proto\"$\n\tWALHeader\022\027\n" +
-      "\017has_compression\030\001 \001(\010\"\337\001\n\006WALKey\022\033\n\023enc" +
+      "\017has_compression\030\001 \001(\010\"\202\002\n\006WALKey\022\033\n\023enc" +
       "oded_region_name\030\001 \002(\014\022\022\n\ntable_name\030\002 \002" +
       "(\014\022\033\n\023log_sequence_number\030\003 \002(\004\022\022\n\nwrite" +
       "_time\030\004 \002(\004\022\035\n\ncluster_id\030\005 \001(\0132\005.UUIDB\002" +
       "\030\001\022\034\n\006scopes\030\006 \003(\0132\014.FamilyScope\022\032\n\022foll" +
       "owing_kv_count\030\007 \001(\r\022\032\n\013cluster_ids\030\010 \003(" +
-      "\0132\005.UUID\"=\n\013FamilyScope\022\016\n\006family\030\001 \002(\014\022" +
+      "\0132\005.UUID\022\022\n\nnonceGroup\030\t \001(\004\022\r\n\005nonce\030\n " +
-      "\036\n\nscope_type\030\002 \002(\0162\n.ScopeType\"\251\001\n\024Comp" +
+      "\001(\004\"=\n\013FamilyScope\022\016\n\006family\030\001 \002(\014\022\036\n\nsc" +
-      "actionDescriptor\022\022\n\ntable_name\030\001 \002(\014\022\033\n\023",
+      "ope_type\030\002 \002(\0162\n.ScopeType\"\251\001\n\024Compactio",
-      "encoded_region_name\030\002 \002(\014\022\023\n\013family_name" +
+      "nDescriptor\022\022\n\ntable_name\030\001 \002(\014\022\033\n\023encod" +
-      "\030\003 \002(\014\022\030\n\020compaction_input\030\004 \003(\t\022\031\n\021comp" +
+      "ed_region_name\030\002 \002(\014\022\023\n\013family_name\030\003 \002(" +
-      "action_output\030\005 \003(\t\022\026\n\016store_home_dir\030\006 " +
+      "\014\022\030\n\020compaction_input\030\004 \003(\t\022\031\n\021compactio" +
-      "\002(\t\"\014\n\nWALTrailer*F\n\tScopeType\022\033\n\027REPLIC" +
+      "n_output\030\005 \003(\t\022\026\n\016store_home_dir\030\006 \002(\t\"\014" +
-      "ATION_SCOPE_LOCAL\020\000\022\034\n\030REPLICATION_SCOPE" +
+      "\n\nWALTrailer*F\n\tScopeType\022\033\n\027REPLICATION" +
-      "_GLOBAL\020\001B?\n*org.apache.hadoop.hbase.pro" +
+      "_SCOPE_LOCAL\020\000\022\034\n\030REPLICATION_SCOPE_GLOB" +
-      "tobuf.generatedB\tWALProtosH\001\210\001\000\240\001\001"
+      "AL\020\001B?\n*org.apache.hadoop.hbase.protobuf" +
+      ".generatedB\tWALProtosH\001\210\001\000\240\001\001"
     };
     com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner assigner =
       new com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner() {
@@ -4845,7 +5026,7 @@ public final class WALProtos {
           internal_static_WALKey_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_WALKey_descriptor,
-              new java.lang.String[] { "EncodedRegionName", "TableName", "LogSequenceNumber", "WriteTime", "ClusterId", "Scopes", "FollowingKvCount", "ClusterIds", });
+              new java.lang.String[] { "EncodedRegionName", "TableName", "LogSequenceNumber", "WriteTime", "ClusterId", "Scopes", "FollowingKvCount", "ClusterIds", "NonceGroup", "Nonce", });
           internal_static_FamilyScope_descriptor =
             getDescriptor().getMessageTypes().get(2);
           internal_static_FamilyScope_fieldAccessorTable = new

hbase-protocol/src/main/protobuf/Client.proto

@@ -133,6 +133,8 @@ message MutationProto {
   // 'cell' field above which is non-null when the cells are pb'd.
   optional int32 associated_cell_count = 8;
 
+  optional uint64 nonce = 9;
+
   enum Durability {
     USE_DEFAULT  = 0;
     SKIP_WAL     = 1;
@@ -182,6 +184,7 @@ message MutateRequest {
   required RegionSpecifier region = 1;
   required MutationProto mutation = 2;
   optional Condition condition = 3;
+  optional uint64 nonce_group = 4;
 }
 
 message MutateResponse {
@@ -345,6 +348,7 @@ message RegionActionResult {
  */
 message MultiRequest {
   repeated RegionAction regionAction = 1;
+  optional uint64 nonceGroup = 2;
 }
 
 message MultiResponse {

hbase-protocol/src/main/protobuf/MultiRowMutation.proto

@@ -30,6 +30,8 @@ message MultiRowMutationProcessorResponse{
 
 message MutateRowsRequest {
   repeated MutationProto mutation_request = 1;
+  optional uint64 nonce_group = 2;
+  optional uint64 nonce = 3;
 }
 
 message MutateRowsResponse {

hbase-protocol/src/main/protobuf/RowProcessor.proto

@@ -30,6 +30,8 @@ message ProcessRequest {
   required string row_processor_class_name = 1;
   optional string row_processor_initializer_message_name = 2;
   optional bytes  row_processor_initializer_message = 3;
+  optional uint64 nonce_group = 4;
+  optional uint64 nonce = 5;
 }
 
 message ProcessResponse {

hbase-protocol/src/main/protobuf/WAL.proto

@@ -43,11 +43,16 @@ message WALKey {
 
   repeated FamilyScope scopes = 6;
   optional uint32 following_kv_count = 7;
+
   /*
   This field contains the list of clusters that have
   consumed the change
   */
   repeated UUID cluster_ids = 8;
+
+  optional uint64 nonceGroup = 9;
+  optional uint64 nonce = 10;
+
 /*
   optional CustomEntryType custom_entry_type = 9;
 

hbase-server/src/main/java/org/apache/hadoop/hbase/client/CoprocessorHConnection.java

@@ -380,4 +380,9 @@ public class CoprocessorHConnection implements HConnection {
   public boolean isDeadServer(ServerName serverName) {
     return delegate.isDeadServer(serverName);
   }
+
+  @Override
+  public NonceGenerator getNonceGenerator() {
+    return null; // don't use nonces for coprocessor connection
+  }
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/BaseRowProcessorEndpoint.java

@@ -26,6 +26,7 @@ import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.hbase.Coprocessor;
 import org.apache.hadoop.hbase.CoprocessorEnvironment;
 import org.apache.hadoop.hbase.HBaseInterfaceAudience;
+import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.protobuf.ResponseConverter;
 import org.apache.hadoop.hbase.protobuf.generated.RowProcessorProtos.ProcessRequest;
 import org.apache.hadoop.hbase.protobuf.generated.RowProcessorProtos.ProcessResponse;
@@ -68,7 +69,9 @@ extends RowProcessorService implements CoprocessorService, Coprocessor {
     try {
       RowProcessor<S,T> processor = constructRowProcessorFromRequest(request);
       HRegion region = env.getRegion();
-      region.processRowsWithLocks(processor);
+      long nonceGroup = request.hasNonceGroup() ? request.getNonceGroup() : HConstants.NO_NONCE;
+      long nonce = request.hasNonce() ? request.getNonce() : HConstants.NO_NONCE;
+      region.processRowsWithLocks(processor, nonceGroup, nonce);
       T result = processor.getResult();
       ProcessResponse.Builder b = ProcessResponse.newBuilder();
       b.setRowProcessorResult(result.toByteString());

hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MultiRowMutationEndpoint.java

@@ -28,6 +28,7 @@ import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.hbase.Coprocessor;
 import org.apache.hadoop.hbase.CoprocessorEnvironment;
 import org.apache.hadoop.hbase.HBaseInterfaceAudience;
+import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.client.Mutation;
 import org.apache.hadoop.hbase.regionserver.HRegion;
@@ -110,7 +111,9 @@ CoprocessorService, Coprocessor {
         rowsToLock.add(m.getRow());
       }
       // call utility method on region
-      env.getRegion().mutateRowsWithLocks(mutations, rowsToLock);
+      long nonceGroup = request.hasNonceGroup() ? request.getNonceGroup() : HConstants.NO_NONCE;
+      long nonce = request.hasNonce() ? request.getNonce() : HConstants.NO_NONCE;
+      env.getRegion().mutateRowsWithLocks(mutations, rowsToLock, nonceGroup, nonce);
     } catch (IOException e) {
       ResponseConverter.setControllerException(controller, e);
     }

hbase-server/src/main/java/org/apache/hadoop/hbase/protobuf/ReplicationProtbufUtil.java

@@ -31,6 +31,7 @@ import java.util.UUID;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.CellScanner;
+import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.KeyValue;
 import org.apache.hadoop.hbase.io.SizedCellScanner;
 import org.apache.hadoop.hbase.ipc.PayloadCarryingRpcController;
@@ -86,6 +87,7 @@ public class ReplicationProtbufUtil {
     HBaseProtos.UUID.Builder uuidBuilder = HBaseProtos.UUID.newBuilder();
     for (HLog.Entry entry: entries) {
       entryBuilder.clear();
+      // TODO: this duplicates a lot in HLogKey#getBuilder
       WALProtos.WALKey.Builder keyBuilder = entryBuilder.getKeyBuilder();
       HLogKey key = entry.getKey();
       keyBuilder.setEncodedRegionName(
@@ -93,6 +95,12 @@ public class ReplicationProtbufUtil {
       keyBuilder.setTableName(ZeroCopyLiteralByteString.wrap(key.getTablename().getName()));
       keyBuilder.setLogSequenceNumber(key.getLogSeqNum());
       keyBuilder.setWriteTime(key.getWriteTime());
+      if (key.getNonce() != HConstants.NO_NONCE) {
+        keyBuilder.setNonce(key.getNonce());
+      }
+      if (key.getNonceGroup() != HConstants.NO_NONCE) {
+        keyBuilder.setNonceGroup(key.getNonceGroup());
+      }
       for(UUID clusterId : key.getClusterIds()) {
         uuidBuilder.setLeastSigBits(clusterId.getLeastSignificantBits());
         uuidBuilder.setMostSigBits(clusterId.getMostSignificantBits());

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java

@@ -68,6 +68,7 @@ import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.CellUtil;
 import org.apache.hadoop.hbase.CompoundConfiguration;
+import org.apache.hadoop.hbase.DoNotRetryIOException;
 import org.apache.hadoop.hbase.DroppedSnapshotException;
 import org.apache.hadoop.hbase.HBaseConfiguration;
 import org.apache.hadoop.hbase.HColumnDescriptor;
@@ -122,6 +123,8 @@ import org.apache.hadoop.hbase.regionserver.compactions.CompactionContext;
 import org.apache.hadoop.hbase.regionserver.wal.HLog;
 import org.apache.hadoop.hbase.regionserver.wal.HLogFactory;
 import org.apache.hadoop.hbase.regionserver.wal.HLogKey;
+import org.apache.hadoop.hbase.regionserver.wal.HLogSplitter;
+import org.apache.hadoop.hbase.regionserver.wal.HLogSplitter.MutationReplay;
 import org.apache.hadoop.hbase.regionserver.wal.HLogUtil;
 import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
 import org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils;
@@ -1897,7 +1900,7 @@ public class HRegion implements HeapSize { // , Writable{
    * accumulating status codes and tracking the index at which processing
    * is proceeding.
    */
-  private static class BatchOperationInProgress<T> {
+  private abstract static class BatchOperationInProgress<T> {
     T[] operations;
     int nextIndexToProcess = 0;
     OperationStatus[] retCodeDetails;
@@ -1910,21 +1913,82 @@ public class HRegion implements HeapSize { // , Writable{
       Arrays.fill(this.retCodeDetails, OperationStatus.NOT_RUN);
     }
 
+    public abstract Mutation getMutation(int index);
+    public abstract long getNonceGroup(int index);
+    public abstract long getNonce(int index);
+    /** This method is potentially expensive and should only be used for non-replay CP path. */
+    public abstract Mutation[] getMutationsForCoprocs();
+    public abstract boolean isInReplay();
+
     public boolean isDone() {
       return nextIndexToProcess == operations.length;
     }
   }
 
-  /**
+  private static class MutationBatch extends BatchOperationInProgress<Mutation> {
-   * Perform a batch of mutations.
+    private long nonceGroup;
-   * It supports only Put and Delete mutations and will ignore other types passed.
+    private long nonce;
-   * @param mutations the list of mutations
+    public MutationBatch(Mutation[] operations, long nonceGroup, long nonce) {
-   * @return an array of OperationStatus which internally contains the
+      super(operations);
-   *         OperationStatusCode and the exceptionMessage if any.
+      this.nonceGroup = nonceGroup;
-   * @throws IOException
+      this.nonce = nonce;
-   */
+    }
-  public OperationStatus[] batchMutate(Mutation[] mutations) throws IOException {
+
-    return batchMutate(mutations, false);
+    public Mutation getMutation(int index) {
+      return this.operations[index];
+    }
+
+    @Override
+    public long getNonceGroup(int index) {
+      return nonceGroup;
+    }
+
+    @Override
+    public long getNonce(int index) {
+      return nonce;
+    }
+
+    @Override
+    public Mutation[] getMutationsForCoprocs() {
+      return this.operations;
+    }
+
+    @Override
+    public boolean isInReplay() {
+      return false;
+    }
+  }
+
+  private static class ReplayBatch extends BatchOperationInProgress<HLogSplitter.MutationReplay> {
+    public ReplayBatch(MutationReplay[] operations) {
+      super(operations);
+    }
+
+    @Override
+    public Mutation getMutation(int index) {
+      return this.operations[index].mutation;
+    }
+
+    @Override
+    public long getNonceGroup(int index) {
+      return this.operations[index].nonceGroup;
+    }
+
+    @Override
+    public long getNonce(int index) {
+      return this.operations[index].nonce;
+    }
+
+    @Override
+    public Mutation[] getMutationsForCoprocs() {
+      assert false;
+      throw new RuntimeException("Should not be called for replay batch");
+    }
+
+    @Override
+    public boolean isInReplay() {
+      return true;
+    }
   }
 
   /**
@@ -1935,21 +1999,48 @@ public class HRegion implements HeapSize { // , Writable{
    *         OperationStatusCode and the exceptionMessage if any.
    * @throws IOException
    */
-  OperationStatus[] batchMutate(Mutation[] mutations, boolean isReplay)
+  public OperationStatus[] batchMutate(
+      Mutation[] mutations, long nonceGroup, long nonce) throws IOException {
+    // As it stands, this is used for 3 things
+    //  * batchMutate with single mutation - put/delete, separate or from checkAndMutate.
+    //  * coprocessor calls (see ex. BulkDeleteEndpoint).
+    // So nonces are not really ever used by HBase. They could be by coprocs, and checkAnd...
+    return batchMutate(new MutationBatch(mutations, nonceGroup, nonce));
+  }
+
+  public OperationStatus[] batchMutate(Mutation[] mutations) throws IOException {
+    return batchMutate(mutations, HConstants.NO_NONCE, HConstants.NO_NONCE);
+  }
+
+  /**
+   * Replay a batch of mutations.
+   * @param mutations mutations to replay.
+   * @return
+   * @throws IOException
+   */
+  public OperationStatus[] batchReplay(HLogSplitter.MutationReplay[] mutations)
       throws IOException {
-    BatchOperationInProgress<Mutation> batchOp =
+    return batchMutate(new ReplayBatch(mutations));
-      new BatchOperationInProgress<Mutation>(mutations);
+  }
 
+  /**
+   * Perform a batch of mutations.
+   * It supports only Put and Delete mutations and will ignore other types passed.
+   * @param mutations the list of mutations
+   * @return an array of OperationStatus which internally contains the
+   *         OperationStatusCode and the exceptionMessage if any.
+   * @throws IOException
+   */
+  OperationStatus[] batchMutate(BatchOperationInProgress<?> batchOp) throws IOException {
     boolean initialized = false;
-
     while (!batchOp.isDone()) {
-      if (!isReplay) {
+      if (!batchOp.isInReplay()) {
         checkReadOnly();
       }
       checkResources();
 
       long newSize;
-      if (isReplay) {
+      if (batchOp.isInReplay()) {
         startRegionOperation(Operation.REPLAY_BATCH_MUTATE);
       } else {
         startRegionOperation(Operation.BATCH_MUTATE);
@@ -1957,13 +2048,13 @@ public class HRegion implements HeapSize { // , Writable{
 
       try {
         if (!initialized) {
-          if (!isReplay) {
+          if (!batchOp.isInReplay()) {
             this.writeRequestsCount.increment();
             doPreMutationHook(batchOp);
           }
           initialized = true;
         }
-        long addedSize = doMiniBatchMutation(batchOp, isReplay);
+        long addedSize = doMiniBatchMutation(batchOp);
         newSize = this.addAndGetGlobalMemstoreSize(addedSize);
       } finally {
         closeRegionOperation();
@@ -1976,13 +2067,13 @@ public class HRegion implements HeapSize { // , Writable{
   }
 
 
-  private void doPreMutationHook(BatchOperationInProgress<Mutation> batchOp)
+  private void doPreMutationHook(BatchOperationInProgress<?> batchOp)
       throws IOException {
     /* Run coprocessor pre hook outside of locks to avoid deadlock */
     WALEdit walEdit = new WALEdit();
     if (coprocessorHost != null) {
       for (int i = 0 ; i < batchOp.operations.length; i++) {
-        Mutation m = batchOp.operations[i];
+        Mutation m = batchOp.getMutation(i);
         if (m instanceof Put) {
           if (coprocessorHost.prePut((Put) m, walEdit, m.getDurability())) {
             // pre hook says skip this Put
@@ -2011,9 +2102,8 @@ public class HRegion implements HeapSize { // , Writable{
   }
 
   @SuppressWarnings("unchecked")
-  private long doMiniBatchMutation(BatchOperationInProgress<Mutation> batchOp,
+  private long doMiniBatchMutation(BatchOperationInProgress<?> batchOp) throws IOException {
-      boolean isInReplay) throws IOException {
+    boolean isInReplay = batchOp.isInReplay();
-
     // variable to note if all Put items are for the same CF -- metrics related
     boolean putsCfSetConsistent = true;
     //The set of columnFamilies first seen for Put.
@@ -2023,6 +2113,7 @@ public class HRegion implements HeapSize { // , Writable{
     //The set of columnFamilies first seen for Delete.
     Set<byte[]> deletesCfSet = null;
 
+    long currentNonceGroup = HConstants.NO_NONCE, currentNonce = HConstants.NO_NONCE;
     WALEdit walEdit = new WALEdit(isInReplay);
     MultiVersionConsistencyControl.WriteEntry w = null;
     long txid = 0;
@@ -2046,7 +2137,7 @@ public class HRegion implements HeapSize { // , Writable{
       int numReadyToWrite = 0;
       long now = EnvironmentEdgeManager.currentTimeMillis();
       while (lastIndexExclusive < batchOp.operations.length) {
-        Mutation mutation = batchOp.operations[lastIndexExclusive];
+        Mutation mutation = batchOp.getMutation(lastIndexExclusive);
         boolean isPutMutation = mutation instanceof Put;
 
         Map<byte[], List<Cell>> familyMap = mutation.getFamilyCellMap();
@@ -2145,7 +2236,7 @@ public class HRegion implements HeapSize { // , Writable{
         if (batchOp.retCodeDetails[i].getOperationStatusCode()
             != OperationStatusCode.NOT_RUN) continue;
 
-        Mutation mutation = batchOp.operations[i];
+        Mutation mutation = batchOp.getMutation(i);
         if (mutation instanceof Put) {
           updateKVTimestamps(familyMaps[i].values(), byteNow);
           noOfPuts++;
@@ -2167,7 +2258,7 @@ public class HRegion implements HeapSize { // , Writable{
       // calling the pre CP hook for batch mutation
       if (!isInReplay && coprocessorHost != null) {
         MiniBatchOperationInProgress<Mutation> miniBatchOp =
-          new MiniBatchOperationInProgress<Mutation>(batchOp.operations,
+          new MiniBatchOperationInProgress<Mutation>(batchOp.getMutationsForCoprocs(),
           batchOp.retCodeDetails, batchOp.walEditsFromCoprocessors, firstIndex, lastIndexExclusive);
         if (coprocessorHost.preBatchMutate(miniBatchOp)) return 0L;
       }
@@ -2193,6 +2284,7 @@ public class HRegion implements HeapSize { // , Writable{
       // ------------------------------------
       // STEP 4. Build WAL edit
       // ----------------------------------
+      boolean hasWalAppends = false;
       Durability durability = Durability.USE_DEFAULT;
       for (int i = firstIndex; i < lastIndexExclusive; i++) {
         // Skip puts that were determined to be invalid during preprocessing
@@ -2202,7 +2294,7 @@ public class HRegion implements HeapSize { // , Writable{
         }
         batchOp.retCodeDetails[i] = OperationStatus.SUCCESS;
 
-        Mutation m = batchOp.operations[i];
+        Mutation m = batchOp.getMutation(i);
         Durability tmpDur = getEffectiveDurability(m.getDurability());
         if (tmpDur.ordinal() > durability.ordinal()) {
           durability = tmpDur;
@@ -2212,6 +2304,22 @@ public class HRegion implements HeapSize { // , Writable{
           continue;
         }
 
+        long nonceGroup = batchOp.getNonceGroup(i), nonce = batchOp.getNonce(i);
+        // In replay, the batch may contain multiple nonces. If so, write WALEdit for each.
+        // Given how nonces are originally written, these should be contiguous.
+        // txid should always increase, so having the last one is ok.
+        if (nonceGroup != currentNonceGroup || nonce != currentNonce) {
+          if (walEdit.size() > 0) {
+            assert isInReplay;
+            txid = this.log.appendNoSync(this.getRegionInfo(), htableDescriptor.getTableName(),
+                  walEdit, m.getClusterIds(), now, htableDescriptor, this.sequenceId, true,
+                  currentNonceGroup, currentNonce);
+            hasWalAppends = true;
+          }
+          currentNonceGroup = nonceGroup;
+          currentNonce = nonce;
+        }
+
         // Add WAL edits by CP
         WALEdit fromCP = batchOp.walEditsFromCoprocessors[i];
         if (fromCP != null) {
@@ -2223,12 +2331,14 @@ public class HRegion implements HeapSize { // , Writable{
       }
 
       // -------------------------
-      // STEP 5. Append the edit to WAL. Do not sync wal.
+      // STEP 5. Append the final edit to WAL. Do not sync wal.
       // -------------------------
-      Mutation mutation = batchOp.operations[firstIndex];
+      Mutation mutation = batchOp.getMutation(firstIndex);
       if (walEdit.size() > 0) {
         txid = this.log.appendNoSync(this.getRegionInfo(), this.htableDescriptor.getTableName(),
-              walEdit, mutation.getClusterIds(), now, this.htableDescriptor, this.sequenceId);
+              walEdit, mutation.getClusterIds(), now, this.htableDescriptor, this.sequenceId,
+              true, currentNonceGroup, currentNonce);
+        hasWalAppends = true;
       }
 
       // -------------------------------
@@ -2243,14 +2353,14 @@ public class HRegion implements HeapSize { // , Writable{
       // -------------------------
       // STEP 7. Sync wal.
       // -------------------------
-      if (walEdit.size() > 0) {
+      if (hasWalAppends) {
         syncOrDefer(txid, durability);
       }
       walSyncSuccessful = true;
       // calling the post CP hook for batch mutation
       if (!isInReplay && coprocessorHost != null) {
         MiniBatchOperationInProgress<Mutation> miniBatchOp =
-          new MiniBatchOperationInProgress<Mutation>(batchOp.operations,
+          new MiniBatchOperationInProgress<Mutation>(batchOp.getMutationsForCoprocs(),
           batchOp.retCodeDetails, batchOp.walEditsFromCoprocessors, firstIndex, lastIndexExclusive);
         coprocessorHost.postBatchMutate(miniBatchOp);
       }
@@ -2274,7 +2384,7 @@ public class HRegion implements HeapSize { // , Writable{
               != OperationStatusCode.SUCCESS) {
             continue;
           }
-          Mutation m = batchOp.operations[i];
+          Mutation m = batchOp.getMutation(i);
           if (m instanceof Put) {
             coprocessorHost.postPut((Put) m, walEdit, m.getDurability());
           } else {
@@ -2435,9 +2545,10 @@ public class HRegion implements HeapSize { // , Writable{
     }
   }
 
-  private void doBatchMutate(Mutation mutation) throws IOException,
+  private void doBatchMutate(Mutation mutation) throws IOException, DoNotRetryIOException {
-      org.apache.hadoop.hbase.DoNotRetryIOException {
+    // Currently this is only called for puts and deletes, so no nonces.
-    OperationStatus[] batchMutate = this.batchMutate(new Mutation[] { mutation });
+    OperationStatus[] batchMutate = this.batchMutate(new Mutation[] { mutation },
+        HConstants.NO_NONCE, HConstants.NO_NONCE);
     if (batchMutate[0].getOperationStatusCode().equals(OperationStatusCode.SANITY_CHECK_FAILURE)) {
       throw new FailedSanityCheckException(batchMutate[0].getExceptionMsg());
     } else if (batchMutate[0].getOperationStatusCode().equals(OperationStatusCode.BAD_FAMILY)) {
@@ -2628,7 +2739,7 @@ public class HRegion implements HeapSize { // , Writable{
    * called when a Put/Delete has updated memstore but subequently fails to update
    * the wal. This method is then invoked to rollback the memstore.
    */
-  private void rollbackMemstore(BatchOperationInProgress<Mutation> batchOp,
+  private void rollbackMemstore(BatchOperationInProgress<?> batchOp,
                                 Map<byte[], List<Cell>>[] familyMaps,
                                 int start, int end) {
     int kvsRolledback = 0;
@@ -2901,6 +3012,7 @@ public class HRegion implements HeapSize { // , Writable{
       HLog.Entry entry;
       Store store = null;
       boolean reported_once = false;
+      ServerNonceManager ng = this.rsServices == null ? null : this.rsServices.getNonceManager();
 
       try {
         // How many edits seen before we check elapsed time
@@ -2916,6 +3028,10 @@ public class HRegion implements HeapSize { // , Writable{
           HLogKey key = entry.getKey();
           WALEdit val = entry.getEdit();
 
+          if (ng != null) { // some test, or nonces disabled
+            ng.reportOperationFromWal(key.getNonceGroup(), key.getNonce(), key.getWriteTime());
+          }
+
           if (reporter != null) {
             intervalEdits += val.size();
             if (intervalEdits >= interval) {
@@ -4395,35 +4511,47 @@ public class HRegion implements HeapSize { // , Writable{
   }
 
   public void mutateRow(RowMutations rm) throws IOException {
+    // Don't need nonces here - RowMutations only supports puts and deletes
     mutateRowsWithLocks(rm.getMutations(), Collections.singleton(rm.getRow()));
   }
 
+  /**
+   * Perform atomic mutations within the region w/o nonces.
+   * See {@link #mutateRowsWithLocks(Collection, Collection, long, long)}
+   */
+  public void mutateRowsWithLocks(Collection<Mutation> mutations,
+      Collection<byte[]> rowsToLock) throws IOException {
+    mutateRowsWithLocks(mutations, rowsToLock, HConstants.NO_NONCE, HConstants.NO_NONCE);
+  }
+
   /**
    * Perform atomic mutations within the region.
    * @param mutations The list of mutations to perform.
    * <code>mutations</code> can contain operations for multiple rows.
    * Caller has to ensure that all rows are contained in this region.
    * @param rowsToLock Rows to lock
+   * @param nonceGroup Optional nonce group of the operation (client Id)
+   * @param nonce Optional nonce of the operation (unique random id to ensure "more idempotence")
    * If multiple rows are locked care should be taken that
    * <code>rowsToLock</code> is sorted in order to avoid deadlocks.
    * @throws IOException
    */
   public void mutateRowsWithLocks(Collection<Mutation> mutations,
-      Collection<byte[]> rowsToLock) throws IOException {
+      Collection<byte[]> rowsToLock, long nonceGroup, long nonce) throws IOException {
-
+    MultiRowMutationProcessor proc = new MultiRowMutationProcessor(mutations, rowsToLock);
-    MultiRowMutationProcessor proc =
+    processRowsWithLocks(proc, -1, nonceGroup, nonce);
-        new MultiRowMutationProcessor(mutations, rowsToLock);
-    processRowsWithLocks(proc, -1);
   }
 
   /**
    * Performs atomic multiple reads and writes on a given row.
    *
    * @param processor The object defines the reads and writes to a row.
+   * @param nonceGroup Optional nonce group of the operation (client Id)
+   * @param nonce Optional nonce of the operation (unique random id to ensure "more idempotence")
    */
-  public void processRowsWithLocks(RowProcessor<?,?> processor)
+  public void processRowsWithLocks(RowProcessor<?,?> processor, long nonceGroup, long nonce)
       throws IOException {
-    processRowsWithLocks(processor, rowProcessorTimeout);
+    processRowsWithLocks(processor, rowProcessorTimeout, nonceGroup, nonce);
   }
 
   /**
@@ -4432,9 +4560,11 @@ public class HRegion implements HeapSize { // , Writable{
    * @param processor The object defines the reads and writes to a row.
    * @param timeout The timeout of the processor.process() execution
    *                Use a negative number to switch off the time bound
+   * @param nonceGroup Optional nonce group of the operation (client Id)
+   * @param nonce Optional nonce of the operation (unique random id to ensure "more idempotence")
    */
-  public void processRowsWithLocks(RowProcessor<?,?> processor, long timeout)
+  public void processRowsWithLocks(RowProcessor<?,?> processor, long timeout,
-      throws IOException {
+      long nonceGroup, long nonce) throws IOException {
 
     for (byte[] row : processor.getRowsToLock()) {
       checkRow(row, "processRowsWithLocks");
@@ -4506,7 +4636,7 @@ public class HRegion implements HeapSize { // , Writable{
           if (!walEdit.isEmpty()) {
             txid = this.log.appendNoSync(this.getRegionInfo(),
               this.htableDescriptor.getTableName(), walEdit, processor.getClusterIds(), now,
-              this.htableDescriptor, this.sequenceId);
+              this.htableDescriptor, this.sequenceId, true, nonceGroup, nonce);
           }
           // 8. Release region lock
           if (locked) {
@@ -4609,6 +4739,10 @@ public class HRegion implements HeapSize { // , Writable{
     }
   }
 
+  public Result append(Append append) throws IOException {
+    return append(append, HConstants.NO_NONCE, HConstants.NO_NONCE);
+  }
+
   // TODO: There's a lot of boiler plate code identical
   // to increment... See how to better unify that.
   /**
@@ -4618,7 +4752,7 @@ public class HRegion implements HeapSize { // , Writable{
    * @return new keyvalues after increment
    * @throws IOException
    */
-  public Result append(Append append)
+  public Result append(Append append, long nonceGroup, long nonce)
       throws IOException {
     byte[] row = append.getRow();
     checkRow(row, "append");
@@ -4749,7 +4883,8 @@ public class HRegion implements HeapSize { // , Writable{
             // as a Put.
             txid = this.log.appendNoSync(this.getRegionInfo(),
               this.htableDescriptor.getTableName(), walEdits, new ArrayList<UUID>(),
-              EnvironmentEdgeManager.currentTimeMillis(), this.htableDescriptor, this.sequenceId);
+              EnvironmentEdgeManager.currentTimeMillis(), this.htableDescriptor, this.sequenceId,
+              true, nonceGroup, nonce);
           } else {
             recordMutationWithoutWal(append.getFamilyCellMap());
           }
@@ -4801,13 +4936,17 @@ public class HRegion implements HeapSize { // , Writable{
     return append.isReturnResults() ? Result.create(allKVs) : null;
   }
 
+  public Result increment(Increment increment) throws IOException {
+    return increment(increment, HConstants.NO_NONCE, HConstants.NO_NONCE);
+  }
+
   /**
    * Perform one or more increment operations on a row.
    * @param increment
    * @return new keyvalues after increment
    * @throws IOException
    */
-  public Result increment(Increment increment)
+  public Result increment(Increment increment, long nonceGroup, long nonce)
   throws IOException {
     byte [] row = increment.getRow();
     checkRow(row, "increment");
@@ -4923,7 +5062,8 @@ public class HRegion implements HeapSize { // , Writable{
             // as a Put.
             txid = this.log.appendNoSync(this.getRegionInfo(),
               this.htableDescriptor.getTableName(), walEdits, new ArrayList<UUID>(),
-              EnvironmentEdgeManager.currentTimeMillis(), this.htableDescriptor, this.sequenceId);
+              EnvironmentEdgeManager.currentTimeMillis(), this.htableDescriptor, this.sequenceId,
+              true, nonceGroup, nonce);
           } else {
             recordMutationWithoutWal(increment.getFamilyCellMap());
           }

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java

@@ -19,6 +19,7 @@
 package org.apache.hadoop.hbase.regionserver;
 
 import java.io.IOException;
+import java.io.InterruptedIOException;
 import java.lang.Thread.UncaughtExceptionHandler;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -93,6 +94,7 @@ import org.apache.hadoop.hbase.client.RowMutations;
 import org.apache.hadoop.hbase.client.Scan;
 import org.apache.hadoop.hbase.coprocessor.CoprocessorHost;
 import org.apache.hadoop.hbase.exceptions.FailedSanityCheckException;
+import org.apache.hadoop.hbase.exceptions.OperationConflictException;
 import org.apache.hadoop.hbase.exceptions.OutOfOrderScannerNextException;
 import org.apache.hadoop.hbase.exceptions.RegionMovedException;
 import org.apache.hadoop.hbase.exceptions.RegionOpeningException;
@@ -441,6 +443,9 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
   /** The health check chore. */
   private HealthCheckChore healthCheckChore;
 
+  /** The nonce manager chore. */
+  private Chore nonceManagerChore;
+
   /**
    * The server name the Master sees us as.  Its made from the hostname the
    * master passes us, port, and server startcode. Gets set after registration
@@ -490,6 +495,26 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
   // Table level lock manager for locking for region operations
   private TableLockManager tableLockManager;
 
+  /**
+   * Nonce manager. Nonces are used to make operations like increment and append idempotent
+   * in the case where client doesn't receive the response from a successful operation and
+   * retries. We track the successful ops for some time via a nonce sent by client and handle
+   * duplicate operations (currently, by failing them; in future we might use MVCC to return
+   * result). Nonces are also recovered from WAL during, recovery; however, the caveats (from
+   * HBASE-3787) are:
+   * - WAL recovery is optimized, and under high load we won't read nearly nonce-timeout worth
+   *   of past records. If we don't read the records, we don't read and recover the nonces.
+   *   Some WALs within nonce-timeout at recovery may not even be present due to rolling/cleanup.
+   * - There's no WAL recovery during normal region move, so nonces will not be transfered.
+   * We can have separate additional "Nonce WAL". It will just contain bunch of numbers and
+   * won't be flushed on main path - because WAL itself also contains nonces, if we only flush
+   * it before memstore flush, for a given nonce we will either see it in the WAL (if it was
+   * never flushed to disk, it will be part of recovery), or we'll see it as part of the nonce
+   * log (or both occasionally, which doesn't matter). Nonce log file can be deleted after the
+   * latest nonce in it expired. It can also be recovered during move.
+   */
+  private final ServerNonceManager nonceManager;
+
   private UserProvider userProvider;
 
   /**
@@ -529,6 +554,9 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
 
     this.sleeper = new Sleeper(this.msgInterval, this);
 
+    boolean isNoncesEnabled = conf.getBoolean(HConstants.HBASE_RS_NONCES_ENABLED, true);
+    this.nonceManager = isNoncesEnabled ? new ServerNonceManager(this.conf) : null;
+
     this.maxScannerResultSize = conf.getLong(
       HConstants.HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE_KEY,
       HConstants.DEFAULT_HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE);
@@ -789,6 +817,11 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
     // Create the thread to clean the moved regions list
     movedRegionsCleaner = MovedRegionsCleaner.createAndStart(this);
 
+    if (this.nonceManager != null) {
+      // Create the chore that cleans up nonces.
+      nonceManagerChore = this.nonceManager.createCleanupChore(this);
+    }
+
     // Setup RPC client for master communication
     rpcClient = new RpcClient(conf, clusterId, new InetSocketAddress(
         this.isa.getAddress(), 0));
@@ -910,6 +943,9 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
     if (this.healthCheckChore != null) {
       this.healthCheckChore.interrupt();
     }
+    if (this.nonceManagerChore != null) {
+      this.nonceManagerChore.interrupt();
+    }
 
     // Stop the snapshot handler, forcefully killing all running tasks
     try {
@@ -1556,8 +1592,11 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
     Threads.setDaemonThreadRunning(this.periodicFlusher.getThread(), n +
         ".periodicFlusher", uncaughtExceptionHandler);
     if (this.healthCheckChore != null) {
-    Threads
+      Threads.setDaemonThreadRunning(this.healthCheckChore.getThread(), n + ".healthChecker",
-        .setDaemonThreadRunning(this.healthCheckChore.getThread(), n + ".healthChecker",
+            uncaughtExceptionHandler);
+    }
+    if (this.nonceManagerChore != null) {
+      Threads.setDaemonThreadRunning(this.nonceManagerChore.getThread(), n + ".nonceCleaner",
             uncaughtExceptionHandler);
     }
 
@@ -1811,6 +1850,9 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
    * have already been called.
    */
   protected void join() {
+    if (this.nonceManagerChore != null) {
+      Threads.shutdown(this.nonceManagerChore.getThread());
+    }
     Threads.shutdown(this.compactionChecker.getThread());
     Threads.shutdown(this.periodicFlusher.getThread());
     this.cacheFlusher.join();
@@ -2826,15 +2868,19 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
       if (!region.getRegionInfo().isMetaTable()) {
         cacheFlusher.reclaimMemStoreMemory();
       }
+      long nonceGroup = request.hasNonceGroup()
+          ? request.getNonceGroup() : HConstants.NO_NONCE;
       Result r = null;
       Boolean processed = null;
       MutationType type = mutation.getMutateType();
       switch (type) {
       case APPEND:
-        r = append(region, mutation, cellScanner);
+        // TODO: this doesn't actually check anything.
+        r = append(region, mutation, cellScanner, nonceGroup);
         break;
       case INCREMENT:
-        r = increment(region, mutation, cellScanner);
+        // TODO: this doesn't actually check anything.
+        r = increment(region, mutation, cellScanner, nonceGroup);
         break;
       case PUT:
         Put put = ProtobufUtil.toPut(mutation, cellScanner);
@@ -3251,6 +3297,8 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
     CellScanner cellScanner = controller != null ? controller.cellScanner(): null;
     if (controller != null) controller.setCellScanner(null);
 
+    long nonceGroup = request.hasNonceGroup() ? request.getNonceGroup() : HConstants.NO_NONCE;
+
     // this will contain all the cells that we need to return. It's created later, if needed.
     List<CellScannable> cellsToReturn = null;
     MultiResponse.Builder responseBuilder = MultiResponse.newBuilder();
@@ -3279,7 +3327,7 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
       } else {
         // doNonAtomicRegionMutation manages the exception internally
         cellsToReturn = doNonAtomicRegionMutation(region, regionAction, cellScanner,
-            regionActionResultBuilder, cellsToReturn);
+            regionActionResultBuilder, cellsToReturn, nonceGroup);
       }
       responseBuilder.addRegionActionResult(regionActionResultBuilder.build());
     }
@@ -3303,7 +3351,7 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
    */
   private List<CellScannable> doNonAtomicRegionMutation(final HRegion region,
       final RegionAction actions, final CellScanner cellScanner,
-      final RegionActionResult.Builder builder, List<CellScannable> cellsToReturn) {
+      final RegionActionResult.Builder builder, List<CellScannable> cellsToReturn, long nonceGroup) {
     // Gather up CONTIGUOUS Puts and Deletes in this mutations List.  Idea is that rather than do
     // one at a time, we instead pass them in batch.  Be aware that the corresponding
     // ResultOrException instance that matches each Put or Delete is then added down in the
@@ -3326,10 +3374,10 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
           }
           switch (type) {
           case APPEND:
-            r = append(region, action.getMutation(), cellScanner);
+            r = append(region, action.getMutation(), cellScanner, nonceGroup);
             break;
           case INCREMENT:
-            r = increment(region, action.getMutation(), cellScanner);
+            r = increment(region, action.getMutation(), cellScanner,  nonceGroup);
             break;
           case PUT:
           case DELETE:
@@ -3862,12 +3910,18 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
         entries.get(0).getKey().getEncodedRegionName().toStringUtf8());
       RegionCoprocessorHost coprocessorHost = region.getCoprocessorHost();
       List<Pair<HLogKey, WALEdit>> walEntries = new ArrayList<Pair<HLogKey, WALEdit>>();
-      List<Pair<MutationType, Mutation>> mutations = new ArrayList<Pair<MutationType, Mutation>>();
+      List<HLogSplitter.MutationReplay> mutations = new ArrayList<HLogSplitter.MutationReplay>();
       for (WALEntry entry : entries) {
+        if (nonceManager != null) {
+          long nonceGroup = entry.getKey().hasNonceGroup()
+              ? entry.getKey().getNonceGroup() : HConstants.NO_NONCE;
+          long nonce = entry.getKey().hasNonce() ? entry.getKey().getNonce() : HConstants.NO_NONCE;
+          nonceManager.reportOperationFromWal(nonceGroup, nonce, entry.getKey().getWriteTime());
+        }
         Pair<HLogKey, WALEdit> walEntry = (coprocessorHost == null) ? null :
           new Pair<HLogKey, WALEdit>();
-        List<Pair<MutationType, Mutation>> edits = HLogSplitter.getMutationsFromWALEntry(entry,
+        List<HLogSplitter.MutationReplay> edits =
-          cells, walEntry);
+            HLogSplitter.getMutationsFromWALEntry(entry, cells, walEntry);
         if (coprocessorHost != null) {
           // Start coprocessor replay here. The coprocessor is for each WALEdit instead of a
           // KeyValue.
@@ -3882,7 +3936,7 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
       }
 
       if (!mutations.isEmpty()) {
-        OperationStatus[] result = doBatchOp(region, mutations, true);
+        OperationStatus[] result = doReplayBatchOp(region, mutations);
         // check if it's a partial success
         for (int i = 0; result != null && i < result.length; i++) {
           if (result[i] != OperationStatus.SUCCESS) {
@@ -3987,7 +4041,7 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
    * @throws IOException
    */
   protected Result append(final HRegion region,
-      final MutationProto m, final CellScanner cellScanner) throws IOException {
+      final MutationProto m, final CellScanner cellScanner, long nonceGroup) throws IOException {
     long before = EnvironmentEdgeManager.currentTimeMillis();
     Append append = ProtobufUtil.toAppend(m, cellScanner);
     Result r = null;
@@ -3995,7 +4049,14 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
       r = region.getCoprocessorHost().preAppend(append);
     }
     if (r == null) {
-      r = region.append(append);
+      long nonce = startNonceOperation(m, nonceGroup);
+      boolean success = false;
+      try {
+        r = region.append(append, nonceGroup, nonce);
+        success = true;
+      } finally {
+        endNonceOperation(m, nonceGroup, success);
+      }
       if (region.getCoprocessorHost() != null) {
         region.getCoprocessorHost().postAppend(append, r);
       }
@@ -4013,8 +4074,7 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
    * @throws IOException
    */
   protected Result increment(final HRegion region, final MutationProto mutation,
-      final CellScanner cells)
+      final CellScanner cells, long nonceGroup) throws IOException {
-  throws IOException {
     long before = EnvironmentEdgeManager.currentTimeMillis();
     Increment increment = ProtobufUtil.toIncrement(mutation, cells);
     Result r = null;
@@ -4022,7 +4082,14 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
       r = region.getCoprocessorHost().preIncrement(increment);
     }
     if (r == null) {
-      r = region.increment(increment);
+      long nonce = startNonceOperation(mutation, nonceGroup);
+      boolean success = false;
+      try {
+        r = region.increment(increment, nonceGroup, nonce);
+        success = true;
+      } finally {
+        endNonceOperation(mutation, nonceGroup, success);
+      }
       if (region.getCoprocessorHost() != null) {
         r = region.getCoprocessorHost().postIncrement(increment, r);
       }
@@ -4031,6 +4098,49 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
     return r;
   }
 
+  /**
+   * Starts the nonce operation for a mutation, if needed.
+   * @param mutation Mutation.
+   * @param nonceGroup Nonce group from the request.
+   * @returns Nonce used (can be NO_NONCE).
+   */
+  private long startNonceOperation(final MutationProto mutation, long nonceGroup)
+      throws IOException, OperationConflictException {
+    if (nonceManager == null || !mutation.hasNonce()) return HConstants.NO_NONCE;
+    boolean canProceed = false;
+    try {
+      canProceed = nonceManager.startOperation(nonceGroup, mutation.getNonce(), this);
+    } catch (InterruptedException ex) {
+      // Probably should not happen.
+      throw new InterruptedIOException("Nonce start operation interrupted");
+    }
+    if (!canProceed) {
+      // TODO: instead, we could convert append/increment to get w/mvcc
+      String message = "The operation with nonce {" + nonceGroup + ", " + mutation.getNonce()
+          + "} on row [" + Bytes.toString(mutation.getRow().toByteArray())
+          + "] may have already completed";
+      throw new OperationConflictException(message);
+    }
+    return mutation.getNonce();
+  }
+
+  /**
+   * Ends nonce operation for a mutation, if needed.
+   * @param mutation Mutation.
+   * @param nonceGroup Nonce group from the request. Always 0 in initial implementation.
+   * @param success Whether the operation for this nonce has succeeded.
+   */
+  private void endNonceOperation(final MutationProto mutation, long nonceGroup,
+      boolean success) {
+    if (nonceManager == null || !mutation.hasNonce()) return;
+    nonceManager.endOperation(nonceGroup, mutation.getNonce(), success);
+  }
+
+  @Override
+  public ServerNonceManager getNonceManager() {
+    return this.nonceManager;
+  }
+
   /**
    * Execute a list of Put/Delete mutations.
    *
@@ -4063,7 +4173,7 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
         cacheFlusher.reclaimMemStoreMemory();
       }
 
-      OperationStatus codes[] = region.batchMutate(mArray, false);
+      OperationStatus codes[] = region.batchMutate(mArray);
       for (i = 0; i < codes.length; i++) {
         int index = mutations.get(i).getIndex();
         Exception e = null;
@@ -4119,32 +4229,31 @@ public class HRegionServer implements ClientProtos.ClientService.BlockingInterfa
    * constructing MultiResponse to save a possible loop if caller doesn't need MultiResponse.
    * @param region
    * @param mutations
-   * @param isReplay
    * @return an array of OperationStatus which internally contains the OperationStatusCode and the
    *         exceptionMessage if any
    * @throws IOException
    */
-  protected OperationStatus [] doBatchOp(final HRegion region,
+  protected OperationStatus [] doReplayBatchOp(final HRegion region,
-      final List<Pair<MutationType, Mutation>> mutations, boolean isReplay)
+      final List<HLogSplitter.MutationReplay> mutations) throws IOException {
-  throws IOException {
+    HLogSplitter.MutationReplay[] mArray = new HLogSplitter.MutationReplay[mutations.size()];
-    Mutation[] mArray = new Mutation[mutations.size()];
+
     long before = EnvironmentEdgeManager.currentTimeMillis();
     boolean batchContainsPuts = false, batchContainsDelete = false;
     try {
       int i = 0;
-      for (Pair<MutationType, Mutation> m : mutations) {
+      for (HLogSplitter.MutationReplay m : mutations) {
-        if (m.getFirst() == MutationType.PUT) {
+        if (m.type == MutationType.PUT) {
           batchContainsPuts = true;
         } else {
           batchContainsDelete = true;
         }
-        mArray[i++] = m.getSecond();
+        mArray[i++] = m;
       }
       requestCount.add(mutations.size());
       if (!region.getRegionInfo().isMetaTable()) {
         cacheFlusher.reclaimMemStoreMemory();
       }
-      return region.batchMutate(mArray, isReplay);
+      return region.batchReplay(mArray);
     } finally {
       long after = EnvironmentEdgeManager.currentTimeMillis();
       if (batchContainsPuts) {

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RegionServerServices.java

@@ -115,4 +115,10 @@ public interface RegionServerServices
    * @return set of recovering regions on the hosting region server
    */
   Map<String, HRegion> getRecoveringRegions();
+
+  /**
+   * Only required for "old" log replay; if it's removed, remove this.
+   * @return The RegionServer's NonceManager
+   */
+  public ServerNonceManager getNonceManager();
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ServerNonceManager.java

@@ -0,0 +1,280 @@
+/**
+ *
+ * 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.hbase.regionserver;
+
+import java.util.Date;
+import java.text.SimpleDateFormat;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.Map;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.Chore;
+import org.apache.hadoop.hbase.HConstants;
+import org.apache.hadoop.hbase.Stoppable;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
+import org.apache.hadoop.hbase.util.Pair;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+
+import com.google.common.annotations.VisibleForTesting;
+
+/**
+ * Implementation of nonce manager that stores nonces in a hash map and cleans them up after
+ * some time; if nonce group/client ID is supplied, nonces are stored by client ID.
+ */
+@InterfaceAudience.Private
+public class ServerNonceManager {
+  public static final String HASH_NONCE_GRACE_PERIOD_KEY = "hbase.server.hashNonce.gracePeriod";
+  private static final Log LOG = LogFactory.getLog(ServerNonceManager.class);
+
+  /** The time to wait in an extremely unlikely case of a conflict with a running op.
+   * Only here so that tests could override it and not wait. */
+  private int conflictWaitIterationMs = 30000;
+
+  private static final SimpleDateFormat tsFormat = new SimpleDateFormat("HH:mm:ss.SSS");
+
+  // This object is used to synchronize on in case of collisions, and for cleanup.
+  private static class OperationContext {
+    static final int DONT_PROCEED = 0;
+    static final int PROCEED = 1;
+    static final int WAIT = 2;
+
+    // 0..1 - state, 2..2 - whether anyone is waiting, 3.. - ts of last activity
+    private long data = 0;
+    private static final long STATE_BITS = 3;
+    private static final long WAITING_BIT = 4;
+    private static final long ALL_FLAG_BITS = WAITING_BIT | STATE_BITS;
+
+    @Override
+    public String toString() {
+      return "[state " + getState() + ", hasWait " + hasWait() + ", activity "
+          + tsFormat.format(new Date(getActivityTime())) + "]";
+    }
+
+    public OperationContext() {
+      setState(WAIT);
+      reportActivity();
+    }
+
+    public void setState(int state) {
+      this.data = (this.data & ~STATE_BITS) | state;
+    }
+
+    public int getState() {
+      return (int)(this.data & STATE_BITS);
+    }
+
+    public void setHasWait() {
+      this.data = this.data | WAITING_BIT;
+    }
+
+    public boolean hasWait() {
+      return (this.data & WAITING_BIT) == WAITING_BIT;
+    }
+
+    public void reportActivity() {
+      long now = EnvironmentEdgeManager.currentTimeMillis();
+      this.data = (this.data & ALL_FLAG_BITS) | (now << 3);
+    }
+
+    public boolean isExpired(long minRelevantTime) {
+      return getActivityTime() < (minRelevantTime & (~0l >>> 3));
+    }
+
+    private long getActivityTime() {
+      return this.data >>> 3;
+    }
+  }
+
+  /**
+   * This implementation is not smart and just treats nonce group and nonce as random bits.
+   */
+  // TODO: we could use pure byte arrays, but then we wouldn't be able to use hash map.
+  private class NonceKey {
+    private long group;
+    private long nonce;
+
+    public NonceKey(long group, long nonce) {
+      assert nonce != HConstants.NO_NONCE;
+      this.group = group;
+      this.nonce = nonce;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+      if (obj == null || !(obj instanceof NonceKey)) return false;
+      NonceKey nk = ((NonceKey)obj);
+      return this.nonce == nk.nonce && this.group == nk.group;
+    }
+
+    @Override
+    public int hashCode() {
+      return (int)((group >> 32) ^ group ^ (nonce >> 32) ^ nonce);
+    }
+
+    @Override
+    public String toString() {
+      return "[" + group + ":" + nonce + "]";
+    }
+  }
+
+  /**
+   * Nonces.
+   * Approximate overhead per nonce: 64 bytes from hashmap, 32 from two objects (k/v),
+   * NK: 16 bytes (2 longs), OC: 8 bytes (1 long) - so, 120 bytes.
+   * With 30min expiration time, 5k increments/appends per sec., we'd use approximately 1Gb,
+   * which is a realistic worst case. If it's much worse, we could use some sort of memory
+   * limit and cleanup.
+   */
+  private ConcurrentHashMap<NonceKey, OperationContext> nonces =
+      new ConcurrentHashMap<NonceKey, OperationContext>();
+
+  private int deleteNonceGracePeriod;
+
+  public ServerNonceManager(Configuration conf) {
+    // Default - 30 minutes.
+    deleteNonceGracePeriod = conf.getInt(HASH_NONCE_GRACE_PERIOD_KEY, 30 * 60 * 1000);
+    if (deleteNonceGracePeriod < 60 * 1000) {
+      LOG.warn("Nonce grace period " + deleteNonceGracePeriod
+          + " is less than a minute; might be too small to be useful");
+    }
+  }
+
+  @VisibleForTesting
+  public void setConflictWaitIterationMs(int conflictWaitIterationMs) {
+    this.conflictWaitIterationMs = conflictWaitIterationMs;
+  }
+
+  /**
+   * Starts the operation if operation with such nonce has not already succeeded. If the
+   * operation is in progress, waits for it to end and checks whether it has succeeded.
+   * @param group Nonce group.
+   * @param nonce Nonce.
+   * @param stoppable Stoppable that terminates waiting (if any) when the server is stopped.
+   * @return true if the operation has not already succeeded and can proceed; false otherwise.
+   */
+  public boolean startOperation(long group, long nonce, Stoppable stoppable)
+      throws InterruptedException {
+    if (nonce == HConstants.NO_NONCE) return true;
+    NonceKey nk = new NonceKey(group, nonce);
+    OperationContext ctx = new OperationContext();
+    while (true) {
+      OperationContext oldResult = nonces.putIfAbsent(nk, ctx);
+      if (oldResult == null) return true;
+
+      // Collision with some operation - should be extremely rare.
+      synchronized (oldResult) {
+        int oldState = oldResult.getState();
+        LOG.debug("Conflict detected by nonce: " + nk + ", " + oldResult);
+        if (oldState != OperationContext.WAIT) {
+          return oldState == OperationContext.PROCEED; // operation ended
+        }
+        oldResult.setHasWait();
+        oldResult.wait(this.conflictWaitIterationMs); // operation is still active... wait and loop
+        if (stoppable.isStopped()) {
+          throw new InterruptedException("Server stopped");
+        }
+      }
+    }
+  }
+
+  /**
+   * Ends the operation started by startOperation.
+   * @param group Nonce group.
+   * @param nonce Nonce.
+   * @param success Whether the operation has succeeded.
+   */
+  public void endOperation(long group, long nonce, boolean success) {
+    if (nonce == HConstants.NO_NONCE) return;
+    NonceKey nk = new NonceKey(group, nonce);
+    OperationContext newResult = nonces.get(nk);
+    assert newResult != null;
+    synchronized (newResult) {
+      assert newResult.getState() == OperationContext.WAIT;
+      // If we failed, other retries can proceed.
+      newResult.setState(success ? OperationContext.DONT_PROCEED : OperationContext.PROCEED);
+      if (success) {
+        newResult.reportActivity(); // Set time to use for cleanup.
+      } else {
+        OperationContext val = nonces.remove(nk);
+        assert val == newResult;
+      }
+      if (newResult.hasWait()) {
+        LOG.debug("Conflict with running op ended: " + nk + ", " + newResult);
+        newResult.notifyAll();
+      }
+    }
+  }
+
+  /**
+   * Reports the operation from WAL during replay.
+   * @param group Nonce group.
+   * @param nonce Nonce.
+   * @param writeTime Entry write time, used to ignore entries that are too old.
+   */
+  public void reportOperationFromWal(long group, long nonce, long writeTime) {
+    if (nonce == HConstants.NO_NONCE) return;
+    // Give the write time some slack in case the clocks are not synchronized.
+    long now = EnvironmentEdgeManager.currentTimeMillis();
+    if (now > writeTime + (deleteNonceGracePeriod * 1.5)) return;
+    OperationContext newResult = new OperationContext();
+    newResult.setState(OperationContext.DONT_PROCEED);
+    NonceKey nk = new NonceKey(group, nonce);
+    OperationContext oldResult = nonces.putIfAbsent(nk, newResult);
+    if (oldResult != null) {
+      // Some schemes can have collisions (for example, expiring hashes), so just log it.
+      // We have no idea about the semantics here, so this is the least of many evils.
+      LOG.warn("Nonce collision during WAL recovery: " + nk
+          + ", " + oldResult + " with " + newResult);
+    }
+  }
+
+  /**
+   * Creates a chore that is used to clean up old nonces.
+   * @param stoppable Stoppable for the chore.
+   * @return Chore; the chore is not started.
+   */
+  public Chore createCleanupChore(Stoppable stoppable) {
+    // By default, it will run every 6 minutes (30 / 5).
+    return new Chore("nonceCleaner", deleteNonceGracePeriod / 5, stoppable) {
+      @Override
+      protected void chore() {
+        cleanUpOldNonces();
+      }
+    };
+  }
+
+  private void cleanUpOldNonces() {
+    long cutoff = EnvironmentEdgeManager.currentTimeMillis() - deleteNonceGracePeriod;
+    for (Map.Entry<NonceKey, OperationContext> entry : nonces.entrySet()) {
+      OperationContext oc = entry.getValue();
+      if (!oc.isExpired(cutoff)) continue;
+      synchronized (oc) {
+        if (oc.getState() == OperationContext.WAIT || !oc.isExpired(cutoff)) continue;
+        nonces.remove(entry.getKey());
+      }
+    }
+  }
+}

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/FSHLog.java

@@ -66,6 +66,8 @@ import org.apache.hadoop.util.StringUtils;
 import org.cloudera.htrace.Trace;
 import org.cloudera.htrace.TraceScope;
 
+import com.google.common.annotations.VisibleForTesting;
+
 /**
  * HLog stores all the edits to the HStore.  Its the hbase write-ahead-log
  * implementation.
@@ -898,21 +900,16 @@ class FSHLog implements HLog, Syncable {
    * @return New log key.
    */
   protected HLogKey makeKey(byte[] encodedRegionName, TableName tableName, long seqnum,
-      long now, List<UUID> clusterIds) {
+      long now, List<UUID> clusterIds, long nonceGroup, long nonce) {
-    return new HLogKey(encodedRegionName, tableName, seqnum, now, clusterIds);
+    return new HLogKey(encodedRegionName, tableName, seqnum, now, clusterIds, nonceGroup, nonce);
   }
 
   @Override
+  @VisibleForTesting
   public void append(HRegionInfo info, TableName tableName, WALEdit edits,
-    final long now, HTableDescriptor htd, AtomicLong sequenceId)
+    final long now, HTableDescriptor htd, AtomicLong sequenceId) throws IOException {
-  throws IOException {
+    append(info, tableName, edits, new ArrayList<UUID>(), now, htd, true, true, sequenceId,
-    append(info, tableName, edits, now, htd, true, sequenceId);
+        HConstants.NO_NONCE, HConstants.NO_NONCE);
-  }
-
-  @Override
-  public void append(HRegionInfo info, TableName tableName, WALEdit edits, final long now,
-      HTableDescriptor htd, boolean isInMemstore, AtomicLong sequenceId) throws IOException {
-    append(info, tableName, edits, new ArrayList<UUID>(), now, htd, true, isInMemstore, sequenceId);
   }
 
   /**
@@ -944,8 +941,8 @@ class FSHLog implements HLog, Syncable {
    */
   @SuppressWarnings("deprecation")
   private long append(HRegionInfo info, TableName tableName, WALEdit edits, List<UUID> clusterIds,
-      final long now, HTableDescriptor htd, boolean doSync, boolean isInMemstore, AtomicLong sequenceId)
+      final long now, HTableDescriptor htd, boolean doSync, boolean isInMemstore, 
-    throws IOException {
+      AtomicLong sequenceId, long nonceGroup, long nonce) throws IOException {
       if (edits.isEmpty()) return this.unflushedEntries.get();
       if (this.closed) {
         throw new IOException("Cannot append; log is closed");
@@ -966,7 +963,8 @@ class FSHLog implements HLog, Syncable {
           // actual  name.
           byte [] encodedRegionName = info.getEncodedNameAsBytes();
           if (isInMemstore) this.oldestUnflushedSeqNums.putIfAbsent(encodedRegionName, seqNum);
-          HLogKey logKey = makeKey(encodedRegionName, tableName, seqNum, now, clusterIds);
+          HLogKey logKey = makeKey(
+            encodedRegionName, tableName, seqNum, now, clusterIds, nonceGroup, nonce);
           doWrite(info, logKey, edits, htd);
           this.numEntries.incrementAndGet();
           txid = this.unflushedEntries.incrementAndGet();
@@ -975,6 +973,8 @@ class FSHLog implements HLog, Syncable {
           }
           this.latestSequenceNums.put(encodedRegionName, seqNum);
         }
+        // TODO: note that only tests currently call append w/sync.
+        //       Therefore, this code here is not actually used by anything.
         // Sync if catalog region, and if not then check if that table supports
         // deferred log flushing
         if (doSync &&
@@ -991,9 +991,10 @@ class FSHLog implements HLog, Syncable {
 
   @Override
   public long appendNoSync(HRegionInfo info, TableName tableName, WALEdit edits,
-      List<UUID> clusterIds, final long now, HTableDescriptor htd, AtomicLong sequenceId)
+      List<UUID> clusterIds, final long now, HTableDescriptor htd, AtomicLong sequenceId,
-    throws IOException {
+      boolean isInMemstore, long nonceGroup, long nonce) throws IOException {
-    return append(info, tableName, edits, clusterIds, now, htd, false, true, sequenceId);
+    return append(info, tableName, edits, clusterIds,
+        now, htd, false, isInMemstore, sequenceId, nonceGroup, nonce);
   }
 
   /**

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLog.java

@@ -40,6 +40,8 @@ import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.protobuf.generated.WALProtos.WALTrailer;
 import org.apache.hadoop.io.Writable;
 
+import com.google.common.annotations.VisibleForTesting;
+
 
 @InterfaceAudience.Private
 // TODO: Rename interface to WAL
@@ -260,24 +262,10 @@ public interface HLog {
    * except it causes a sync on the log
    * @param sequenceId of the region.
    */
+  @VisibleForTesting
   public void append(HRegionInfo info, TableName tableName, WALEdit edits,
       final long now, HTableDescriptor htd, AtomicLong sequenceId) throws IOException;
 
-  /**
-   * Append a set of edits to the log. Log edits are keyed by (encoded)
-   * regionName, row name, and log-sequence-id. The HLog is flushed after this
-   * transaction is written to the log.
-   * @param info
-   * @param tableName
-   * @param edits
-   * @param now
-   * @param htd
-   * @param isInMemstore Whether the record is in memstore. False for system records.
-   * @param sequenceId of the region.
-   */
-  public void append(HRegionInfo info, TableName tableName, WALEdit edits, final long now,
-      HTableDescriptor htd, boolean isInMemstore, AtomicLong sequenceId) throws IOException;
-
   /**
    * Append a set of edits to the log. Log edits are keyed by (encoded) regionName, rowname, and
    * log-sequence-id. The HLog is not flushed after this transaction is written to the log.
@@ -291,8 +279,9 @@ public interface HLog {
    * @return txid of this transaction
    * @throws IOException
    */
-  public long appendNoSync(HRegionInfo info, TableName tableName, WALEdit edits,
+  long appendNoSync(HRegionInfo info, TableName tableName, WALEdit edits,
-      List<UUID> clusterIds, final long now, HTableDescriptor htd, AtomicLong sequenceId) throws IOException;
+      List<UUID> clusterIds, final long now, HTableDescriptor htd, AtomicLong sequenceId,
+      boolean isInMemstore, long nonceGroup, long nonce) throws IOException;
 
   // TODO: Do we need all these versions of sync?
   void hsync() throws IOException;

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLogKey.java

@@ -45,6 +45,7 @@ import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.io.WritableComparable;
 import org.apache.hadoop.io.WritableUtils;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.ZeroCopyLiteralByteString;
 
@@ -119,18 +120,23 @@ public class HLogKey implements WritableComparable<HLogKey> {
 
   private NavigableMap<byte[], Integer> scopes;
 
+  private long nonceGroup = HConstants.NO_NONCE;
+  private long nonce = HConstants.NO_NONCE;
+
   private CompressionContext compressionContext;
 
   public HLogKey() {
     init(null, null, 0L, HConstants.LATEST_TIMESTAMP,
-        new ArrayList<UUID>());
+        new ArrayList<UUID>(), HConstants.NO_NONCE, HConstants.NO_NONCE);
   }
 
+  @VisibleForTesting
   public HLogKey(final byte[] encodedRegionName, final TableName tablename, long logSeqNum,
       final long now, UUID clusterId) {
     List<UUID> clusterIds = new ArrayList<UUID>();
     clusterIds.add(clusterId);
-    init(encodedRegionName, tablename, logSeqNum, now, clusterIds);
+    init(encodedRegionName, tablename, logSeqNum, now, clusterIds,
+        HConstants.NO_NONCE, HConstants.NO_NONCE);
   }
 
   /**
@@ -146,17 +152,19 @@ public class HLogKey implements WritableComparable<HLogKey> {
    * @param clusterIds the clusters that have consumed the change(used in Replication)
    */
   public HLogKey(final byte [] encodedRegionName, final TableName tablename,
-      long logSeqNum, final long now, List<UUID> clusterIds){
+      long logSeqNum, final long now, List<UUID> clusterIds, long nonceGroup, long nonce) {
-    init(encodedRegionName, tablename, logSeqNum, now, clusterIds);
+    init(encodedRegionName, tablename, logSeqNum, now, clusterIds, nonceGroup, nonce);
   }
 
   protected void init(final byte [] encodedRegionName, final TableName tablename,
-      long logSeqNum, final long now, List<UUID> clusterIds) {
+      long logSeqNum, final long now, List<UUID> clusterIds, long nonceGroup, long nonce) {
     this.logSeqNum = logSeqNum;
     this.writeTime = now;
     this.clusterIds = clusterIds;
     this.encodedRegionName = encodedRegionName;
     this.tablename = tablename;
+    this.nonceGroup = nonceGroup;
+    this.nonce = nonce;
   }
 
   /**
@@ -192,6 +200,16 @@ public class HLogKey implements WritableComparable<HLogKey> {
     return scopes;
   }
 
+  /** @return The nonce group */
+  public long getNonceGroup() {
+    return nonceGroup;
+  }
+
+  /** @return The nonce */
+  public long getNonce() {
+    return nonce;
+  }
+
   public void setScopes(NavigableMap<byte[], Integer> scopes) {
     this.scopes = scopes;
   }
@@ -435,6 +453,12 @@ public class HLogKey implements WritableComparable<HLogKey> {
     }
     builder.setLogSequenceNumber(this.logSeqNum);
     builder.setWriteTime(writeTime);
+    if (this.nonce != HConstants.NO_NONCE) {
+      builder.setNonce(nonce);
+    }
+    if (this.nonceGroup != HConstants.NO_NONCE) {
+      builder.setNonceGroup(nonceGroup);
+    }
     HBaseProtos.UUID.Builder uuidBuilder = HBaseProtos.UUID.newBuilder();
     for (UUID clusterId : clusterIds) {
       uuidBuilder.setLeastSigBits(clusterId.getLeastSignificantBits());
@@ -474,6 +498,12 @@ public class HLogKey implements WritableComparable<HLogKey> {
     for (HBaseProtos.UUID clusterId : walKey.getClusterIdsList()) {
       clusterIds.add(new UUID(clusterId.getMostSigBits(), clusterId.getLeastSigBits()));
     }
+    if (walKey.hasNonceGroup()) {
+      this.nonceGroup = walKey.getNonceGroup();
+    }
+    if (walKey.hasNonce()) {
+      this.nonce = walKey.getNonce();
+    }
     this.scopes = null;
     if (walKey.getScopesCount() > 0) {
       this.scopes = new TreeMap<byte[], Integer>(Bytes.BYTES_COMPARATOR);

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLogSplitter.java

@@ -1836,6 +1836,21 @@ public class HLogSplitter {
     }
   }
 
+  /** A struct used by getMutationsFromWALEntry */
+  public static class MutationReplay {
+    public MutationReplay(MutationType type, Mutation mutation, long nonceGroup, long nonce) {
+      this.type = type;
+      this.mutation = mutation;
+      this.nonceGroup = nonceGroup;
+      this.nonce = nonce;
+    }
+
+    public final MutationType type;
+    public final Mutation mutation;
+    public final long nonceGroup;
+    public final long nonce;
+  }
+
   /**
    * This function is used to construct mutations from a WALEntry. It also reconstructs HLogKey &
    * WALEdit from the passed in WALEntry
@@ -1846,16 +1861,16 @@ public class HLogSplitter {
    * @return list of Pair<MutationType, Mutation> to be replayed
    * @throws IOException
    */
-  public static List<Pair<MutationType, Mutation>> getMutationsFromWALEntry(WALEntry entry,
+  public static List<MutationReplay> getMutationsFromWALEntry(WALEntry entry,
       CellScanner cells, Pair<HLogKey, WALEdit> logEntry) throws IOException {
 
     if (entry == null) {
       // return an empty array
-      return new ArrayList<Pair<MutationType, Mutation>>();
+      return new ArrayList<MutationReplay>();
     }
 
     int count = entry.getAssociatedCellCount();
-    List<Pair<MutationType, Mutation>> mutations = new ArrayList<Pair<MutationType, Mutation>>();
+    List<MutationReplay> mutations = new ArrayList<MutationReplay>();
     Cell previousCell = null;
     Mutation m = null;
     HLogKey key = null;
@@ -1877,10 +1892,16 @@ public class HLogSplitter {
         // Create new mutation
         if (CellUtil.isDelete(cell)) {
           m = new Delete(cell.getRowArray(), cell.getRowOffset(), cell.getRowLength());
-          mutations.add(new Pair<MutationType, Mutation>(MutationType.DELETE, m));
+          // Deletes don't have nonces.
+          mutations.add(new MutationReplay(
+              MutationType.DELETE, m, HConstants.NO_NONCE, HConstants.NO_NONCE));
         } else {
           m = new Put(cell.getRowArray(), cell.getRowOffset(), cell.getRowLength());
-          mutations.add(new Pair<MutationType, Mutation>(MutationType.PUT, m));
+          // Puts might come from increment or append, thus we need nonces.
+          long nonceGroup = entry.getKey().hasNonceGroup()
+              ? entry.getKey().getNonceGroup() : HConstants.NO_NONCE;
+          long nonce = entry.getKey().hasNonce() ? entry.getKey().getNonce() : HConstants.NO_NONCE;
+          mutations.add(new MutationReplay(MutationType.PUT, m, nonceGroup, nonce));
         }
       }
       if (CellUtil.isDelete(cell)) {
@@ -1900,7 +1921,7 @@ public class HLogSplitter {
       }
       key = new HLogKey(walKey.getEncodedRegionName().toByteArray(), TableName.valueOf(walKey
               .getTableName().toByteArray()), walKey.getLogSequenceNumber(), walKey.getWriteTime(),
-              clusterIds);
+              clusterIds, walKey.getNonceGroup(), walKey.getNonce());
       logEntry.setFirst(key);
       logEntry.setSecond(val);
     }

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLogUtil.java

@@ -20,8 +20,10 @@
 package org.apache.hadoop.hbase.regionserver.wal;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.NavigableSet;
 import java.util.TreeSet;
+import java.util.UUID;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -262,8 +264,12 @@ public class HLogUtil {
   public static void writeCompactionMarker(HLog log, HTableDescriptor htd, HRegionInfo info,
       final CompactionDescriptor c, AtomicLong sequenceId) throws IOException {
     WALEdit e = WALEdit.createCompaction(c);
-    log.append(info, TableName.valueOf(c.getTableName().toByteArray()), e,
+    long now = EnvironmentEdgeManager.currentTimeMillis();
-        EnvironmentEdgeManager.currentTimeMillis(), htd, false, sequenceId);
+    TableName tn = TableName.valueOf(c.getTableName().toByteArray());
+    long txid = log.appendNoSync(info, tn, e, new ArrayList<UUID>(), now, htd, sequenceId,
+        false, HConstants.NO_NONCE, HConstants.NO_NONCE);
+    log.sync(txid);
+
     if (LOG.isTraceEnabled()) {
       LOG.trace("Appended compaction marker " + TextFormat.shortDebugString(c));
     }

hbase-server/src/main/java/org/apache/hadoop/hbase/snapshot/SnapshotLogSplitter.java

@@ -171,8 +171,8 @@ class SnapshotLogSplitter implements Closeable {
         }
 
         // Append Entry
-        key = new HLogKey(newRegionName, tableName,
+        key = new HLogKey(newRegionName, tableName, key.getLogSeqNum(), key.getWriteTime(),
-                          key.getLogSeqNum(), key.getWriteTime(), key.getClusterIds());
+                          key.getClusterIds(), key.getNonceGroup(), key.getNonce());
         writer.append(new HLog.Entry(key, entry.getEdit()));
       }
     } catch (IOException e) {

hbase-server/src/test/java/org/apache/hadoop/hbase/MockRegionServerServices.java

@@ -40,6 +40,7 @@ import org.apache.hadoop.hbase.regionserver.HRegion;
 import org.apache.hadoop.hbase.regionserver.Leases;
 import org.apache.hadoop.hbase.regionserver.RegionServerAccounting;
 import org.apache.hadoop.hbase.regionserver.RegionServerServices;
+import org.apache.hadoop.hbase.regionserver.ServerNonceManager;
 import org.apache.hadoop.hbase.regionserver.wal.HLog;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
@@ -192,7 +193,6 @@ class MockRegionServerServices implements RegionServerServices {
 
   @Override
   public HLog getWAL(HRegionInfo regionInfo) throws IOException {
-    // TODO Auto-generated method stub
     return null;
   }
 
@@ -221,4 +221,10 @@ class MockRegionServerServices implements RegionServerServices {
   public int getPriority(RPCProtos.RequestHeader header, Message param) {
     return 0;
   }
+
+  @Override
+  public ServerNonceManager getNonceManager() {
+    // TODO Auto-generated method stub
+    return null;
+  }
 }

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestMultiParallel.java

@@ -27,6 +27,7 @@ import java.io.IOException;
 import java.lang.reflect.Field;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ThreadPoolExecutor;
 
 import org.apache.commons.logging.Log;
@@ -37,11 +38,13 @@ import org.apache.hadoop.hbase.CellUtil;
 import org.apache.hadoop.hbase.HBaseTestingUtility;
 import org.apache.hadoop.hbase.MediumTests;
 import org.apache.hadoop.hbase.Waiter;
+import org.apache.hadoop.hbase.exceptions.OperationConflictException;
 import org.apache.hadoop.hbase.ipc.RpcClient;
 import org.apache.hadoop.hbase.ipc.RpcServer;
 import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.util.JVMClusterUtil;
+import org.apache.hadoop.hbase.util.Threads;
 import org.apache.log4j.Level;
 import org.junit.AfterClass;
 import org.junit.Assert;
@@ -481,6 +484,96 @@ public class TestMultiParallel {
     table.close();
   }
 
+  @Test(timeout=300000)
+  public void testNonceCollision() throws Exception {
+    LOG.info("test=testNonceCollision");
+    HTable table = new HTable(UTIL.getConfiguration(), TEST_TABLE);
+    Put put = new Put(ONE_ROW);
+    put.add(BYTES_FAMILY, QUALIFIER, Bytes.toBytes(0L));
+
+    // Replace nonce manager with the one that returns each nonce twice.
+    NonceGenerator cnm = new PerClientRandomNonceGenerator() {
+      long lastNonce = -1;
+      @Override
+      public synchronized long newNonce() {
+        long nonce = 0;
+        if (lastNonce == -1) {
+          lastNonce = nonce = super.newNonce();
+        } else {
+          nonce = lastNonce;
+          lastNonce = -1L;
+        }
+        return nonce;
+      }
+    };
+    NonceGenerator oldCnm =
+        HConnectionManager.injectNonceGeneratorForTesting(table.getConnection(), cnm);
+
+    // First test sequential requests.
+    try {
+      Increment inc = new Increment(ONE_ROW);
+      inc.addColumn(BYTES_FAMILY, QUALIFIER, 1L);
+      table.increment(inc);
+      inc = new Increment(ONE_ROW);
+      inc.addColumn(BYTES_FAMILY, QUALIFIER, 1L);
+      try {
+        table.increment(inc);
+        fail("Should have thrown an exception");
+      } catch (OperationConflictException ex) {
+      }
+      Get get = new Get(ONE_ROW);
+      get.addColumn(BYTES_FAMILY, QUALIFIER);
+      Result result = table.get(get);
+      validateResult(result, QUALIFIER, Bytes.toBytes(1L));
+
+      // Now run a bunch of requests in parallel, exactly half should succeed.
+      int numRequests = 40;
+      final CountDownLatch startedLatch = new CountDownLatch(numRequests);
+      final CountDownLatch startLatch = new CountDownLatch(1);
+      final CountDownLatch doneLatch = new CountDownLatch(numRequests);
+      for (int i = 0; i < numRequests; ++i) {
+        Runnable r = new Runnable() {
+          @Override
+          public void run() {
+            HTable table = null;
+            try {
+              table = new HTable(UTIL.getConfiguration(), TEST_TABLE);
+            } catch (IOException e) {
+              fail("Not expected");
+            }
+            Increment inc = new Increment(ONE_ROW);
+            inc.addColumn(BYTES_FAMILY, QUALIFIER, 1L);
+            startedLatch.countDown();
+            try {
+              startLatch.await();
+            } catch (InterruptedException e) {
+              fail("Not expected");
+            }
+            try {
+              table.increment(inc);
+            } catch (OperationConflictException ex) { // Some threads are expected to fail.
+            } catch (IOException ioEx) {
+              fail("Not expected");
+            }
+            doneLatch.countDown();
+          }
+        };
+        Threads.setDaemonThreadRunning(new Thread(r));
+      }
+      startedLatch.await(); // Wait until all threads are ready...
+      startLatch.countDown(); // ...and unleash the herd!
+      doneLatch.await();
+      // Now verify
+      get = new Get(ONE_ROW);
+      get.addColumn(BYTES_FAMILY, QUALIFIER);
+      result = table.get(get);
+      validateResult(result, QUALIFIER, Bytes.toBytes((numRequests / 2) + 1L));
+      table.close();
+    } finally {
+      HConnectionManager.injectNonceGeneratorForTesting(table.getConnection(), oldCnm);
+    }
+  }
+
   @Test(timeout=300000)
   public void testBatchWithMixedActions() throws Exception {
     LOG.info("test=testBatchWithMixedActions");
@@ -558,10 +651,13 @@ public class TestMultiParallel {
   }
 
   private void validateResult(Object r1, byte[] qual, byte[] val) {
-    // TODO provide nice assert here or something.
     Result r = (Result)r1;
     Assert.assertTrue(r.containsColumn(BYTES_FAMILY, qual));
-    Assert.assertEquals(0, Bytes.compareTo(val, r.getValue(BYTES_FAMILY, qual)));
+    byte[] value = r.getValue(BYTES_FAMILY, qual);
+    if (0 != Bytes.compareTo(val, value)) {
+      fail("Expected [" + Bytes.toStringBinary(val)
+          + "] but got [" + Bytes.toStringBinary(value) + "]");
+    }
   }
 
   private List<Row> constructPutRequests() {

hbase-server/src/test/java/org/apache/hadoop/hbase/master/MockRegionServer.java

@@ -91,6 +91,7 @@ import org.apache.hadoop.hbase.regionserver.HRegion;
 import org.apache.hadoop.hbase.regionserver.Leases;
 import org.apache.hadoop.hbase.regionserver.RegionServerAccounting;
 import org.apache.hadoop.hbase.regionserver.RegionServerServices;
+import org.apache.hadoop.hbase.regionserver.ServerNonceManager;
 import org.apache.hadoop.hbase.regionserver.wal.HLog;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
@@ -554,4 +555,9 @@ ClientProtos.ClientService.BlockingInterface, RegionServerServices {
       UpdateFavoredNodesRequest request) throws ServiceException {
     return null;
   }
+
+  @Override
+  public ServerNonceManager getNonceManager() {
+    return null;
+  }
 }

hbase-server/src/test/java/org/apache/hadoop/hbase/master/TestDistributedLogSplitting.java

@@ -25,6 +25,7 @@ import static org.apache.hadoop.hbase.SplitLogCounters.tot_wkr_task_acquired;
 import static org.apache.hadoop.hbase.SplitLogCounters.tot_wkr_task_done;
 import static org.apache.hadoop.hbase.SplitLogCounters.tot_wkr_task_err;
 import static org.apache.hadoop.hbase.SplitLogCounters.tot_wkr_task_resigned;
+import static org.junit.Assert.*;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
@@ -35,6 +36,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.NavigableSet;
 import java.util.Set;
@@ -68,9 +70,14 @@ import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.SplitLogCounters;
 import org.apache.hadoop.hbase.Waiter;
 import org.apache.hadoop.hbase.client.Delete;
+import org.apache.hadoop.hbase.client.HConnectionManager;
 import org.apache.hadoop.hbase.client.HTable;
+import org.apache.hadoop.hbase.client.Increment;
+import org.apache.hadoop.hbase.client.NonceGenerator;
+import org.apache.hadoop.hbase.client.PerClientRandomNonceGenerator;
 import org.apache.hadoop.hbase.client.Put;
 import org.apache.hadoop.hbase.client.RetriesExhaustedWithDetailsException;
+import org.apache.hadoop.hbase.exceptions.OperationConflictException;
 import org.apache.hadoop.hbase.exceptions.RegionInRecoveryException;
 import org.apache.hadoop.hbase.master.SplitLogManager.TaskBatch;
 import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
@@ -172,7 +179,7 @@ public class TestDistributedLogSplitting {
     try {
       if (TEST_UTIL.getHBaseCluster() != null) {
         for (MasterThread mt : TEST_UTIL.getHBaseCluster().getLiveMasterThreads()) {
-          mt.getMaster().abort("closing...", new Exception("Trace info"));
+          mt.getMaster().abort("closing...", null);
         }
       }
       TEST_UTIL.shutdownMiniHBaseCluster();
@@ -273,6 +280,80 @@ public class TestDistributedLogSplitting {
     zkw.close();
   }
 
+  private static class NonceGeneratorWithDups extends PerClientRandomNonceGenerator {
+    private boolean isDups = false;
+    private LinkedList<Long> nonces = new LinkedList<Long>();
+
+    public void startDups() {
+      isDups = true;
+    }
+
+    @Override
+    public long newNonce() {
+      long nonce = isDups ? nonces.removeFirst() : super.newNonce();
+      if (!isDups) {
+        nonces.add(nonce);
+      }
+      return nonce;
+    }
+  }
+
+  @Test(timeout = 300000)
+  public void testNonceRecovery() throws Exception {
+    LOG.info("testNonceRecovery");
+    final String TABLE_NAME = "table";
+    final String FAMILY_NAME = "family";
+    final int NUM_REGIONS_TO_CREATE = 40;
+
+    conf.setLong("hbase.regionserver.hlog.blocksize", 100*1024);
+    conf.setBoolean(HConstants.DISTRIBUTED_LOG_REPLAY_KEY, true);
+    startCluster(NUM_RS);
+    master.balanceSwitch(false);
+
+    final ZooKeeperWatcher zkw = new ZooKeeperWatcher(conf, "table-creation", null);
+    HTable ht = installTable(zkw, TABLE_NAME, FAMILY_NAME, NUM_REGIONS_TO_CREATE);
+    NonceGeneratorWithDups ng = new NonceGeneratorWithDups();
+    NonceGenerator oldNg =
+        HConnectionManager.injectNonceGeneratorForTesting(ht.getConnection(), ng);
+
+    try {
+      List<Increment> reqs = new ArrayList<Increment>();
+      for (RegionServerThread rst : cluster.getLiveRegionServerThreads()) {
+        HRegionServer hrs = rst.getRegionServer();
+        List<HRegionInfo> hris = ProtobufUtil.getOnlineRegions(hrs);
+        for (HRegionInfo hri : hris) {
+          if (TABLE_NAME.equalsIgnoreCase(hri.getTable().getNameAsString())) {
+            byte[] key = hri.getStartKey();
+            if (key == null || key.length == 0) {
+              key = Bytes.copy(hri.getEndKey());
+              --(key[key.length - 1]);
+            }
+            Increment incr = new Increment(key);
+            incr.addColumn(Bytes.toBytes(FAMILY_NAME), Bytes.toBytes("q"), 1);
+            ht.increment(incr);
+            reqs.add(incr);
+          }
+        }
+      }
+
+      HRegionServer hrs = findRSToKill(false, "table");
+      abortRSAndWaitForRecovery(hrs, zkw, NUM_REGIONS_TO_CREATE);
+      ng.startDups();
+      for (Increment incr : reqs) {
+        try {
+          ht.increment(incr);
+          fail("should have thrown");
+        } catch (OperationConflictException ope) {
+          LOG.debug("Caught as expected: " + ope.getMessage());
+        }
+      }
+    } finally {
+      HConnectionManager.injectNonceGeneratorForTesting(ht.getConnection(), oldNg);
+      ht.close();
+      zkw.close();
+    }
+  }
+
   @Test(timeout = 300000)
   public void testLogReplayWithMetaRSDown() throws Exception {
     LOG.info("testRecoveredEditsReplayWithMetaRSDown");

hbase-server/src/test/java/org/apache/hadoop/hbase/protobuf/TestProtobufUtil.java

@@ -22,6 +22,7 @@ import static org.junit.Assert.assertEquals;
 
 import java.io.IOException;
 
+import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.SmallTests;
 import org.apache.hadoop.hbase.client.Append;
 import org.apache.hadoop.hbase.client.Delete;
@@ -220,7 +221,7 @@ public class TestProtobufUtil {
 
     Increment increment = ProtobufUtil.toIncrement(proto, null);
     assertEquals(mutateBuilder.build(),
-      ProtobufUtil.toMutation(increment, MutationProto.newBuilder()));
+      ProtobufUtil.toMutation(increment, MutationProto.newBuilder(), HConstants.NO_NONCE));
   }
 
   /**

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestHRegion.java

@@ -33,9 +33,7 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
-import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.*;
-import static org.mockito.Matchers.anyLong;
-import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
@@ -3800,10 +3798,11 @@ public class TestHRegion {
     put.add(family, Bytes.toBytes("q1"), Bytes.toBytes("v1"));
     put.setDurability(mutationDurability);
     region.put(put);
+
     //verify append called or not
     verify(log, expectAppend ? times(1) : never())
       .appendNoSync((HRegionInfo)any(), eq(tableName), (WALEdit)any(), (List<UUID>)any(),
-        anyLong(), (HTableDescriptor)any(), (AtomicLong)any());
+        anyLong(), (HTableDescriptor)any(), (AtomicLong)any(), anyBoolean(), anyLong(), anyLong());
 
     // verify sync called or not
     if (expectSync || expectSyncFromLogSyncer) {

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestServerNonceManager.java

@@ -0,0 +1,281 @@
+/*
+ *
+ * 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.hbase.regionserver;
+
+import static org.apache.hadoop.hbase.HConstants.NO_NONCE;
+import static org.junit.Assert.*;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.Chore;
+import org.apache.hadoop.hbase.HBaseConfiguration;
+import org.apache.hadoop.hbase.SmallTests;
+import org.apache.hadoop.hbase.Stoppable;
+import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
+import org.apache.hadoop.hbase.util.ManualEnvironmentEdge;
+import org.apache.hadoop.hbase.util.Threads;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+import org.mockito.Mockito;
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
+
+@Category(SmallTests.class)
+public class TestServerNonceManager {
+
+  @Test
+  public void testNormalStartEnd() throws Exception {
+    final long[] numbers = new long[] { NO_NONCE, 1, 2, Long.MAX_VALUE, Long.MIN_VALUE };
+    ServerNonceManager nm = createManager();
+    for (int i = 0; i < numbers.length; ++i) {
+      for (int j = 0; j < numbers.length; ++j) {
+        assertTrue(nm.startOperation(numbers[i], numbers[j], createStoppable()));
+      }
+    }
+    // Should be able to start operation the second time w/o nonces.
+    for (int i = 0; i < numbers.length; ++i) {
+      assertTrue(nm.startOperation(numbers[i], NO_NONCE, createStoppable()));
+    }
+    // Fail all operations - should be able to restart.
+    for (int i = 0; i < numbers.length; ++i) {
+      for (int j = 0; j < numbers.length; ++j) {
+        nm.endOperation(numbers[i], numbers[j], false);
+        assertTrue(nm.startOperation(numbers[i], numbers[j], createStoppable()));
+      }
+    }
+    // Succeed all operations - should not be able to restart, except for NO_NONCE.
+    for (int i = 0; i < numbers.length; ++i) {
+      for (int j = 0; j < numbers.length; ++j) {
+        nm.endOperation(numbers[i], numbers[j], true);
+        assertEquals(numbers[j] == NO_NONCE,
+            nm.startOperation(numbers[i], numbers[j], createStoppable()));
+      }
+    }
+  }
+
+  @Test
+  public void testNoEndWithoutStart() {
+    ServerNonceManager nm = createManager();
+    try {
+      nm.endOperation(NO_NONCE, 1, true);
+      fail("Should have thrown");
+    } catch (AssertionError err) {}
+  }
+
+  @Test
+  public void testCleanup() throws Exception {
+    ManualEnvironmentEdge edge = new ManualEnvironmentEdge();
+    EnvironmentEdgeManager.injectEdge(edge);
+    try {
+      ServerNonceManager nm = createManager(6);
+      Chore cleanup = nm.createCleanupChore(Mockito.mock(Stoppable.class));
+      edge.setValue(1);
+      assertTrue(nm.startOperation(NO_NONCE, 1, createStoppable()));
+      assertTrue(nm.startOperation(NO_NONCE, 2, createStoppable()));
+      assertTrue(nm.startOperation(NO_NONCE, 3, createStoppable()));
+      edge.setValue(2);
+      nm.endOperation(NO_NONCE, 1, true);
+      edge.setValue(4);
+      nm.endOperation(NO_NONCE, 2, true);
+      edge.setValue(9);
+      cleanup.choreForTesting();
+      // Nonce 1 has been cleaned up.
+      assertTrue(nm.startOperation(NO_NONCE, 1, createStoppable()));
+      // Nonce 2 has not been cleaned up.
+      assertFalse(nm.startOperation(NO_NONCE, 2, createStoppable()));
+      // Nonce 3 was active and active ops should never be cleaned up; try to end and start.
+      nm.endOperation(NO_NONCE, 3, false);
+      assertTrue(nm.startOperation(NO_NONCE, 3, createStoppable()));
+      edge.setValue(11);
+      cleanup.choreForTesting();
+      // Now, nonce 2 has been cleaned up.
+      assertTrue(nm.startOperation(NO_NONCE, 2, createStoppable()));
+    } finally {
+      EnvironmentEdgeManager.reset();
+    }
+  }
+
+  @Test
+  public void testWalNonces() throws Exception {
+    ManualEnvironmentEdge edge = new ManualEnvironmentEdge();
+    EnvironmentEdgeManager.injectEdge(edge);
+    try {
+      ServerNonceManager nm = createManager(6);
+      Chore cleanup = nm.createCleanupChore(Mockito.mock(Stoppable.class));
+      // Add nonces from WAL, including dups.
+      edge.setValue(12);
+      nm.reportOperationFromWal(NO_NONCE, 1, 8);
+      nm.reportOperationFromWal(NO_NONCE, 2, 2);
+      nm.reportOperationFromWal(NO_NONCE, 3, 5);
+      nm.reportOperationFromWal(NO_NONCE, 3, 6);
+      // WAL nonces should prevent cross-server conflicts.
+      assertFalse(nm.startOperation(NO_NONCE, 1, createStoppable()));
+      // Make sure we ignore very old nonces, but not borderline old nonces.
+      assertTrue(nm.startOperation(NO_NONCE, 2, createStoppable()));
+      assertFalse(nm.startOperation(NO_NONCE, 3, createStoppable()));
+      // Make sure grace period is counted from recovery time.
+      edge.setValue(17);
+      cleanup.choreForTesting();
+      assertFalse(nm.startOperation(NO_NONCE, 1, createStoppable()));
+      assertFalse(nm.startOperation(NO_NONCE, 3, createStoppable()));
+      edge.setValue(19);
+      cleanup.choreForTesting();
+      assertTrue(nm.startOperation(NO_NONCE, 1, createStoppable()));
+      assertTrue(nm.startOperation(NO_NONCE, 3, createStoppable()));
+    } finally {
+      EnvironmentEdgeManager.reset();
+    }
+  }
+
+  @Test
+  public void testConcurrentAttempts() throws Exception {
+    final ServerNonceManager nm = createManager();
+
+    nm.startOperation(NO_NONCE, 1, createStoppable());
+    TestRunnable tr = new TestRunnable(nm, 1, false, createStoppable());
+    Thread t = tr.start();
+    waitForThreadToBlockOrExit(t);
+    nm.endOperation(NO_NONCE, 1, true); // operation succeeded
+    t.join(); // thread must now unblock and not proceed (result checked inside).
+    tr.propagateError();
+
+    nm.startOperation(NO_NONCE, 2, createStoppable());
+    tr = new TestRunnable(nm, 2, true, createStoppable());
+    t = tr.start();
+    waitForThreadToBlockOrExit(t);
+    nm.endOperation(NO_NONCE, 2, false);
+    t.join(); // thread must now unblock and allow us to proceed (result checked inside).
+    tr.propagateError();
+    nm.endOperation(NO_NONCE, 2, true); // that is to say we should be able to end operation
+
+    nm.startOperation(NO_NONCE, 3, createStoppable());
+    tr = new TestRunnable(nm, 4, true, createStoppable());
+    tr.start().join();  // nonce 3 must have no bearing on nonce 4
+    tr.propagateError();
+  }
+
+  @Test
+  public void testStopWaiting() throws Exception {
+    final ServerNonceManager nm = createManager();
+    nm.setConflictWaitIterationMs(1);
+    Stoppable stoppingStoppable = createStoppable();
+    Mockito.when(stoppingStoppable.isStopped()).thenAnswer(new Answer<Boolean>() {
+      AtomicInteger answer = new AtomicInteger(3);
+      @Override
+      public Boolean answer(InvocationOnMock invocation) throws Throwable {
+        return 0 < answer.decrementAndGet();
+      }
+    });
+
+    nm.startOperation(NO_NONCE, 1, createStoppable());
+    TestRunnable tr = new TestRunnable(nm, 1, null, stoppingStoppable);
+    Thread t = tr.start();
+    waitForThreadToBlockOrExit(t);
+    // thread must eventually throw
+    t.join();
+    tr.propagateError();
+  }
+
+  private void waitForThreadToBlockOrExit(Thread t) throws InterruptedException {
+    for (int i = 9; i >= 0; --i) {
+      if (t.getState() == Thread.State.TIMED_WAITING || t.getState() == Thread.State.WAITING
+          || t.getState() == Thread.State.BLOCKED || t.getState() == Thread.State.TERMINATED) {
+        return;
+      }
+      if (i > 0) Thread.sleep(300);
+    }
+    // Thread didn't block in 3 seconds. What is it doing? Continue the test, we'd rather
+    // have a very strange false positive then false negative due to timing.
+  }
+
+  private static class TestRunnable implements Runnable {
+    public final CountDownLatch startedLatch = new CountDownLatch(1); // It's the final countdown!
+
+    private final ServerNonceManager nm;
+    private final long nonce;
+    private final Boolean expected;
+    private final Stoppable stoppable;
+
+    private Throwable throwable = null;
+
+    public TestRunnable(ServerNonceManager nm, long nonce, Boolean expected, Stoppable stoppable) {
+      this.nm = nm;
+      this.nonce = nonce;
+      this.expected = expected;
+      this.stoppable = stoppable;
+    }
+
+    public void propagateError() throws Exception {
+      if (throwable == null) return;
+      throw new Exception(throwable);
+    }
+
+    public Thread start() {
+      Thread t = new Thread(this);
+      t = Threads.setDaemonThreadRunning(t);
+      try {
+        startedLatch.await();
+      } catch (InterruptedException e) {
+        fail("Unexpected");
+      }
+      return t;
+    }
+
+    @Override
+    public void run() {
+      startedLatch.countDown();
+      boolean shouldThrow = expected == null;
+      boolean hasThrown = true;
+      try {
+        boolean result = nm.startOperation(NO_NONCE, nonce, stoppable);
+        hasThrown = false;
+        if (!shouldThrow) {
+          assertEquals(expected.booleanValue(), result);
+        }
+      } catch (Throwable t) {
+        if (!shouldThrow) {
+          throwable = t;
+        }
+      }
+      if (shouldThrow && !hasThrown) {
+        throwable = new AssertionError("Should have thrown");
+      }
+    }
+  }
+
+  private Stoppable createStoppable() {
+    Stoppable s = Mockito.mock(Stoppable.class);
+    Mockito.when(s.isStopped()).thenReturn(false);
+    return s;
+  }
+
+  private ServerNonceManager createManager() {
+    return createManager(null);
+  }
+
+  private ServerNonceManager createManager(Integer gracePeriod) {
+    Configuration conf = HBaseConfiguration.create();
+    if (gracePeriod != null) {
+      conf.setInt(ServerNonceManager.HASH_NONCE_GRACE_PERIOD_KEY, gracePeriod.intValue());
+    }
+    return new ServerNonceManager(conf);
+  }
+}

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/wal/HLogPerformanceEvaluation.java

@@ -39,6 +39,7 @@ import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.HBaseConfiguration;
 import org.apache.hadoop.hbase.HBaseTestingUtility;
 import org.apache.hadoop.hbase.HColumnDescriptor;
+import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.HTableDescriptor;
 import org.apache.hadoop.hbase.KeyValue;
@@ -104,6 +105,8 @@ public final class HLogPerformanceEvaluation extends Configured implements Tool
       byte[] value = new byte[valueSize];
       Random rand = new Random(Thread.currentThread().getId());
       HLog hlog = region.getLog();
+      ArrayList<UUID> clusters = new ArrayList<UUID>();
+      long nonce = HConstants.NO_NONCE;
 
       try {
         long startTime = System.currentTimeMillis();
@@ -114,8 +117,8 @@ public final class HLogPerformanceEvaluation extends Configured implements Tool
           addFamilyMapToWALEdit(put.getFamilyCellMap(), walEdit);
           HRegionInfo hri = region.getRegionInfo();
           if (this.noSync) {
-            hlog.appendNoSync(hri, hri.getTable(), walEdit, new ArrayList<UUID>(), now, htd,
+            hlog.appendNoSync(hri, hri.getTable(), walEdit, clusters, now, htd,
-              region.getSequenceId());
+              region.getSequenceId(), true, nonce, nonce);
           } else {
             hlog.append(hri, hri.getTable(), walEdit, now, htd, region.getSequenceId());
           }