From 2f1923a8233b0c999494cd4b33f85b70dc5d7b12 Mon Sep 17 00:00:00 2001 From: Phil Yang Date: Thu, 25 May 2017 15:18:58 +0800 Subject: [PATCH] HBASE-15576 Scanning cursor to prevent blocking long time on ResultScanner.next() --- .../hadoop/hbase/client/ClientScanner.java | 15 + .../hadoop/hbase/client/ClientUtil.java | 4 + .../apache/hadoop/hbase/client/Cursor.java | 41 + .../apache/hadoop/hbase/client/Result.java | 45 + .../org/apache/hadoop/hbase/client/Scan.java | 43 + .../hadoop/hbase/client/ScannerCallable.java | 14 +- .../client/ScannerCallableWithReplicas.java | 4 + .../hbase/shaded/protobuf/ProtobufUtil.java | 24 + .../protobuf/generated/ClientProtos.java | 1086 +++++++++++++++-- .../src/main/protobuf/Client.proto | 14 +- .../protobuf/generated/ClientProtos.java | 1058 ++++++++++++++-- hbase-protocol/src/main/protobuf/Client.proto | 14 +- .../hbase/regionserver/RSRpcServices.java | 18 +- .../hbase/regionserver/ScannerContext.java | 13 + .../hbase/regionserver/StoreScanner.java | 1 + .../hbase/regionserver/TestScannerCursor.java | 191 +++ 16 files changed, 2344 insertions(+), 241 deletions(-) create mode 100644 hbase-client/src/main/java/org/apache/hadoop/hbase/client/Cursor.java create mode 100644 hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestScannerCursor.java diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientScanner.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientScanner.java index fa5f8689e37..59cf005cd7a 100644 --- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientScanner.java +++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientScanner.java @@ -499,6 +499,21 @@ public abstract class ClientScanner extends AbstractClientScanner { break; } } + if (cache.isEmpty() && !closed && scan.isNeedCursorResult()) { + if (callable.isHeartbeatMessage() && callable.getCursor() != null) { + // Use cursor row key from server + cache.add(Result.createCursorResult(callable.getCursor())); + break; + } + if (values.length > 0) { + // It is size limit exceed and we need return the last Result's row. + // When user setBatch and the scanner is reopened, the server may return Results that + // user has seen and the last Result can not be seen because the number is not enough. + // So the row keys of results may not be same, we must use the last one. + cache.add(Result.createCursorResult(new Cursor(values[values.length - 1].getRow()))); + break; + } + } if (countdown <= 0) { // we have enough result. closeScannerIfExhausted(regionExhausted); diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientUtil.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientUtil.java index e4a84d5c538..a83908030a2 100644 --- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientUtil.java +++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientUtil.java @@ -27,4 +27,8 @@ public class ClientUtil { public static boolean areScanStartRowAndStopRowEqual(byte[] startRow, byte[] stopRow) { return startRow != null && startRow.length > 0 && Bytes.equals(startRow, stopRow); } + + public static Cursor createCursor(byte[] row) { + return new Cursor(row); + } } diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Cursor.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Cursor.java new file mode 100644 index 00000000000..1d4b4b5c00a --- /dev/null +++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Cursor.java @@ -0,0 +1,41 @@ +/** + * 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.hbase.classification.InterfaceAudience; + +/** + * Scan cursor to tell client where server is scanning + * {@link Scan#setNeedCursorResult(boolean)} + * {@link Result#isCursor()} + * {@link Result#getCursor()} + */ +@InterfaceAudience.Public +public class Cursor { + + private final byte[] row; + + Cursor(byte[] row) { + this.row = row; + } + + public byte[] getRow() { + return row; + } +} diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java index 63aab807a26..94e1b908aac 100644 --- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java +++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java @@ -108,6 +108,8 @@ public class Result implements CellScannable, CellScanner { private final boolean readonly; + private Cursor cursor = null; + /** * Creates an empty Result w/ no KeyValue payload; returns null if you call {@link #rawCells()}. * Use this to represent no results if {@code null} won't do or in old 'mapred' as opposed @@ -173,6 +175,15 @@ public class Result implements CellScannable, CellScanner { return new Result(cells, null, stale, mayHaveMoreCellsInRow); } + public static Result createCursorResult(Cursor cursor) { + return new Result(cursor); + } + + private Result(Cursor cursor) { + this.cursor = cursor; + this.readonly = false; + } + /** Private ctor. Use {@link #create(Cell[])}. */ private Result(Cell[] cells, Boolean exists, boolean stale, boolean mayHaveMoreCellsInRow) { this.cells = cells; @@ -948,4 +959,38 @@ public class Result implements CellScannable, CellScanner { throw new UnsupportedOperationException("Attempting to modify readonly EMPTY_RESULT!"); } } + + /** + * Return true if this Result is a cursor to tell users where the server has scanned. + * In this Result the only meaningful method is {@link #getCursor()}. + * + * {@code + * while (r = scanner.next() && r != null) { + * if(r.isCursor()){ + * // scanning is not end, it is a cursor, save its row key and close scanner if you want, or + * // just continue the loop to call next(). + * } else { + * // just like before + * } + * } + * // scanning is end + * + * } + * {@link Scan#setNeedCursorResult(boolean)} + * {@link Cursor} + * {@link #getCursor()} + */ + public boolean isCursor() { + return cursor != null ; + } + + /** + * Return the cursor if this Result is a cursor result. + * {@link Scan#setNeedCursorResult(boolean)} + * {@link Cursor} + * {@link #isCursor()} + */ + public Cursor getCursor(){ + return cursor; + } } diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Scan.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Scan.java index 2746263b650..639f43e4e87 100644 --- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Scan.java +++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Scan.java @@ -185,6 +185,9 @@ public class Scan extends Query { * Control whether to use pread at server side. */ private ReadType readType = ReadType.DEFAULT; + + private boolean needCursorResult = false; + /** * Create a Scan operation across all rows. */ @@ -272,6 +275,7 @@ public class Scan extends Query { } this.mvccReadPoint = scan.getMvccReadPoint(); this.limit = scan.getLimit(); + this.needCursorResult = scan.isNeedCursorResult(); } /** @@ -1170,4 +1174,43 @@ public class Scan extends Query { Scan resetMvccReadPoint() { return setMvccReadPoint(-1L); } + + /** + * When the server is slow or we scan a table with many deleted data or we use a sparse filter, + * the server will response heartbeat to prevent timeout. However the scanner will return a Result + * only when client can do it. So if there are many heartbeats, the blocking time on + * ResultScanner#next() may be very long, which is not friendly to online services. + * + * Set this to true then you can get a special Result whose #isCursor() returns true and is not + * contains any real data. It only tells you where the server has scanned. You can call next + * to continue scanning or open a new scanner with this row key as start row whenever you want. + * + * Users can get a cursor when and only when there is a response from the server but we can not + * return a Result to users, for example, this response is a heartbeat or there are partial cells + * but users do not allow partial result. + * + * Now the cursor is in row level which means the special Result will only contains a row key. + * {@link Result#isCursor()} + * {@link Result#getCursor()} + * {@link Cursor} + */ + public Scan setNeedCursorResult(boolean needCursorResult) { + this.needCursorResult = needCursorResult; + return this; + } + + public boolean isNeedCursorResult() { + return needCursorResult; + } + + /** + * Create a new Scan with a cursor. It only set the position information like start row key. + * The others (like cfs, stop row, limit) should still be filled in by the user. + * {@link Result#isCursor()} + * {@link Result#getCursor()} + * {@link Cursor} + */ + public static Scan createScanFromCursor(Cursor cursor) { + return new Scan().withStartRow(cursor.getRow()); + } } diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScannerCallable.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScannerCallable.java index ffac566e23e..4227e41eacb 100644 --- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScannerCallable.java +++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScannerCallable.java @@ -87,6 +87,8 @@ public class ScannerCallable extends ClientServiceCallable { */ protected boolean heartbeatMessage = false; + protected Cursor cursor; + // indicate if it is a remote server call protected boolean isRegionServerRemote = true; private long nextCallSeq = 0; @@ -148,7 +150,7 @@ public class ScannerCallable extends ClientServiceCallable { checkIfRegionServerIsRemote(); instantiated = true; } - + cursor = null; // check how often we retry. if (reload) { incRPCRetriesMetrics(scanMetrics, isRegionServerRemote); @@ -242,7 +244,11 @@ public class ScannerCallable extends ClientServiceCallable { response = next(); } long timestamp = System.currentTimeMillis(); - setHeartbeatMessage(response.hasHeartbeatMessage() && response.getHeartbeatMessage()); + boolean isHeartBeat = response.hasHeartbeatMessage() && response.getHeartbeatMessage(); + setHeartbeatMessage(isHeartBeat); + if (isHeartBeat && scan.isNeedCursorResult() && response.hasCursor()) { + cursor = ProtobufUtil.toCursor(response.getCursor()); + } Result[] rrs = ResponseConverter.getResults(getRpcControllerCellScanner(), response); if (logScannerActivity) { long now = System.currentTimeMillis(); @@ -288,6 +294,10 @@ public class ScannerCallable extends ClientServiceCallable { return heartbeatMessage; } + public Cursor getCursor() { + return cursor; + } + private void setHeartbeatMessage(boolean heartbeatMessage) { this.heartbeatMessage = heartbeatMessage; } diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScannerCallableWithReplicas.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScannerCallableWithReplicas.java index bcd5d21d912..0cdd4ddbef4 100644 --- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScannerCallableWithReplicas.java +++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScannerCallableWithReplicas.java @@ -302,6 +302,10 @@ class ScannerCallableWithReplicas implements RetryingCallable { return currentScannerCallable != null && currentScannerCallable.isHeartbeatMessage(); } + public Cursor getCursor() { + return currentScannerCallable != null ? currentScannerCallable.getCursor() : null; + } + private void addCallsForCurrentReplica( ResultBoundedCompletionService> cs, RegionLocations rl) { RetryingRPC retryingOnReplica = new RetryingRPC(currentScannerCallable); diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java index 8a4e4124307..5c4dd550219 100644 --- a/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java +++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java @@ -65,6 +65,7 @@ import org.apache.hadoop.hbase.client.Append; import org.apache.hadoop.hbase.client.ClientUtil; import org.apache.hadoop.hbase.client.CompactionState; import org.apache.hadoop.hbase.client.Consistency; +import org.apache.hadoop.hbase.client.Cursor; import org.apache.hadoop.hbase.client.Delete; import org.apache.hadoop.hbase.client.Durability; import org.apache.hadoop.hbase.client.Get; @@ -185,6 +186,7 @@ import org.apache.hadoop.hbase.util.Methods; import org.apache.hadoop.hbase.util.NonceKey; import org.apache.hadoop.hbase.util.VersionInfo; import org.apache.hadoop.ipc.RemoteException; +import org.apache.hadoop.mapreduce.tools.CLI; /** * Protobufs utility. @@ -1099,6 +1101,9 @@ public final class ProtobufUtil { if (scan.getReadType() != Scan.ReadType.DEFAULT) { scanBuilder.setReadType(toReadType(scan.getReadType())); } + if (scan.isNeedCursorResult()) { + scanBuilder.setNeedCursorResult(true); + } return scanBuilder.build(); } @@ -1207,9 +1212,28 @@ public final class ProtobufUtil { } else if (proto.hasReadType()) { scan.setReadType(toReadType(proto.getReadType())); } + if (proto.getNeedCursorResult()) { + scan.setNeedCursorResult(true); + } return scan; } + public static ClientProtos.Cursor toCursor(Cursor cursor) { + ClientProtos.Cursor.Builder builder = ClientProtos.Cursor.newBuilder(); + ClientProtos.Cursor.newBuilder().setRow(ByteString.copyFrom(cursor.getRow())); + return builder.build(); + } + + public static ClientProtos.Cursor toCursor(Cell cell) { + return ClientProtos.Cursor.newBuilder() + .setRow(ByteString.copyFrom(cell.getRowArray(), cell.getRowOffset(), cell.getRowLength())) + .build(); + } + + public static Cursor toCursor(ClientProtos.Cursor cursor) { + return ClientUtil.createCursor(cursor.getRow().toByteArray()); + } + /** * Create a protocol buffer Get based on a client Get. * diff --git a/hbase-protocol-shaded/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/generated/ClientProtos.java b/hbase-protocol-shaded/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/generated/ClientProtos.java index a5f81e62731..b93f6cc7e04 100644 --- a/hbase-protocol-shaded/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/generated/ClientProtos.java +++ b/hbase-protocol-shaded/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/generated/ClientProtos.java @@ -14598,6 +14598,15 @@ public final class ClientProtos { * optional .hbase.pb.Scan.ReadType readType = 23 [default = DEFAULT]; */ org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Scan.ReadType getReadType(); + + /** + * optional bool need_cursor_result = 24 [default = false]; + */ + boolean hasNeedCursorResult(); + /** + * optional bool need_cursor_result = 24 [default = false]; + */ + boolean getNeedCursorResult(); } /** * 
@@ -14642,6 +14651,7 @@ public final class ClientProtos {
       includeStartRow_ = true;
       includeStopRow_ = false;
       readType_ = 0;
+      needCursorResult_ = false;
     }
 
     @java.lang.Override
@@ -14827,6 +14837,11 @@ public final class ClientProtos {
               }
               break;
             }
+            case 192: {
+              bitField0_ |= 0x00100000;
+              needCursorResult_ = input.readBool();
+              break;
+            }
           }
         }
       } catch (org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException e) {
@@ -15387,6 +15402,21 @@ public final class ClientProtos {
       return result == null ? org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Scan.ReadType.DEFAULT : result;
     }
 
+    public static final int NEED_CURSOR_RESULT_FIELD_NUMBER = 24;
+    private boolean needCursorResult_;
+    /**
+     * optional bool need_cursor_result = 24 [default = false];
+     */
+    public boolean hasNeedCursorResult() {
+      return ((bitField0_ & 0x00100000) == 0x00100000);
+    }
+    /**
+     * optional bool need_cursor_result = 24 [default = false];
+     */
+    public boolean getNeedCursorResult() {
+      return needCursorResult_;
+    }
+
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
       byte isInitialized = memoizedIsInitialized;
@@ -15492,6 +15522,9 @@ public final class ClientProtos {
       if (((bitField0_ & 0x00080000) == 0x00080000)) {
         output.writeEnum(23, readType_);
       }
+      if (((bitField0_ & 0x00100000) == 0x00100000)) {
+        output.writeBool(24, needCursorResult_);
+      }
       unknownFields.writeTo(output);
     }
 
@@ -15592,6 +15625,10 @@ public final class ClientProtos {
         size += org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedOutputStream
           .computeEnumSize(23, readType_);
       }
+      if (((bitField0_ & 0x00100000) == 0x00100000)) {
+        size += org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedOutputStream
+          .computeBoolSize(24, needCursorResult_);
+      }
       size += unknownFields.getSerializedSize();
       memoizedSize = size;
       return size;
@@ -15713,6 +15750,11 @@ public final class ClientProtos {
       if (hasReadType()) {
         result = result && readType_ == other.readType_;
       }
+      result = result && (hasNeedCursorResult() == other.hasNeedCursorResult());
+      if (hasNeedCursorResult()) {
+        result = result && (getNeedCursorResult()
+            == other.getNeedCursorResult());
+      }
       result = result && unknownFields.equals(other.unknownFields);
       return result;
     }
@@ -15825,6 +15867,11 @@ public final class ClientProtos {
         hash = (37 * hash) + READTYPE_FIELD_NUMBER;
         hash = (53 * hash) + readType_;
       }
+      if (hasNeedCursorResult()) {
+        hash = (37 * hash) + NEED_CURSOR_RESULT_FIELD_NUMBER;
+        hash = (53 * hash) + org.apache.hadoop.hbase.shaded.com.google.protobuf.Internal.hashBoolean(
+            getNeedCursorResult());
+      }
       hash = (29 * hash) + unknownFields.hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -16024,6 +16071,8 @@ public final class ClientProtos {
         bitField0_ = (bitField0_ & ~0x00200000);
         readType_ = 0;
         bitField0_ = (bitField0_ & ~0x00400000);
+        needCursorResult_ = false;
+        bitField0_ = (bitField0_ & ~0x00800000);
         return this;
       }
 
@@ -16163,6 +16212,10 @@ public final class ClientProtos {
           to_bitField0_ |= 0x00080000;
         }
         result.readType_ = readType_;
+        if (((from_bitField0_ & 0x00800000) == 0x00800000)) {
+          to_bitField0_ |= 0x00100000;
+        }
+        result.needCursorResult_ = needCursorResult_;
         result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
@@ -16343,6 +16396,9 @@ public final class ClientProtos {
         if (other.hasReadType()) {
           setReadType(other.getReadType());
         }
+        if (other.hasNeedCursorResult()) {
+          setNeedCursorResult(other.getNeedCursorResult());
+        }
         this.mergeUnknownFields(other.unknownFields);
         onChanged();
         return this;
@@ -17952,6 +18008,38 @@ public final class ClientProtos {
         onChanged();
         return this;
       }
+
+      private boolean needCursorResult_ ;
+      /**
+       * optional bool need_cursor_result = 24 [default = false];
+       */
+      public boolean hasNeedCursorResult() {
+        return ((bitField0_ & 0x00800000) == 0x00800000);
+      }
+      /**
+       * optional bool need_cursor_result = 24 [default = false];
+       */
+      public boolean getNeedCursorResult() {
+        return needCursorResult_;
+      }
+      /**
+       * optional bool need_cursor_result = 24 [default = false];
+       */
+      public Builder setNeedCursorResult(boolean value) {
+        bitField0_ |= 0x00800000;
+        needCursorResult_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * optional bool need_cursor_result = 24 [default = false];
+       */
+      public Builder clearNeedCursorResult() {
+        bitField0_ = (bitField0_ & ~0x00800000);
+        needCursorResult_ = false;
+        onChanged();
+        return this;
+      }
       public final Builder setUnknownFields(
           final org.apache.hadoop.hbase.shaded.com.google.protobuf.UnknownFieldSet unknownFields) {
         return super.setUnknownFields(unknownFields);
@@ -19644,6 +19732,485 @@ public final class ClientProtos {
 
   }
 
+  public interface CursorOrBuilder extends
+      // @@protoc_insertion_point(interface_extends:hbase.pb.Cursor)
+      org.apache.hadoop.hbase.shaded.com.google.protobuf.MessageOrBuilder {
+
+    /**
+     * optional bytes row = 1;
+     */
+    boolean hasRow();
+    /**
+     * optional bytes row = 1;
+     */
+    org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString getRow();
+  }
+  /**
+   * 
+   **
+   * Scan cursor to tell client where we are scanning.
+   * 

+   *
+   * Protobuf type {@code hbase.pb.Cursor}
+   */
+  public  static final class Cursor extends
+      org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3 implements
+      // @@protoc_insertion_point(message_implements:hbase.pb.Cursor)
+      CursorOrBuilder {
+    // Use Cursor.newBuilder() to construct.
+    private Cursor(org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.Builder builder) {
+      super(builder);
+    }
+    private Cursor() {
+      row_ = org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString.EMPTY;
+    }
+
+    @java.lang.Override
+    public final org.apache.hadoop.hbase.shaded.com.google.protobuf.UnknownFieldSet
+    getUnknownFields() {
+      return this.unknownFields;
+    }
+    private Cursor(
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedInputStream input,
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException {
+      this();
+      int mutable_bitField0_ = 0;
+      org.apache.hadoop.hbase.shaded.com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.UnknownFieldSet.newBuilder();
+      try {
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            default: {
+              if (!parseUnknownField(input, unknownFields,
+                                     extensionRegistry, tag)) {
+                done = true;
+              }
+              break;
+            }
+            case 10: {
+              bitField0_ |= 0x00000001;
+              row_ = input.readBytes();
+              break;
+            }
+          }
+        }
+      } catch (org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException e) {
+        throw e.setUnfinishedMessage(this);
+      } catch (java.io.IOException e) {
+        throw new org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException(
+            e).setUnfinishedMessage(this);
+      } finally {
+        this.unknownFields = unknownFields.build();
+        makeExtensionsImmutable();
+      }
+    }
+    public static final org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.internal_static_hbase_pb_Cursor_descriptor;
+    }
+
+    protected org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.internal_static_hbase_pb_Cursor_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.class, org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.Builder.class);
+    }
+
+    private int bitField0_;
+    public static final int ROW_FIELD_NUMBER = 1;
+    private org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString row_;
+    /**
+     * optional bytes row = 1;
+     */
+    public boolean hasRow() {
+      return ((bitField0_ & 0x00000001) == 0x00000001);
+    }
+    /**
+     * optional bytes row = 1;
+     */
+    public org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString getRow() {
+      return row_;
+    }
+
+    private byte memoizedIsInitialized = -1;
+    public final boolean isInitialized() {
+      byte isInitialized = memoizedIsInitialized;
+      if (isInitialized == 1) return true;
+      if (isInitialized == 0) return false;
+
+      memoizedIsInitialized = 1;
+      return true;
+    }
+
+    public void writeTo(org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedOutputStream output)
+                        throws java.io.IOException {
+      if (((bitField0_ & 0x00000001) == 0x00000001)) {
+        output.writeBytes(1, row_);
+      }
+      unknownFields.writeTo(output);
+    }
+
+    public int getSerializedSize() {
+      int size = memoizedSize;
+      if (size != -1) return size;
+
+      size = 0;
+      if (((bitField0_ & 0x00000001) == 0x00000001)) {
+        size += org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedOutputStream
+          .computeBytesSize(1, row_);
+      }
+      size += unknownFields.getSerializedSize();
+      memoizedSize = size;
+      return size;
+    }
+
+    private static final long serialVersionUID = 0L;
+    @java.lang.Override
+    public boolean equals(final java.lang.Object obj) {
+      if (obj == this) {
+       return true;
+      }
+      if (!(obj instanceof org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor)) {
+        return super.equals(obj);
+      }
+      org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor other = (org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor) obj;
+
+      boolean result = true;
+      result = result && (hasRow() == other.hasRow());
+      if (hasRow()) {
+        result = result && getRow()
+            .equals(other.getRow());
+      }
+      result = result && unknownFields.equals(other.unknownFields);
+      return result;
+    }
+
+    @java.lang.Override
+    public int hashCode() {
+      if (memoizedHashCode != 0) {
+        return memoizedHashCode;
+      }
+      int hash = 41;
+      hash = (19 * hash) + getDescriptor().hashCode();
+      if (hasRow()) {
+        hash = (37 * hash) + ROW_FIELD_NUMBER;
+        hash = (53 * hash) + getRow().hashCode();
+      }
+      hash = (29 * hash) + unknownFields.hashCode();
+      memoizedHashCode = hash;
+      return hash;
+    }
+
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parseFrom(
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString data)
+        throws org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data);
+    }
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parseFrom(
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString data,
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data, extensionRegistry);
+    }
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parseFrom(byte[] data)
+        throws org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data);
+    }
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parseFrom(
+        byte[] data,
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data, extensionRegistry);
+    }
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parseFrom(java.io.InputStream input)
+        throws java.io.IOException {
+      return org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3
+          .parseWithIOException(PARSER, input);
+    }
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parseFrom(
+        java.io.InputStream input,
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3
+          .parseWithIOException(PARSER, input, extensionRegistry);
+    }
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parseDelimitedFrom(java.io.InputStream input)
+        throws java.io.IOException {
+      return org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3
+          .parseDelimitedWithIOException(PARSER, input);
+    }
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parseDelimitedFrom(
+        java.io.InputStream input,
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3
+          .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+    }
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parseFrom(
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedInputStream input)
+        throws java.io.IOException {
+      return org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3
+          .parseWithIOException(PARSER, input);
+    }
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parseFrom(
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedInputStream input,
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3
+          .parseWithIOException(PARSER, input, extensionRegistry);
+    }
+
+    public Builder newBuilderForType() { return newBuilder(); }
+    public static Builder newBuilder() {
+      return DEFAULT_INSTANCE.toBuilder();
+    }
+    public static Builder newBuilder(org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor prototype) {
+      return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+    }
+    public Builder toBuilder() {
+      return this == DEFAULT_INSTANCE
+          ? new Builder() : new Builder().mergeFrom(this);
+    }
+
+    @java.lang.Override
+    protected Builder newBuilderForType(
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      Builder builder = new Builder(parent);
+      return builder;
+    }
+    /**
+     * 
+     **
+     * Scan cursor to tell client where we are scanning.
+     * 

+     *
+     * Protobuf type {@code hbase.pb.Cursor}
+     */
+    public static final class Builder extends
+        org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.Builder implements
+        // @@protoc_insertion_point(builder_implements:hbase.pb.Cursor)
+        org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.CursorOrBuilder {
+      public static final org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.Descriptor
+          getDescriptor() {
+        return org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.internal_static_hbase_pb_Cursor_descriptor;
+      }
+
+      protected org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+          internalGetFieldAccessorTable() {
+        return org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.internal_static_hbase_pb_Cursor_fieldAccessorTable
+            .ensureFieldAccessorsInitialized(
+                org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.class, org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.Builder.class);
+      }
+
+      // Construct using org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.newBuilder()
+      private Builder() {
+        maybeForceBuilderInitialization();
+      }
+
+      private Builder(
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        super(parent);
+        maybeForceBuilderInitialization();
+      }
+      private void maybeForceBuilderInitialization() {
+        if (org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3
+                .alwaysUseFieldBuilders) {
+        }
+      }
+      public Builder clear() {
+        super.clear();
+        row_ = org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString.EMPTY;
+        bitField0_ = (bitField0_ & ~0x00000001);
+        return this;
+      }
+
+      public org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.Descriptor
+          getDescriptorForType() {
+        return org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.internal_static_hbase_pb_Cursor_descriptor;
+      }
+
+      public org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor getDefaultInstanceForType() {
+        return org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.getDefaultInstance();
+      }
+
+      public org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor build() {
+        org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor result = buildPartial();
+        if (!result.isInitialized()) {
+          throw newUninitializedMessageException(result);
+        }
+        return result;
+      }
+
+      public org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor buildPartial() {
+        org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor result = new org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor(this);
+        int from_bitField0_ = bitField0_;
+        int to_bitField0_ = 0;
+        if (((from_bitField0_ & 0x00000001) == 0x00000001)) {
+          to_bitField0_ |= 0x00000001;
+        }
+        result.row_ = row_;
+        result.bitField0_ = to_bitField0_;
+        onBuilt();
+        return result;
+      }
+
+      public Builder clone() {
+        return (Builder) super.clone();
+      }
+      public Builder setField(
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.FieldDescriptor field,
+          Object value) {
+        return (Builder) super.setField(field, value);
+      }
+      public Builder clearField(
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.FieldDescriptor field) {
+        return (Builder) super.clearField(field);
+      }
+      public Builder clearOneof(
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+        return (Builder) super.clearOneof(oneof);
+      }
+      public Builder setRepeatedField(
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.FieldDescriptor field,
+          int index, Object value) {
+        return (Builder) super.setRepeatedField(field, index, value);
+      }
+      public Builder addRepeatedField(
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.FieldDescriptor field,
+          Object value) {
+        return (Builder) super.addRepeatedField(field, value);
+      }
+      public Builder mergeFrom(org.apache.hadoop.hbase.shaded.com.google.protobuf.Message other) {
+        if (other instanceof org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor) {
+          return mergeFrom((org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor)other);
+        } else {
+          super.mergeFrom(other);
+          return this;
+        }
+      }
+
+      public Builder mergeFrom(org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor other) {
+        if (other == org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.getDefaultInstance()) return this;
+        if (other.hasRow()) {
+          setRow(other.getRow());
+        }
+        this.mergeUnknownFields(other.unknownFields);
+        onChanged();
+        return this;
+      }
+
+      public final boolean isInitialized() {
+        return true;
+      }
+
+      public Builder mergeFrom(
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedInputStream input,
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+          throws java.io.IOException {
+        org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor parsedMessage = null;
+        try {
+          parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        } catch (org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException e) {
+          parsedMessage = (org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor) e.getUnfinishedMessage();
+          throw e.unwrapIOException();
+        } finally {
+          if (parsedMessage != null) {
+            mergeFrom(parsedMessage);
+          }
+        }
+        return this;
+      }
+      private int bitField0_;
+
+      private org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString row_ = org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString.EMPTY;
+      /**
+       * optional bytes row = 1;
+       */
+      public boolean hasRow() {
+        return ((bitField0_ & 0x00000001) == 0x00000001);
+      }
+      /**
+       * optional bytes row = 1;
+       */
+      public org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString getRow() {
+        return row_;
+      }
+      /**
+       * optional bytes row = 1;
+       */
+      public Builder setRow(org.apache.hadoop.hbase.shaded.com.google.protobuf.ByteString value) {
+        if (value == null) {
+    throw new NullPointerException();
+  }
+  bitField0_ |= 0x00000001;
+        row_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * optional bytes row = 1;
+       */
+      public Builder clearRow() {
+        bitField0_ = (bitField0_ & ~0x00000001);
+        row_ = getDefaultInstance().getRow();
+        onChanged();
+        return this;
+      }
+      public final Builder setUnknownFields(
+          final org.apache.hadoop.hbase.shaded.com.google.protobuf.UnknownFieldSet unknownFields) {
+        return super.setUnknownFields(unknownFields);
+      }
+
+      public final Builder mergeUnknownFields(
+          final org.apache.hadoop.hbase.shaded.com.google.protobuf.UnknownFieldSet unknownFields) {
+        return super.mergeUnknownFields(unknownFields);
+      }
+
+
+      // @@protoc_insertion_point(builder_scope:hbase.pb.Cursor)
+    }
+
+    // @@protoc_insertion_point(class_scope:hbase.pb.Cursor)
+    private static final org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor DEFAULT_INSTANCE;
+    static {
+      DEFAULT_INSTANCE = new org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor();
+    }
+
+    public static org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor getDefaultInstance() {
+      return DEFAULT_INSTANCE;
+    }
+
+    @java.lang.Deprecated public static final org.apache.hadoop.hbase.shaded.com.google.protobuf.Parser
+        PARSER = new org.apache.hadoop.hbase.shaded.com.google.protobuf.AbstractParser() {
+      public Cursor parsePartialFrom(
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedInputStream input,
+          org.apache.hadoop.hbase.shaded.com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+          throws org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException {
+          return new Cursor(input, extensionRegistry);
+      }
+    };
+
+    public static org.apache.hadoop.hbase.shaded.com.google.protobuf.Parser parser() {
+      return PARSER;
+    }
+
+    @java.lang.Override
+    public org.apache.hadoop.hbase.shaded.com.google.protobuf.Parser getParserForType() {
+      return PARSER;
+    }
+
+    public org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor getDefaultInstanceForType() {
+      return DEFAULT_INSTANCE;
+    }
+
+  }
+
   public interface ScanResponseOrBuilder extends
       // @@protoc_insertion_point(interface_extends:hbase.pb.ScanResponse)
       org.apache.hadoop.hbase.shaded.com.google.protobuf.MessageOrBuilder {
@@ -19919,6 +20486,34 @@ public final class ClientProtos {
      * optional uint64 mvcc_read_point = 11 [default = 0];
      */
     long getMvccReadPoint();
+
+    /**
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     *
+     * optional .hbase.pb.Cursor cursor = 12;
+     */
+    boolean hasCursor();
+    /**
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     *
+     * optional .hbase.pb.Cursor cursor = 12;
+     */
+    org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor getCursor();
+    /**
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     *
+     * optional .hbase.pb.Cursor cursor = 12;
+     */
+    org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.CursorOrBuilder getCursorOrBuilder();
   }
   /**
    * 
@@ -20077,6 +20672,19 @@ public final class ClientProtos {
               mvccReadPoint_ = input.readUInt64();
               break;
             }
+            case 98: {
+              org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.Builder subBuilder = null;
+              if (((bitField0_ & 0x00000100) == 0x00000100)) {
+                subBuilder = cursor_.toBuilder();
+              }
+              cursor_ = input.readMessage(org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.PARSER, extensionRegistry);
+              if (subBuilder != null) {
+                subBuilder.mergeFrom(cursor_);
+                cursor_ = subBuilder.buildPartial();
+              }
+              bitField0_ |= 0x00000100;
+              break;
+            }
           }
         }
       } catch (org.apache.hadoop.hbase.shaded.com.google.protobuf.InvalidProtocolBufferException e) {
@@ -20462,6 +21070,42 @@ public final class ClientProtos {
       return mvccReadPoint_;
     }
 
+    public static final int CURSOR_FIELD_NUMBER = 12;
+    private org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor cursor_;
+    /**
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     *
+     * optional .hbase.pb.Cursor cursor = 12;
+     */
+    public boolean hasCursor() {
+      return ((bitField0_ & 0x00000100) == 0x00000100);
+    }
+    /**
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     *
+     * optional .hbase.pb.Cursor cursor = 12;
+     */
+    public org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor getCursor() {
+      return cursor_ == null ? org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.getDefaultInstance() : cursor_;
+    }
+    /**
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     *
+     * optional .hbase.pb.Cursor cursor = 12;
+     */
+    public org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.CursorOrBuilder getCursorOrBuilder() {
+      return cursor_ == null ? org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.getDefaultInstance() : cursor_;
+    }
+
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
       byte isInitialized = memoizedIsInitialized;
@@ -20507,6 +21151,9 @@ public final class ClientProtos {
       if (((bitField0_ & 0x00000080) == 0x00000080)) {
         output.writeUInt64(11, mvccReadPoint_);
       }
+      if (((bitField0_ & 0x00000100) == 0x00000100)) {
+        output.writeMessage(12, getCursor());
+      }
       unknownFields.writeTo(output);
     }
 
@@ -20566,6 +21213,10 @@ public final class ClientProtos {
         size += org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedOutputStream
           .computeUInt64Size(11, mvccReadPoint_);
       }
+      if (((bitField0_ & 0x00000100) == 0x00000100)) {
+        size += org.apache.hadoop.hbase.shaded.com.google.protobuf.CodedOutputStream
+          .computeMessageSize(12, getCursor());
+      }
       size += unknownFields.getSerializedSize();
       memoizedSize = size;
       return size;
@@ -20629,6 +21280,11 @@ public final class ClientProtos {
         result = result && (getMvccReadPoint()
             == other.getMvccReadPoint());
       }
+      result = result && (hasCursor() == other.hasCursor());
+      if (hasCursor()) {
+        result = result && getCursor()
+            .equals(other.getCursor());
+      }
       result = result && unknownFields.equals(other.unknownFields);
       return result;
     }
@@ -20690,6 +21346,10 @@ public final class ClientProtos {
         hash = (53 * hash) + org.apache.hadoop.hbase.shaded.com.google.protobuf.Internal.hashLong(
             getMvccReadPoint());
       }
+      if (hasCursor()) {
+        hash = (37 * hash) + CURSOR_FIELD_NUMBER;
+        hash = (53 * hash) + getCursor().hashCode();
+      }
       hash = (29 * hash) + unknownFields.hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -20812,6 +21472,7 @@ public final class ClientProtos {
                 .alwaysUseFieldBuilders) {
           getResultsFieldBuilder();
           getScanMetricsFieldBuilder();
+          getCursorFieldBuilder();
         }
       }
       public Builder clear() {
@@ -20846,6 +21507,12 @@ public final class ClientProtos {
         bitField0_ = (bitField0_ & ~0x00000200);
         mvccReadPoint_ = 0L;
         bitField0_ = (bitField0_ & ~0x00000400);
+        if (cursorBuilder_ == null) {
+          cursor_ = null;
+        } else {
+          cursorBuilder_.clear();
+        }
+        bitField0_ = (bitField0_ & ~0x00000800);
         return this;
       }
 
@@ -20925,6 +21592,14 @@ public final class ClientProtos {
           to_bitField0_ |= 0x00000080;
         }
         result.mvccReadPoint_ = mvccReadPoint_;
+        if (((from_bitField0_ & 0x00000800) == 0x00000800)) {
+          to_bitField0_ |= 0x00000100;
+        }
+        if (cursorBuilder_ == null) {
+          result.cursor_ = cursor_;
+        } else {
+          result.cursor_ = cursorBuilder_.build();
+        }
         result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
@@ -21037,6 +21712,9 @@ public final class ClientProtos {
         if (other.hasMvccReadPoint()) {
           setMvccReadPoint(other.getMvccReadPoint());
         }
+        if (other.hasCursor()) {
+          mergeCursor(other.getCursor());
+        }
         this.mergeUnknownFields(other.unknownFields);
         onChanged();
         return this;
@@ -22156,6 +22834,169 @@ public final class ClientProtos {
         onChanged();
         return this;
       }
+
+      private org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor cursor_ = null;
+      private org.apache.hadoop.hbase.shaded.com.google.protobuf.SingleFieldBuilderV3<
+          org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor, org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.Builder, org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.CursorOrBuilder> cursorBuilder_;
+      /**
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       *
+       * optional .hbase.pb.Cursor cursor = 12;
+       */
+      public boolean hasCursor() {
+        return ((bitField0_ & 0x00000800) == 0x00000800);
+      }
+      /**
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       *
+       * optional .hbase.pb.Cursor cursor = 12;
+       */
+      public org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor getCursor() {
+        if (cursorBuilder_ == null) {
+          return cursor_ == null ? org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.getDefaultInstance() : cursor_;
+        } else {
+          return cursorBuilder_.getMessage();
+        }
+      }
+      /**
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       *
+       * optional .hbase.pb.Cursor cursor = 12;
+       */
+      public Builder setCursor(org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor value) {
+        if (cursorBuilder_ == null) {
+          if (value == null) {
+            throw new NullPointerException();
+          }
+          cursor_ = value;
+          onChanged();
+        } else {
+          cursorBuilder_.setMessage(value);
+        }
+        bitField0_ |= 0x00000800;
+        return this;
+      }
+      /**
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       *
+       * optional .hbase.pb.Cursor cursor = 12;
+       */
+      public Builder setCursor(
+          org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.Builder builderForValue) {
+        if (cursorBuilder_ == null) {
+          cursor_ = builderForValue.build();
+          onChanged();
+        } else {
+          cursorBuilder_.setMessage(builderForValue.build());
+        }
+        bitField0_ |= 0x00000800;
+        return this;
+      }
+      /**
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       *
+       * optional .hbase.pb.Cursor cursor = 12;
+       */
+      public Builder mergeCursor(org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor value) {
+        if (cursorBuilder_ == null) {
+          if (((bitField0_ & 0x00000800) == 0x00000800) &&
+              cursor_ != null &&
+              cursor_ != org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.getDefaultInstance()) {
+            cursor_ =
+              org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.newBuilder(cursor_).mergeFrom(value).buildPartial();
+          } else {
+            cursor_ = value;
+          }
+          onChanged();
+        } else {
+          cursorBuilder_.mergeFrom(value);
+        }
+        bitField0_ |= 0x00000800;
+        return this;
+      }
+      /**
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       *
+       * optional .hbase.pb.Cursor cursor = 12;
+       */
+      public Builder clearCursor() {
+        if (cursorBuilder_ == null) {
+          cursor_ = null;
+          onChanged();
+        } else {
+          cursorBuilder_.clear();
+        }
+        bitField0_ = (bitField0_ & ~0x00000800);
+        return this;
+      }
+      /**
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       *
+       * optional .hbase.pb.Cursor cursor = 12;
+       */
+      public org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.Builder getCursorBuilder() {
+        bitField0_ |= 0x00000800;
+        onChanged();
+        return getCursorFieldBuilder().getBuilder();
+      }
+      /**
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       *
+       * optional .hbase.pb.Cursor cursor = 12;
+       */
+      public org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.CursorOrBuilder getCursorOrBuilder() {
+        if (cursorBuilder_ != null) {
+          return cursorBuilder_.getMessageOrBuilder();
+        } else {
+          return cursor_ == null ?
+              org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.getDefaultInstance() : cursor_;
+        }
+      }
+      /**
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       *
+       * optional .hbase.pb.Cursor cursor = 12;
+       */
+      private org.apache.hadoop.hbase.shaded.com.google.protobuf.SingleFieldBuilderV3<
+          org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor, org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.Builder, org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.CursorOrBuilder>
+          getCursorFieldBuilder() {
+        if (cursorBuilder_ == null) {
+          cursorBuilder_ = new org.apache.hadoop.hbase.shaded.com.google.protobuf.SingleFieldBuilderV3<
+              org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor, org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.Cursor.Builder, org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.CursorOrBuilder>(
+                  getCursor(),
+                  getParentForChildren(),
+                  isClean());
+          cursor_ = null;
+        }
+        return cursorBuilder_;
+      }
       public final Builder setUnknownFields(
           final org.apache.hadoop.hbase.shaded.com.google.protobuf.UnknownFieldSet unknownFields) {
         return super.setUnknownFields(unknownFields);
@@ -40988,6 +41829,11 @@ public final class ClientProtos {
   private static final 
     org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
       internal_static_hbase_pb_ScanRequest_fieldAccessorTable;
+  private static final org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.Descriptor
+    internal_static_hbase_pb_Cursor_descriptor;
+  private static final
+    org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_hbase_pb_Cursor_fieldAccessorTable;
   private static final org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.Descriptor
     internal_static_hbase_pb_ScanResponse_descriptor;
   private static final 
@@ -41157,7 +42003,7 @@ public final class ClientProtos {
       "tion\030\003 \001(\0132\023.hbase.pb.Condition\022\023\n\013nonce" +
       "_group\030\004 \001(\004\"E\n\016MutateResponse\022 \n\006result" +
       "\030\001 \001(\0132\020.hbase.pb.Result\022\021\n\tprocessed\030\002 " +
-      "\001(\010\"\203\006\n\004Scan\022 \n\006column\030\001 \003(\0132\020.hbase.pb." +
+      "\001(\010\"\246\006\n\004Scan\022 \n\006column\030\001 \003(\0132\020.hbase.pb." +
       "Column\022*\n\tattribute\030\002 \003(\0132\027.hbase.pb.Nam" +
       "eBytesPair\022\021\n\tstart_row\030\003 \001(\014\022\020\n\010stop_ro" +
       "w\030\004 \001(\014\022 \n\006filter\030\005 \001(\0132\020.hbase.pb.Filte" +
@@ -41175,99 +42021,101 @@ public final class ClientProtos {
       "nt\030\024 \001(\004:\0010\022\037\n\021include_start_row\030\025 \001(\010:\004" +
       "true\022\037\n\020include_stop_row\030\026 \001(\010:\005false\0222\n" +
       "\010readType\030\027 \001(\0162\027.hbase.pb.Scan.ReadType" +
-      ":\007DEFAULT\".\n\010ReadType\022\013\n\007DEFAULT\020\000\022\n\n\006ST" +
-      "REAM\020\001\022\t\n\005PREAD\020\002\"\300\002\n\013ScanRequest\022)\n\006reg" +
-      "ion\030\001 \001(\0132\031.hbase.pb.RegionSpecifier\022\034\n\004" +
-      "scan\030\002 \001(\0132\016.hbase.pb.Scan\022\022\n\nscanner_id" +
-      "\030\003 \001(\004\022\026\n\016number_of_rows\030\004 \001(\r\022\025\n\rclose_" +
-      "scanner\030\005 \001(\010\022\025\n\rnext_call_seq\030\006 \001(\004\022\037\n\027" +
-      "client_handles_partials\030\007 \001(\010\022!\n\031client_",
-      "handles_heartbeats\030\010 \001(\010\022\032\n\022track_scan_m" +
-      "etrics\030\t \001(\010\022\024\n\005renew\030\n \001(\010:\005false\022\030\n\rli" +
-      "mit_of_rows\030\013 \001(\r:\0010\"\266\002\n\014ScanResponse\022\030\n" +
-      "\020cells_per_result\030\001 \003(\r\022\022\n\nscanner_id\030\002 " +
-      "\001(\004\022\024\n\014more_results\030\003 \001(\010\022\013\n\003ttl\030\004 \001(\r\022!" +
-      "\n\007results\030\005 \003(\0132\020.hbase.pb.Result\022\r\n\005sta" +
-      "le\030\006 \001(\010\022\037\n\027partial_flag_per_result\030\007 \003(" +
-      "\010\022\036\n\026more_results_in_region\030\010 \001(\010\022\031\n\021hea" +
-      "rtbeat_message\030\t \001(\010\022+\n\014scan_metrics\030\n \001" +
-      "(\0132\025.hbase.pb.ScanMetrics\022\032\n\017mvcc_read_p",
-      "oint\030\013 \001(\004:\0010\"\240\002\n\024BulkLoadHFileRequest\022)" +
-      "\n\006region\030\001 \002(\0132\031.hbase.pb.RegionSpecifie" +
-      "r\022>\n\013family_path\030\002 \003(\0132).hbase.pb.BulkLo" +
-      "adHFileRequest.FamilyPath\022\026\n\016assign_seq_" +
-      "num\030\003 \001(\010\022+\n\010fs_token\030\004 \001(\0132\031.hbase.pb.D" +
-      "elegationToken\022\022\n\nbulk_token\030\005 \001(\t\022\030\n\tco" +
-      "py_file\030\006 \001(\010:\005false\032*\n\nFamilyPath\022\016\n\006fa" +
-      "mily\030\001 \002(\014\022\014\n\004path\030\002 \002(\t\"\'\n\025BulkLoadHFil" +
-      "eResponse\022\016\n\006loaded\030\001 \002(\010\"V\n\017DelegationT" +
-      "oken\022\022\n\nidentifier\030\001 \001(\014\022\020\n\010password\030\002 \001",
-      "(\014\022\014\n\004kind\030\003 \001(\t\022\017\n\007service\030\004 \001(\t\"l\n\026Pre" +
-      "pareBulkLoadRequest\022\'\n\ntable_name\030\001 \002(\0132" +
-      "\023.hbase.pb.TableName\022)\n\006region\030\002 \001(\0132\031.h" +
-      "base.pb.RegionSpecifier\"-\n\027PrepareBulkLo" +
-      "adResponse\022\022\n\nbulk_token\030\001 \002(\t\"W\n\026Cleanu" +
-      "pBulkLoadRequest\022\022\n\nbulk_token\030\001 \002(\t\022)\n\006" +
-      "region\030\002 \001(\0132\031.hbase.pb.RegionSpecifier\"" +
-      "\031\n\027CleanupBulkLoadResponse\"a\n\026Coprocesso" +
-      "rServiceCall\022\013\n\003row\030\001 \002(\014\022\024\n\014service_nam" +
-      "e\030\002 \002(\t\022\023\n\013method_name\030\003 \002(\t\022\017\n\007request\030",
-      "\004 \002(\014\"B\n\030CoprocessorServiceResult\022&\n\005val" +
-      "ue\030\001 \001(\0132\027.hbase.pb.NameBytesPair\"v\n\031Cop" +
-      "rocessorServiceRequest\022)\n\006region\030\001 \002(\0132\031" +
-      ".hbase.pb.RegionSpecifier\022.\n\004call\030\002 \002(\0132" +
-      " .hbase.pb.CoprocessorServiceCall\"o\n\032Cop" +
-      "rocessorServiceResponse\022)\n\006region\030\001 \002(\0132" +
-      "\031.hbase.pb.RegionSpecifier\022&\n\005value\030\002 \002(" +
-      "\0132\027.hbase.pb.NameBytesPair\"\226\001\n\006Action\022\r\n" +
-      "\005index\030\001 \001(\r\022)\n\010mutation\030\002 \001(\0132\027.hbase.p" +
-      "b.MutationProto\022\032\n\003get\030\003 \001(\0132\r.hbase.pb.",
-      "Get\0226\n\014service_call\030\004 \001(\0132 .hbase.pb.Cop" +
-      "rocessorServiceCall\"k\n\014RegionAction\022)\n\006r" +
-      "egion\030\001 \002(\0132\031.hbase.pb.RegionSpecifier\022\016" +
-      "\n\006atomic\030\002 \001(\010\022 \n\006action\030\003 \003(\0132\020.hbase.p" +
-      "b.Action\"c\n\017RegionLoadStats\022\027\n\014memstoreL" +
-      "oad\030\001 \001(\005:\0010\022\030\n\rheapOccupancy\030\002 \001(\005:\0010\022\035" +
-      "\n\022compactionPressure\030\003 \001(\005:\0010\"j\n\024MultiRe" +
-      "gionLoadStats\022)\n\006region\030\001 \003(\0132\031.hbase.pb" +
-      ".RegionSpecifier\022\'\n\004stat\030\002 \003(\0132\031.hbase.p" +
-      "b.RegionLoadStats\"\336\001\n\021ResultOrException\022",
-      "\r\n\005index\030\001 \001(\r\022 \n\006result\030\002 \001(\0132\020.hbase.p" +
-      "b.Result\022*\n\texception\030\003 \001(\0132\027.hbase.pb.N" +
-      "ameBytesPair\022:\n\016service_result\030\004 \001(\0132\".h" +
-      "base.pb.CoprocessorServiceResult\0220\n\tload" +
-      "Stats\030\005 \001(\0132\031.hbase.pb.RegionLoadStatsB\002" +
-      "\030\001\"x\n\022RegionActionResult\0226\n\021resultOrExce" +
-      "ption\030\001 \003(\0132\033.hbase.pb.ResultOrException" +
-      "\022*\n\texception\030\002 \001(\0132\027.hbase.pb.NameBytes" +
-      "Pair\"x\n\014MultiRequest\022,\n\014regionAction\030\001 \003" +
-      "(\0132\026.hbase.pb.RegionAction\022\022\n\nnonceGroup",
-      "\030\002 \001(\004\022&\n\tcondition\030\003 \001(\0132\023.hbase.pb.Con" +
-      "dition\"\226\001\n\rMultiResponse\0228\n\022regionAction" +
-      "Result\030\001 \003(\0132\034.hbase.pb.RegionActionResu" +
-      "lt\022\021\n\tprocessed\030\002 \001(\010\0228\n\020regionStatistic" +
-      "s\030\003 \001(\0132\036.hbase.pb.MultiRegionLoadStats*" +
-      "\'\n\013Consistency\022\n\n\006STRONG\020\000\022\014\n\010TIMELINE\020\001" +
-      "2\263\005\n\rClientService\0222\n\003Get\022\024.hbase.pb.Get" +
-      "Request\032\025.hbase.pb.GetResponse\022;\n\006Mutate" +
-      "\022\027.hbase.pb.MutateRequest\032\030.hbase.pb.Mut" +
-      "ateResponse\0225\n\004Scan\022\025.hbase.pb.ScanReque",
-      "st\032\026.hbase.pb.ScanResponse\022P\n\rBulkLoadHF" +
-      "ile\022\036.hbase.pb.BulkLoadHFileRequest\032\037.hb" +
-      "ase.pb.BulkLoadHFileResponse\022V\n\017PrepareB" +
-      "ulkLoad\022 .hbase.pb.PrepareBulkLoadReques" +
-      "t\032!.hbase.pb.PrepareBulkLoadResponse\022V\n\017" +
-      "CleanupBulkLoad\022 .hbase.pb.CleanupBulkLo" +
-      "adRequest\032!.hbase.pb.CleanupBulkLoadResp" +
-      "onse\022X\n\013ExecService\022#.hbase.pb.Coprocess" +
-      "orServiceRequest\032$.hbase.pb.CoprocessorS" +
-      "erviceResponse\022d\n\027ExecRegionServerServic",
-      "e\022#.hbase.pb.CoprocessorServiceRequest\032$" +
-      ".hbase.pb.CoprocessorServiceResponse\0228\n\005" +
-      "Multi\022\026.hbase.pb.MultiRequest\032\027.hbase.pb" +
-      ".MultiResponseBI\n1org.apache.hadoop.hbas" +
-      "e.shaded.protobuf.generatedB\014ClientProto" +
-      "sH\001\210\001\001\240\001\001"
+      ":\007DEFAULT\022!\n\022need_cursor_result\030\030 \001(\010:\005f" +
+      "alse\".\n\010ReadType\022\013\n\007DEFAULT\020\000\022\n\n\006STREAM\020" +
+      "\001\022\t\n\005PREAD\020\002\"\300\002\n\013ScanRequest\022)\n\006region\030\001" +
+      " \001(\0132\031.hbase.pb.RegionSpecifier\022\034\n\004scan\030" +
+      "\002 \001(\0132\016.hbase.pb.Scan\022\022\n\nscanner_id\030\003 \001(" +
+      "\004\022\026\n\016number_of_rows\030\004 \001(\r\022\025\n\rclose_scann" +
+      "er\030\005 \001(\010\022\025\n\rnext_call_seq\030\006 \001(\004\022\037\n\027clien",
+      "t_handles_partials\030\007 \001(\010\022!\n\031client_handl" +
+      "es_heartbeats\030\010 \001(\010\022\032\n\022track_scan_metric" +
+      "s\030\t \001(\010\022\024\n\005renew\030\n \001(\010:\005false\022\030\n\rlimit_o" +
+      "f_rows\030\013 \001(\r:\0010\"\025\n\006Cursor\022\013\n\003row\030\001 \001(\014\"\330" +
+      "\002\n\014ScanResponse\022\030\n\020cells_per_result\030\001 \003(" +
+      "\r\022\022\n\nscanner_id\030\002 \001(\004\022\024\n\014more_results\030\003 " +
+      "\001(\010\022\013\n\003ttl\030\004 \001(\r\022!\n\007results\030\005 \003(\0132\020.hbas" +
+      "e.pb.Result\022\r\n\005stale\030\006 \001(\010\022\037\n\027partial_fl" +
+      "ag_per_result\030\007 \003(\010\022\036\n\026more_results_in_r" +
+      "egion\030\010 \001(\010\022\031\n\021heartbeat_message\030\t \001(\010\022+",
+      "\n\014scan_metrics\030\n \001(\0132\025.hbase.pb.ScanMetr" +
+      "ics\022\032\n\017mvcc_read_point\030\013 \001(\004:\0010\022 \n\006curso" +
+      "r\030\014 \001(\0132\020.hbase.pb.Cursor\"\240\002\n\024BulkLoadHF" +
+      "ileRequest\022)\n\006region\030\001 \002(\0132\031.hbase.pb.Re" +
+      "gionSpecifier\022>\n\013family_path\030\002 \003(\0132).hba" +
+      "se.pb.BulkLoadHFileRequest.FamilyPath\022\026\n" +
+      "\016assign_seq_num\030\003 \001(\010\022+\n\010fs_token\030\004 \001(\0132" +
+      "\031.hbase.pb.DelegationToken\022\022\n\nbulk_token" +
+      "\030\005 \001(\t\022\030\n\tcopy_file\030\006 \001(\010:\005false\032*\n\nFami" +
+      "lyPath\022\016\n\006family\030\001 \002(\014\022\014\n\004path\030\002 \002(\t\"\'\n\025",
+      "BulkLoadHFileResponse\022\016\n\006loaded\030\001 \002(\010\"V\n" +
+      "\017DelegationToken\022\022\n\nidentifier\030\001 \001(\014\022\020\n\010" +
+      "password\030\002 \001(\014\022\014\n\004kind\030\003 \001(\t\022\017\n\007service\030" +
+      "\004 \001(\t\"l\n\026PrepareBulkLoadRequest\022\'\n\ntable" +
+      "_name\030\001 \002(\0132\023.hbase.pb.TableName\022)\n\006regi" +
+      "on\030\002 \001(\0132\031.hbase.pb.RegionSpecifier\"-\n\027P" +
+      "repareBulkLoadResponse\022\022\n\nbulk_token\030\001 \002" +
+      "(\t\"W\n\026CleanupBulkLoadRequest\022\022\n\nbulk_tok" +
+      "en\030\001 \002(\t\022)\n\006region\030\002 \001(\0132\031.hbase.pb.Regi" +
+      "onSpecifier\"\031\n\027CleanupBulkLoadResponse\"a",
+      "\n\026CoprocessorServiceCall\022\013\n\003row\030\001 \002(\014\022\024\n" +
+      "\014service_name\030\002 \002(\t\022\023\n\013method_name\030\003 \002(\t" +
+      "\022\017\n\007request\030\004 \002(\014\"B\n\030CoprocessorServiceR" +
+      "esult\022&\n\005value\030\001 \001(\0132\027.hbase.pb.NameByte" +
+      "sPair\"v\n\031CoprocessorServiceRequest\022)\n\006re" +
+      "gion\030\001 \002(\0132\031.hbase.pb.RegionSpecifier\022.\n" +
+      "\004call\030\002 \002(\0132 .hbase.pb.CoprocessorServic" +
+      "eCall\"o\n\032CoprocessorServiceResponse\022)\n\006r" +
+      "egion\030\001 \002(\0132\031.hbase.pb.RegionSpecifier\022&" +
+      "\n\005value\030\002 \002(\0132\027.hbase.pb.NameBytesPair\"\226",
+      "\001\n\006Action\022\r\n\005index\030\001 \001(\r\022)\n\010mutation\030\002 \001" +
+      "(\0132\027.hbase.pb.MutationProto\022\032\n\003get\030\003 \001(\013" +
+      "2\r.hbase.pb.Get\0226\n\014service_call\030\004 \001(\0132 ." +
+      "hbase.pb.CoprocessorServiceCall\"k\n\014Regio" +
+      "nAction\022)\n\006region\030\001 \002(\0132\031.hbase.pb.Regio" +
+      "nSpecifier\022\016\n\006atomic\030\002 \001(\010\022 \n\006action\030\003 \003" +
+      "(\0132\020.hbase.pb.Action\"c\n\017RegionLoadStats\022" +
+      "\027\n\014memstoreLoad\030\001 \001(\005:\0010\022\030\n\rheapOccupanc" +
+      "y\030\002 \001(\005:\0010\022\035\n\022compactionPressure\030\003 \001(\005:\001" +
+      "0\"j\n\024MultiRegionLoadStats\022)\n\006region\030\001 \003(",
+      "\0132\031.hbase.pb.RegionSpecifier\022\'\n\004stat\030\002 \003" +
+      "(\0132\031.hbase.pb.RegionLoadStats\"\336\001\n\021Result" +
+      "OrException\022\r\n\005index\030\001 \001(\r\022 \n\006result\030\002 \001" +
+      "(\0132\020.hbase.pb.Result\022*\n\texception\030\003 \001(\0132" +
+      "\027.hbase.pb.NameBytesPair\022:\n\016service_resu" +
+      "lt\030\004 \001(\0132\".hbase.pb.CoprocessorServiceRe" +
+      "sult\0220\n\tloadStats\030\005 \001(\0132\031.hbase.pb.Regio" +
+      "nLoadStatsB\002\030\001\"x\n\022RegionActionResult\0226\n\021" +
+      "resultOrException\030\001 \003(\0132\033.hbase.pb.Resul" +
+      "tOrException\022*\n\texception\030\002 \001(\0132\027.hbase.",
+      "pb.NameBytesPair\"x\n\014MultiRequest\022,\n\014regi" +
+      "onAction\030\001 \003(\0132\026.hbase.pb.RegionAction\022\022" +
+      "\n\nnonceGroup\030\002 \001(\004\022&\n\tcondition\030\003 \001(\0132\023." +
+      "hbase.pb.Condition\"\226\001\n\rMultiResponse\0228\n\022" +
+      "regionActionResult\030\001 \003(\0132\034.hbase.pb.Regi" +
+      "onActionResult\022\021\n\tprocessed\030\002 \001(\010\0228\n\020reg" +
+      "ionStatistics\030\003 \001(\0132\036.hbase.pb.MultiRegi" +
+      "onLoadStats*\'\n\013Consistency\022\n\n\006STRONG\020\000\022\014" +
+      "\n\010TIMELINE\020\0012\263\005\n\rClientService\0222\n\003Get\022\024." +
+      "hbase.pb.GetRequest\032\025.hbase.pb.GetRespon",
+      "se\022;\n\006Mutate\022\027.hbase.pb.MutateRequest\032\030." +
+      "hbase.pb.MutateResponse\0225\n\004Scan\022\025.hbase." +
+      "pb.ScanRequest\032\026.hbase.pb.ScanResponse\022P" +
+      "\n\rBulkLoadHFile\022\036.hbase.pb.BulkLoadHFile" +
+      "Request\032\037.hbase.pb.BulkLoadHFileResponse" +
+      "\022V\n\017PrepareBulkLoad\022 .hbase.pb.PrepareBu" +
+      "lkLoadRequest\032!.hbase.pb.PrepareBulkLoad" +
+      "Response\022V\n\017CleanupBulkLoad\022 .hbase.pb.C" +
+      "leanupBulkLoadRequest\032!.hbase.pb.Cleanup" +
+      "BulkLoadResponse\022X\n\013ExecService\022#.hbase.",
+      "pb.CoprocessorServiceRequest\032$.hbase.pb." +
+      "CoprocessorServiceResponse\022d\n\027ExecRegion" +
+      "ServerService\022#.hbase.pb.CoprocessorServ" +
+      "iceRequest\032$.hbase.pb.CoprocessorService" +
+      "Response\0228\n\005Multi\022\026.hbase.pb.MultiReques" +
+      "t\032\027.hbase.pb.MultiResponseBI\n1org.apache" +
+      ".hadoop.hbase.shaded.protobuf.generatedB" +
+      "\014ClientProtosH\001\210\001\001\240\001\001"
     };
     org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner assigner =
         new org.apache.hadoop.hbase.shaded.com.google.protobuf.Descriptors.FileDescriptor.    InternalDescriptorAssigner() {
@@ -41369,21 +42217,27 @@ public final class ClientProtos {
     internal_static_hbase_pb_Scan_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_Scan_descriptor,
-        new java.lang.String[] { "Column", "Attribute", "StartRow", "StopRow", "Filter", "TimeRange", "MaxVersions", "CacheBlocks", "BatchSize", "MaxResultSize", "StoreLimit", "StoreOffset", "LoadColumnFamiliesOnDemand", "Small", "Reversed", "Consistency", "Caching", "AllowPartialResults", "CfTimeRange", "MvccReadPoint", "IncludeStartRow", "IncludeStopRow", "ReadType", });
+        new java.lang.String[] { "Column", "Attribute", "StartRow", "StopRow", "Filter", "TimeRange", "MaxVersions", "CacheBlocks", "BatchSize", "MaxResultSize", "StoreLimit", "StoreOffset", "LoadColumnFamiliesOnDemand", "Small", "Reversed", "Consistency", "Caching", "AllowPartialResults", "CfTimeRange", "MvccReadPoint", "IncludeStartRow", "IncludeStopRow", "ReadType", "NeedCursorResult", });
     internal_static_hbase_pb_ScanRequest_descriptor =
       getDescriptor().getMessageTypes().get(12);
     internal_static_hbase_pb_ScanRequest_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_ScanRequest_descriptor,
         new java.lang.String[] { "Region", "Scan", "ScannerId", "NumberOfRows", "CloseScanner", "NextCallSeq", "ClientHandlesPartials", "ClientHandlesHeartbeats", "TrackScanMetrics", "Renew", "LimitOfRows", });
-    internal_static_hbase_pb_ScanResponse_descriptor =
+    internal_static_hbase_pb_Cursor_descriptor =
       getDescriptor().getMessageTypes().get(13);
+    internal_static_hbase_pb_Cursor_fieldAccessorTable = new
+      org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_hbase_pb_Cursor_descriptor,
+        new java.lang.String[] { "Row", });
+    internal_static_hbase_pb_ScanResponse_descriptor =
+      getDescriptor().getMessageTypes().get(14);
     internal_static_hbase_pb_ScanResponse_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_ScanResponse_descriptor,
-        new java.lang.String[] { "CellsPerResult", "ScannerId", "MoreResults", "Ttl", "Results", "Stale", "PartialFlagPerResult", "MoreResultsInRegion", "HeartbeatMessage", "ScanMetrics", "MvccReadPoint", });
+        new java.lang.String[] { "CellsPerResult", "ScannerId", "MoreResults", "Ttl", "Results", "Stale", "PartialFlagPerResult", "MoreResultsInRegion", "HeartbeatMessage", "ScanMetrics", "MvccReadPoint", "Cursor", });
     internal_static_hbase_pb_BulkLoadHFileRequest_descriptor =
-      getDescriptor().getMessageTypes().get(14);
+      getDescriptor().getMessageTypes().get(15);
     internal_static_hbase_pb_BulkLoadHFileRequest_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_BulkLoadHFileRequest_descriptor,
@@ -41395,109 +42249,109 @@ public final class ClientProtos {
         internal_static_hbase_pb_BulkLoadHFileRequest_FamilyPath_descriptor,
         new java.lang.String[] { "Family", "Path", });
     internal_static_hbase_pb_BulkLoadHFileResponse_descriptor =
-      getDescriptor().getMessageTypes().get(15);
+      getDescriptor().getMessageTypes().get(16);
     internal_static_hbase_pb_BulkLoadHFileResponse_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_BulkLoadHFileResponse_descriptor,
         new java.lang.String[] { "Loaded", });
     internal_static_hbase_pb_DelegationToken_descriptor =
-      getDescriptor().getMessageTypes().get(16);
+      getDescriptor().getMessageTypes().get(17);
     internal_static_hbase_pb_DelegationToken_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_DelegationToken_descriptor,
         new java.lang.String[] { "Identifier", "Password", "Kind", "Service", });
     internal_static_hbase_pb_PrepareBulkLoadRequest_descriptor =
-      getDescriptor().getMessageTypes().get(17);
+      getDescriptor().getMessageTypes().get(18);
     internal_static_hbase_pb_PrepareBulkLoadRequest_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_PrepareBulkLoadRequest_descriptor,
         new java.lang.String[] { "TableName", "Region", });
     internal_static_hbase_pb_PrepareBulkLoadResponse_descriptor =
-      getDescriptor().getMessageTypes().get(18);
+      getDescriptor().getMessageTypes().get(19);
     internal_static_hbase_pb_PrepareBulkLoadResponse_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_PrepareBulkLoadResponse_descriptor,
         new java.lang.String[] { "BulkToken", });
     internal_static_hbase_pb_CleanupBulkLoadRequest_descriptor =
-      getDescriptor().getMessageTypes().get(19);
+      getDescriptor().getMessageTypes().get(20);
     internal_static_hbase_pb_CleanupBulkLoadRequest_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_CleanupBulkLoadRequest_descriptor,
         new java.lang.String[] { "BulkToken", "Region", });
     internal_static_hbase_pb_CleanupBulkLoadResponse_descriptor =
-      getDescriptor().getMessageTypes().get(20);
+      getDescriptor().getMessageTypes().get(21);
     internal_static_hbase_pb_CleanupBulkLoadResponse_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_CleanupBulkLoadResponse_descriptor,
         new java.lang.String[] { });
     internal_static_hbase_pb_CoprocessorServiceCall_descriptor =
-      getDescriptor().getMessageTypes().get(21);
+      getDescriptor().getMessageTypes().get(22);
     internal_static_hbase_pb_CoprocessorServiceCall_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_CoprocessorServiceCall_descriptor,
         new java.lang.String[] { "Row", "ServiceName", "MethodName", "Request", });
     internal_static_hbase_pb_CoprocessorServiceResult_descriptor =
-      getDescriptor().getMessageTypes().get(22);
+      getDescriptor().getMessageTypes().get(23);
     internal_static_hbase_pb_CoprocessorServiceResult_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_CoprocessorServiceResult_descriptor,
         new java.lang.String[] { "Value", });
     internal_static_hbase_pb_CoprocessorServiceRequest_descriptor =
-      getDescriptor().getMessageTypes().get(23);
+      getDescriptor().getMessageTypes().get(24);
     internal_static_hbase_pb_CoprocessorServiceRequest_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_CoprocessorServiceRequest_descriptor,
         new java.lang.String[] { "Region", "Call", });
     internal_static_hbase_pb_CoprocessorServiceResponse_descriptor =
-      getDescriptor().getMessageTypes().get(24);
+      getDescriptor().getMessageTypes().get(25);
     internal_static_hbase_pb_CoprocessorServiceResponse_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_CoprocessorServiceResponse_descriptor,
         new java.lang.String[] { "Region", "Value", });
     internal_static_hbase_pb_Action_descriptor =
-      getDescriptor().getMessageTypes().get(25);
+      getDescriptor().getMessageTypes().get(26);
     internal_static_hbase_pb_Action_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_Action_descriptor,
         new java.lang.String[] { "Index", "Mutation", "Get", "ServiceCall", });
     internal_static_hbase_pb_RegionAction_descriptor =
-      getDescriptor().getMessageTypes().get(26);
+      getDescriptor().getMessageTypes().get(27);
     internal_static_hbase_pb_RegionAction_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_RegionAction_descriptor,
         new java.lang.String[] { "Region", "Atomic", "Action", });
     internal_static_hbase_pb_RegionLoadStats_descriptor =
-      getDescriptor().getMessageTypes().get(27);
+      getDescriptor().getMessageTypes().get(28);
     internal_static_hbase_pb_RegionLoadStats_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_RegionLoadStats_descriptor,
         new java.lang.String[] { "MemstoreLoad", "HeapOccupancy", "CompactionPressure", });
     internal_static_hbase_pb_MultiRegionLoadStats_descriptor =
-      getDescriptor().getMessageTypes().get(28);
+      getDescriptor().getMessageTypes().get(29);
     internal_static_hbase_pb_MultiRegionLoadStats_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_MultiRegionLoadStats_descriptor,
         new java.lang.String[] { "Region", "Stat", });
     internal_static_hbase_pb_ResultOrException_descriptor =
-      getDescriptor().getMessageTypes().get(29);
+      getDescriptor().getMessageTypes().get(30);
     internal_static_hbase_pb_ResultOrException_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_ResultOrException_descriptor,
         new java.lang.String[] { "Index", "Result", "Exception", "ServiceResult", "LoadStats", });
     internal_static_hbase_pb_RegionActionResult_descriptor =
-      getDescriptor().getMessageTypes().get(30);
+      getDescriptor().getMessageTypes().get(31);
     internal_static_hbase_pb_RegionActionResult_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_RegionActionResult_descriptor,
         new java.lang.String[] { "ResultOrException", "Exception", });
     internal_static_hbase_pb_MultiRequest_descriptor =
-      getDescriptor().getMessageTypes().get(31);
+      getDescriptor().getMessageTypes().get(32);
     internal_static_hbase_pb_MultiRequest_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_MultiRequest_descriptor,
         new java.lang.String[] { "RegionAction", "NonceGroup", "Condition", });
     internal_static_hbase_pb_MultiResponse_descriptor =
-      getDescriptor().getMessageTypes().get(32);
+      getDescriptor().getMessageTypes().get(33);
     internal_static_hbase_pb_MultiResponse_fieldAccessorTable = new
       org.apache.hadoop.hbase.shaded.com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_hbase_pb_MultiResponse_descriptor,
diff --git a/hbase-protocol-shaded/src/main/protobuf/Client.proto b/hbase-protocol-shaded/src/main/protobuf/Client.proto
index 82bfb70a0f0..14d2b4c071c 100644
--- a/hbase-protocol-shaded/src/main/protobuf/Client.proto
+++ b/hbase-protocol-shaded/src/main/protobuf/Client.proto
@@ -259,13 +259,13 @@ message Scan {
   optional uint64 mvcc_read_point = 20 [default = 0];
   optional bool include_start_row = 21 [default = true];
   optional bool include_stop_row = 22 [default = false];
-
   enum ReadType {
     DEFAULT = 0;
     STREAM = 1;
     PREAD = 2;
   }
   optional ReadType readType = 23 [default = DEFAULT];
+  optional bool need_cursor_result = 24 [default = false];
 }
 
 /**
@@ -294,6 +294,14 @@ message ScanRequest {
   optional uint32 limit_of_rows = 11 [default = 0];
 }
 
+/**
+* Scan cursor to tell client where we are scanning.
+*
+ */
+message Cursor {
+  optional bytes row = 1;
+}
+
 /**
  * The scan response. If there are no more results, more_results will
  * be false.  If it is not specified, it means there are more.
@@ -346,6 +354,10 @@ message ScanResponse {
   // make use of this mvcc_read_point when restarting a scanner to get a consistent view
   // of a row.
   optional uint64 mvcc_read_point = 11 [default = 0];
+
+  // If the Scan need cursor, return the row key we are scanning in heartbeat message.
+  // If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+  optional Cursor cursor = 12;
 }
 
 /**
diff --git a/hbase-protocol/src/main/java/org/apache/hadoop/hbase/protobuf/generated/ClientProtos.java b/hbase-protocol/src/main/java/org/apache/hadoop/hbase/protobuf/generated/ClientProtos.java
index 1bb57c43f40..e25064faff4 100644
--- a/hbase-protocol/src/main/java/org/apache/hadoop/hbase/protobuf/generated/ClientProtos.java
+++ b/hbase-protocol/src/main/java/org/apache/hadoop/hbase/protobuf/generated/ClientProtos.java
@@ -14267,6 +14267,16 @@ public final class ClientProtos {
      * optional .hbase.pb.Scan.ReadType readType = 23 [default = DEFAULT];
      */
     org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Scan.ReadType getReadType();
+
+    // optional bool need_cursor_result = 24 [default = false];
+    /**
+     * optional bool need_cursor_result = 24 [default = false];
+     */
+    boolean hasNeedCursorResult();
+    /**
+     * optional bool need_cursor_result = 24 [default = false];
+     */
+    boolean getNeedCursorResult();
   }
   /**
    * Protobuf type {@code hbase.pb.Scan}
@@ -14482,6 +14492,11 @@ public final class ClientProtos {
               }
               break;
             }
+            case 192: {
+              bitField0_ |= 0x00100000;
+              needCursorResult_ = input.readBool();
+              break;
+            }
           }
         }
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
@@ -15070,6 +15085,22 @@ public final class ClientProtos {
       return readType_;
     }
 
+    // optional bool need_cursor_result = 24 [default = false];
+    public static final int NEED_CURSOR_RESULT_FIELD_NUMBER = 24;
+    private boolean needCursorResult_;
+    /**
+     * optional bool need_cursor_result = 24 [default = false];
+     */
+    public boolean hasNeedCursorResult() {
+      return ((bitField0_ & 0x00100000) == 0x00100000);
+    }
+    /**
+     * optional bool need_cursor_result = 24 [default = false];
+     */
+    public boolean getNeedCursorResult() {
+      return needCursorResult_;
+    }
+
     private void initFields() {
       column_ = java.util.Collections.emptyList();
       attribute_ = java.util.Collections.emptyList();
@@ -15094,6 +15125,7 @@ public final class ClientProtos {
       includeStartRow_ = true;
       includeStopRow_ = false;
       readType_ = org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Scan.ReadType.DEFAULT;
+      needCursorResult_ = false;
     }
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
@@ -15200,6 +15232,9 @@ public final class ClientProtos {
       if (((bitField0_ & 0x00080000) == 0x00080000)) {
         output.writeEnum(23, readType_.getNumber());
       }
+      if (((bitField0_ & 0x00100000) == 0x00100000)) {
+        output.writeBool(24, needCursorResult_);
+      }
       getUnknownFields().writeTo(output);
     }
 
@@ -15301,6 +15336,10 @@ public final class ClientProtos {
         size += com.google.protobuf.CodedOutputStream
           .computeEnumSize(23, readType_.getNumber());
       }
+      if (((bitField0_ & 0x00100000) == 0x00100000)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeBoolSize(24, needCursorResult_);
+      }
       size += getUnknownFields().getSerializedSize();
       memoizedSerializedSize = size;
       return size;
@@ -15430,6 +15469,11 @@ public final class ClientProtos {
         result = result &&
             (getReadType() == other.getReadType());
       }
+      result = result && (hasNeedCursorResult() == other.hasNeedCursorResult());
+      if (hasNeedCursorResult()) {
+        result = result && (getNeedCursorResult()
+            == other.getNeedCursorResult());
+      }
       result = result &&
           getUnknownFields().equals(other.getUnknownFields());
       return result;
@@ -15535,6 +15579,10 @@ public final class ClientProtos {
         hash = (37 * hash) + READTYPE_FIELD_NUMBER;
         hash = (53 * hash) + hashEnum(getReadType());
       }
+      if (hasNeedCursorResult()) {
+        hash = (37 * hash) + NEED_CURSOR_RESULT_FIELD_NUMBER;
+        hash = (53 * hash) + hashBoolean(getNeedCursorResult());
+      }
       hash = (29 * hash) + getUnknownFields().hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -15726,6 +15774,8 @@ public final class ClientProtos {
         bitField0_ = (bitField0_ & ~0x00200000);
         readType_ = org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Scan.ReadType.DEFAULT;
         bitField0_ = (bitField0_ & ~0x00400000);
+        needCursorResult_ = false;
+        bitField0_ = (bitField0_ & ~0x00800000);
         return this;
       }
 
@@ -15869,6 +15919,10 @@ public final class ClientProtos {
           to_bitField0_ |= 0x00080000;
         }
         result.readType_ = readType_;
+        if (((from_bitField0_ & 0x00800000) == 0x00800000)) {
+          to_bitField0_ |= 0x00100000;
+        }
+        result.needCursorResult_ = needCursorResult_;
         result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
@@ -16023,6 +16077,9 @@ public final class ClientProtos {
         if (other.hasReadType()) {
           setReadType(other.getReadType());
         }
+        if (other.hasNeedCursorResult()) {
+          setNeedCursorResult(other.getNeedCursorResult());
+        }
         this.mergeUnknownFields(other.getUnknownFields());
         return this;
       }
@@ -17650,6 +17707,39 @@ public final class ClientProtos {
         return this;
       }
 
+      // optional bool need_cursor_result = 24 [default = false];
+      private boolean needCursorResult_ ;
+      /**
+       * optional bool need_cursor_result = 24 [default = false];
+       */
+      public boolean hasNeedCursorResult() {
+        return ((bitField0_ & 0x00800000) == 0x00800000);
+      }
+      /**
+       * optional bool need_cursor_result = 24 [default = false];
+       */
+      public boolean getNeedCursorResult() {
+        return needCursorResult_;
+      }
+      /**
+       * optional bool need_cursor_result = 24 [default = false];
+       */
+      public Builder setNeedCursorResult(boolean value) {
+        bitField0_ |= 0x00800000;
+        needCursorResult_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * optional bool need_cursor_result = 24 [default = false];
+       */
+      public Builder clearNeedCursorResult() {
+        bitField0_ = (bitField0_ & ~0x00800000);
+        needCursorResult_ = false;
+        onChanged();
+        return this;
+      }
+
       // @@protoc_insertion_point(builder_scope:hbase.pb.Scan)
     }
 
@@ -19299,6 +19389,453 @@ public final class ClientProtos {
     // @@protoc_insertion_point(class_scope:hbase.pb.ScanRequest)
   }
 
+  public interface CursorOrBuilder
+      extends com.google.protobuf.MessageOrBuilder {
+
+    // optional bytes row = 1;
+    /**
+     * optional bytes row = 1;
+     */
+    boolean hasRow();
+    /**
+     * optional bytes row = 1;
+     */
+    com.google.protobuf.ByteString getRow();
+  }
+  /**
+   * Protobuf type {@code hbase.pb.Cursor}
+   *
+   * 
+   **
+   * Scan cursor to tell client where we are scanning.
+   * 

+   */
+  public static final class Cursor extends
+      com.google.protobuf.GeneratedMessage
+      implements CursorOrBuilder {
+    // Use Cursor.newBuilder() to construct.
+    private Cursor(com.google.protobuf.GeneratedMessage.Builder builder) {
+      super(builder);
+      this.unknownFields = builder.getUnknownFields();
+    }
+    private Cursor(boolean noInit) { this.unknownFields = com.google.protobuf.UnknownFieldSet.getDefaultInstance(); }
+
+    private static final Cursor defaultInstance;
+    public static Cursor getDefaultInstance() {
+      return defaultInstance;
+    }
+
+    public Cursor getDefaultInstanceForType() {
+      return defaultInstance;
+    }
+
+    private final com.google.protobuf.UnknownFieldSet unknownFields;
+    @java.lang.Override
+    public final com.google.protobuf.UnknownFieldSet
+        getUnknownFields() {
+      return this.unknownFields;
+    }
+    private Cursor(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      initFields();
+      int mutable_bitField0_ = 0;
+      com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+          com.google.protobuf.UnknownFieldSet.newBuilder();
+      try {
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            default: {
+              if (!parseUnknownField(input, unknownFields,
+                                     extensionRegistry, tag)) {
+                done = true;
+              }
+              break;
+            }
+            case 10: {
+              bitField0_ |= 0x00000001;
+              row_ = input.readBytes();
+              break;
+            }
+          }
+        }
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        throw e.setUnfinishedMessage(this);
+      } catch (java.io.IOException e) {
+        throw new com.google.protobuf.InvalidProtocolBufferException(
+            e.getMessage()).setUnfinishedMessage(this);
+      } finally {
+        this.unknownFields = unknownFields.build();
+        makeExtensionsImmutable();
+      }
+    }
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.apache.hadoop.hbase.protobuf.generated.ClientProtos.internal_static_hbase_pb_Cursor_descriptor;
+    }
+
+    protected com.google.protobuf.GeneratedMessage.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.apache.hadoop.hbase.protobuf.generated.ClientProtos.internal_static_hbase_pb_Cursor_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.class, org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.Builder.class);
+    }
+
+    public static com.google.protobuf.Parser PARSER =
+        new com.google.protobuf.AbstractParser() {
+      public Cursor parsePartialFrom(
+          com.google.protobuf.CodedInputStream input,
+          com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+          throws com.google.protobuf.InvalidProtocolBufferException {
+        return new Cursor(input, extensionRegistry);
+      }
+    };
+
+    @java.lang.Override
+    public com.google.protobuf.Parser getParserForType() {
+      return PARSER;
+    }
+
+    private int bitField0_;
+    // optional bytes row = 1;
+    public static final int ROW_FIELD_NUMBER = 1;
+    private com.google.protobuf.ByteString row_;
+    /**
+     * optional bytes row = 1;
+     */
+    public boolean hasRow() {
+      return ((bitField0_ & 0x00000001) == 0x00000001);
+    }
+    /**
+     * optional bytes row = 1;
+     */
+    public com.google.protobuf.ByteString getRow() {
+      return row_;
+    }
+
+    private void initFields() {
+      row_ = com.google.protobuf.ByteString.EMPTY;
+    }
+    private byte memoizedIsInitialized = -1;
+    public final boolean isInitialized() {
+      byte isInitialized = memoizedIsInitialized;
+      if (isInitialized != -1) return isInitialized == 1;
+
+      memoizedIsInitialized = 1;
+      return true;
+    }
+
+    public void writeTo(com.google.protobuf.CodedOutputStream output)
+                        throws java.io.IOException {
+      getSerializedSize();
+      if (((bitField0_ & 0x00000001) == 0x00000001)) {
+        output.writeBytes(1, row_);
+      }
+      getUnknownFields().writeTo(output);
+    }
+
+    private int memoizedSerializedSize = -1;
+    public int getSerializedSize() {
+      int size = memoizedSerializedSize;
+      if (size != -1) return size;
+
+      size = 0;
+      if (((bitField0_ & 0x00000001) == 0x00000001)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeBytesSize(1, row_);
+      }
+      size += getUnknownFields().getSerializedSize();
+      memoizedSerializedSize = size;
+      return size;
+    }
+
+    private static final long serialVersionUID = 0L;
+    @java.lang.Override
+    protected java.lang.Object writeReplace()
+        throws java.io.ObjectStreamException {
+      return super.writeReplace();
+    }
+
+    @java.lang.Override
+    public boolean equals(final java.lang.Object obj) {
+      if (obj == this) {
+       return true;
+      }
+      if (!(obj instanceof org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor)) {
+        return super.equals(obj);
+      }
+      org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor other = (org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor) obj;
+
+      boolean result = true;
+      result = result && (hasRow() == other.hasRow());
+      if (hasRow()) {
+        result = result && getRow()
+            .equals(other.getRow());
+      }
+      result = result &&
+          getUnknownFields().equals(other.getUnknownFields());
+      return result;
+    }
+
+    private int memoizedHashCode = 0;
+    @java.lang.Override
+    public int hashCode() {
+      if (memoizedHashCode != 0) {
+        return memoizedHashCode;
+      }
+      int hash = 41;
+      hash = (19 * hash) + getDescriptorForType().hashCode();
+      if (hasRow()) {
+        hash = (37 * hash) + ROW_FIELD_NUMBER;
+        hash = (53 * hash) + getRow().hashCode();
+      }
+      hash = (29 * hash) + getUnknownFields().hashCode();
+      memoizedHashCode = hash;
+      return hash;
+    }
+
+    public static org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parseFrom(
+        com.google.protobuf.ByteString data)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data);
+    }
+    public static org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parseFrom(
+        com.google.protobuf.ByteString data,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data, extensionRegistry);
+    }
+    public static org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parseFrom(byte[] data)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data);
+    }
+    public static org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parseFrom(
+        byte[] data,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data, extensionRegistry);
+    }
+    public static org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parseFrom(java.io.InputStream input)
+        throws java.io.IOException {
+      return PARSER.parseFrom(input);
+    }
+    public static org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parseFrom(
+        java.io.InputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return PARSER.parseFrom(input, extensionRegistry);
+    }
+    public static org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parseDelimitedFrom(java.io.InputStream input)
+        throws java.io.IOException {
+      return PARSER.parseDelimitedFrom(input);
+    }
+    public static org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parseDelimitedFrom(
+        java.io.InputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return PARSER.parseDelimitedFrom(input, extensionRegistry);
+    }
+    public static org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parseFrom(
+        com.google.protobuf.CodedInputStream input)
+        throws java.io.IOException {
+      return PARSER.parseFrom(input);
+    }
+    public static org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parseFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return PARSER.parseFrom(input, extensionRegistry);
+    }
+
+    public static Builder newBuilder() { return Builder.create(); }
+    public Builder newBuilderForType() { return newBuilder(); }
+    public static Builder newBuilder(org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor prototype) {
+      return newBuilder().mergeFrom(prototype);
+    }
+    public Builder toBuilder() { return newBuilder(this); }
+
+    @java.lang.Override
+    protected Builder newBuilderForType(
+        com.google.protobuf.GeneratedMessage.BuilderParent parent) {
+      Builder builder = new Builder(parent);
+      return builder;
+    }
+    /**
+     * Protobuf type {@code hbase.pb.Cursor}
+     *
+     * 
+     **
+     * Scan cursor to tell client where we are scanning.
+     * 

+     */
+    public static final class Builder extends
+        com.google.protobuf.GeneratedMessage.Builder
+       implements org.apache.hadoop.hbase.protobuf.generated.ClientProtos.CursorOrBuilder {
+      public static final com.google.protobuf.Descriptors.Descriptor
+          getDescriptor() {
+        return org.apache.hadoop.hbase.protobuf.generated.ClientProtos.internal_static_hbase_pb_Cursor_descriptor;
+      }
+
+      protected com.google.protobuf.GeneratedMessage.FieldAccessorTable
+          internalGetFieldAccessorTable() {
+        return org.apache.hadoop.hbase.protobuf.generated.ClientProtos.internal_static_hbase_pb_Cursor_fieldAccessorTable
+            .ensureFieldAccessorsInitialized(
+                org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.class, org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.Builder.class);
+      }
+
+      // Construct using org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.newBuilder()
+      private Builder() {
+        maybeForceBuilderInitialization();
+      }
+
+      private Builder(
+          com.google.protobuf.GeneratedMessage.BuilderParent parent) {
+        super(parent);
+        maybeForceBuilderInitialization();
+      }
+      private void maybeForceBuilderInitialization() {
+        if (com.google.protobuf.GeneratedMessage.alwaysUseFieldBuilders) {
+        }
+      }
+      private static Builder create() {
+        return new Builder();
+      }
+
+      public Builder clear() {
+        super.clear();
+        row_ = com.google.protobuf.ByteString.EMPTY;
+        bitField0_ = (bitField0_ & ~0x00000001);
+        return this;
+      }
+
+      public Builder clone() {
+        return create().mergeFrom(buildPartial());
+      }
+
+      public com.google.protobuf.Descriptors.Descriptor
+          getDescriptorForType() {
+        return org.apache.hadoop.hbase.protobuf.generated.ClientProtos.internal_static_hbase_pb_Cursor_descriptor;
+      }
+
+      public org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor getDefaultInstanceForType() {
+        return org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.getDefaultInstance();
+      }
+
+      public org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor build() {
+        org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor result = buildPartial();
+        if (!result.isInitialized()) {
+          throw newUninitializedMessageException(result);
+        }
+        return result;
+      }
+
+      public org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor buildPartial() {
+        org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor result = new org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor(this);
+        int from_bitField0_ = bitField0_;
+        int to_bitField0_ = 0;
+        if (((from_bitField0_ & 0x00000001) == 0x00000001)) {
+          to_bitField0_ |= 0x00000001;
+        }
+        result.row_ = row_;
+        result.bitField0_ = to_bitField0_;
+        onBuilt();
+        return result;
+      }
+
+      public Builder mergeFrom(com.google.protobuf.Message other) {
+        if (other instanceof org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor) {
+          return mergeFrom((org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor)other);
+        } else {
+          super.mergeFrom(other);
+          return this;
+        }
+      }
+
+      public Builder mergeFrom(org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor other) {
+        if (other == org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.getDefaultInstance()) return this;
+        if (other.hasRow()) {
+          setRow(other.getRow());
+        }
+        this.mergeUnknownFields(other.getUnknownFields());
+        return this;
+      }
+
+      public final boolean isInitialized() {
+        return true;
+      }
+
+      public Builder mergeFrom(
+          com.google.protobuf.CodedInputStream input,
+          com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+          throws java.io.IOException {
+        org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor parsedMessage = null;
+        try {
+          parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+          parsedMessage = (org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor) e.getUnfinishedMessage();
+          throw e;
+        } finally {
+          if (parsedMessage != null) {
+            mergeFrom(parsedMessage);
+          }
+        }
+        return this;
+      }
+      private int bitField0_;
+
+      // optional bytes row = 1;
+      private com.google.protobuf.ByteString row_ = com.google.protobuf.ByteString.EMPTY;
+      /**
+       * optional bytes row = 1;
+       */
+      public boolean hasRow() {
+        return ((bitField0_ & 0x00000001) == 0x00000001);
+      }
+      /**
+       * optional bytes row = 1;
+       */
+      public com.google.protobuf.ByteString getRow() {
+        return row_;
+      }
+      /**
+       * optional bytes row = 1;
+       */
+      public Builder setRow(com.google.protobuf.ByteString value) {
+        if (value == null) {
+    throw new NullPointerException();
+  }
+  bitField0_ |= 0x00000001;
+        row_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       * optional bytes row = 1;
+       */
+      public Builder clearRow() {
+        bitField0_ = (bitField0_ & ~0x00000001);
+        row_ = getDefaultInstance().getRow();
+        onChanged();
+        return this;
+      }
+
+      // @@protoc_insertion_point(builder_scope:hbase.pb.Cursor)
+    }
+
+    static {
+      defaultInstance = new Cursor(true);
+      defaultInstance.initFields();
+    }
+
+    // @@protoc_insertion_point(class_scope:hbase.pb.Cursor)
+  }
+
   public interface ScanResponseOrBuilder
       extends com.google.protobuf.MessageOrBuilder {
 
@@ -19584,6 +20121,35 @@ public final class ClientProtos {
      * 

      */
     long getMvccReadPoint();
+
+    // optional .hbase.pb.Cursor cursor = 12;
+    /**
+     * optional .hbase.pb.Cursor cursor = 12;
+     *
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     */
+    boolean hasCursor();
+    /**
+     * optional .hbase.pb.Cursor cursor = 12;
+     *
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     */
+    org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor getCursor();
+    /**
+     * optional .hbase.pb.Cursor cursor = 12;
+     *
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     */
+    org.apache.hadoop.hbase.protobuf.generated.ClientProtos.CursorOrBuilder getCursorOrBuilder();
   }
   /**
    * Protobuf type {@code hbase.pb.ScanResponse}
@@ -19740,6 +20306,19 @@ public final class ClientProtos {
               mvccReadPoint_ = input.readUInt64();
               break;
             }
+            case 98: {
+              org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.Builder subBuilder = null;
+              if (((bitField0_ & 0x00000100) == 0x00000100)) {
+                subBuilder = cursor_.toBuilder();
+              }
+              cursor_ = input.readMessage(org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.PARSER, extensionRegistry);
+              if (subBuilder != null) {
+                subBuilder.mergeFrom(cursor_);
+                cursor_ = subBuilder.buildPartial();
+              }
+              bitField0_ |= 0x00000100;
+              break;
+            }
           }
         }
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
@@ -20151,6 +20730,43 @@ public final class ClientProtos {
       return mvccReadPoint_;
     }
 
+    // optional .hbase.pb.Cursor cursor = 12;
+    public static final int CURSOR_FIELD_NUMBER = 12;
+    private org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor cursor_;
+    /**
+     * optional .hbase.pb.Cursor cursor = 12;
+     *
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     */
+    public boolean hasCursor() {
+      return ((bitField0_ & 0x00000100) == 0x00000100);
+    }
+    /**
+     * optional .hbase.pb.Cursor cursor = 12;
+     *
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     */
+    public org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor getCursor() {
+      return cursor_;
+    }
+    /**
+     * optional .hbase.pb.Cursor cursor = 12;
+     *
+     * 
+     * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+     * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+     * 

+     */
+    public org.apache.hadoop.hbase.protobuf.generated.ClientProtos.CursorOrBuilder getCursorOrBuilder() {
+      return cursor_;
+    }
+
     private void initFields() {
       cellsPerResult_ = java.util.Collections.emptyList();
       scannerId_ = 0L;
@@ -20163,6 +20779,7 @@ public final class ClientProtos {
       heartbeatMessage_ = false;
       scanMetrics_ = org.apache.hadoop.hbase.protobuf.generated.MapReduceProtos.ScanMetrics.getDefaultInstance();
       mvccReadPoint_ = 0L;
+      cursor_ = org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.getDefaultInstance();
     }
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
@@ -20209,6 +20826,9 @@ public final class ClientProtos {
       if (((bitField0_ & 0x00000080) == 0x00000080)) {
         output.writeUInt64(11, mvccReadPoint_);
       }
+      if (((bitField0_ & 0x00000100) == 0x00000100)) {
+        output.writeMessage(12, cursor_);
+      }
       getUnknownFields().writeTo(output);
     }
 
@@ -20269,6 +20889,10 @@ public final class ClientProtos {
         size += com.google.protobuf.CodedOutputStream
           .computeUInt64Size(11, mvccReadPoint_);
       }
+      if (((bitField0_ & 0x00000100) == 0x00000100)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeMessageSize(12, cursor_);
+      }
       size += getUnknownFields().getSerializedSize();
       memoizedSerializedSize = size;
       return size;
@@ -20338,6 +20962,11 @@ public final class ClientProtos {
         result = result && (getMvccReadPoint()
             == other.getMvccReadPoint());
       }
+      result = result && (hasCursor() == other.hasCursor());
+      if (hasCursor()) {
+        result = result && getCursor()
+            .equals(other.getCursor());
+      }
       result = result &&
           getUnknownFields().equals(other.getUnknownFields());
       return result;
@@ -20395,6 +21024,10 @@ public final class ClientProtos {
         hash = (37 * hash) + MVCC_READ_POINT_FIELD_NUMBER;
         hash = (53 * hash) + hashLong(getMvccReadPoint());
       }
+      if (hasCursor()) {
+        hash = (37 * hash) + CURSOR_FIELD_NUMBER;
+        hash = (53 * hash) + getCursor().hashCode();
+      }
       hash = (29 * hash) + getUnknownFields().hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -20504,6 +21137,7 @@ public final class ClientProtos {
         if (com.google.protobuf.GeneratedMessage.alwaysUseFieldBuilders) {
           getResultsFieldBuilder();
           getScanMetricsFieldBuilder();
+          getCursorFieldBuilder();
         }
       }
       private static Builder create() {
@@ -20542,6 +21176,12 @@ public final class ClientProtos {
         bitField0_ = (bitField0_ & ~0x00000200);
         mvccReadPoint_ = 0L;
         bitField0_ = (bitField0_ & ~0x00000400);
+        if (cursorBuilder_ == null) {
+          cursor_ = org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.getDefaultInstance();
+        } else {
+          cursorBuilder_.clear();
+        }
+        bitField0_ = (bitField0_ & ~0x00000800);
         return this;
       }
 
@@ -20625,6 +21265,14 @@ public final class ClientProtos {
           to_bitField0_ |= 0x00000080;
         }
         result.mvccReadPoint_ = mvccReadPoint_;
+        if (((from_bitField0_ & 0x00000800) == 0x00000800)) {
+          to_bitField0_ |= 0x00000100;
+        }
+        if (cursorBuilder_ == null) {
+          result.cursor_ = cursor_;
+        } else {
+          result.cursor_ = cursorBuilder_.build();
+        }
         result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
@@ -20711,6 +21359,9 @@ public final class ClientProtos {
         if (other.hasMvccReadPoint()) {
           setMvccReadPoint(other.getMvccReadPoint());
         }
+        if (other.hasCursor()) {
+          mergeCursor(other.getCursor());
+        }
         this.mergeUnknownFields(other.getUnknownFields());
         return this;
       }
@@ -21836,6 +22487,168 @@ public final class ClientProtos {
         return this;
       }
 
+      // optional .hbase.pb.Cursor cursor = 12;
+      private org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor cursor_ = org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.getDefaultInstance();
+      private com.google.protobuf.SingleFieldBuilder<
+          org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor, org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.Builder, org.apache.hadoop.hbase.protobuf.generated.ClientProtos.CursorOrBuilder> cursorBuilder_;
+      /**
+       * optional .hbase.pb.Cursor cursor = 12;
+       *
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       */
+      public boolean hasCursor() {
+        return ((bitField0_ & 0x00000800) == 0x00000800);
+      }
+      /**
+       * optional .hbase.pb.Cursor cursor = 12;
+       *
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       */
+      public org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor getCursor() {
+        if (cursorBuilder_ == null) {
+          return cursor_;
+        } else {
+          return cursorBuilder_.getMessage();
+        }
+      }
+      /**
+       * optional .hbase.pb.Cursor cursor = 12;
+       *
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       */
+      public Builder setCursor(org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor value) {
+        if (cursorBuilder_ == null) {
+          if (value == null) {
+            throw new NullPointerException();
+          }
+          cursor_ = value;
+          onChanged();
+        } else {
+          cursorBuilder_.setMessage(value);
+        }
+        bitField0_ |= 0x00000800;
+        return this;
+      }
+      /**
+       * optional .hbase.pb.Cursor cursor = 12;
+       *
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       */
+      public Builder setCursor(
+          org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.Builder builderForValue) {
+        if (cursorBuilder_ == null) {
+          cursor_ = builderForValue.build();
+          onChanged();
+        } else {
+          cursorBuilder_.setMessage(builderForValue.build());
+        }
+        bitField0_ |= 0x00000800;
+        return this;
+      }
+      /**
+       * optional .hbase.pb.Cursor cursor = 12;
+       *
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       */
+      public Builder mergeCursor(org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor value) {
+        if (cursorBuilder_ == null) {
+          if (((bitField0_ & 0x00000800) == 0x00000800) &&
+              cursor_ != org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.getDefaultInstance()) {
+            cursor_ =
+              org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.newBuilder(cursor_).mergeFrom(value).buildPartial();
+          } else {
+            cursor_ = value;
+          }
+          onChanged();
+        } else {
+          cursorBuilder_.mergeFrom(value);
+        }
+        bitField0_ |= 0x00000800;
+        return this;
+      }
+      /**
+       * optional .hbase.pb.Cursor cursor = 12;
+       *
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       */
+      public Builder clearCursor() {
+        if (cursorBuilder_ == null) {
+          cursor_ = org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.getDefaultInstance();
+          onChanged();
+        } else {
+          cursorBuilder_.clear();
+        }
+        bitField0_ = (bitField0_ & ~0x00000800);
+        return this;
+      }
+      /**
+       * optional .hbase.pb.Cursor cursor = 12;
+       *
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       */
+      public org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.Builder getCursorBuilder() {
+        bitField0_ |= 0x00000800;
+        onChanged();
+        return getCursorFieldBuilder().getBuilder();
+      }
+      /**
+       * optional .hbase.pb.Cursor cursor = 12;
+       *
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       */
+      public org.apache.hadoop.hbase.protobuf.generated.ClientProtos.CursorOrBuilder getCursorOrBuilder() {
+        if (cursorBuilder_ != null) {
+          return cursorBuilder_.getMessageOrBuilder();
+        } else {
+          return cursor_;
+        }
+      }
+      /**
+       * optional .hbase.pb.Cursor cursor = 12;
+       *
+       * 
+       * If the Scan need cursor, return the row key we are scanning in heartbeat message.
+       * If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+       * 

+       */
+      private com.google.protobuf.SingleFieldBuilder<
+          org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor, org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.Builder, org.apache.hadoop.hbase.protobuf.generated.ClientProtos.CursorOrBuilder>
+          getCursorFieldBuilder() {
+        if (cursorBuilder_ == null) {
+          cursorBuilder_ = new com.google.protobuf.SingleFieldBuilder<
+              org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor, org.apache.hadoop.hbase.protobuf.generated.ClientProtos.Cursor.Builder, org.apache.hadoop.hbase.protobuf.generated.ClientProtos.CursorOrBuilder>(
+                  cursor_,
+                  getParentForChildren(),
+                  isClean());
+          cursor_ = null;
+        }
+        return cursorBuilder_;
+      }
+
       // @@protoc_insertion_point(builder_scope:hbase.pb.ScanResponse)
     }
 
@@ -40063,6 +40876,11 @@ public final class ClientProtos {
   private static
     com.google.protobuf.GeneratedMessage.FieldAccessorTable
       internal_static_hbase_pb_ScanRequest_fieldAccessorTable;
+  private static com.google.protobuf.Descriptors.Descriptor
+    internal_static_hbase_pb_Cursor_descriptor;
+  private static
+    com.google.protobuf.GeneratedMessage.FieldAccessorTable
+      internal_static_hbase_pb_Cursor_fieldAccessorTable;
   private static com.google.protobuf.Descriptors.Descriptor
     internal_static_hbase_pb_ScanResponse_descriptor;
   private static
@@ -40232,7 +41050,7 @@ public final class ClientProtos {
       "tion\030\003 \001(\0132\023.hbase.pb.Condition\022\023\n\013nonce" +
       "_group\030\004 \001(\004\"E\n\016MutateResponse\022 \n\006result" +
       "\030\001 \001(\0132\020.hbase.pb.Result\022\021\n\tprocessed\030\002 " +
-      "\001(\010\"\203\006\n\004Scan\022 \n\006column\030\001 \003(\0132\020.hbase.pb." +
+      "\001(\010\"\246\006\n\004Scan\022 \n\006column\030\001 \003(\0132\020.hbase.pb." +
       "Column\022*\n\tattribute\030\002 \003(\0132\027.hbase.pb.Nam" +
       "eBytesPair\022\021\n\tstart_row\030\003 \001(\014\022\020\n\010stop_ro" +
       "w\030\004 \001(\014\022 \n\006filter\030\005 \001(\0132\020.hbase.pb.Filte" +
@@ -40250,99 +41068,101 @@ public final class ClientProtos {
       "nt\030\024 \001(\004:\0010\022\037\n\021include_start_row\030\025 \001(\010:\004" +
       "true\022\037\n\020include_stop_row\030\026 \001(\010:\005false\0222\n" +
       "\010readType\030\027 \001(\0162\027.hbase.pb.Scan.ReadType" +
-      ":\007DEFAULT\".\n\010ReadType\022\013\n\007DEFAULT\020\000\022\n\n\006ST" +
-      "REAM\020\001\022\t\n\005PREAD\020\002\"\300\002\n\013ScanRequest\022)\n\006reg" +
-      "ion\030\001 \001(\0132\031.hbase.pb.RegionSpecifier\022\034\n\004" +
-      "scan\030\002 \001(\0132\016.hbase.pb.Scan\022\022\n\nscanner_id" +
-      "\030\003 \001(\004\022\026\n\016number_of_rows\030\004 \001(\r\022\025\n\rclose_" +
-      "scanner\030\005 \001(\010\022\025\n\rnext_call_seq\030\006 \001(\004\022\037\n\027" +
-      "client_handles_partials\030\007 \001(\010\022!\n\031client_",
-      "handles_heartbeats\030\010 \001(\010\022\032\n\022track_scan_m" +
-      "etrics\030\t \001(\010\022\024\n\005renew\030\n \001(\010:\005false\022\030\n\rli" +
-      "mit_of_rows\030\013 \001(\r:\0010\"\266\002\n\014ScanResponse\022\030\n" +
-      "\020cells_per_result\030\001 \003(\r\022\022\n\nscanner_id\030\002 " +
-      "\001(\004\022\024\n\014more_results\030\003 \001(\010\022\013\n\003ttl\030\004 \001(\r\022!" +
-      "\n\007results\030\005 \003(\0132\020.hbase.pb.Result\022\r\n\005sta" +
-      "le\030\006 \001(\010\022\037\n\027partial_flag_per_result\030\007 \003(" +
-      "\010\022\036\n\026more_results_in_region\030\010 \001(\010\022\031\n\021hea" +
-      "rtbeat_message\030\t \001(\010\022+\n\014scan_metrics\030\n \001" +
-      "(\0132\025.hbase.pb.ScanMetrics\022\032\n\017mvcc_read_p",
-      "oint\030\013 \001(\004:\0010\"\240\002\n\024BulkLoadHFileRequest\022)" +
-      "\n\006region\030\001 \002(\0132\031.hbase.pb.RegionSpecifie" +
-      "r\022>\n\013family_path\030\002 \003(\0132).hbase.pb.BulkLo" +
-      "adHFileRequest.FamilyPath\022\026\n\016assign_seq_" +
-      "num\030\003 \001(\010\022+\n\010fs_token\030\004 \001(\0132\031.hbase.pb.D" +
-      "elegationToken\022\022\n\nbulk_token\030\005 \001(\t\022\030\n\tco" +
-      "py_file\030\006 \001(\010:\005false\032*\n\nFamilyPath\022\016\n\006fa" +
-      "mily\030\001 \002(\014\022\014\n\004path\030\002 \002(\t\"\'\n\025BulkLoadHFil" +
-      "eResponse\022\016\n\006loaded\030\001 \002(\010\"V\n\017DelegationT" +
-      "oken\022\022\n\nidentifier\030\001 \001(\014\022\020\n\010password\030\002 \001",
-      "(\014\022\014\n\004kind\030\003 \001(\t\022\017\n\007service\030\004 \001(\t\"l\n\026Pre" +
-      "pareBulkLoadRequest\022\'\n\ntable_name\030\001 \002(\0132" +
-      "\023.hbase.pb.TableName\022)\n\006region\030\002 \001(\0132\031.h" +
-      "base.pb.RegionSpecifier\"-\n\027PrepareBulkLo" +
-      "adResponse\022\022\n\nbulk_token\030\001 \002(\t\"W\n\026Cleanu" +
-      "pBulkLoadRequest\022\022\n\nbulk_token\030\001 \002(\t\022)\n\006" +
-      "region\030\002 \001(\0132\031.hbase.pb.RegionSpecifier\"" +
-      "\031\n\027CleanupBulkLoadResponse\"a\n\026Coprocesso" +
-      "rServiceCall\022\013\n\003row\030\001 \002(\014\022\024\n\014service_nam" +
-      "e\030\002 \002(\t\022\023\n\013method_name\030\003 \002(\t\022\017\n\007request\030",
-      "\004 \002(\014\"B\n\030CoprocessorServiceResult\022&\n\005val" +
-      "ue\030\001 \001(\0132\027.hbase.pb.NameBytesPair\"v\n\031Cop" +
-      "rocessorServiceRequest\022)\n\006region\030\001 \002(\0132\031" +
-      ".hbase.pb.RegionSpecifier\022.\n\004call\030\002 \002(\0132" +
-      " .hbase.pb.CoprocessorServiceCall\"o\n\032Cop" +
-      "rocessorServiceResponse\022)\n\006region\030\001 \002(\0132" +
-      "\031.hbase.pb.RegionSpecifier\022&\n\005value\030\002 \002(" +
-      "\0132\027.hbase.pb.NameBytesPair\"\226\001\n\006Action\022\r\n" +
-      "\005index\030\001 \001(\r\022)\n\010mutation\030\002 \001(\0132\027.hbase.p" +
-      "b.MutationProto\022\032\n\003get\030\003 \001(\0132\r.hbase.pb.",
-      "Get\0226\n\014service_call\030\004 \001(\0132 .hbase.pb.Cop" +
-      "rocessorServiceCall\"k\n\014RegionAction\022)\n\006r" +
-      "egion\030\001 \002(\0132\031.hbase.pb.RegionSpecifier\022\016" +
-      "\n\006atomic\030\002 \001(\010\022 \n\006action\030\003 \003(\0132\020.hbase.p" +
-      "b.Action\"c\n\017RegionLoadStats\022\027\n\014memstoreL" +
-      "oad\030\001 \001(\005:\0010\022\030\n\rheapOccupancy\030\002 \001(\005:\0010\022\035" +
-      "\n\022compactionPressure\030\003 \001(\005:\0010\"j\n\024MultiRe" +
-      "gionLoadStats\022)\n\006region\030\001 \003(\0132\031.hbase.pb" +
-      ".RegionSpecifier\022\'\n\004stat\030\002 \003(\0132\031.hbase.p" +
-      "b.RegionLoadStats\"\336\001\n\021ResultOrException\022",
-      "\r\n\005index\030\001 \001(\r\022 \n\006result\030\002 \001(\0132\020.hbase.p" +
-      "b.Result\022*\n\texception\030\003 \001(\0132\027.hbase.pb.N" +
-      "ameBytesPair\022:\n\016service_result\030\004 \001(\0132\".h" +
-      "base.pb.CoprocessorServiceResult\0220\n\tload" +
-      "Stats\030\005 \001(\0132\031.hbase.pb.RegionLoadStatsB\002" +
-      "\030\001\"x\n\022RegionActionResult\0226\n\021resultOrExce" +
-      "ption\030\001 \003(\0132\033.hbase.pb.ResultOrException" +
-      "\022*\n\texception\030\002 \001(\0132\027.hbase.pb.NameBytes" +
-      "Pair\"x\n\014MultiRequest\022,\n\014regionAction\030\001 \003" +
-      "(\0132\026.hbase.pb.RegionAction\022\022\n\nnonceGroup",
-      "\030\002 \001(\004\022&\n\tcondition\030\003 \001(\0132\023.hbase.pb.Con" +
-      "dition\"\226\001\n\rMultiResponse\0228\n\022regionAction" +
-      "Result\030\001 \003(\0132\034.hbase.pb.RegionActionResu" +
-      "lt\022\021\n\tprocessed\030\002 \001(\010\0228\n\020regionStatistic" +
-      "s\030\003 \001(\0132\036.hbase.pb.MultiRegionLoadStats*" +
-      "\'\n\013Consistency\022\n\n\006STRONG\020\000\022\014\n\010TIMELINE\020\001" +
-      "2\263\005\n\rClientService\0222\n\003Get\022\024.hbase.pb.Get" +
-      "Request\032\025.hbase.pb.GetResponse\022;\n\006Mutate" +
-      "\022\027.hbase.pb.MutateRequest\032\030.hbase.pb.Mut" +
-      "ateResponse\0225\n\004Scan\022\025.hbase.pb.ScanReque",
-      "st\032\026.hbase.pb.ScanResponse\022P\n\rBulkLoadHF" +
-      "ile\022\036.hbase.pb.BulkLoadHFileRequest\032\037.hb" +
-      "ase.pb.BulkLoadHFileResponse\022V\n\017PrepareB" +
-      "ulkLoad\022 .hbase.pb.PrepareBulkLoadReques" +
-      "t\032!.hbase.pb.PrepareBulkLoadResponse\022V\n\017" +
-      "CleanupBulkLoad\022 .hbase.pb.CleanupBulkLo" +
-      "adRequest\032!.hbase.pb.CleanupBulkLoadResp" +
-      "onse\022X\n\013ExecService\022#.hbase.pb.Coprocess" +
-      "orServiceRequest\032$.hbase.pb.CoprocessorS" +
-      "erviceResponse\022d\n\027ExecRegionServerServic",
-      "e\022#.hbase.pb.CoprocessorServiceRequest\032$" +
-      ".hbase.pb.CoprocessorServiceResponse\0228\n\005" +
-      "Multi\022\026.hbase.pb.MultiRequest\032\027.hbase.pb" +
-      ".MultiResponseBB\n*org.apache.hadoop.hbas" +
-      "e.protobuf.generatedB\014ClientProtosH\001\210\001\001\240" +
-      "\001\001"
+      ":\007DEFAULT\022!\n\022need_cursor_result\030\030 \001(\010:\005f" +
+      "alse\".\n\010ReadType\022\013\n\007DEFAULT\020\000\022\n\n\006STREAM\020" +
+      "\001\022\t\n\005PREAD\020\002\"\300\002\n\013ScanRequest\022)\n\006region\030\001" +
+      " \001(\0132\031.hbase.pb.RegionSpecifier\022\034\n\004scan\030" +
+      "\002 \001(\0132\016.hbase.pb.Scan\022\022\n\nscanner_id\030\003 \001(" +
+      "\004\022\026\n\016number_of_rows\030\004 \001(\r\022\025\n\rclose_scann" +
+      "er\030\005 \001(\010\022\025\n\rnext_call_seq\030\006 \001(\004\022\037\n\027clien",
+      "t_handles_partials\030\007 \001(\010\022!\n\031client_handl" +
+      "es_heartbeats\030\010 \001(\010\022\032\n\022track_scan_metric" +
+      "s\030\t \001(\010\022\024\n\005renew\030\n \001(\010:\005false\022\030\n\rlimit_o" +
+      "f_rows\030\013 \001(\r:\0010\"\025\n\006Cursor\022\013\n\003row\030\001 \001(\014\"\330" +
+      "\002\n\014ScanResponse\022\030\n\020cells_per_result\030\001 \003(" +
+      "\r\022\022\n\nscanner_id\030\002 \001(\004\022\024\n\014more_results\030\003 " +
+      "\001(\010\022\013\n\003ttl\030\004 \001(\r\022!\n\007results\030\005 \003(\0132\020.hbas" +
+      "e.pb.Result\022\r\n\005stale\030\006 \001(\010\022\037\n\027partial_fl" +
+      "ag_per_result\030\007 \003(\010\022\036\n\026more_results_in_r" +
+      "egion\030\010 \001(\010\022\031\n\021heartbeat_message\030\t \001(\010\022+",
+      "\n\014scan_metrics\030\n \001(\0132\025.hbase.pb.ScanMetr" +
+      "ics\022\032\n\017mvcc_read_point\030\013 \001(\004:\0010\022 \n\006curso" +
+      "r\030\014 \001(\0132\020.hbase.pb.Cursor\"\240\002\n\024BulkLoadHF" +
+      "ileRequest\022)\n\006region\030\001 \002(\0132\031.hbase.pb.Re" +
+      "gionSpecifier\022>\n\013family_path\030\002 \003(\0132).hba" +
+      "se.pb.BulkLoadHFileRequest.FamilyPath\022\026\n" +
+      "\016assign_seq_num\030\003 \001(\010\022+\n\010fs_token\030\004 \001(\0132" +
+      "\031.hbase.pb.DelegationToken\022\022\n\nbulk_token" +
+      "\030\005 \001(\t\022\030\n\tcopy_file\030\006 \001(\010:\005false\032*\n\nFami" +
+      "lyPath\022\016\n\006family\030\001 \002(\014\022\014\n\004path\030\002 \002(\t\"\'\n\025",
+      "BulkLoadHFileResponse\022\016\n\006loaded\030\001 \002(\010\"V\n" +
+      "\017DelegationToken\022\022\n\nidentifier\030\001 \001(\014\022\020\n\010" +
+      "password\030\002 \001(\014\022\014\n\004kind\030\003 \001(\t\022\017\n\007service\030" +
+      "\004 \001(\t\"l\n\026PrepareBulkLoadRequest\022\'\n\ntable" +
+      "_name\030\001 \002(\0132\023.hbase.pb.TableName\022)\n\006regi" +
+      "on\030\002 \001(\0132\031.hbase.pb.RegionSpecifier\"-\n\027P" +
+      "repareBulkLoadResponse\022\022\n\nbulk_token\030\001 \002" +
+      "(\t\"W\n\026CleanupBulkLoadRequest\022\022\n\nbulk_tok" +
+      "en\030\001 \002(\t\022)\n\006region\030\002 \001(\0132\031.hbase.pb.Regi" +
+      "onSpecifier\"\031\n\027CleanupBulkLoadResponse\"a",
+      "\n\026CoprocessorServiceCall\022\013\n\003row\030\001 \002(\014\022\024\n" +
+      "\014service_name\030\002 \002(\t\022\023\n\013method_name\030\003 \002(\t" +
+      "\022\017\n\007request\030\004 \002(\014\"B\n\030CoprocessorServiceR" +
+      "esult\022&\n\005value\030\001 \001(\0132\027.hbase.pb.NameByte" +
+      "sPair\"v\n\031CoprocessorServiceRequest\022)\n\006re" +
+      "gion\030\001 \002(\0132\031.hbase.pb.RegionSpecifier\022.\n" +
+      "\004call\030\002 \002(\0132 .hbase.pb.CoprocessorServic" +
+      "eCall\"o\n\032CoprocessorServiceResponse\022)\n\006r" +
+      "egion\030\001 \002(\0132\031.hbase.pb.RegionSpecifier\022&" +
+      "\n\005value\030\002 \002(\0132\027.hbase.pb.NameBytesPair\"\226",
+      "\001\n\006Action\022\r\n\005index\030\001 \001(\r\022)\n\010mutation\030\002 \001" +
+      "(\0132\027.hbase.pb.MutationProto\022\032\n\003get\030\003 \001(\013" +
+      "2\r.hbase.pb.Get\0226\n\014service_call\030\004 \001(\0132 ." +
+      "hbase.pb.CoprocessorServiceCall\"k\n\014Regio" +
+      "nAction\022)\n\006region\030\001 \002(\0132\031.hbase.pb.Regio" +
+      "nSpecifier\022\016\n\006atomic\030\002 \001(\010\022 \n\006action\030\003 \003" +
+      "(\0132\020.hbase.pb.Action\"c\n\017RegionLoadStats\022" +
+      "\027\n\014memstoreLoad\030\001 \001(\005:\0010\022\030\n\rheapOccupanc" +
+      "y\030\002 \001(\005:\0010\022\035\n\022compactionPressure\030\003 \001(\005:\001" +
+      "0\"j\n\024MultiRegionLoadStats\022)\n\006region\030\001 \003(",
+      "\0132\031.hbase.pb.RegionSpecifier\022\'\n\004stat\030\002 \003" +
+      "(\0132\031.hbase.pb.RegionLoadStats\"\336\001\n\021Result" +
+      "OrException\022\r\n\005index\030\001 \001(\r\022 \n\006result\030\002 \001" +
+      "(\0132\020.hbase.pb.Result\022*\n\texception\030\003 \001(\0132" +
+      "\027.hbase.pb.NameBytesPair\022:\n\016service_resu" +
+      "lt\030\004 \001(\0132\".hbase.pb.CoprocessorServiceRe" +
+      "sult\0220\n\tloadStats\030\005 \001(\0132\031.hbase.pb.Regio" +
+      "nLoadStatsB\002\030\001\"x\n\022RegionActionResult\0226\n\021" +
+      "resultOrException\030\001 \003(\0132\033.hbase.pb.Resul" +
+      "tOrException\022*\n\texception\030\002 \001(\0132\027.hbase.",
+      "pb.NameBytesPair\"x\n\014MultiRequest\022,\n\014regi" +
+      "onAction\030\001 \003(\0132\026.hbase.pb.RegionAction\022\022" +
+      "\n\nnonceGroup\030\002 \001(\004\022&\n\tcondition\030\003 \001(\0132\023." +
+      "hbase.pb.Condition\"\226\001\n\rMultiResponse\0228\n\022" +
+      "regionActionResult\030\001 \003(\0132\034.hbase.pb.Regi" +
+      "onActionResult\022\021\n\tprocessed\030\002 \001(\010\0228\n\020reg" +
+      "ionStatistics\030\003 \001(\0132\036.hbase.pb.MultiRegi" +
+      "onLoadStats*\'\n\013Consistency\022\n\n\006STRONG\020\000\022\014" +
+      "\n\010TIMELINE\020\0012\263\005\n\rClientService\0222\n\003Get\022\024." +
+      "hbase.pb.GetRequest\032\025.hbase.pb.GetRespon",
+      "se\022;\n\006Mutate\022\027.hbase.pb.MutateRequest\032\030." +
+      "hbase.pb.MutateResponse\0225\n\004Scan\022\025.hbase." +
+      "pb.ScanRequest\032\026.hbase.pb.ScanResponse\022P" +
+      "\n\rBulkLoadHFile\022\036.hbase.pb.BulkLoadHFile" +
+      "Request\032\037.hbase.pb.BulkLoadHFileResponse" +
+      "\022V\n\017PrepareBulkLoad\022 .hbase.pb.PrepareBu" +
+      "lkLoadRequest\032!.hbase.pb.PrepareBulkLoad" +
+      "Response\022V\n\017CleanupBulkLoad\022 .hbase.pb.C" +
+      "leanupBulkLoadRequest\032!.hbase.pb.Cleanup" +
+      "BulkLoadResponse\022X\n\013ExecService\022#.hbase.",
+      "pb.CoprocessorServiceRequest\032$.hbase.pb." +
+      "CoprocessorServiceResponse\022d\n\027ExecRegion" +
+      "ServerService\022#.hbase.pb.CoprocessorServ" +
+      "iceRequest\032$.hbase.pb.CoprocessorService" +
+      "Response\0228\n\005Multi\022\026.hbase.pb.MultiReques" +
+      "t\032\027.hbase.pb.MultiResponseBB\n*org.apache" +
+      ".hadoop.hbase.protobuf.generatedB\014Client" +
+      "ProtosH\001\210\001\001\240\001\001"
     };
     com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner assigner =
       new com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner() {
@@ -40432,21 +41252,27 @@ public final class ClientProtos {
           internal_static_hbase_pb_Scan_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_Scan_descriptor,
-              new java.lang.String[] { "Column", "Attribute", "StartRow", "StopRow", "Filter", "TimeRange", "MaxVersions", "CacheBlocks", "BatchSize", "MaxResultSize", "StoreLimit", "StoreOffset", "LoadColumnFamiliesOnDemand", "Small", "Reversed", "Consistency", "Caching", "AllowPartialResults", "CfTimeRange", "MvccReadPoint", "IncludeStartRow", "IncludeStopRow", "ReadType", });
+              new java.lang.String[] { "Column", "Attribute", "StartRow", "StopRow", "Filter", "TimeRange", "MaxVersions", "CacheBlocks", "BatchSize", "MaxResultSize", "StoreLimit", "StoreOffset", "LoadColumnFamiliesOnDemand", "Small", "Reversed", "Consistency", "Caching", "AllowPartialResults", "CfTimeRange", "MvccReadPoint", "IncludeStartRow", "IncludeStopRow", "ReadType", "NeedCursorResult", });
           internal_static_hbase_pb_ScanRequest_descriptor =
             getDescriptor().getMessageTypes().get(12);
           internal_static_hbase_pb_ScanRequest_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_ScanRequest_descriptor,
               new java.lang.String[] { "Region", "Scan", "ScannerId", "NumberOfRows", "CloseScanner", "NextCallSeq", "ClientHandlesPartials", "ClientHandlesHeartbeats", "TrackScanMetrics", "Renew", "LimitOfRows", });
-          internal_static_hbase_pb_ScanResponse_descriptor =
+          internal_static_hbase_pb_Cursor_descriptor =
             getDescriptor().getMessageTypes().get(13);
+          internal_static_hbase_pb_Cursor_fieldAccessorTable = new
+            com.google.protobuf.GeneratedMessage.FieldAccessorTable(
+              internal_static_hbase_pb_Cursor_descriptor,
+              new java.lang.String[] { "Row", });
+          internal_static_hbase_pb_ScanResponse_descriptor =
+            getDescriptor().getMessageTypes().get(14);
           internal_static_hbase_pb_ScanResponse_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_ScanResponse_descriptor,
-              new java.lang.String[] { "CellsPerResult", "ScannerId", "MoreResults", "Ttl", "Results", "Stale", "PartialFlagPerResult", "MoreResultsInRegion", "HeartbeatMessage", "ScanMetrics", "MvccReadPoint", });
+              new java.lang.String[] { "CellsPerResult", "ScannerId", "MoreResults", "Ttl", "Results", "Stale", "PartialFlagPerResult", "MoreResultsInRegion", "HeartbeatMessage", "ScanMetrics", "MvccReadPoint", "Cursor", });
           internal_static_hbase_pb_BulkLoadHFileRequest_descriptor =
-            getDescriptor().getMessageTypes().get(14);
+            getDescriptor().getMessageTypes().get(15);
           internal_static_hbase_pb_BulkLoadHFileRequest_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_BulkLoadHFileRequest_descriptor,
@@ -40458,109 +41284,109 @@ public final class ClientProtos {
               internal_static_hbase_pb_BulkLoadHFileRequest_FamilyPath_descriptor,
               new java.lang.String[] { "Family", "Path", });
           internal_static_hbase_pb_BulkLoadHFileResponse_descriptor =
-            getDescriptor().getMessageTypes().get(15);
+            getDescriptor().getMessageTypes().get(16);
           internal_static_hbase_pb_BulkLoadHFileResponse_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_BulkLoadHFileResponse_descriptor,
               new java.lang.String[] { "Loaded", });
           internal_static_hbase_pb_DelegationToken_descriptor =
-            getDescriptor().getMessageTypes().get(16);
+            getDescriptor().getMessageTypes().get(17);
           internal_static_hbase_pb_DelegationToken_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_DelegationToken_descriptor,
               new java.lang.String[] { "Identifier", "Password", "Kind", "Service", });
           internal_static_hbase_pb_PrepareBulkLoadRequest_descriptor =
-            getDescriptor().getMessageTypes().get(17);
+            getDescriptor().getMessageTypes().get(18);
           internal_static_hbase_pb_PrepareBulkLoadRequest_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_PrepareBulkLoadRequest_descriptor,
               new java.lang.String[] { "TableName", "Region", });
           internal_static_hbase_pb_PrepareBulkLoadResponse_descriptor =
-            getDescriptor().getMessageTypes().get(18);
+            getDescriptor().getMessageTypes().get(19);
           internal_static_hbase_pb_PrepareBulkLoadResponse_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_PrepareBulkLoadResponse_descriptor,
               new java.lang.String[] { "BulkToken", });
           internal_static_hbase_pb_CleanupBulkLoadRequest_descriptor =
-            getDescriptor().getMessageTypes().get(19);
+            getDescriptor().getMessageTypes().get(20);
           internal_static_hbase_pb_CleanupBulkLoadRequest_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_CleanupBulkLoadRequest_descriptor,
               new java.lang.String[] { "BulkToken", "Region", });
           internal_static_hbase_pb_CleanupBulkLoadResponse_descriptor =
-            getDescriptor().getMessageTypes().get(20);
+            getDescriptor().getMessageTypes().get(21);
           internal_static_hbase_pb_CleanupBulkLoadResponse_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_CleanupBulkLoadResponse_descriptor,
               new java.lang.String[] { });
           internal_static_hbase_pb_CoprocessorServiceCall_descriptor =
-            getDescriptor().getMessageTypes().get(21);
+            getDescriptor().getMessageTypes().get(22);
           internal_static_hbase_pb_CoprocessorServiceCall_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_CoprocessorServiceCall_descriptor,
               new java.lang.String[] { "Row", "ServiceName", "MethodName", "Request", });
           internal_static_hbase_pb_CoprocessorServiceResult_descriptor =
-            getDescriptor().getMessageTypes().get(22);
+            getDescriptor().getMessageTypes().get(23);
           internal_static_hbase_pb_CoprocessorServiceResult_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_CoprocessorServiceResult_descriptor,
               new java.lang.String[] { "Value", });
           internal_static_hbase_pb_CoprocessorServiceRequest_descriptor =
-            getDescriptor().getMessageTypes().get(23);
+            getDescriptor().getMessageTypes().get(24);
           internal_static_hbase_pb_CoprocessorServiceRequest_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_CoprocessorServiceRequest_descriptor,
               new java.lang.String[] { "Region", "Call", });
           internal_static_hbase_pb_CoprocessorServiceResponse_descriptor =
-            getDescriptor().getMessageTypes().get(24);
+            getDescriptor().getMessageTypes().get(25);
           internal_static_hbase_pb_CoprocessorServiceResponse_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_CoprocessorServiceResponse_descriptor,
               new java.lang.String[] { "Region", "Value", });
           internal_static_hbase_pb_Action_descriptor =
-            getDescriptor().getMessageTypes().get(25);
+            getDescriptor().getMessageTypes().get(26);
           internal_static_hbase_pb_Action_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_Action_descriptor,
               new java.lang.String[] { "Index", "Mutation", "Get", "ServiceCall", });
           internal_static_hbase_pb_RegionAction_descriptor =
-            getDescriptor().getMessageTypes().get(26);
+            getDescriptor().getMessageTypes().get(27);
           internal_static_hbase_pb_RegionAction_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_RegionAction_descriptor,
               new java.lang.String[] { "Region", "Atomic", "Action", });
           internal_static_hbase_pb_RegionLoadStats_descriptor =
-            getDescriptor().getMessageTypes().get(27);
+            getDescriptor().getMessageTypes().get(28);
           internal_static_hbase_pb_RegionLoadStats_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_RegionLoadStats_descriptor,
               new java.lang.String[] { "MemstoreLoad", "HeapOccupancy", "CompactionPressure", });
           internal_static_hbase_pb_MultiRegionLoadStats_descriptor =
-            getDescriptor().getMessageTypes().get(28);
+            getDescriptor().getMessageTypes().get(29);
           internal_static_hbase_pb_MultiRegionLoadStats_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_MultiRegionLoadStats_descriptor,
               new java.lang.String[] { "Region", "Stat", });
           internal_static_hbase_pb_ResultOrException_descriptor =
-            getDescriptor().getMessageTypes().get(29);
+            getDescriptor().getMessageTypes().get(30);
           internal_static_hbase_pb_ResultOrException_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_ResultOrException_descriptor,
               new java.lang.String[] { "Index", "Result", "Exception", "ServiceResult", "LoadStats", });
           internal_static_hbase_pb_RegionActionResult_descriptor =
-            getDescriptor().getMessageTypes().get(30);
+            getDescriptor().getMessageTypes().get(31);
           internal_static_hbase_pb_RegionActionResult_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_RegionActionResult_descriptor,
               new java.lang.String[] { "ResultOrException", "Exception", });
           internal_static_hbase_pb_MultiRequest_descriptor =
-            getDescriptor().getMessageTypes().get(31);
+            getDescriptor().getMessageTypes().get(32);
           internal_static_hbase_pb_MultiRequest_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_MultiRequest_descriptor,
               new java.lang.String[] { "RegionAction", "NonceGroup", "Condition", });
           internal_static_hbase_pb_MultiResponse_descriptor =
-            getDescriptor().getMessageTypes().get(32);
+            getDescriptor().getMessageTypes().get(33);
           internal_static_hbase_pb_MultiResponse_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_hbase_pb_MultiResponse_descriptor,
diff --git a/hbase-protocol/src/main/protobuf/Client.proto b/hbase-protocol/src/main/protobuf/Client.proto
index bbb2c455e48..725a2b5e6d1 100644
--- a/hbase-protocol/src/main/protobuf/Client.proto
+++ b/hbase-protocol/src/main/protobuf/Client.proto
@@ -259,13 +259,13 @@ message Scan {
   optional uint64 mvcc_read_point = 20 [default = 0];
   optional bool include_start_row = 21 [default = true];
   optional bool include_stop_row = 22 [default = false];
-
   enum ReadType {
     DEFAULT = 0;
     STREAM = 1;
     PREAD = 2;
   }
   optional ReadType readType = 23 [default = DEFAULT];
+  optional bool need_cursor_result = 24 [default = false];
 }
 
 /**
@@ -294,6 +294,14 @@ message ScanRequest {
   optional uint32 limit_of_rows = 11 [default = 0];
 }
 
+/**
+* Scan cursor to tell client where we are scanning.
+*
+ */
+message Cursor {
+  optional bytes row = 1;
+}
+
 /**
  * The scan response. If there are no more results, more_results will
  * be false.  If it is not specified, it means there are more.
@@ -346,6 +354,10 @@ message ScanResponse {
   // make use of this mvcc_read_point when restarting a scanner to get a consistent view
   // of a row.
   optional uint64 mvcc_read_point = 11 [default = 0];
+
+  // If the Scan need cursor, return the row key we are scanning in heartbeat message.
+  // If the Scan doesn't need a cursor, don't set this field to reduce network IO.
+  optional Cursor cursor = 12;
 }
 
 /**
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java
index 2bae0449c3d..1d049442506 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java
@@ -380,14 +380,16 @@ public class RSRpcServices implements HBaseRPCErrorHandler,
     private final RpcCallback closeCallBack;
     private final RpcCallback shippedCallback;
     private byte[] rowOfLastPartialResult;
+    private boolean needCursor;
 
     public RegionScannerHolder(String scannerName, RegionScanner s, Region r,
-        RpcCallback closeCallBack, RpcCallback shippedCallback) {
+        RpcCallback closeCallBack, RpcCallback shippedCallback, boolean needCursor) {
       this.scannerName = scannerName;
       this.s = s;
       this.r = r;
       this.closeCallBack = closeCallBack;
       this.shippedCallback = shippedCallback;
+      this.needCursor = needCursor;
     }
 
     public long getNextCallSeq() {
@@ -1295,8 +1297,8 @@ public class RSRpcServices implements HBaseRPCErrorHandler,
     return lastBlock;
   }
 
-  private RegionScannerHolder addScanner(String scannerName, RegionScanner s, Region r)
-      throws LeaseStillHeldException {
+  private RegionScannerHolder addScanner(String scannerName, RegionScanner s, Region r,
+      boolean needCursor) throws LeaseStillHeldException {
     Lease lease = regionServer.leases.createLease(scannerName, this.scannerLeaseTimeoutPeriod,
       new ScannerListener(scannerName));
     RpcCallback shippedCallback = new RegionScannerShippedCallBack(scannerName, s, lease);
@@ -1307,7 +1309,7 @@ public class RSRpcServices implements HBaseRPCErrorHandler,
       closeCallback = new RegionScannerCloseCallBack(s);
     }
     RegionScannerHolder rsh =
-        new RegionScannerHolder(scannerName, s, r, closeCallback, shippedCallback);
+        new RegionScannerHolder(scannerName, s, r, closeCallback, shippedCallback, needCursor);
     RegionScannerHolder existing = scanners.putIfAbsent(scannerName, rsh);
     assert existing == null : "scannerId must be unique within regionserver's whole lifecycle!";
     return rsh;
@@ -2857,7 +2859,7 @@ public class RSRpcServices implements HBaseRPCErrorHandler,
     builder.setMvccReadPoint(scanner.getMvccReadPoint());
     builder.setTtl(scannerLeaseTimeoutPeriod);
     String scannerName = String.valueOf(scannerId);
-    return addScanner(scannerName, scanner, region);
+    return addScanner(scannerName, scanner, region, scan.isNeedCursorResult());
   }
 
   private void checkScanNextCallSeq(ScanRequest request, RegionScannerHolder rsh)
@@ -3054,6 +3056,12 @@ public class RSRpcServices implements HBaseRPCErrorHandler,
             if (moreRows) {
               // Heartbeat messages occur when the time limit has been reached.
               builder.setHeartbeatMessage(timeLimitReached);
+              if (timeLimitReached && rsh.needCursor) {
+                Cell readingCell = scannerContext.getPeekedCellInHeartbeat();
+                if (readingCell != null ) {
+                  builder.setCursor(ProtobufUtil.toCursor(readingCell));
+                }
+              }
             }
             break;
           }
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ScannerContext.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ScannerContext.java
index 19c106bbaa8..2bab82e51cc 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ScannerContext.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ScannerContext.java
@@ -19,6 +19,9 @@ package org.apache.hadoop.hbase.regionserver;
 
 import java.util.List;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.HBaseInterfaceAudience;
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.classification.InterfaceStability;
@@ -94,6 +97,8 @@ public class ScannerContext {
   boolean keepProgress;
   private static boolean DEFAULT_KEEP_PROGRESS = false;
 
+  private Cell peekedCellInHeartbeat = null;
+
   /**
    * Tracks the relevant server side metrics during scans. null when metrics should not be tracked
    */
@@ -328,6 +333,14 @@ public class ScannerContext {
         || checkTimeLimit(checkerScope);
   }
 
+  public Cell getPeekedCellInHeartbeat() {
+    return peekedCellInHeartbeat;
+  }
+
+  public void setPeekedCellInHeartbeat(Cell peekedCellInHeartbeat) {
+    this.peekedCellInHeartbeat = peekedCellInHeartbeat;
+  }
+
   @Override
   public String toString() {
     StringBuilder sb = new StringBuilder();
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java
index b063060b7fb..4593a4dddbe 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java
@@ -585,6 +585,7 @@ public class StoreScanner extends NonReversedNonLazyKeyValueScanner
       if ((kvsScanned % cellsPerHeartbeatCheck == 0)) {
         scannerContext.updateTimeProgress();
         if (scannerContext.checkTimeLimit(LimitScope.BETWEEN_CELLS)) {
+          scannerContext.setPeekedCellInHeartbeat(prevCell);
           return scannerContext.setScannerState(NextState.TIME_LIMIT_REACHED).hasMoreValues();
         }
       }
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestScannerCursor.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestScannerCursor.java
new file mode 100644
index 00000000000..e40b808f194
--- /dev/null
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestScannerCursor.java
@@ -0,0 +1,191 @@
+/**
+ * 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.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.Cell;
+import org.apache.hadoop.hbase.CellUtil;
+import org.apache.hadoop.hbase.HBaseTestingUtility;
+import org.apache.hadoop.hbase.HConstants;
+import org.apache.hadoop.hbase.HTestConst;
+import org.apache.hadoop.hbase.KeyValue;
+import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.Put;
+import org.apache.hadoop.hbase.client.Result;
+import org.apache.hadoop.hbase.client.ResultScanner;
+import org.apache.hadoop.hbase.client.Scan;
+import org.apache.hadoop.hbase.client.Table;
+import org.apache.hadoop.hbase.filter.Filter;
+import org.apache.hadoop.hbase.filter.FilterBase;
+import org.apache.hadoop.hbase.testclassification.MediumTests;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.apache.hadoop.hbase.util.Threads;
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+@Category(MediumTests.class)
+public class TestScannerCursor {
+
+  private static final Log LOG =
+      LogFactory.getLog(TestScannerCursor.class);
+
+  private final static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
+
+  private static Table TABLE = null;
+
+  /**
+   * Table configuration
+   */
+  private static TableName TABLE_NAME = TableName.valueOf("TestScannerCursor");
+
+  private static int NUM_ROWS = 5;
+  private static byte[] ROW = Bytes.toBytes("testRow");
+  private static byte[][] ROWS = HTestConst.makeNAscii(ROW, NUM_ROWS);
+
+  private static int NUM_FAMILIES = 2;
+  private static byte[] FAMILY = Bytes.toBytes("testFamily");
+  private static byte[][] FAMILIES = HTestConst.makeNAscii(FAMILY, NUM_FAMILIES);
+
+  private static int NUM_QUALIFIERS = 2;
+  private static byte[] QUALIFIER = Bytes.toBytes("testQualifier");
+  private static byte[][] QUALIFIERS = HTestConst.makeNAscii(QUALIFIER, NUM_QUALIFIERS);
+
+  private static int VALUE_SIZE = 10;
+  private static byte[] VALUE = Bytes.createMaxByteArray(VALUE_SIZE);
+
+  private static final int TIMEOUT = 4000;
+
+  @BeforeClass
+  public static void setUpBeforeClass() throws Exception {
+    Configuration conf = TEST_UTIL.getConfiguration();
+
+    conf.setInt(HConstants.HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD, TIMEOUT);
+    conf.setInt(HConstants.HBASE_RPC_TIMEOUT_KEY, TIMEOUT);
+
+    // Check the timeout condition after every cell
+    conf.setLong(StoreScanner.HBASE_CELLS_SCANNED_PER_HEARTBEAT_CHECK, 1);
+    TEST_UTIL.startMiniCluster(1);
+
+    TABLE = createTestTable(TABLE_NAME, ROWS, FAMILIES, QUALIFIERS, VALUE);
+
+  }
+
+  static Table createTestTable(TableName name, byte[][] rows, byte[][] families,
+      byte[][] qualifiers, byte[] cellValue) throws IOException {
+    Table ht = TEST_UTIL.createTable(name, families);
+    List puts = createPuts(rows, families, qualifiers, cellValue);
+    ht.put(puts);
+    return ht;
+  }
+
+  static ArrayList createPuts(byte[][] rows, byte[][] families, byte[][] qualifiers,
+      byte[] value) throws IOException {
+    Put put;
+    ArrayList puts = new ArrayList<>();
+
+    for (int row = 0; row < rows.length; row++) {
+      put = new Put(rows[row]);
+      for (int fam = 0; fam < families.length; fam++) {
+        for (int qual = 0; qual < qualifiers.length; qual++) {
+          KeyValue kv = new KeyValue(rows[row], families[fam], qualifiers[qual], qual, value);
+          put.add(kv);
+        }
+      }
+      puts.add(put);
+    }
+
+    return puts;
+  }
+
+  @AfterClass
+  public static void tearDownAfterClass() throws Exception {
+    TEST_UTIL.shutdownMiniCluster();
+  }
+
+  public static class SparseFilter extends FilterBase {
+
+    @Override
+    public ReturnCode filterKeyValue(Cell v) throws IOException {
+      Threads.sleep(TIMEOUT / 2 + 100);
+      return Bytes.equals(CellUtil.cloneRow(v), ROWS[NUM_ROWS - 1]) ? ReturnCode.INCLUDE
+          : ReturnCode.SKIP;
+    }
+
+    public static Filter parseFrom(final byte[] pbBytes) {
+      return new SparseFilter();
+    }
+  }
+
+  @Test
+  public void testHeartbeatWithSparseFilter() throws Exception {
+    Scan scan = new Scan();
+    scan.setMaxResultSize(Long.MAX_VALUE);
+    scan.setCaching(Integer.MAX_VALUE);
+    scan.setNeedCursorResult(true);
+    scan.setAllowPartialResults(true);
+    scan.setFilter(new SparseFilter());
+    try(ResultScanner scanner = TABLE.getScanner(scan)) {
+      int num = 0;
+      Result r;
+      while ((r = scanner.next()) != null) {
+
+        if (num < (NUM_ROWS - 1) * NUM_FAMILIES * NUM_QUALIFIERS) {
+          Assert.assertTrue(r.isCursor());
+          Assert.assertArrayEquals(ROWS[num / NUM_FAMILIES / NUM_QUALIFIERS], r.getCursor().getRow());
+        } else {
+          Assert.assertFalse(r.isCursor());
+          Assert.assertArrayEquals(ROWS[num / NUM_FAMILIES / NUM_QUALIFIERS], r.getRow());
+        }
+        num++;
+      }
+    }
+  }
+
+  @Test
+  public void testSizeLimit() throws IOException {
+    Scan scan = new Scan();
+    scan.setMaxResultSize(1);
+    scan.setCaching(Integer.MAX_VALUE);
+    scan.setNeedCursorResult(true);
+    try (ResultScanner scanner = TABLE.getScanner(scan)) {
+      int num = 0;
+      Result r;
+      while ((r = scanner.next()) != null) {
+
+        if (num % (NUM_FAMILIES * NUM_QUALIFIERS) != (NUM_FAMILIES * NUM_QUALIFIERS)-1) {
+          Assert.assertTrue(r.isCursor());
+          Assert.assertArrayEquals(ROWS[num / NUM_FAMILIES / NUM_QUALIFIERS], r.getCursor().getRow());
+        } else {
+          Assert.assertFalse(r.isCursor());
+          Assert.assertArrayEquals(ROWS[num / NUM_FAMILIES / NUM_QUALIFIERS], r.getRow());
+        }
+        num++;
+      }
+    }
+  }
+
+}