Bug 2597: Batch modification operations in TransactionProxy
[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / test / java / org / opendaylight / controller / cluster / datastore / TransactionProxyTest.java
index bdcca42d15c45553d6feb8ff6cc9bd7a792795dc..6573308c12100914badbedc5d0296b90e096a2b7 100644 (file)
@@ -1,20 +1,57 @@
 package org.opendaylight.controller.cluster.datastore;
 
-import akka.actor.ActorPath;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Matchers.argThat;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Matchers.isA;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.opendaylight.controller.cluster.datastore.TransactionProxy.TransactionType.READ_ONLY;
+import static org.opendaylight.controller.cluster.datastore.TransactionProxy.TransactionType.READ_WRITE;
+import static org.opendaylight.controller.cluster.datastore.TransactionProxy.TransactionType.WRITE_ONLY;
 import akka.actor.ActorRef;
 import akka.actor.ActorSelection;
+import akka.actor.ActorSystem;
 import akka.actor.Props;
 import akka.dispatch.Futures;
+import akka.testkit.JavaTestKit;
 import com.google.common.base.Optional;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Uninterruptibles;
+import com.typesafe.config.Config;
+import com.typesafe.config.ConfigFactory;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+import org.junit.AfterClass;
+import org.junit.Assert;
 import org.junit.Before;
+import org.junit.BeforeClass;
 import org.junit.Test;
+import org.mockito.ArgumentCaptor;
 import org.mockito.ArgumentMatcher;
+import org.mockito.InOrder;
 import org.mockito.Mock;
+import org.mockito.Mockito;
 import org.mockito.MockitoAnnotations;
+import org.opendaylight.controller.cluster.datastore.DatastoreContext.Builder;
 import org.opendaylight.controller.cluster.datastore.TransactionProxy.TransactionType;
 import org.opendaylight.controller.cluster.datastore.exceptions.PrimaryNotFoundException;
 import org.opendaylight.controller.cluster.datastore.exceptions.TimeoutException;
+import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
+import org.opendaylight.controller.cluster.datastore.messages.BatchedModificationsReply;
 import org.opendaylight.controller.cluster.datastore.messages.CloseTransaction;
 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
 import org.opendaylight.controller.cluster.datastore.messages.DataExists;
@@ -29,44 +66,33 @@ import org.opendaylight.controller.cluster.datastore.messages.ReadyTransaction;
 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
 import org.opendaylight.controller.cluster.datastore.messages.WriteData;
 import org.opendaylight.controller.cluster.datastore.messages.WriteDataReply;
+import org.opendaylight.controller.cluster.datastore.modification.AbstractModification;
+import org.opendaylight.controller.cluster.datastore.modification.DeleteModification;
+import org.opendaylight.controller.cluster.datastore.modification.MergeModification;
+import org.opendaylight.controller.cluster.datastore.modification.Modification;
+import org.opendaylight.controller.cluster.datastore.modification.WriteModification;
 import org.opendaylight.controller.cluster.datastore.shardstrategy.DefaultShardStrategy;
 import org.opendaylight.controller.cluster.datastore.shardstrategy.ShardStrategyFactory;
 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
 import org.opendaylight.controller.cluster.datastore.utils.DoNothingActor;
 import org.opendaylight.controller.cluster.datastore.utils.MockConfiguration;
+import org.opendaylight.controller.md.cluster.datastore.model.CarsModel;
 import org.opendaylight.controller.md.cluster.datastore.model.TestModel;
 import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
+import org.opendaylight.controller.protobuff.messages.transaction.ShardTransactionMessages;
 import org.opendaylight.controller.protobuff.messages.transaction.ShardTransactionMessages.CreateTransactionReply;
 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
 import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNodes;
 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 import scala.concurrent.Await;
 import scala.concurrent.Future;
+import scala.concurrent.Promise;
 import scala.concurrent.duration.Duration;
 
-import java.util.List;
-import java.util.concurrent.TimeUnit;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
-import static org.mockito.Matchers.any;
-import static org.mockito.Matchers.anyString;
-import static org.mockito.Mockito.argThat;
-import static org.mockito.Mockito.doReturn;
-import static org.mockito.Mockito.doThrow;
-import static org.mockito.Mockito.eq;
-import static org.mockito.Mockito.isA;
-import static org.mockito.Mockito.times;
-import static org.mockito.Mockito.verify;
-import static org.opendaylight.controller.cluster.datastore.TransactionProxy.TransactionType.READ_ONLY;
-import static org.opendaylight.controller.cluster.datastore.TransactionProxy.TransactionType.READ_WRITE;
-import static org.opendaylight.controller.cluster.datastore.TransactionProxy.TransactionType.WRITE_ONLY;
-
 @SuppressWarnings("resource")
-public class TransactionProxyTest extends AbstractActorTest {
+public class TransactionProxyTest {
 
     @SuppressWarnings("serial")
     static class TestException extends RuntimeException {
@@ -76,6 +102,8 @@ public class TransactionProxyTest extends AbstractActorTest {
         CheckedFuture<?, ReadFailedException> invoke(TransactionProxy proxy) throws Exception;
     }
 
+    private static ActorSystem system;
+
     private final Configuration configuration = new MockConfiguration();
 
     @Mock
@@ -83,7 +111,29 @@ public class TransactionProxyTest extends AbstractActorTest {
 
     private SchemaContext schemaContext;
 
-    String memberName = "mock-member";
+    @Mock
+    private ClusterWrapper mockClusterWrapper;
+
+    private final String memberName = "mock-member";
+
+    private final Builder dataStoreContextBuilder = DatastoreContext.newBuilder().operationTimeoutInSeconds(2).
+            shardBatchedModificationCount(1);
+
+    @BeforeClass
+    public static void setUpClass() throws IOException {
+
+        Config config = ConfigFactory.parseMap(ImmutableMap.<String, Object>builder().
+                put("akka.actor.default-dispatcher.type",
+                        "akka.testkit.CallingThreadDispatcherConfigurator").build()).
+                withFallback(ConfigFactory.load());
+        system = ActorSystem.create("test", config);
+    }
+
+    @AfterClass
+    public static void tearDownClass() throws IOException {
+        JavaTestKit.shutdownActorSystem(system);
+        system = null;
+    }
 
     @Before
     public void setUp(){
@@ -92,27 +142,40 @@ public class TransactionProxyTest extends AbstractActorTest {
         schemaContext = TestModel.createTestContext();
 
         doReturn(getSystem()).when(mockActorContext).getActorSystem();
+        doReturn(getSystem().dispatchers().defaultGlobalDispatcher()).when(mockActorContext).getClientDispatcher();
         doReturn(memberName).when(mockActorContext).getCurrentMemberName();
         doReturn(schemaContext).when(mockActorContext).getSchemaContext();
+        doReturn(mockClusterWrapper).when(mockActorContext).getClusterWrapper();
+        doReturn(mockClusterWrapper).when(mockActorContext).getClusterWrapper();
+        doReturn(dataStoreContextBuilder.build()).when(mockActorContext).getDatastoreContext();
+        doReturn(10).when(mockActorContext).getTransactionOutstandingOperationLimit();
 
         ShardStrategyFactory.setConfiguration(configuration);
     }
 
+    private ActorSystem getSystem() {
+        return system;
+    }
+
     private CreateTransaction eqCreateTransaction(final String memberName,
             final TransactionType type) {
         ArgumentMatcher<CreateTransaction> matcher = new ArgumentMatcher<CreateTransaction>() {
             @Override
             public boolean matches(Object argument) {
-                CreateTransaction obj = CreateTransaction.fromSerializable(argument);
-                return obj.getTransactionId().startsWith(memberName) &&
-                       obj.getTransactionType() == type.ordinal();
+                if(CreateTransaction.SERIALIZABLE_CLASS.equals(argument.getClass())) {
+                    CreateTransaction obj = CreateTransaction.fromSerializable(argument);
+                    return obj.getTransactionId().startsWith(memberName) &&
+                            obj.getTransactionType() == type.ordinal();
+                }
+
+                return false;
             }
         };
 
         return argThat(matcher);
     }
 
-    private DataExists eqDataExists() {
+    private DataExists eqSerializedDataExists() {
         ArgumentMatcher<DataExists> matcher = new ArgumentMatcher<DataExists>() {
             @Override
             public boolean matches(Object argument) {
@@ -124,118 +187,195 @@ public class TransactionProxyTest extends AbstractActorTest {
         return argThat(matcher);
     }
 
-    private ReadData eqReadData() {
+    private DataExists eqDataExists() {
+        ArgumentMatcher<DataExists> matcher = new ArgumentMatcher<DataExists>() {
+            @Override
+            public boolean matches(Object argument) {
+                return (argument instanceof DataExists) &&
+                    ((DataExists)argument).getPath().equals(TestModel.TEST_PATH);
+            }
+        };
+
+        return argThat(matcher);
+    }
+
+    private ReadData eqSerializedReadData() {
+        return eqSerializedReadData(TestModel.TEST_PATH);
+    }
+
+    private ReadData eqSerializedReadData(final YangInstanceIdentifier path) {
         ArgumentMatcher<ReadData> matcher = new ArgumentMatcher<ReadData>() {
             @Override
             public boolean matches(Object argument) {
                 return ReadData.SERIALIZABLE_CLASS.equals(argument.getClass()) &&
-                       ReadData.fromSerializable(argument).getPath().equals(TestModel.TEST_PATH);
+                       ReadData.fromSerializable(argument).getPath().equals(path);
+            }
+        };
+
+        return argThat(matcher);
+    }
+
+    private ReadData eqReadData() {
+        ArgumentMatcher<ReadData> matcher = new ArgumentMatcher<ReadData>() {
+            @Override
+            public boolean matches(Object argument) {
+                return (argument instanceof ReadData) &&
+                    ((ReadData)argument).getPath().equals(TestModel.TEST_PATH);
             }
         };
 
         return argThat(matcher);
     }
 
-    private WriteData eqWriteData(final NormalizedNode<?, ?> nodeToWrite) {
+    private WriteData eqLegacyWriteData(final NormalizedNode<?, ?> nodeToWrite) {
         ArgumentMatcher<WriteData> matcher = new ArgumentMatcher<WriteData>() {
             @Override
             public boolean matches(Object argument) {
-                if(!WriteData.SERIALIZABLE_CLASS.equals(argument.getClass())) {
-                    return false;
+                if(ShardTransactionMessages.WriteData.class.equals(argument.getClass())) {
+                    WriteData obj = WriteData.fromSerializable(argument);
+                    return obj.getPath().equals(TestModel.TEST_PATH) && obj.getData().equals(nodeToWrite);
                 }
 
-                WriteData obj = WriteData.fromSerializable(argument, schemaContext);
-                return obj.getPath().equals(TestModel.TEST_PATH) &&
-                       obj.getData().equals(nodeToWrite);
+                return false;
             }
         };
 
         return argThat(matcher);
     }
 
-    private MergeData eqMergeData(final NormalizedNode<?, ?> nodeToWrite) {
+    private MergeData eqLegacyMergeData(final NormalizedNode<?, ?> nodeToWrite) {
         ArgumentMatcher<MergeData> matcher = new ArgumentMatcher<MergeData>() {
             @Override
             public boolean matches(Object argument) {
-                if(!MergeData.SERIALIZABLE_CLASS.equals(argument.getClass())) {
-                    return false;
+                if(ShardTransactionMessages.MergeData.class.equals(argument.getClass())) {
+                    MergeData obj = MergeData.fromSerializable(argument);
+                    return obj.getPath().equals(TestModel.TEST_PATH) && obj.getData().equals(nodeToWrite);
                 }
 
-                MergeData obj = MergeData.fromSerializable(argument, schemaContext);
-                return obj.getPath().equals(TestModel.TEST_PATH) &&
-                       obj.getData().equals(nodeToWrite);
+                return false;
             }
         };
 
         return argThat(matcher);
     }
 
-    private DeleteData eqDeleteData() {
+    private DeleteData eqLegacyDeleteData(final YangInstanceIdentifier expPath) {
         ArgumentMatcher<DeleteData> matcher = new ArgumentMatcher<DeleteData>() {
             @Override
             public boolean matches(Object argument) {
-                return DeleteData.SERIALIZABLE_CLASS.equals(argument.getClass()) &&
-                       DeleteData.fromSerializable(argument).getPath().equals(TestModel.TEST_PATH);
+                return ShardTransactionMessages.DeleteData.class.equals(argument.getClass()) &&
+                       DeleteData.fromSerializable(argument).getPath().equals(expPath);
             }
         };
 
         return argThat(matcher);
     }
 
-    private Future<Object> readyTxReply(ActorPath path) {
+    private Future<Object> readySerializedTxReply(String path) {
         return Futures.successful((Object)new ReadyTransactionReply(path).toSerializable());
     }
 
-    private Future<Object> readDataReply(NormalizedNode<?, ?> data) {
-        return Futures.successful(new ReadDataReply(schemaContext, data).toSerializable());
+    private Future<Object> readyTxReply(String path) {
+        return Futures.successful((Object)new ReadyTransactionReply(path));
+    }
+
+    private Future<Object> readSerializedDataReply(NormalizedNode<?, ?> data,
+            short transactionVersion) {
+        return Futures.successful(new ReadDataReply(data, transactionVersion).toSerializable());
+    }
+
+    private Future<Object> readSerializedDataReply(NormalizedNode<?, ?> data) {
+        return readSerializedDataReply(data, DataStoreVersions.CURRENT_VERSION);
+    }
+
+    private Future<ReadDataReply> readDataReply(NormalizedNode<?, ?> data) {
+        return Futures.successful(new ReadDataReply(data, DataStoreVersions.CURRENT_VERSION));
     }
 
-    private Future<Object> dataExistsReply(boolean exists) {
+    private Future<Object> dataExistsSerializedReply(boolean exists) {
         return Futures.successful(new DataExistsReply(exists).toSerializable());
     }
 
-    private Future<Object> writeDataReply() {
-        return Futures.successful(new WriteDataReply().toSerializable());
+    private Future<DataExistsReply> dataExistsReply(boolean exists) {
+        return Futures.successful(new DataExistsReply(exists));
     }
 
-    private Future<Object> mergeDataReply() {
-        return Futures.successful(new MergeDataReply().toSerializable());
+    private Future<BatchedModificationsReply> batchedModificationsReply(int count) {
+        return Futures.successful(new BatchedModificationsReply(count));
     }
 
-    private Future<Object> deleteDataReply() {
-        return Futures.successful(new DeleteDataReply().toSerializable());
+    private Future<Object> incompleteFuture(){
+        return mock(Future.class);
     }
 
     private ActorSelection actorSelection(ActorRef actorRef) {
         return getSystem().actorSelection(actorRef.path());
     }
 
-    private CreateTransactionReply createTransactionReply(ActorRef actorRef){
+    private void expectBatchedModifications(ActorRef actorRef, int count) {
+        doReturn(batchedModificationsReply(count)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), isA(BatchedModifications.class));
+    }
+
+    private void expectBatchedModifications(int count) {
+        doReturn(batchedModificationsReply(count)).when(mockActorContext).executeOperationAsync(
+                any(ActorSelection.class), isA(BatchedModifications.class));
+    }
+
+    private void expectIncompleteBatchedModifications() {
+        doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
+                any(ActorSelection.class), isA(BatchedModifications.class));
+    }
+
+    private void expectReadyTransaction(ActorRef actorRef) {
+        doReturn(readySerializedTxReply(actorRef.path().toString())).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), isA(ReadyTransaction.SERIALIZABLE_CLASS));
+    }
+
+    private void expectFailedBatchedModifications(ActorRef actorRef) {
+        doReturn(Futures.failed(new TestException())).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), isA(BatchedModifications.class));
+    }
+
+    private CreateTransactionReply createTransactionReply(ActorRef actorRef, int transactionVersion){
         return CreateTransactionReply.newBuilder()
             .setTransactionActorPath(actorRef.path().toString())
-            .setTransactionId("txn-1").build();
+            .setTransactionId("txn-1")
+            .setMessageVersion(transactionVersion)
+            .build();
     }
 
-    private ActorRef setupActorContextWithInitialCreateTransaction(TransactionType type) {
-        ActorRef actorRef = getSystem().actorOf(Props.create(DoNothingActor.class));
-        doReturn(getSystem().actorSelection(actorRef.path())).
+    private ActorRef setupActorContextWithoutInitialCreateTransaction(ActorSystem actorSystem) {
+        ActorRef actorRef = actorSystem.actorOf(Props.create(DoNothingActor.class));
+        doReturn(actorSystem.actorSelection(actorRef.path())).
                 when(mockActorContext).actorSelection(actorRef.path().toString());
 
-        doReturn(Optional.of(getSystem().actorSelection(actorRef.path()))).
-                when(mockActorContext).findPrimaryShard(eq(DefaultShardStrategy.DEFAULT_SHARD));
+        doReturn(Futures.successful(actorSystem.actorSelection(actorRef.path()))).
+                when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
 
-        doReturn(createTransactionReply(actorRef)).when(mockActorContext).
-                executeOperation(eq(getSystem().actorSelection(actorRef.path())),
-                        eqCreateTransaction(memberName, type));
+        doReturn(false).when(mockActorContext).isPathLocal(actorRef.path().toString());
+
+        doReturn(10).when(mockActorContext).getTransactionOutstandingOperationLimit();
+
+        return actorRef;
+    }
 
-        doReturn(actorRef.path().toString()).when(mockActorContext).resolvePath(
-                anyString(), eq(actorRef.path().toString()));
+    private ActorRef setupActorContextWithInitialCreateTransaction(ActorSystem actorSystem,
+            TransactionType type, int transactionVersion) {
+        ActorRef actorRef = setupActorContextWithoutInitialCreateTransaction(actorSystem);
 
-        doReturn(actorRef.path()).when(mockActorContext).actorFor(actorRef.path().toString());
+        doReturn(Futures.successful(createTransactionReply(actorRef, transactionVersion))).when(mockActorContext).
+                executeOperationAsync(eq(actorSystem.actorSelection(actorRef.path())),
+                        eqCreateTransaction(memberName, type));
 
         return actorRef;
     }
 
+    private ActorRef setupActorContextWithInitialCreateTransaction(ActorSystem actorSystem, TransactionType type) {
+        return setupActorContextWithInitialCreateTransaction(actorSystem, type, DataStoreVersions.CURRENT_VERSION);
+    }
+
+
     private void propagateReadFailedExceptionCause(CheckedFuture<?, ReadFailedException> future)
             throws Throwable {
 
@@ -249,13 +389,12 @@ public class TransactionProxyTest extends AbstractActorTest {
 
     @Test
     public void testRead() throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(READ_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_ONLY);
 
-        doReturn(readDataReply(null)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqReadData());
+        doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData());
 
         Optional<NormalizedNode<?, ?>> readOptional = transactionProxy.read(
                 TestModel.TEST_PATH).get(5, TimeUnit.SECONDS);
@@ -264,8 +403,8 @@ public class TransactionProxyTest extends AbstractActorTest {
 
         NormalizedNode<?, ?> expectedNode = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(readDataReply(expectedNode)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqReadData());
+        doReturn(readSerializedDataReply(expectedNode)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData());
 
         readOptional = transactionProxy.read(TestModel.TEST_PATH).get(5, TimeUnit.SECONDS);
 
@@ -276,26 +415,24 @@ public class TransactionProxyTest extends AbstractActorTest {
 
     @Test(expected = ReadFailedException.class)
     public void testReadWithInvalidReplyMessageType() throws Exception {
-        setupActorContextWithInitialCreateTransaction(READ_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
 
         doReturn(Futures.successful(new Object())).when(mockActorContext).
-                executeOperationAsync(any(ActorSelection.class), any());
+                executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_ONLY);
 
         transactionProxy.read(TestModel.TEST_PATH).checkedGet(5, TimeUnit.SECONDS);
     }
 
     @Test(expected = TestException.class)
     public void testReadWithAsyncRemoteOperatonFailure() throws Throwable {
-        setupActorContextWithInitialCreateTransaction(READ_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
 
         doReturn(Futures.failed(new TestException())).when(mockActorContext).
-                executeOperationAsync(any(ActorSelection.class), any());
+                executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_ONLY);
 
         propagateReadFailedExceptionCause(transactionProxy.read(TestModel.TEST_PATH));
     }
@@ -305,12 +442,14 @@ public class TransactionProxyTest extends AbstractActorTest {
         ActorRef actorRef = getSystem().actorOf(Props.create(DoNothingActor.class));
 
         if (exToThrow instanceof PrimaryNotFoundException) {
-            doReturn(Optional.absent()).when(mockActorContext).findPrimaryShard(anyString());
+            doReturn(Futures.failed(exToThrow)).when(mockActorContext).findPrimaryShardAsync(anyString());
         } else {
-            doReturn(Optional.of(getSystem().actorSelection(actorRef.path()))).
-                    when(mockActorContext).findPrimaryShard(anyString());
+            doReturn(Futures.successful(getSystem().actorSelection(actorRef.path()))).
+                    when(mockActorContext).findPrimaryShardAsync(anyString());
         }
-        doThrow(exToThrow).when(mockActorContext).executeOperation(any(ActorSelection.class), any());
+
+        doReturn(Futures.failed(exToThrow)).when(mockActorContext).executeOperationAsync(
+                any(ActorSelection.class), any());
 
         TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_ONLY);
 
@@ -344,21 +483,19 @@ public class TransactionProxyTest extends AbstractActorTest {
 
     @Test(expected = TestException.class)
     public void testReadWithPriorRecordingOperationFailure() throws Throwable {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(READ_WRITE);
+        doReturn(dataStoreContextBuilder.shardBatchedModificationCount(2).build()).
+                when(mockActorContext).getDatastoreContext();
 
-        NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
-        doReturn(writeDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqWriteData(nodeToWrite));
+        NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(Futures.failed(new TestException())).when(mockActorContext).
-                executeOperationAsync(eq(actorSelection(actorRef)), eqDeleteData());
+        expectFailedBatchedModifications(actorRef);
 
-        doReturn(readDataReply(null)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqReadData());
+        doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
 
         transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
@@ -368,24 +505,22 @@ public class TransactionProxyTest extends AbstractActorTest {
             propagateReadFailedExceptionCause(transactionProxy.read(TestModel.TEST_PATH));
         } finally {
             verify(mockActorContext, times(0)).executeOperationAsync(
-                    eq(actorSelection(actorRef)), eqReadData());
+                    eq(actorSelection(actorRef)), eqSerializedReadData());
         }
     }
 
     @Test
     public void testReadWithPriorRecordingOperationSuccessful() throws Throwable {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(READ_WRITE);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
         NormalizedNode<?, ?> expectedNode = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(writeDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqWriteData(expectedNode));
+        expectBatchedModifications(actorRef, 1);
 
-        doReturn(readDataReply(expectedNode)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqReadData());
+        doReturn(readSerializedDataReply(expectedNode)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
 
         transactionProxy.write(TestModel.TEST_PATH, expectedNode);
 
@@ -393,35 +528,55 @@ public class TransactionProxyTest extends AbstractActorTest {
                 TestModel.TEST_PATH).get(5, TimeUnit.SECONDS);
 
         assertEquals("NormalizedNode isPresent", true, readOptional.isPresent());
-
         assertEquals("Response NormalizedNode", expectedNode, readOptional.get());
+
+        InOrder inOrder = Mockito.inOrder(mockActorContext);
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), isA(BatchedModifications.class));
+
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData());
     }
 
     @Test(expected=IllegalStateException.class)
     public void testReadPreConditionCheck() {
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
+        transactionProxy.read(TestModel.TEST_PATH);
+    }
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+    @Test(expected=IllegalArgumentException.class)
+    public void testInvalidCreateTransactionReply() throws Throwable {
+        ActorRef actorRef = getSystem().actorOf(Props.create(DoNothingActor.class));
 
-        transactionProxy.read(TestModel.TEST_PATH);
+        doReturn(getSystem().actorSelection(actorRef.path())).when(mockActorContext).
+            actorSelection(actorRef.path().toString());
+
+        doReturn(Futures.successful(getSystem().actorSelection(actorRef.path()))).
+            when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
+
+        doReturn(Futures.successful(new Object())).when(mockActorContext).executeOperationAsync(
+            eq(getSystem().actorSelection(actorRef.path())), eqCreateTransaction(memberName, READ_ONLY));
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_ONLY);
+
+        propagateReadFailedExceptionCause(transactionProxy.read(TestModel.TEST_PATH));
     }
 
     @Test
     public void testExists() throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(READ_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_ONLY);
 
-        doReturn(dataExistsReply(false)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqDataExists());
+        doReturn(dataExistsSerializedReply(false)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedDataExists());
 
         Boolean exists = transactionProxy.exists(TestModel.TEST_PATH).checkedGet();
 
         assertEquals("Exists response", false, exists);
 
-        doReturn(dataExistsReply(true)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqDataExists());
+        doReturn(dataExistsSerializedReply(true)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedDataExists());
 
         exists = transactionProxy.exists(TestModel.TEST_PATH).checkedGet();
 
@@ -440,10 +595,10 @@ public class TransactionProxyTest extends AbstractActorTest {
 
     @Test(expected = ReadFailedException.class)
     public void testExistsWithInvalidReplyMessageType() throws Exception {
-        setupActorContextWithInitialCreateTransaction(READ_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
 
         doReturn(Futures.successful(new Object())).when(mockActorContext).
-                executeOperationAsync(any(ActorSelection.class), any());
+                executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedDataExists());
 
         TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
                 READ_ONLY);
@@ -453,31 +608,29 @@ public class TransactionProxyTest extends AbstractActorTest {
 
     @Test(expected = TestException.class)
     public void testExistsWithAsyncRemoteOperatonFailure() throws Throwable {
-        setupActorContextWithInitialCreateTransaction(READ_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
 
         doReturn(Futures.failed(new TestException())).when(mockActorContext).
-                executeOperationAsync(any(ActorSelection.class), any());
+                executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedDataExists());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_ONLY);
 
         propagateReadFailedExceptionCause(transactionProxy.exists(TestModel.TEST_PATH));
     }
 
     @Test(expected = TestException.class)
     public void testExistsWithPriorRecordingOperationFailure() throws Throwable {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(READ_WRITE);
+        doReturn(dataStoreContextBuilder.shardBatchedModificationCount(2).build()).
+                when(mockActorContext).getDatastoreContext();
 
-        NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
-        doReturn(writeDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqWriteData(nodeToWrite));
+        NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(Futures.failed(new TestException())).when(mockActorContext).
-                executeOperationAsync(eq(actorSelection(actorRef)), eqDeleteData());
+        expectFailedBatchedModifications(actorRef);
 
-        doReturn(dataExistsReply(false)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqDataExists());
+        doReturn(dataExistsSerializedReply(false)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedDataExists());
 
         TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
                 READ_WRITE);
@@ -490,38 +643,40 @@ public class TransactionProxyTest extends AbstractActorTest {
             propagateReadFailedExceptionCause(transactionProxy.exists(TestModel.TEST_PATH));
         } finally {
             verify(mockActorContext, times(0)).executeOperationAsync(
-                    eq(actorSelection(actorRef)), eqDataExists());
+                    eq(actorSelection(actorRef)), eqSerializedDataExists());
         }
     }
 
     @Test
     public void testExistsWithPriorRecordingOperationSuccessful() throws Throwable {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(READ_WRITE);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(writeDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqWriteData(nodeToWrite));
+        expectBatchedModifications(actorRef, 1);
 
-        doReturn(dataExistsReply(true)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqDataExists());
+        doReturn(dataExistsSerializedReply(true)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedDataExists());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
 
         transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
         Boolean exists = transactionProxy.exists(TestModel.TEST_PATH).checkedGet();
 
         assertEquals("Exists response", true, exists);
-    }
 
-    @Test(expected=IllegalStateException.class)
-    public void testxistsPreConditionCheck() {
+        InOrder inOrder = Mockito.inOrder(mockActorContext);
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), isA(BatchedModifications.class));
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedDataExists());
+    }
 
+    @Test(expected=IllegalStateException.class)
+    public void testExistsPreConditionCheck() {
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
         transactionProxy.exists(TestModel.TEST_PATH);
     }
 
@@ -542,7 +697,7 @@ public class TransactionProxyTest extends AbstractActorTest {
                     // Expected
                 }
             } else {
-                assertEquals("Recording operation Future result type", expResultType,
+                assertEquals(String.format("Recording operation %d Future result type", i +1 ), expResultType,
                              Await.result(future, Duration.create(5, TimeUnit.SECONDS)).getClass());
             }
         }
@@ -550,99 +705,153 @@ public class TransactionProxyTest extends AbstractActorTest {
 
     @Test
     public void testWrite() throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(WRITE_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(writeDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqWriteData(nodeToWrite));
+        expectBatchedModifications(actorRef, 1);
+        expectReadyTransaction(actorRef);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
 
         transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
-        verify(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqWriteData(nodeToWrite));
+        // This sends the batched modification.
+        transactionProxy.ready();
+
+        verifyOneBatchedModification(actorRef, new WriteModification(TestModel.TEST_PATH, nodeToWrite));
 
         verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                WriteDataReply.SERIALIZABLE_CLASS);
+                BatchedModificationsReply.class);
     }
 
-    @Test(expected=IllegalStateException.class)
-    public void testWritePreConditionCheck() {
+    @Test
+    public void testWriteAfterAsyncRead() throws Throwable {
+        ActorRef actorRef = setupActorContextWithoutInitialCreateTransaction(getSystem());
+
+        Promise<Object> createTxPromise = akka.dispatch.Futures.promise();
+        doReturn(createTxPromise).when(mockActorContext).executeOperationAsync(
+                eq(getSystem().actorSelection(actorRef.path())),
+                eqCreateTransaction(memberName, READ_WRITE));
+
+        doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData());
+
+        expectBatchedModifications(actorRef, 1);
+        expectReadyTransaction(actorRef);
+
+        final NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+        final TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
+
+        final CountDownLatch readComplete = new CountDownLatch(1);
+        final AtomicReference<Throwable> caughtEx = new AtomicReference<>();
+        com.google.common.util.concurrent.Futures.addCallback(transactionProxy.read(TestModel.TEST_PATH),
+                new  FutureCallback<Optional<NormalizedNode<?, ?>>>() {
+                    @Override
+                    public void onSuccess(Optional<NormalizedNode<?, ?>> result) {
+                        try {
+                            transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+                        } catch (Exception e) {
+                            caughtEx.set(e);
+                        } finally {
+                            readComplete.countDown();
+                        }
+                    }
+
+                    @Override
+                    public void onFailure(Throwable t) {
+                        caughtEx.set(t);
+                        readComplete.countDown();
+                    }
+                });
+
+        createTxPromise.success(createTransactionReply(actorRef, DataStoreVersions.CURRENT_VERSION));
+
+        Uninterruptibles.awaitUninterruptibly(readComplete, 5, TimeUnit.SECONDS);
+
+        if(caughtEx.get() != null) {
+            throw caughtEx.get();
+        }
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        // This sends the batched modification.
+        transactionProxy.ready();
+
+        verifyOneBatchedModification(actorRef, new WriteModification(TestModel.TEST_PATH, nodeToWrite));
 
-        transactionProxy.write(TestModel.TEST_PATH,
-                ImmutableNodes.containerNode(TestModel.TEST_QNAME));
+        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
+                BatchedModificationsReply.class);
     }
 
     @Test(expected=IllegalStateException.class)
-    public void testWriteAfterReadyPreConditionCheck() {
+    public void testWritePreConditionCheck() {
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_ONLY);
+        transactionProxy.write(TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
+    }
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+    @Test(expected=IllegalStateException.class)
+    public void testWriteAfterReadyPreConditionCheck() {
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
 
         transactionProxy.ready();
 
-        transactionProxy.write(TestModel.TEST_PATH,
-                ImmutableNodes.containerNode(TestModel.TEST_QNAME));
+        transactionProxy.write(TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
     }
 
     @Test
     public void testMerge() throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(WRITE_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(mergeDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqMergeData(nodeToWrite));
+        expectBatchedModifications(actorRef, 1);
+        expectReadyTransaction(actorRef);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
 
         transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
 
-        verify(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqMergeData(nodeToWrite));
+        // This sends the batched modification.
+        transactionProxy.ready();
+
+        verifyOneBatchedModification(actorRef, new MergeModification(TestModel.TEST_PATH, nodeToWrite));
 
         verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                MergeDataReply.SERIALIZABLE_CLASS);
+                BatchedModificationsReply.class);
     }
 
     @Test
     public void testDelete() throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(WRITE_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
-        doReturn(deleteDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqDeleteData());
+        expectBatchedModifications(actorRef, 1);
+        expectReadyTransaction(actorRef);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
 
         transactionProxy.delete(TestModel.TEST_PATH);
 
-        verify(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqDeleteData());
+        // This sends the batched modification.
+        transactionProxy.ready();
+
+        verifyOneBatchedModification(actorRef, new DeleteModification(TestModel.TEST_PATH));
 
         verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                DeleteDataReply.SERIALIZABLE_CLASS);
+                BatchedModificationsReply.class);
     }
 
-    private void verifyCohortPathFutures(ThreePhaseCommitCohortProxy proxy,
-            Object... expReplies) throws Exception {
+    private void verifyCohortFutures(ThreePhaseCommitCohortProxy proxy,
+        Object... expReplies) throws Exception {
         assertEquals("getReadyOperationFutures size", expReplies.length,
-                proxy.getCohortPathFutures().size());
+                proxy.getCohortFutures().size());
 
         int i = 0;
-        for( Future<ActorPath> future: proxy.getCohortPathFutures()) {
+        for( Future<ActorSelection> future: proxy.getCohortFutures()) {
             assertNotNull("Ready operation Future is null", future);
 
             Object expReply = expReplies[i++];
-            if(expReply instanceof ActorPath) {
-                ActorPath actual = Await.result(future, Duration.create(5, TimeUnit.SECONDS));
+            if(expReply instanceof ActorSelection) {
+                ActorSelection actual = Await.result(future, Duration.create(5, TimeUnit.SECONDS));
                 assertEquals("Cohort actor path", expReply, actual);
             } else {
                 // Expecting exception.
@@ -656,24 +865,19 @@ public class TransactionProxyTest extends AbstractActorTest {
         }
     }
 
-    @SuppressWarnings("unchecked")
     @Test
     public void testReady() throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(READ_WRITE);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(readDataReply(null)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqReadData());
-
-        doReturn(writeDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqWriteData(nodeToWrite));
+        doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        doReturn(readyTxReply(actorRef.path())).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), isA(ReadyTransaction.SERIALIZABLE_CLASS));
+        expectBatchedModifications(actorRef, 1);
+        expectReadyTransaction(actorRef);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
 
         transactionProxy.read(TestModel.TEST_PATH);
 
@@ -686,31 +890,95 @@ public class TransactionProxyTest extends AbstractActorTest {
         ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
 
         verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                WriteDataReply.SERIALIZABLE_CLASS);
+                BatchedModificationsReply.class);
+
+        verifyCohortFutures(proxy, getSystem().actorSelection(actorRef.path()));
+
+        verify(mockActorContext).executeOperationAsync(eq(actorSelection(actorRef)),
+                isA(BatchedModifications.class));
+    }
+
+    private ActorRef testCompatibilityWithHeliumVersion(short version) throws Exception {
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(),
+                READ_WRITE, version);
+
+        NormalizedNode<?, ?> testNode = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+        doReturn(readSerializedDataReply(testNode, version)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData());
+
+        doReturn(Futures.successful(new WriteDataReply().toSerializable(version))).when(mockActorContext).
+                executeOperationAsync(eq(actorSelection(actorRef)), eqLegacyWriteData(testNode));
+
+        doReturn(Futures.successful(new MergeDataReply().toSerializable(version))).when(mockActorContext).
+                executeOperationAsync(eq(actorSelection(actorRef)), eqLegacyMergeData(testNode));
+
+        doReturn(Futures.successful(new DeleteDataReply().toSerializable(version))).when(mockActorContext).
+                executeOperationAsync(eq(actorSelection(actorRef)), eqLegacyDeleteData(TestModel.TEST_PATH));
+
+        expectReadyTransaction(actorRef);
+
+        doReturn(actorRef.path().toString()).when(mockActorContext).resolvePath(eq(actorRef.path().toString()),
+                eq(actorRef.path().toString()));
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
+
+        Optional<NormalizedNode<?, ?>> readOptional = transactionProxy.read(TestModel.TEST_PATH).
+                get(5, TimeUnit.SECONDS);
+
+        assertEquals("NormalizedNode isPresent", true, readOptional.isPresent());
+        assertEquals("Response NormalizedNode", testNode, readOptional.get());
+
+        transactionProxy.write(TestModel.TEST_PATH, testNode);
+
+        transactionProxy.merge(TestModel.TEST_PATH, testNode);
+
+        transactionProxy.delete(TestModel.TEST_PATH);
+
+        DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
+
+        assertTrue(ready instanceof ThreePhaseCommitCohortProxy);
+
+        ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
+
+        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
+                ShardTransactionMessages.WriteDataReply.class, ShardTransactionMessages.MergeDataReply.class,
+                ShardTransactionMessages.DeleteDataReply.class);
+
+        verifyCohortFutures(proxy, getSystem().actorSelection(actorRef.path()));
+
+        return actorRef;
+    }
 
-        verifyCohortPathFutures(proxy, actorRef.path());
+    @Test
+    public void testCompatibilityWithBaseHeliumVersion() throws Exception {
+        ActorRef actorRef = testCompatibilityWithHeliumVersion(DataStoreVersions.BASE_HELIUM_VERSION);
+
+        verify(mockActorContext).resolvePath(eq(actorRef.path().toString()),
+                eq(actorRef.path().toString()));
+    }
+
+    @Test
+    public void testCompatibilityWithHeliumR1Version() throws Exception {
+        ActorRef actorRef = testCompatibilityWithHeliumVersion(DataStoreVersions.HELIUM_1_VERSION);
+
+        verify(mockActorContext, Mockito.never()).resolvePath(eq(actorRef.path().toString()),
+                eq(actorRef.path().toString()));
     }
 
-    @SuppressWarnings("unchecked")
     @Test
     public void testReadyWithRecordingOperationFailure() throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(WRITE_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(mergeDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqMergeData(nodeToWrite));
-
-        doReturn(Futures.failed(new TestException())).when(mockActorContext).
-                executeOperationAsync(eq(actorSelection(actorRef)), eqWriteData(nodeToWrite));
+        expectFailedBatchedModifications(actorRef);
 
-        doReturn(readyTxReply(actorRef.path())).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), isA(ReadyTransaction.SERIALIZABLE_CLASS));
+        expectReadyTransaction(actorRef);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        doReturn(false).when(mockActorContext).isPathLocal(actorRef.path().toString());
 
-        transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
 
         transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
@@ -720,28 +988,24 @@ public class TransactionProxyTest extends AbstractActorTest {
 
         ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
 
-        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                MergeDataReply.SERIALIZABLE_CLASS, TestException.class);
+        verifyCohortFutures(proxy, TestException.class);
 
-        verifyCohortPathFutures(proxy, TestException.class);
+        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(), TestException.class);
     }
 
-    @SuppressWarnings("unchecked")
     @Test
     public void testReadyWithReplyFailure() throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(WRITE_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(mergeDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqMergeData(nodeToWrite));
+        expectBatchedModifications(actorRef, 1);
 
         doReturn(Futures.failed(new TestException())).when(mockActorContext).
                 executeOperationAsync(eq(actorSelection(actorRef)),
                         isA(ReadyTransaction.SERIALIZABLE_CLASS));
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
 
         transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
 
@@ -752,20 +1016,18 @@ public class TransactionProxyTest extends AbstractActorTest {
         ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
 
         verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                MergeDataReply.SERIALIZABLE_CLASS);
+                BatchedModificationsReply.class);
 
-        verifyCohortPathFutures(proxy, TestException.class);
+        verifyCohortFutures(proxy, TestException.class);
     }
 
     @Test
     public void testReadyWithInitialCreateTransactionFailure() throws Exception {
 
-        doReturn(Optional.absent()).when(mockActorContext).findPrimaryShard(anyString());
-//        doThrow(new PrimaryNotFoundException("mock")).when(mockActorContext).executeShardOperation(
-//                anyString(), any());
+        doReturn(Futures.failed(new PrimaryNotFoundException("mock"))).when(
+                mockActorContext).findPrimaryShardAsync(anyString());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
@@ -781,25 +1043,22 @@ public class TransactionProxyTest extends AbstractActorTest {
 
         ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
 
-        verifyCohortPathFutures(proxy, PrimaryNotFoundException.class);
+        verifyCohortFutures(proxy, PrimaryNotFoundException.class);
     }
 
-    @SuppressWarnings("unchecked")
     @Test
     public void testReadyWithInvalidReplyMessageType() throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(WRITE_ONLY);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(writeDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqWriteData(nodeToWrite));
+        expectBatchedModifications(actorRef, 1);
 
         doReturn(Futures.successful(new Object())).when(mockActorContext).
                 executeOperationAsync(eq(actorSelection(actorRef)),
                         isA(ReadyTransaction.SERIALIZABLE_CLASS));
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
 
         transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
@@ -809,12 +1068,12 @@ public class TransactionProxyTest extends AbstractActorTest {
 
         ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
 
-        verifyCohortPathFutures(proxy, IllegalArgumentException.class);
+        verifyCohortFutures(proxy, IllegalArgumentException.class);
     }
 
     @Test
     public void testGetIdentifier() {
-        setupActorContextWithInitialCreateTransaction(READ_ONLY);
+        setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
         TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
                 TransactionProxy.TransactionType.READ_ONLY);
 
@@ -823,16 +1082,14 @@ public class TransactionProxyTest extends AbstractActorTest {
         assertTrue("Invalid identifier: " + id, id.toString().startsWith(memberName));
     }
 
-    @SuppressWarnings("unchecked")
     @Test
     public void testClose() throws Exception{
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(READ_WRITE);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
-        doReturn(readDataReply(null)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqReadData());
+        doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
 
         transactionProxy.read(TestModel.TEST_PATH);
 
@@ -841,4 +1098,717 @@ public class TransactionProxyTest extends AbstractActorTest {
         verify(mockActorContext).sendOperationAsync(
                 eq(actorSelection(actorRef)), isA(CloseTransaction.SERIALIZABLE_CLASS));
     }
+
+
+    /**
+     * Method to test a local Tx actor. The Tx paths are matched to decide if the
+     * Tx actor is local or not. This is done by mocking the Tx actor path
+     * and the caller paths and ensuring that the paths have the remote-address format
+     *
+     * Note: Since the default akka provider for test is not a RemoteActorRefProvider,
+     * the paths returned for the actors for all the tests are not qualified remote paths.
+     * Hence are treated as non-local/remote actors. In short, all tests except
+     * few below run for remote actors
+     *
+     * @throws Exception
+     */
+    @Test
+    public void testLocalTxActorRead() throws Exception {
+        ActorSystem actorSystem = getSystem();
+        ActorRef shardActorRef = actorSystem.actorOf(Props.create(DoNothingActor.class));
+
+        doReturn(actorSystem.actorSelection(shardActorRef.path())).
+            when(mockActorContext).actorSelection(shardActorRef.path().toString());
+
+        doReturn(Futures.successful(actorSystem.actorSelection(shardActorRef.path()))).
+            when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
+
+        String actorPath = "akka.tcp://system@127.0.0.1:2550/user/tx-actor";
+        CreateTransactionReply createTransactionReply = CreateTransactionReply.newBuilder()
+            .setTransactionId("txn-1").setTransactionActorPath(actorPath).build();
+
+        doReturn(Futures.successful(createTransactionReply)).when(mockActorContext).
+            executeOperationAsync(eq(actorSystem.actorSelection(shardActorRef.path())),
+                eqCreateTransaction(memberName, READ_ONLY));
+
+        doReturn(true).when(mockActorContext).isPathLocal(actorPath);
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,READ_ONLY);
+
+        // negative test case with null as the reply
+        doReturn(readDataReply(null)).when(mockActorContext).executeOperationAsync(
+            any(ActorSelection.class), eqReadData());
+
+        Optional<NormalizedNode<?, ?>> readOptional = transactionProxy.read(
+            TestModel.TEST_PATH).get(5, TimeUnit.SECONDS);
+
+        assertEquals("NormalizedNode isPresent", false, readOptional.isPresent());
+
+        // test case with node as read data reply
+        NormalizedNode<?, ?> expectedNode = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+        doReturn(readDataReply(expectedNode)).when(mockActorContext).executeOperationAsync(
+            any(ActorSelection.class), eqReadData());
+
+        readOptional = transactionProxy.read(TestModel.TEST_PATH).get(5, TimeUnit.SECONDS);
+
+        assertEquals("NormalizedNode isPresent", true, readOptional.isPresent());
+
+        assertEquals("Response NormalizedNode", expectedNode, readOptional.get());
+
+        // test for local data exists
+        doReturn(dataExistsReply(true)).when(mockActorContext).executeOperationAsync(
+            any(ActorSelection.class), eqDataExists());
+
+        boolean exists = transactionProxy.exists(TestModel.TEST_PATH).checkedGet();
+
+        assertEquals("Exists response", true, exists);
+    }
+
+    @Test
+    public void testLocalTxActorReady() throws Exception {
+        ActorSystem actorSystem = getSystem();
+        ActorRef shardActorRef = actorSystem.actorOf(Props.create(DoNothingActor.class));
+
+        doReturn(actorSystem.actorSelection(shardActorRef.path())).
+            when(mockActorContext).actorSelection(shardActorRef.path().toString());
+
+        doReturn(Futures.successful(actorSystem.actorSelection(shardActorRef.path()))).
+            when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
+
+        String actorPath = "akka.tcp://system@127.0.0.1:2550/user/tx-actor";
+        CreateTransactionReply createTransactionReply = CreateTransactionReply.newBuilder().
+            setTransactionId("txn-1").setTransactionActorPath(actorPath).
+            setMessageVersion(DataStoreVersions.CURRENT_VERSION).build();
+
+        doReturn(Futures.successful(createTransactionReply)).when(mockActorContext).
+            executeOperationAsync(eq(actorSystem.actorSelection(shardActorRef.path())),
+                eqCreateTransaction(memberName, WRITE_ONLY));
+
+        doReturn(true).when(mockActorContext).isPathLocal(actorPath);
+
+        doReturn(batchedModificationsReply(1)).when(mockActorContext).executeOperationAsync(
+                any(ActorSelection.class), isA(BatchedModifications.class));
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
+
+        NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+        transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+
+        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
+                BatchedModificationsReply.class);
+
+        // testing ready
+        doReturn(readyTxReply(shardActorRef.path().toString())).when(mockActorContext).executeOperationAsync(
+            any(ActorSelection.class), isA(ReadyTransaction.class));
+
+        DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
+
+        assertTrue(ready instanceof ThreePhaseCommitCohortProxy);
+
+        ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
+
+        verifyCohortFutures(proxy, getSystem().actorSelection(shardActorRef.path()));
+    }
+
+    private static interface TransactionProxyOperation {
+        void run(TransactionProxy transactionProxy);
+    }
+
+    private void throttleOperation(TransactionProxyOperation operation) {
+        throttleOperation(operation, 1, true);
+    }
+
+    private void throttleOperation(TransactionProxyOperation operation, int outstandingOpsLimit, boolean shardFound){
+        ActorSystem actorSystem = getSystem();
+        ActorRef shardActorRef = actorSystem.actorOf(Props.create(DoNothingActor.class));
+
+        doReturn(outstandingOpsLimit).when(mockActorContext).getTransactionOutstandingOperationLimit();
+
+        doReturn(actorSystem.actorSelection(shardActorRef.path())).
+                when(mockActorContext).actorSelection(shardActorRef.path().toString());
+
+        if(shardFound) {
+            doReturn(Futures.successful(actorSystem.actorSelection(shardActorRef.path()))).
+                    when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
+        } else {
+            doReturn(Futures.failed(new Exception("not found")))
+                    .when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
+        }
+
+        String actorPath = "akka.tcp://system@127.0.0.1:2550/user/tx-actor";
+        CreateTransactionReply createTransactionReply = CreateTransactionReply.newBuilder().
+                setTransactionId("txn-1").setTransactionActorPath(actorPath).
+                setMessageVersion(DataStoreVersions.CURRENT_VERSION).build();
+
+        doReturn(Futures.successful(createTransactionReply)).when(mockActorContext).
+                executeOperationAsync(eq(actorSystem.actorSelection(shardActorRef.path())),
+                        eqCreateTransaction(memberName, READ_WRITE));
+
+        doReturn(true).when(mockActorContext).isPathLocal(actorPath);
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
+
+        long start = System.nanoTime();
+
+        operation.run(transactionProxy);
+
+        long end = System.nanoTime();
+
+        long expected = TimeUnit.SECONDS.toNanos(mockActorContext.getDatastoreContext().getOperationTimeoutInSeconds());
+        Assert.assertTrue(String.format("Expected elapsed time: %s. Actual: %s",
+                expected, (end-start)), (end - start) > expected);
+
+    }
+
+    private void completeOperation(TransactionProxyOperation operation){
+        completeOperation(operation, true);
+    }
+
+    private void completeOperation(TransactionProxyOperation operation, boolean shardFound){
+        ActorSystem actorSystem = getSystem();
+        ActorRef shardActorRef = actorSystem.actorOf(Props.create(DoNothingActor.class));
+
+        doReturn(1).when(mockActorContext).getTransactionOutstandingOperationLimit();
+
+        doReturn(actorSystem.actorSelection(shardActorRef.path())).
+                when(mockActorContext).actorSelection(shardActorRef.path().toString());
+
+        if(shardFound) {
+            doReturn(Futures.successful(actorSystem.actorSelection(shardActorRef.path()))).
+                    when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
+        } else {
+            doReturn(Futures.failed(new Exception("not found")))
+                    .when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
+        }
+
+        String actorPath = "akka.tcp://system@127.0.0.1:2550/user/tx-actor";
+        CreateTransactionReply createTransactionReply = CreateTransactionReply.newBuilder().
+                setTransactionId("txn-1").setTransactionActorPath(actorPath).
+                setMessageVersion(DataStoreVersions.CURRENT_VERSION).build();
+
+        doReturn(Futures.successful(createTransactionReply)).when(mockActorContext).
+                executeOperationAsync(eq(actorSystem.actorSelection(shardActorRef.path())),
+                        eqCreateTransaction(memberName, READ_WRITE));
+
+        doReturn(true).when(mockActorContext).isPathLocal(actorPath);
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
+
+        long start = System.nanoTime();
+
+        operation.run(transactionProxy);
+
+        long end = System.nanoTime();
+
+        long expected = TimeUnit.SECONDS.toNanos(mockActorContext.getDatastoreContext().getOperationTimeoutInSeconds());
+        Assert.assertTrue(String.format("Expected elapsed time: %s. Actual: %s",
+                expected, (end-start)), (end - start) <= expected);
+    }
+
+    public void testWriteThrottling(boolean shardFound){
+
+        throttleOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+                expectBatchedModifications(2);
+
+                transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+
+                transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+            }
+        }, 1, shardFound);
+    }
+
+    @Test
+    public void testWriteThrottlingWhenShardFound(){
+        throttleOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+                expectIncompleteBatchedModifications();
+
+                transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+
+                transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+            }
+        });
+    }
+
+    @Test
+    public void testWriteThrottlingWhenShardNotFound(){
+        // Confirm that there is no throttling when the Shard is not found
+        completeOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+                expectBatchedModifications(2);
+
+                transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+
+                transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+            }
+        }, false);
+
+    }
+
+
+    @Test
+    public void testWriteCompletion(){
+        completeOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+                expectBatchedModifications(2);
+
+                transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+
+                transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+            }
+        });
+    }
+
+    @Test
+    public void testMergeThrottlingWhenShardFound(){
+
+        throttleOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToMerge = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+                expectIncompleteBatchedModifications();
+
+                transactionProxy.merge(TestModel.TEST_PATH, nodeToMerge);
+
+                transactionProxy.merge(TestModel.TEST_PATH, nodeToMerge);
+            }
+        });
+    }
+
+    @Test
+    public void testMergeThrottlingWhenShardNotFound(){
+
+        completeOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToMerge = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+                expectBatchedModifications(2);
+
+                transactionProxy.merge(TestModel.TEST_PATH, nodeToMerge);
+
+                transactionProxy.merge(TestModel.TEST_PATH, nodeToMerge);
+            }
+        }, false);
+    }
+
+    @Test
+    public void testMergeCompletion(){
+        completeOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToMerge = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+                expectBatchedModifications(2);
+
+                transactionProxy.merge(TestModel.TEST_PATH, nodeToMerge);
+
+                transactionProxy.merge(TestModel.TEST_PATH, nodeToMerge);
+            }
+        });
+
+    }
+
+    @Test
+    public void testDeleteThrottlingWhenShardFound(){
+
+        throttleOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                expectIncompleteBatchedModifications();
+
+                transactionProxy.delete(TestModel.TEST_PATH);
+
+                transactionProxy.delete(TestModel.TEST_PATH);
+            }
+        });
+    }
+
+
+    @Test
+    public void testDeleteThrottlingWhenShardNotFound(){
+
+        completeOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                expectBatchedModifications(2);
+
+                transactionProxy.delete(TestModel.TEST_PATH);
+
+                transactionProxy.delete(TestModel.TEST_PATH);
+            }
+        }, false);
+    }
+
+    @Test
+    public void testDeleteCompletion(){
+        completeOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                expectBatchedModifications(2);
+
+                transactionProxy.delete(TestModel.TEST_PATH);
+
+                transactionProxy.delete(TestModel.TEST_PATH);
+            }
+        });
+
+    }
+
+    @Test
+    public void testReadThrottlingWhenShardFound(){
+
+        throttleOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
+                        any(ActorSelection.class), eqReadData());
+
+                transactionProxy.read(TestModel.TEST_PATH);
+
+                transactionProxy.read(TestModel.TEST_PATH);
+            }
+        });
+    }
+
+    @Test
+    public void testReadThrottlingWhenShardNotFound(){
+
+        completeOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
+                        any(ActorSelection.class), eqReadData());
+
+                transactionProxy.read(TestModel.TEST_PATH);
+
+                transactionProxy.read(TestModel.TEST_PATH);
+            }
+        }, false);
+    }
+
+
+    @Test
+    public void testReadCompletion(){
+        completeOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToRead = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+                doReturn(readDataReply(nodeToRead)).when(mockActorContext).executeOperationAsync(
+                        any(ActorSelection.class), eqReadData());
+
+                transactionProxy.read(TestModel.TEST_PATH);
+
+                transactionProxy.read(TestModel.TEST_PATH);
+            }
+        });
+
+    }
+
+    @Test
+    public void testExistsThrottlingWhenShardFound(){
+
+        throttleOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
+                        any(ActorSelection.class), eqDataExists());
+
+                transactionProxy.exists(TestModel.TEST_PATH);
+
+                transactionProxy.exists(TestModel.TEST_PATH);
+            }
+        });
+    }
+
+    @Test
+    public void testExistsThrottlingWhenShardNotFound(){
+
+        completeOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
+                        any(ActorSelection.class), eqDataExists());
+
+                transactionProxy.exists(TestModel.TEST_PATH);
+
+                transactionProxy.exists(TestModel.TEST_PATH);
+            }
+        }, false);
+    }
+
+
+    @Test
+    public void testExistsCompletion(){
+        completeOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                doReturn(dataExistsReply(true)).when(mockActorContext).executeOperationAsync(
+                        any(ActorSelection.class), eqDataExists());
+
+                transactionProxy.exists(TestModel.TEST_PATH);
+
+                transactionProxy.exists(TestModel.TEST_PATH);
+            }
+        });
+
+    }
+
+    @Test
+    public void testReadyThrottling(){
+
+        throttleOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+                expectBatchedModifications(1);
+
+                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
+                        any(ActorSelection.class), any(ReadyTransaction.class));
+
+                transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+
+                transactionProxy.ready();
+            }
+        });
+    }
+
+    @Test
+    public void testReadyThrottlingWithTwoTransactionContexts(){
+
+        throttleOperation(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+                NormalizedNode<?, ?> carsNode = ImmutableNodes.containerNode(CarsModel.BASE_QNAME);
+
+                expectBatchedModifications(2);
+
+                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
+                        any(ActorSelection.class), any(ReadyTransaction.class));
+
+                transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+
+                transactionProxy.write(TestModel.TEST_PATH, carsNode);
+
+                transactionProxy.ready();
+            }
+        }, 2, true);
+    }
+
+    @Test
+    public void testModificationOperationBatching() throws Throwable {
+        int shardBatchedModificationCount = 3;
+        doReturn(dataStoreContextBuilder.shardBatchedModificationCount(shardBatchedModificationCount).build()).
+                when(mockActorContext).getDatastoreContext();
+
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
+
+        expectBatchedModifications(actorRef, shardBatchedModificationCount);
+
+        expectReadyTransaction(actorRef);
+
+        YangInstanceIdentifier writePath1 = TestModel.TEST_PATH;
+        NormalizedNode<?, ?> writeNode1 = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+        YangInstanceIdentifier writePath2 = TestModel.OUTER_LIST_PATH;
+        NormalizedNode<?, ?> writeNode2 = ImmutableNodes.containerNode(TestModel.OUTER_LIST_QNAME);
+
+        YangInstanceIdentifier writePath3 = TestModel.INNER_LIST_PATH;
+        NormalizedNode<?, ?> writeNode3 = ImmutableNodes.containerNode(TestModel.INNER_LIST_QNAME);
+
+        YangInstanceIdentifier mergePath1 = TestModel.TEST_PATH;
+        NormalizedNode<?, ?> mergeNode1 = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+        YangInstanceIdentifier mergePath2 = TestModel.OUTER_LIST_PATH;
+        NormalizedNode<?, ?> mergeNode2 = ImmutableNodes.containerNode(TestModel.OUTER_LIST_QNAME);
+
+        YangInstanceIdentifier mergePath3 = TestModel.INNER_LIST_PATH;
+        NormalizedNode<?, ?> mergeNode3 = ImmutableNodes.containerNode(TestModel.INNER_LIST_QNAME);
+
+        YangInstanceIdentifier deletePath1 = TestModel.TEST_PATH;
+        YangInstanceIdentifier deletePath2 = TestModel.OUTER_LIST_PATH;
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
+
+        transactionProxy.write(writePath1, writeNode1);
+        transactionProxy.write(writePath2, writeNode2);
+        transactionProxy.delete(deletePath1);
+        transactionProxy.merge(mergePath1, mergeNode1);
+        transactionProxy.merge(mergePath2, mergeNode2);
+        transactionProxy.write(writePath3, writeNode3);
+        transactionProxy.merge(mergePath3, mergeNode3);
+        transactionProxy.delete(deletePath2);
+
+        // This sends the last batch.
+        transactionProxy.ready();
+
+        List<BatchedModifications> batchedModifications = captureBatchedModifications(actorRef);
+        assertEquals("Captured BatchedModifications count", 3, batchedModifications.size());
+
+        verifyBatchedModifications(batchedModifications.get(0), new WriteModification(writePath1, writeNode1),
+                new WriteModification(writePath2, writeNode2), new DeleteModification(deletePath1));
+
+        verifyBatchedModifications(batchedModifications.get(1), new MergeModification(mergePath1, mergeNode1),
+                new MergeModification(mergePath2, mergeNode2), new WriteModification(writePath3, writeNode3));
+
+        verifyBatchedModifications(batchedModifications.get(2), new MergeModification(mergePath3, mergeNode3),
+                new DeleteModification(deletePath2));
+
+        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
+                BatchedModificationsReply.class, BatchedModificationsReply.class, BatchedModificationsReply.class);
+    }
+
+    @Test
+    public void testModificationOperationBatchingWithInterleavedReads() throws Throwable {
+        int shardBatchedModificationCount = 10;
+        doReturn(dataStoreContextBuilder.shardBatchedModificationCount(shardBatchedModificationCount).build()).
+                when(mockActorContext).getDatastoreContext();
+
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
+
+        expectBatchedModifications(actorRef, shardBatchedModificationCount);
+
+        YangInstanceIdentifier writePath1 = TestModel.TEST_PATH;
+        NormalizedNode<?, ?> writeNode1 = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+        YangInstanceIdentifier writePath2 = TestModel.OUTER_LIST_PATH;
+        NormalizedNode<?, ?> writeNode2 = ImmutableNodes.containerNode(TestModel.OUTER_LIST_QNAME);
+
+        YangInstanceIdentifier mergePath1 = TestModel.TEST_PATH;
+        NormalizedNode<?, ?> mergeNode1 = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+        YangInstanceIdentifier mergePath2 = TestModel.INNER_LIST_PATH;
+        NormalizedNode<?, ?> mergeNode2 = ImmutableNodes.containerNode(TestModel.INNER_LIST_QNAME);
+
+        YangInstanceIdentifier deletePath = TestModel.OUTER_LIST_PATH;
+
+        doReturn(readSerializedDataReply(writeNode2)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData(writePath2));
+
+        doReturn(readSerializedDataReply(mergeNode2)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData(mergePath2));
+
+        doReturn(dataExistsSerializedReply(true)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedDataExists());
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
+
+        transactionProxy.write(writePath1, writeNode1);
+        transactionProxy.write(writePath2, writeNode2);
+
+        Optional<NormalizedNode<?, ?>> readOptional = transactionProxy.read(writePath2).
+                get(5, TimeUnit.SECONDS);
+
+        assertEquals("NormalizedNode isPresent", true, readOptional.isPresent());
+        assertEquals("Response NormalizedNode", writeNode2, readOptional.get());
+
+        transactionProxy.merge(mergePath1, mergeNode1);
+        transactionProxy.merge(mergePath2, mergeNode2);
+
+        readOptional = transactionProxy.read(mergePath2).get(5, TimeUnit.SECONDS);
+
+        transactionProxy.delete(deletePath);
+
+        Boolean exists = transactionProxy.exists(TestModel.TEST_PATH).checkedGet();
+        assertEquals("Exists response", true, exists);
+
+        assertEquals("NormalizedNode isPresent", true, readOptional.isPresent());
+        assertEquals("Response NormalizedNode", mergeNode2, readOptional.get());
+
+        List<BatchedModifications> batchedModifications = captureBatchedModifications(actorRef);
+        assertEquals("Captured BatchedModifications count", 3, batchedModifications.size());
+
+        verifyBatchedModifications(batchedModifications.get(0), new WriteModification(writePath1, writeNode1),
+                new WriteModification(writePath2, writeNode2));
+
+        verifyBatchedModifications(batchedModifications.get(1), new MergeModification(mergePath1, mergeNode1),
+                new MergeModification(mergePath2, mergeNode2));
+
+        verifyBatchedModifications(batchedModifications.get(2), new DeleteModification(deletePath));
+
+        InOrder inOrder = Mockito.inOrder(mockActorContext);
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), isA(BatchedModifications.class));
+
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData(writePath2));
+
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), isA(BatchedModifications.class));
+
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData(mergePath2));
+
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), isA(BatchedModifications.class));
+
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedDataExists());
+
+        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
+                BatchedModificationsReply.class, BatchedModificationsReply.class, BatchedModificationsReply.class);
+    }
+
+    private List<BatchedModifications> captureBatchedModifications(ActorRef actorRef) {
+        ArgumentCaptor<BatchedModifications> batchedModificationsCaptor =
+                ArgumentCaptor.forClass(BatchedModifications.class);
+        verify(mockActorContext, Mockito.atLeastOnce()).executeOperationAsync(
+                eq(actorSelection(actorRef)), batchedModificationsCaptor.capture());
+
+        List<BatchedModifications> batchedModifications = filterCaptured(
+                batchedModificationsCaptor, BatchedModifications.class);
+        return batchedModifications;
+    }
+
+    private <T> List<T> filterCaptured(ArgumentCaptor<T> captor, Class<T> type) {
+        List<T> captured = new ArrayList<>();
+        for(T c: captor.getAllValues()) {
+            if(type.isInstance(c)) {
+                captured.add(c);
+            }
+        }
+
+        return captured;
+    }
+
+    private void verifyOneBatchedModification(ActorRef actorRef, Modification expected) {
+        List<BatchedModifications> batchedModifications = captureBatchedModifications(actorRef);
+        assertEquals("Captured BatchedModifications count", 1, batchedModifications.size());
+
+        verifyBatchedModifications(batchedModifications.get(0), expected);
+    }
+
+    private void verifyBatchedModifications(Object message, Modification... expected) {
+        assertEquals("Message type", BatchedModifications.class, message.getClass());
+        BatchedModifications batchedModifications = (BatchedModifications)message;
+        assertEquals("BatchedModifications size", expected.length, batchedModifications.getModifications().size());
+        for(int i = 0; i < batchedModifications.getModifications().size(); i++) {
+            Modification actual = batchedModifications.getModifications().get(i);
+            assertEquals("Modification type", expected[i].getClass(), actual.getClass());
+            assertEquals("getPath", ((AbstractModification)expected[i]).getPath(),
+                    ((AbstractModification)actual).getPath());
+            if(actual instanceof WriteModification) {
+                assertEquals("getData", ((WriteModification)expected[i]).getData(),
+                        ((WriteModification)actual).getData());
+            }
+        }
+    }
 }