CDS: Retry remote front-end transactions on AskTimeoutException
[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / test / java / org / opendaylight / controller / cluster / datastore / TransactionProxyTest.java
index fa2f9187d6059f1585a1475531556d8563db3c5a..4a9f4246e553012ad9992e3f4d866a99f83350b4 100644 (file)
@@ -3,84 +3,71 @@ package org.opendaylight.controller.cluster.datastore;
 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.never;
 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 static org.opendaylight.controller.cluster.datastore.TransactionType.READ_ONLY;
+import static org.opendaylight.controller.cluster.datastore.TransactionType.READ_WRITE;
+import static org.opendaylight.controller.cluster.datastore.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 akka.util.Timeout;
 import com.google.common.base.Optional;
-import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Sets;
 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.Collection;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
 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.ArgumentMatcher;
-import org.mockito.Mock;
+import org.mockito.InOrder;
 import org.mockito.Mockito;
-import org.mockito.MockitoAnnotations;
-import org.opendaylight.controller.cluster.datastore.TransactionProxy.TransactionType;
+import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
+import org.opendaylight.controller.cluster.datastore.exceptions.NotInitializedException;
 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.CloseTransaction;
-import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
-import org.opendaylight.controller.cluster.datastore.messages.DataExists;
-import org.opendaylight.controller.cluster.datastore.messages.DataExistsReply;
-import org.opendaylight.controller.cluster.datastore.messages.DeleteData;
-import org.opendaylight.controller.cluster.datastore.messages.DeleteDataReply;
-import org.opendaylight.controller.cluster.datastore.messages.MergeData;
-import org.opendaylight.controller.cluster.datastore.messages.MergeDataReply;
-import org.opendaylight.controller.cluster.datastore.messages.ReadData;
-import org.opendaylight.controller.cluster.datastore.messages.ReadDataReply;
+import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
+import org.opendaylight.controller.cluster.datastore.messages.PrimaryShardInfo;
 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.DeleteModification;
+import org.opendaylight.controller.cluster.datastore.modification.MergeModification;
+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.cluster.datastore.utils.NormalizedNodeAggregatorTest;
 import org.opendaylight.controller.md.cluster.datastore.model.CarsModel;
+import org.opendaylight.controller.md.cluster.datastore.model.SchemaContextHelper;
 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.ContainerNode;
 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTree;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot;
 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;
 
 @SuppressWarnings("resource")
-public class TransactionProxyTest {
+public class TransactionProxyTest extends AbstractTransactionProxyTest {
 
     @SuppressWarnings("serial")
     static class TestException extends RuntimeException {
@@ -90,364 +77,11 @@ public class TransactionProxyTest {
         CheckedFuture<?, ReadFailedException> invoke(TransactionProxy proxy) throws Exception;
     }
 
-    private static ActorSystem system;
-
-    private final Configuration configuration = new MockConfiguration();
-
-    @Mock
-    private ActorContext mockActorContext;
-
-    private SchemaContext schemaContext;
-
-    @Mock
-    private ClusterWrapper mockClusterWrapper;
-
-    String memberName = "mock-member";
-
-    @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(){
-        MockitoAnnotations.initMocks(this);
-
-        schemaContext = TestModel.createTestContext();
-
-        DatastoreContext dataStoreContext = DatastoreContext.newBuilder().operationTimeoutInSeconds(2).build();
-
-        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(dataStoreContext).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) {
-                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 eqSerializedDataExists() {
-        ArgumentMatcher<DataExists> matcher = new ArgumentMatcher<DataExists>() {
-            @Override
-            public boolean matches(Object argument) {
-                return DataExists.SERIALIZABLE_CLASS.equals(argument.getClass()) &&
-                       DataExists.fromSerializable(argument).getPath().equals(TestModel.TEST_PATH);
-            }
-        };
-
-        return argThat(matcher);
-    }
-
-    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() {
-        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);
-            }
-        };
-
-        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 eqSerializedWriteData(final NormalizedNode<?, ?> nodeToWrite) {
-        return eqSerializedWriteData(nodeToWrite, DataStoreVersions.CURRENT_VERSION);
-    }
-
-    private WriteData eqSerializedWriteData(final NormalizedNode<?, ?> nodeToWrite,
-            final int transactionVersion) {
-        ArgumentMatcher<WriteData> matcher = new ArgumentMatcher<WriteData>() {
-            @Override
-            public boolean matches(Object argument) {
-                if((transactionVersion >= DataStoreVersions.LITHIUM_VERSION &&
-                        WriteData.SERIALIZABLE_CLASS.equals(argument.getClass())) ||
-                   (transactionVersion < DataStoreVersions.LITHIUM_VERSION &&
-                           ShardTransactionMessages.WriteData.class.equals(argument.getClass()))) {
-
-                    WriteData obj = WriteData.fromSerializable(argument);
-                    return obj.getPath().equals(TestModel.TEST_PATH) &&
-                           obj.getData().equals(nodeToWrite);
-                }
-
-                return false;
-            }
-        };
-
-        return argThat(matcher);
-    }
-
-    private WriteData eqWriteData(final NormalizedNode<?, ?> nodeToWrite) {
-        ArgumentMatcher<WriteData> matcher = new ArgumentMatcher<WriteData>() {
-            @Override
-            public boolean matches(Object argument) {
-                if(argument instanceof WriteData) {
-                    WriteData obj = (WriteData) argument;
-                    return obj.getPath().equals(TestModel.TEST_PATH) &&
-                        obj.getData().equals(nodeToWrite);
-                }
-                return false;
-            }
-        };
-
-        return argThat(matcher);
-    }
-
-    private MergeData eqSerializedMergeData(final NormalizedNode<?, ?> nodeToWrite) {
-        return eqSerializedMergeData(nodeToWrite, DataStoreVersions.CURRENT_VERSION);
-    }
-
-    private MergeData eqSerializedMergeData(final NormalizedNode<?, ?> nodeToWrite,
-            final int transactionVersion) {
-        ArgumentMatcher<MergeData> matcher = new ArgumentMatcher<MergeData>() {
-            @Override
-            public boolean matches(Object argument) {
-                if((transactionVersion >= DataStoreVersions.LITHIUM_VERSION &&
-                        MergeData.SERIALIZABLE_CLASS.equals(argument.getClass())) ||
-                   (transactionVersion < DataStoreVersions.LITHIUM_VERSION &&
-                           ShardTransactionMessages.MergeData.class.equals(argument.getClass()))) {
-
-                    MergeData obj = MergeData.fromSerializable(argument);
-                    return obj.getPath().equals(TestModel.TEST_PATH) &&
-                           obj.getData().equals(nodeToWrite);
-                }
-
-                return false;
-            }
-        };
-
-        return argThat(matcher);
-    }
-
-    private MergeData eqMergeData(final NormalizedNode<?, ?> nodeToWrite) {
-        ArgumentMatcher<MergeData> matcher = new ArgumentMatcher<MergeData>() {
-            @Override
-            public boolean matches(Object argument) {
-                if(argument instanceof MergeData) {
-                    MergeData obj = ((MergeData) argument);
-                    return obj.getPath().equals(TestModel.TEST_PATH) &&
-                        obj.getData().equals(nodeToWrite);
-                }
-
-               return false;
-            }
-        };
-
-        return argThat(matcher);
-    }
-
-    private DeleteData eqSerializedDeleteData() {
-        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 argThat(matcher);
-    }
-
-        private DeleteData eqDeleteData() {
-        ArgumentMatcher<DeleteData> matcher = new ArgumentMatcher<DeleteData>() {
-            @Override
-            public boolean matches(Object argument) {
-                return argument instanceof DeleteData &&
-                    ((DeleteData)argument).getPath().equals(TestModel.TEST_PATH);
-            }
-        };
-
-        return argThat(matcher);
-    }
-
-    private Future<Object> readySerializedTxReply(String path) {
-        return Futures.successful((Object)new ReadyTransactionReply(path).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).toSerializable(transactionVersion));
-    }
-
-    private Future<Object> readSerializedDataReply(NormalizedNode<?, ?> data) {
-        return readSerializedDataReply(data, DataStoreVersions.CURRENT_VERSION);
-    }
-
-    private Future<ReadDataReply> readDataReply(NormalizedNode<?, ?> data) {
-        return Futures.successful(new ReadDataReply(data));
-    }
-
-    private Future<Object> dataExistsSerializedReply(boolean exists) {
-        return Futures.successful(new DataExistsReply(exists).toSerializable());
-    }
-
-    private Future<DataExistsReply> dataExistsReply(boolean exists) {
-        return Futures.successful(new DataExistsReply(exists));
-    }
-
-    private Future<Object> writeSerializedDataReply(short version) {
-        return Futures.successful(new WriteDataReply().toSerializable(version));
-    }
-
-    private Future<Object> writeSerializedDataReply() {
-        return writeSerializedDataReply(DataStoreVersions.CURRENT_VERSION);
-    }
-
-    private Future<WriteDataReply> writeDataReply() {
-        return Futures.successful(new WriteDataReply());
-    }
-
-    private Future<Object> mergeSerializedDataReply(short version) {
-        return Futures.successful(new MergeDataReply().toSerializable(version));
-    }
-
-    private Future<Object> mergeSerializedDataReply() {
-        return mergeSerializedDataReply(DataStoreVersions.CURRENT_VERSION);
-    }
-
-    private Future<Object> incompleteFuture(){
-        return mock(Future.class);
-    }
-
-    private Future<MergeDataReply> mergeDataReply() {
-        return Futures.successful(new MergeDataReply());
-    }
-
-    private Future<Object> deleteSerializedDataReply(short version) {
-        return Futures.successful(new DeleteDataReply().toSerializable(version));
-    }
-
-    private Future<Object> deleteSerializedDataReply() {
-        return deleteSerializedDataReply(DataStoreVersions.CURRENT_VERSION);
-    }
-
-    private Future<DeleteDataReply> deleteDataReply() {
-        return Futures.successful(new DeleteDataReply());
-    }
-
-    private ActorSelection actorSelection(ActorRef actorRef) {
-        return getSystem().actorSelection(actorRef.path());
-    }
-
-    private CreateTransactionReply createTransactionReply(ActorRef actorRef, int transactionVersion){
-        return CreateTransactionReply.newBuilder()
-            .setTransactionActorPath(actorRef.path().toString())
-            .setTransactionId("txn-1")
-            .setMessageVersion(transactionVersion)
-            .build();
-    }
-
-    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(Futures.successful(actorSystem.actorSelection(actorRef.path()))).
-                when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
-
-        doReturn(false).when(mockActorContext).isPathLocal(actorRef.path().toString());
-
-        doReturn(10).when(mockActorContext).getTransactionOutstandingOperationLimit();
-
-        return actorRef;
-    }
-
-    private ActorRef setupActorContextWithInitialCreateTransaction(ActorSystem actorSystem,
-            TransactionType type, int transactionVersion) {
-        ActorRef actorRef = setupActorContextWithoutInitialCreateTransaction(actorSystem);
-
-        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 {
-
-        try {
-            future.checkedGet(5, TimeUnit.SECONDS);
-            fail("Expected ReadFailedException");
-        } catch(ReadFailedException e) {
-            throw e.getCause();
-        }
-    }
-
     @Test
     public void testRead() throws Exception {
         ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
 
         doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
                 eq(actorSelection(actorRef)), eqSerializedReadData());
@@ -476,8 +110,7 @@ public class TransactionProxyTest {
         doReturn(Futures.successful(new Object())).when(mockActorContext).
                 executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
 
         transactionProxy.read(TestModel.TEST_PATH).checkedGet(5, TimeUnit.SECONDS);
     }
@@ -489,8 +122,7 @@ public class TransactionProxyTest {
         doReturn(Futures.failed(new TestException())).when(mockActorContext).
                 executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
 
         propagateReadFailedExceptionCause(transactionProxy.read(TestModel.TEST_PATH));
     }
@@ -502,14 +134,14 @@ public class TransactionProxyTest {
         if (exToThrow instanceof PrimaryNotFoundException) {
             doReturn(Futures.failed(exToThrow)).when(mockActorContext).findPrimaryShardAsync(anyString());
         } else {
-            doReturn(Futures.successful(getSystem().actorSelection(actorRef.path()))).
+            doReturn(primaryShardInfoReply(getSystem(), actorRef)).
                     when(mockActorContext).findPrimaryShardAsync(anyString());
         }
 
         doReturn(Futures.failed(exToThrow)).when(mockActorContext).executeOperationAsync(
-                any(ActorSelection.class), any());
+                any(ActorSelection.class), any(), any(Timeout.class));
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
 
         propagateReadFailedExceptionCause(invoker.invoke(transactionProxy));
     }
@@ -539,50 +171,18 @@ public class TransactionProxyTest {
         testReadWithExceptionOnInitialCreateTransaction(new TestException());
     }
 
-    @Test(expected = TestException.class)
-    public void testReadWithPriorRecordingOperationFailure() throws Throwable {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
-
-        NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
-
-        doReturn(writeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(nodeToWrite));
-
-        doReturn(Futures.failed(new TestException())).when(mockActorContext).
-                executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedDeleteData());
-
-        doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedReadData());
-
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
-
-        transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
-
-        transactionProxy.delete(TestModel.TEST_PATH);
-
-        try {
-            propagateReadFailedExceptionCause(transactionProxy.read(TestModel.TEST_PATH));
-        } finally {
-            verify(mockActorContext, times(0)).executeOperationAsync(
-                    eq(actorSelection(actorRef)), eqSerializedReadData());
-        }
-    }
-
     @Test
     public void testReadWithPriorRecordingOperationSuccessful() throws Throwable {
         ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
         NormalizedNode<?, ?> expectedNode = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(writeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(expectedNode));
+        expectBatchedModifications(actorRef, 1);
 
         doReturn(readSerializedDataReply(expectedNode)).when(mockActorContext).executeOperationAsync(
                 eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
         transactionProxy.write(TestModel.TEST_PATH, expectedNode);
 
@@ -590,16 +190,19 @@ public class TransactionProxyTest {
                 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 transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
         transactionProxy.read(TestModel.TEST_PATH);
     }
 
@@ -610,13 +213,14 @@ public class TransactionProxyTest {
         doReturn(getSystem().actorSelection(actorRef.path())).when(mockActorContext).
             actorSelection(actorRef.path().toString());
 
-        doReturn(Futures.successful(getSystem().actorSelection(actorRef.path()))).
+        doReturn(primaryShardInfoReply(getSystem(), actorRef)).
             when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
 
         doReturn(Futures.successful(new Object())).when(mockActorContext).executeOperationAsync(
-            eq(getSystem().actorSelection(actorRef.path())), eqCreateTransaction(memberName, READ_ONLY));
+            eq(getSystem().actorSelection(actorRef.path())), eqCreateTransaction(memberName, READ_ONLY),
+            any(Timeout.class));
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
 
         propagateReadFailedExceptionCause(transactionProxy.read(TestModel.TEST_PATH));
     }
@@ -625,8 +229,7 @@ public class TransactionProxyTest {
     public void testExists() throws Exception {
         ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
 
         doReturn(dataExistsSerializedReply(false)).when(mockActorContext).executeOperationAsync(
                 eq(actorSelection(actorRef)), eqSerializedDataExists());
@@ -660,8 +263,7 @@ public class TransactionProxyTest {
         doReturn(Futures.successful(new Object())).when(mockActorContext).
                 executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedDataExists());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
 
         transactionProxy.exists(TestModel.TEST_PATH).checkedGet(5, TimeUnit.SECONDS);
     }
@@ -673,135 +275,77 @@ public class TransactionProxyTest {
         doReturn(Futures.failed(new TestException())).when(mockActorContext).
                 executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedDataExists());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
 
         propagateReadFailedExceptionCause(transactionProxy.exists(TestModel.TEST_PATH));
     }
 
-    @Test(expected = TestException.class)
-    public void testExistsWithPriorRecordingOperationFailure() throws Throwable {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
-
-        NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
-
-        doReturn(writeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(nodeToWrite));
-
-        doReturn(Futures.failed(new TestException())).when(mockActorContext).
-                executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedDeleteData());
-
-        doReturn(dataExistsSerializedReply(false)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedDataExists());
-
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
-
-        transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
-
-        transactionProxy.delete(TestModel.TEST_PATH);
-
-        try {
-            propagateReadFailedExceptionCause(transactionProxy.exists(TestModel.TEST_PATH));
-        } finally {
-            verify(mockActorContext, times(0)).executeOperationAsync(
-                    eq(actorSelection(actorRef)), eqSerializedDataExists());
-        }
-    }
-
     @Test
     public void testExistsWithPriorRecordingOperationSuccessful() throws Throwable {
         ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(writeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(nodeToWrite));
+        expectBatchedModifications(actorRef, 1);
 
         doReturn(dataExistsSerializedReply(true)).when(mockActorContext).executeOperationAsync(
                 eq(actorSelection(actorRef)), eqSerializedDataExists());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
         transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
         Boolean exists = transactionProxy.exists(TestModel.TEST_PATH).checkedGet();
 
         assertEquals("Exists response", true, exists);
+
+        InOrder inOrder = Mockito.inOrder(mockActorContext);
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), isA(BatchedModifications.class));
+
+        inOrder.verify(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedDataExists());
     }
 
     @Test(expected=IllegalStateException.class)
     public void testExistsPreConditionCheck() {
-
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
-
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
         transactionProxy.exists(TestModel.TEST_PATH);
     }
 
-    private void verifyRecordingOperationFutures(List<Future<Object>> futures,
-            Class<?>... expResultTypes) throws Exception {
-        assertEquals("getRecordingOperationFutures size", expResultTypes.length, futures.size());
-
-        int i = 0;
-        for( Future<Object> future: futures) {
-            assertNotNull("Recording operation Future is null", future);
-
-            Class<?> expResultType = expResultTypes[i++];
-            if(Throwable.class.isAssignableFrom(expResultType)) {
-                try {
-                    Await.result(future, Duration.create(5, TimeUnit.SECONDS));
-                    fail("Expected exception from recording operation Future");
-                } catch(Exception e) {
-                    // Expected
-                }
-            } else {
-                assertEquals("Recording operation Future result type", expResultType,
-                             Await.result(future, Duration.create(5, TimeUnit.SECONDS)).getClass());
-            }
-        }
-    }
-
     @Test
     public void testWrite() throws Exception {
+        dataStoreContextBuilder.shardBatchedModificationCount(1);
         ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(writeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(nodeToWrite));
+        expectBatchedModifications(actorRef, 1);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
 
         transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
-        verify(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(nodeToWrite));
-
-        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                WriteDataReply.class);
+        verifyOneBatchedModification(actorRef, new WriteModification(TestModel.TEST_PATH, nodeToWrite), false);
     }
 
     @Test
     public void testWriteAfterAsyncRead() throws Throwable {
-        ActorRef actorRef = setupActorContextWithoutInitialCreateTransaction(getSystem());
+        ActorRef actorRef = setupActorContextWithoutInitialCreateTransaction(getSystem(), DefaultShardStrategy.DEFAULT_SHARD);
 
         Promise<Object> createTxPromise = akka.dispatch.Futures.promise();
         doReturn(createTxPromise).when(mockActorContext).executeOperationAsync(
                 eq(getSystem().actorSelection(actorRef.path())),
-                eqCreateTransaction(memberName, READ_WRITE));
+                eqCreateTransaction(memberName, READ_WRITE), any(Timeout.class));
 
         doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
                 eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        final NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+        expectBatchedModificationsReady(actorRef);
 
-        doReturn(writeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(nodeToWrite));
+        final NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        final TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
+        final TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
         final CountDownLatch readComplete = new CountDownLatch(1);
         final AtomicReference<Throwable> caughtEx = new AtomicReference<>();
@@ -833,101 +377,59 @@ public class TransactionProxyTest {
             throw caughtEx.get();
         }
 
-        verify(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(nodeToWrite));
+        // This sends the batched modification.
+        transactionProxy.ready();
 
-        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                WriteDataReply.class);
+        verifyOneBatchedModification(actorRef, new WriteModification(TestModel.TEST_PATH, nodeToWrite), true);
     }
 
     @Test(expected=IllegalStateException.class)
     public void testWritePreConditionCheck() {
-
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_ONLY);
-
-        transactionProxy.write(TestModel.TEST_PATH,
-                ImmutableNodes.containerNode(TestModel.TEST_QNAME));
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
+        transactionProxy.write(TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
     }
 
     @Test(expected=IllegalStateException.class)
     public void testWriteAfterReadyPreConditionCheck() {
-
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, 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 {
+        dataStoreContextBuilder.shardBatchedModificationCount(1);
         ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(mergeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedMergeData(nodeToWrite));
+        expectBatchedModifications(actorRef, 1);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
 
         transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
 
-        verify(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedMergeData(nodeToWrite));
-
-        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                MergeDataReply.class);
+        verifyOneBatchedModification(actorRef, new MergeModification(TestModel.TEST_PATH, nodeToWrite), false);
     }
 
     @Test
     public void testDelete() throws Exception {
+        dataStoreContextBuilder.shardBatchedModificationCount(1);
         ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
-        doReturn(deleteSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedDeleteData());
+        expectBatchedModifications(actorRef, 1);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
 
         transactionProxy.delete(TestModel.TEST_PATH);
 
-        verify(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedDeleteData());
-
-        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                DeleteDataReply.class);
-    }
-
-    private void verifyCohortFutures(ThreePhaseCommitCohortProxy proxy,
-        Object... expReplies) throws Exception {
-        assertEquals("getReadyOperationFutures size", expReplies.length,
-                proxy.getCohortFutures().size());
-
-        int i = 0;
-        for( Future<ActorSelection> future: proxy.getCohortFutures()) {
-            assertNotNull("Ready operation Future is null", future);
-
-            Object expReply = expReplies[i++];
-            if(expReply instanceof ActorSelection) {
-                ActorSelection actual = Await.result(future, Duration.create(5, TimeUnit.SECONDS));
-                assertEquals("Cohort actor path", expReply, actual);
-            } else {
-                // Expecting exception.
-                try {
-                    Await.result(future, Duration.create(5, TimeUnit.SECONDS));
-                    fail("Expected exception from ready operation Future");
-                } catch(Exception e) {
-                    // Expected
-                }
-            }
-        }
+        verifyOneBatchedModification(actorRef, new DeleteModification(TestModel.TEST_PATH), false);
     }
 
     @Test
-    public void testReady() throws Exception {
+    public void testReadWrite() throws Exception {
         ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
@@ -935,218 +437,269 @@ public class TransactionProxyTest {
         doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
                 eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        doReturn(writeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(nodeToWrite));
-
-        doReturn(readySerializedTxReply(actorRef.path().toString())).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), isA(ReadyTransaction.SERIALIZABLE_CLASS));
+        expectBatchedModifications(actorRef, 1);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
         transactionProxy.read(TestModel.TEST_PATH);
 
         transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
-        DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
-
-        assertTrue(ready instanceof ThreePhaseCommitCohortProxy);
+        transactionProxy.read(TestModel.TEST_PATH);
 
-        ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
+        transactionProxy.read(TestModel.TEST_PATH);
 
-        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                WriteDataReply.class);
+        List<BatchedModifications> batchedModifications = captureBatchedModifications(actorRef);
+        assertEquals("Captured BatchedModifications count", 1, batchedModifications.size());
 
-        verifyCohortFutures(proxy, getSystem().actorSelection(actorRef.path()));
+        verifyBatchedModifications(batchedModifications.get(0), false,
+                new WriteModification(TestModel.TEST_PATH, nodeToWrite));
     }
 
-    private ActorRef testCompatibilityWithHeliumVersion(short version) throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(),
-                READ_WRITE, version);
+    @Test
+    public void testReadyWithReadWrite() throws Exception {
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
-        NormalizedNode<?, ?> testNode = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+        NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(readSerializedDataReply(testNode, version)).when(mockActorContext).executeOperationAsync(
+        doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
                 eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        doReturn(writeSerializedDataReply(version)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(testNode, version));
-
-        doReturn(mergeSerializedDataReply(version)).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedMergeData(testNode, version));
-
-        doReturn(readySerializedTxReply(actorRef.path().toString())).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), isA(ReadyTransaction.SERIALIZABLE_CLASS));
-
-        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);
+        expectBatchedModificationsReady(actorRef, true);
 
-        assertEquals("NormalizedNode isPresent", true, readOptional.isPresent());
-        assertEquals("Response NormalizedNode", testNode, readOptional.get());
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
-        transactionProxy.write(TestModel.TEST_PATH, testNode);
+        transactionProxy.read(TestModel.TEST_PATH);
 
-        transactionProxy.merge(TestModel.TEST_PATH, testNode);
+        transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
         DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
 
-        assertTrue(ready instanceof ThreePhaseCommitCohortProxy);
+        assertTrue(ready instanceof SingleCommitCohortProxy);
 
-        ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
+        verifyCohortFutures((SingleCommitCohortProxy)ready, new CommitTransactionReply().toSerializable());
 
-        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                ShardTransactionMessages.WriteDataReply.class, ShardTransactionMessages.MergeDataReply.class);
+        List<BatchedModifications> batchedModifications = captureBatchedModifications(actorRef);
+        assertEquals("Captured BatchedModifications count", 1, batchedModifications.size());
 
-        verifyCohortFutures(proxy, getSystem().actorSelection(actorRef.path()));
+        verifyBatchedModifications(batchedModifications.get(0), true, true,
+                new WriteModification(TestModel.TEST_PATH, nodeToWrite));
 
-        return actorRef;
+        assertEquals("getTotalMessageCount", 1, batchedModifications.get(0).getTotalMessagesSent());
     }
 
     @Test
-    public void testCompatibilityWithBaseHeliumVersion() throws Exception {
-        ActorRef actorRef = testCompatibilityWithHeliumVersion(DataStoreVersions.BASE_HELIUM_VERSION);
+    public void testReadyWithNoModifications() throws Exception {
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
 
-        verify(mockActorContext).resolvePath(eq(actorRef.path().toString()),
-                eq(actorRef.path().toString()));
-    }
+        doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(actorRef)), eqSerializedReadData());
 
-    @Test
-    public void testCompatibilityWithHeliumR1Version() throws Exception {
-        ActorRef actorRef = testCompatibilityWithHeliumVersion(DataStoreVersions.HELIUM_1_VERSION);
+        expectBatchedModificationsReady(actorRef, true);
 
-        verify(mockActorContext, Mockito.never()).resolvePath(eq(actorRef.path().toString()),
-                eq(actorRef.path().toString()));
-    }
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
-    @Test
-    public void testReadyWithRecordingOperationFailure() throws Exception {
-        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
+        transactionProxy.read(TestModel.TEST_PATH);
 
-        NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+        DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
 
-        doReturn(mergeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedMergeData(nodeToWrite));
+        assertTrue(ready instanceof SingleCommitCohortProxy);
 
-        doReturn(Futures.failed(new TestException())).when(mockActorContext).
-                executeOperationAsync(eq(actorSelection(actorRef)), eqSerializedWriteData(nodeToWrite));
+        verifyCohortFutures((SingleCommitCohortProxy)ready, new CommitTransactionReply().toSerializable());
 
-        doReturn(readySerializedTxReply(actorRef.path().toString())).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), isA(ReadyTransaction.SERIALIZABLE_CLASS));
+        List<BatchedModifications> batchedModifications = captureBatchedModifications(actorRef);
+        assertEquals("Captured BatchedModifications count", 1, batchedModifications.size());
 
-        doReturn(false).when(mockActorContext).isPathLocal(actorRef.path().toString());
+        verifyBatchedModifications(batchedModifications.get(0), true, true);
+    }
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+    @Test
+    public void testReadyWithMultipleShardWrites() throws Exception {
+        ActorRef actorRef1 = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
-        transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
+        ActorRef actorRef2 = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY, "junk");
 
-        transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+        expectBatchedModificationsReady(actorRef1);
+        expectBatchedModificationsReady(actorRef2);
 
-        DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
 
-        assertTrue(ready instanceof ThreePhaseCommitCohortProxy);
+        transactionProxy.write(TestModel.JUNK_PATH, ImmutableNodes.containerNode(TestModel.JUNK_QNAME));
+        transactionProxy.write(TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
 
-        ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
+        DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
 
-        verifyCohortFutures(proxy, TestException.class);
+        assertTrue(ready instanceof ThreePhaseCommitCohortProxy);
 
-        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                MergeDataReply.class, TestException.class);
+        verifyCohortFutures((ThreePhaseCommitCohortProxy)ready, actorSelection(actorRef1),
+                actorSelection(actorRef2));
     }
 
     @Test
-    public void testReadyWithReplyFailure() throws Exception {
+    public void testReadyWithWriteOnlyAndLastBatchPending() throws Exception {
+        dataStoreContextBuilder.writeOnlyTransactionOptimizationsEnabled(true);
+
         ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(mergeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedMergeData(nodeToWrite));
-
-        doReturn(Futures.failed(new TestException())).when(mockActorContext).
-                executeOperationAsync(eq(actorSelection(actorRef)),
-                        isA(ReadyTransaction.SERIALIZABLE_CLASS));
+        expectBatchedModificationsReady(actorRef, true);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
 
-        transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
+        transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
         DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
 
-        assertTrue(ready instanceof ThreePhaseCommitCohortProxy);
+        assertTrue(ready instanceof SingleCommitCohortProxy);
 
-        ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
+        verifyCohortFutures((SingleCommitCohortProxy)ready, new CommitTransactionReply().toSerializable());
 
-        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-                MergeDataReply.class);
+        List<BatchedModifications> batchedModifications = captureBatchedModifications(actorRef);
+        assertEquals("Captured BatchedModifications count", 1, batchedModifications.size());
 
-        verifyCohortFutures(proxy, TestException.class);
+        verifyBatchedModifications(batchedModifications.get(0), true, true,
+                new WriteModification(TestModel.TEST_PATH, nodeToWrite));
+
+        verify(mockActorContext, never()).executeOperationAsync(eq(actorSelection(actorRef)),
+                isA(ReadyTransaction.SERIALIZABLE_CLASS));
     }
 
     @Test
-    public void testReadyWithInitialCreateTransactionFailure() throws Exception {
-
-        doReturn(Futures.failed(new PrimaryNotFoundException("mock"))).when(
-                mockActorContext).findPrimaryShardAsync(anyString());
-
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+    public void testReadyWithWriteOnlyAndLastBatchEmpty() throws Exception {
+        dataStoreContextBuilder.shardBatchedModificationCount(1).writeOnlyTransactionOptimizationsEnabled(true);
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
+        expectBatchedModificationsReady(actorRef, true);
 
-        transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
 
-        transactionProxy.delete(TestModel.TEST_PATH);
+        transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
         DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
 
-        assertTrue(ready instanceof ThreePhaseCommitCohortProxy);
+        assertTrue(ready instanceof SingleCommitCohortProxy);
+
+        verifyCohortFutures((SingleCommitCohortProxy)ready, new CommitTransactionReply().toSerializable());
+
+        List<BatchedModifications> batchedModifications = captureBatchedModifications(actorRef);
+        assertEquals("Captured BatchedModifications count", 2, batchedModifications.size());
 
-        ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
+        verifyBatchedModifications(batchedModifications.get(0), false,
+                new WriteModification(TestModel.TEST_PATH, nodeToWrite));
 
-        verifyCohortFutures(proxy, PrimaryNotFoundException.class);
+        verifyBatchedModifications(batchedModifications.get(1), true, true);
+
+        verify(mockActorContext, never()).executeOperationAsync(eq(actorSelection(actorRef)),
+                isA(ReadyTransaction.SERIALIZABLE_CLASS));
     }
 
     @Test
-    public void testReadyWithInvalidReplyMessageType() throws Exception {
+    public void testReadyWithReplyFailure() throws Exception {
+        dataStoreContextBuilder.writeOnlyTransactionOptimizationsEnabled(true);
+
         ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-        doReturn(writeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                eq(actorSelection(actorRef)), eqSerializedWriteData(nodeToWrite));
+        expectFailedBatchedModifications(actorRef);
 
-        doReturn(Futures.successful(new Object())).when(mockActorContext).
-                executeOperationAsync(eq(actorSelection(actorRef)),
-                        isA(ReadyTransaction.SERIALIZABLE_CLASS));
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
+
+        transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
+
+        DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
+
+        assertTrue(ready instanceof SingleCommitCohortProxy);
+
+        verifyCohortFutures((SingleCommitCohortProxy)ready, TestException.class);
+    }
+
+    @Test
+    public void testReadyWithDebugContextEnabled() throws Exception {
+        dataStoreContextBuilder.transactionDebugContextEnabled(true);
+
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
+
+        expectBatchedModificationsReady(actorRef, true);
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                WRITE_ONLY);
+        transactionProxy.merge(TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
+
+        DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
+
+        assertTrue(ready instanceof DebugThreePhaseCommitCohort);
+
+        verifyCohortFutures((DebugThreePhaseCommitCohort)ready, new CommitTransactionReply().toSerializable());
+    }
+
+    private void testWriteOnlyTxWithFindPrimaryShardFailure(Exception toThrow) throws Exception {
+        doReturn(Futures.failed(toThrow)).when(mockActorContext).findPrimaryShardAsync(anyString());
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
+
+        NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+        transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
 
         transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
+        transactionProxy.delete(TestModel.TEST_PATH);
+
         DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
 
-        assertTrue(ready instanceof ThreePhaseCommitCohortProxy);
+        assertTrue(ready instanceof SingleCommitCohortProxy);
+
+        verifyCohortFutures((SingleCommitCohortProxy)ready, toThrow.getClass());
+    }
+
+    @Test
+    public void testWriteOnlyTxWithPrimaryNotFoundException() throws Exception {
+        testWriteOnlyTxWithFindPrimaryShardFailure(new PrimaryNotFoundException("mock"));
+    }
+
+    @Test
+    public void testWriteOnlyTxWithNotInitializedException() throws Exception {
+        testWriteOnlyTxWithFindPrimaryShardFailure(new NotInitializedException("mock"));
+    }
+
+    @Test
+    public void testWriteOnlyTxWithNoShardLeaderException() throws Exception {
+        testWriteOnlyTxWithFindPrimaryShardFailure(new NoShardLeaderException("mock"));
+    }
+
+    @Test
+    public void testReadyWithInvalidReplyMessageType() throws Exception {
+        dataStoreContextBuilder.writeOnlyTransactionOptimizationsEnabled(true);
+        ActorRef actorRef1 = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY);
+
+        ActorRef actorRef2 = setupActorContextWithInitialCreateTransaction(getSystem(), WRITE_ONLY, "junk");
+
+        doReturn(Futures.successful(new Object())).when(mockActorContext).
+                executeOperationAsync(eq(actorSelection(actorRef1)), isA(BatchedModifications.class));
+
+        expectBatchedModificationsReady(actorRef2);
 
-        ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, WRITE_ONLY);
 
-        verifyCohortFutures(proxy, IllegalArgumentException.class);
+        transactionProxy.write(TestModel.JUNK_PATH, ImmutableNodes.containerNode(TestModel.JUNK_QNAME));
+        transactionProxy.write(TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
+
+        DOMStoreThreePhaseCommitCohort ready = transactionProxy.ready();
+
+        assertTrue(ready instanceof ThreePhaseCommitCohortProxy);
+
+        verifyCohortFutures((ThreePhaseCommitCohortProxy)ready, actorSelection(actorRef2),
+                IllegalArgumentException.class);
     }
 
     @Test
     public void testGetIdentifier() {
         setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                TransactionProxy.TransactionType.READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
 
         Object id = transactionProxy.getIdentifier();
         assertNotNull("getIdentifier returned null", id);
@@ -1160,8 +713,7 @@ public class TransactionProxyTest {
         doReturn(readSerializedDataReply(null)).when(mockActorContext).executeOperationAsync(
                 eq(actorSelection(actorRef)), eqSerializedReadData());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,
-                READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
         transactionProxy.read(TestModel.TEST_PATH);
 
@@ -1186,28 +738,10 @@ public class TransactionProxyTest {
      */
     @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);
+        setupActorContextWithInitialCreateTransaction(getSystem(), READ_ONLY);
+        doReturn(true).when(mockActorContext).isPathLocal(anyString());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext,READ_ONLY);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
 
         // negative test case with null as the reply
         doReturn(readDataReply(null)).when(mockActorContext).executeOperationAsync(
@@ -1240,71 +774,22 @@ public class TransactionProxyTest {
     }
 
     @Test
-    public void testLocalTxActorWrite() 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();
+    public void testLocalTxActorReady() throws Exception {
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), READ_WRITE);
+        doReturn(true).when(mockActorContext).isPathLocal(anyString());
 
-        doReturn(Futures.successful(createTransactionReply)).when(mockActorContext).
-        executeOperationAsync(eq(actorSystem.actorSelection(shardActorRef.path())),
-                eqCreateTransaction(memberName, WRITE_ONLY));
+        expectBatchedModificationsReady(actorRef, true);
 
-        doReturn(true).when(mockActorContext).isPathLocal(actorPath);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
         NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
-
-        doReturn(writeDataReply()).when(mockActorContext).executeOperationAsync(
-            any(ActorSelection.class), eqWriteData(nodeToWrite));
-
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, WRITE_ONLY);
         transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
-        verify(mockActorContext).executeOperationAsync(
-            any(ActorSelection.class), eqWriteData(nodeToWrite));
-
-        //testing local merge
-        doReturn(mergeDataReply()).when(mockActorContext).executeOperationAsync(
-            any(ActorSelection.class), eqMergeData(nodeToWrite));
-
-        transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
-
-        verify(mockActorContext).executeOperationAsync(
-            any(ActorSelection.class), eqMergeData(nodeToWrite));
-
-
-        //testing local delete
-        doReturn(deleteDataReply()).when(mockActorContext).executeOperationAsync(
-            any(ActorSelection.class), eqDeleteData());
-
-        transactionProxy.delete(TestModel.TEST_PATH);
-
-        verify(mockActorContext).executeOperationAsync(any(ActorSelection.class), eqDeleteData());
-
-        verifyRecordingOperationFutures(transactionProxy.getRecordedOperationFutures(),
-            WriteDataReply.class, MergeDataReply.class, DeleteDataReply.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);
+        assertTrue(ready instanceof SingleCommitCohortProxy);
 
-        ThreePhaseCommitCohortProxy proxy = (ThreePhaseCommitCohortProxy) ready;
-
-        verifyCohortFutures(proxy, getSystem().actorSelection(shardActorRef.path()));
+        verifyCohortFutures((SingleCommitCohortProxy)ready, new CommitTransactionReply().toSerializable());
     }
 
     private static interface TransactionProxyOperation {
@@ -1316,35 +801,53 @@ public class TransactionProxyTest {
     }
 
     private void throttleOperation(TransactionProxyOperation operation, int outstandingOpsLimit, boolean shardFound){
+        throttleOperation(operation, outstandingOpsLimit, shardFound, TimeUnit.MILLISECONDS.toNanos(
+                mockActorContext.getDatastoreContext().getOperationTimeoutInMillis()));
+    }
+
+    private PrimaryShardInfo newPrimaryShardInfo(ActorRef actorRef){
+        return new PrimaryShardInfo(getSystem().actorSelection(actorRef.path()), DataStoreVersions.CURRENT_VERSION,
+                Optional.<DataTree>absent());
+    }
+
+    private PrimaryShardInfo newPrimaryShardInfo(ActorRef actorRef, Optional<DataTree> dataTreeOptional){
+        return new PrimaryShardInfo(getSystem().actorSelection(actorRef.path()), DataStoreVersions.CURRENT_VERSION,
+                dataTreeOptional);
+    }
+
+
+    private void throttleOperation(TransactionProxyOperation operation, int outstandingOpsLimit, boolean shardFound, long expectedCompletionTime){
         ActorSystem actorSystem = getSystem();
         ActorRef shardActorRef = actorSystem.actorOf(Props.create(DoNothingActor.class));
 
-        doReturn(outstandingOpsLimit).when(mockActorContext).getTransactionOutstandingOperationLimit();
+        // Note that we setting batchedModificationCount to one less than what we need because in TransactionProxy
+        // we now allow one extra permit to be allowed for ready
+        doReturn(dataStoreContextBuilder.operationTimeoutInSeconds(2).
+                shardBatchedModificationCount(outstandingOpsLimit-1).build()).when(mockActorContext).getDatastoreContext();
 
         doReturn(actorSystem.actorSelection(shardActorRef.path())).
                 when(mockActorContext).actorSelection(shardActorRef.path().toString());
 
         if(shardFound) {
-            doReturn(Futures.successful(actorSystem.actorSelection(shardActorRef.path()))).
+            doReturn(Futures.successful(newPrimaryShardInfo(shardActorRef))).
                     when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
+            doReturn(Futures.successful(newPrimaryShardInfo(shardActorRef))).
+                    when(mockActorContext).findPrimaryShardAsync(eq("cars"));
+
         } 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)
-                .build();
 
-        doReturn(Futures.successful(createTransactionReply)).when(mockActorContext).
-                executeOperationAsync(eq(actorSystem.actorSelection(shardActorRef.path())),
-                        eqCreateTransaction(memberName, READ_WRITE));
+        doReturn(incompleteFuture()).when(mockActorContext).
+        executeOperationAsync(eq(actorSystem.actorSelection(shardActorRef.path())),
+                 eqCreateTransaction(memberName, READ_WRITE), any(Timeout.class));
 
         doReturn(true).when(mockActorContext).isPathLocal(actorPath);
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
         long start = System.nanoTime();
 
@@ -1352,9 +855,9 @@ public class TransactionProxyTest {
 
         long end = System.nanoTime();
 
-        Assert.assertTrue(String.format("took less time than expected %s was %s",
-                TimeUnit.SECONDS.toNanos(mockActorContext.getDatastoreContext().getOperationTimeoutInSeconds()),
-                (end-start)), (end - start) > TimeUnit.SECONDS.toNanos(mockActorContext.getDatastoreContext().getOperationTimeoutInSeconds()));
+        Assert.assertTrue(String.format("Expected elapsed time: %s. Actual: %s",
+                expectedCompletionTime, (end-start)),
+                ((end - start) > expectedCompletionTime) && ((end - start) < expectedCompletionTime*2));
 
     }
 
@@ -1366,32 +869,32 @@ public class TransactionProxyTest {
         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()))).
+            doReturn(Futures.successful(newPrimaryShardInfo(shardActorRef))).
                     when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
         } else {
-            doReturn(Futures.failed(new Exception("not found")))
+            doReturn(Futures.failed(new PrimaryNotFoundException("test")))
                     .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();
+        ActorRef txActorRef = actorSystem.actorOf(Props.create(DoNothingActor.class));
+        String actorPath = txActorRef.path().toString();
+        CreateTransactionReply createTransactionReply = CreateTransactionReply.newBuilder().
+                setTransactionId("txn-1").setTransactionActorPath(actorPath).
+                setMessageVersion(DataStoreVersions.CURRENT_VERSION).build();
+
+        doReturn(actorSystem.actorSelection(actorPath)).when(mockActorContext).actorSelection(actorPath);
 
         doReturn(Futures.successful(createTransactionReply)).when(mockActorContext).
                 executeOperationAsync(eq(actorSystem.actorSelection(shardActorRef.path())),
-                        eqCreateTransaction(memberName, READ_WRITE));
+                        eqCreateTransaction(memberName, READ_WRITE), any(Timeout.class));
 
-        doReturn(true).when(mockActorContext).isPathLocal(actorPath);
+        doReturn(true).when(mockActorContext).isPathLocal(anyString());
 
-        TransactionProxy transactionProxy = new TransactionProxy(mockActorContext, READ_WRITE);
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
 
         long start = System.nanoTime();
 
@@ -1399,26 +902,73 @@ public class TransactionProxyTest {
 
         long end = System.nanoTime();
 
-        Assert.assertTrue(String.format("took more time than expected %s was %s",
-                TimeUnit.SECONDS.toNanos(mockActorContext.getDatastoreContext().getOperationTimeoutInSeconds()),
-                (end-start)), (end - start) <= TimeUnit.SECONDS.toNanos(mockActorContext.getDatastoreContext().getOperationTimeoutInSeconds()));
+        long expected = TimeUnit.MILLISECONDS.toNanos(mockActorContext.getDatastoreContext().getOperationTimeoutInMillis());
+        Assert.assertTrue(String.format("Expected elapsed time: %s. Actual: %s",
+                expected, (end-start)), (end - start) <= expected);
     }
 
-    public void testWriteThrottling(boolean shardFound){
+    private void completeOperationLocal(TransactionProxyOperation operation, Optional<DataTree> dataTreeOptional){
+        ActorSystem actorSystem = getSystem();
+        ActorRef shardActorRef = actorSystem.actorOf(Props.create(DoNothingActor.class));
 
-        throttleOperation(new TransactionProxyOperation() {
+        doReturn(actorSystem.actorSelection(shardActorRef.path())).
+                when(mockActorContext).actorSelection(shardActorRef.path().toString());
+
+        doReturn(Futures.successful(newPrimaryShardInfo(shardActorRef, dataTreeOptional))).
+                when(mockActorContext).findPrimaryShardAsync(eq(DefaultShardStrategy.DEFAULT_SHARD));
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_WRITE);
+
+        long start = System.nanoTime();
+
+        operation.run(transactionProxy);
+
+        long end = System.nanoTime();
+
+        long expected = TimeUnit.MILLISECONDS.toNanos(mockActorContext.getDatastoreContext().getOperationTimeoutInMillis());
+        Assert.assertTrue(String.format("Expected elapsed time: %s. Actual: %s",
+                expected, (end-start)), (end - start) <= expected);
+    }
+
+    private Optional<DataTree> createDataTree(){
+        DataTree dataTree = mock(DataTree.class);
+        Optional<DataTree> dataTreeOptional = Optional.of(dataTree);
+        DataTreeSnapshot dataTreeSnapshot = mock(DataTreeSnapshot.class);
+        DataTreeModification dataTreeModification = mock(DataTreeModification.class);
+
+        doReturn(dataTreeSnapshot).when(dataTree).takeSnapshot();
+        doReturn(dataTreeModification).when(dataTreeSnapshot).newModification();
+
+        return dataTreeOptional;
+    }
+
+    private Optional<DataTree> createDataTree(NormalizedNode readResponse){
+        DataTree dataTree = mock(DataTree.class);
+        Optional<DataTree> dataTreeOptional = Optional.of(dataTree);
+        DataTreeSnapshot dataTreeSnapshot = mock(DataTreeSnapshot.class);
+        DataTreeModification dataTreeModification = mock(DataTreeModification.class);
+
+        doReturn(dataTreeSnapshot).when(dataTree).takeSnapshot();
+        doReturn(dataTreeModification).when(dataTreeSnapshot).newModification();
+        doReturn(Optional.of(readResponse)).when(dataTreeModification).readNode(any(YangInstanceIdentifier.class));
+
+        return dataTreeOptional;
+    }
+
+
+    @Test
+    public void testWriteCompletionForLocalShard(){
+        completeOperationLocal(new TransactionProxyOperation() {
             @Override
             public void run(TransactionProxy transactionProxy) {
                 NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqWriteData(nodeToWrite));
-
                 transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
                 transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
+
             }
-        }, 1, shardFound);
+        }, createDataTree());
     }
 
     @Test
@@ -1428,15 +978,13 @@ public class TransactionProxyTest {
             public void run(TransactionProxy transactionProxy) {
                 NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqWriteData(nodeToWrite));
+                expectIncompleteBatchedModifications();
 
                 transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
                 transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
             }
         });
-
     }
 
     @Test
@@ -1447,8 +995,7 @@ public class TransactionProxyTest {
             public void run(TransactionProxy transactionProxy) {
                 NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqWriteData(nodeToWrite));
+                expectBatchedModifications(2);
 
                 transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
@@ -1466,27 +1013,23 @@ public class TransactionProxyTest {
             public void run(TransactionProxy transactionProxy) {
                 NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-                doReturn(writeSerializedDataReply()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqSerializedWriteData(nodeToWrite));
+                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);
 
-                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqMergeData(nodeToMerge));
+                expectIncompleteBatchedModifications();
 
                 transactionProxy.merge(TestModel.TEST_PATH, nodeToMerge);
 
@@ -1497,14 +1040,12 @@ public class TransactionProxyTest {
 
     @Test
     public void testMergeThrottlingWhenShardNotFound(){
-
         completeOperation(new TransactionProxyOperation() {
             @Override
             public void run(TransactionProxy transactionProxy) {
                 NormalizedNode<?, ?> nodeToMerge = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqMergeData(nodeToMerge));
+                expectBatchedModifications(2);
 
                 transactionProxy.merge(TestModel.TEST_PATH, nodeToMerge);
 
@@ -1520,8 +1061,7 @@ public class TransactionProxyTest {
             public void run(TransactionProxy transactionProxy) {
                 NormalizedNode<?, ?> nodeToMerge = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-                doReturn(mergeDataReply()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqMergeData(nodeToMerge));
+                expectBatchedModifications(2);
 
                 transactionProxy.merge(TestModel.TEST_PATH, nodeToMerge);
 
@@ -1531,14 +1071,29 @@ public class TransactionProxyTest {
 
     }
 
+    @Test
+    public void testMergeCompletionForLocalShard(){
+        completeOperationLocal(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+
+                transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
+
+                transactionProxy.merge(TestModel.TEST_PATH, nodeToWrite);
+
+            }
+        }, createDataTree());
+    }
+
+
     @Test
     public void testDeleteThrottlingWhenShardFound(){
 
         throttleOperation(new TransactionProxyOperation() {
             @Override
             public void run(TransactionProxy transactionProxy) {
-                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqDeleteData());
+                expectIncompleteBatchedModifications();
 
                 transactionProxy.delete(TestModel.TEST_PATH);
 
@@ -1554,8 +1109,7 @@ public class TransactionProxyTest {
         completeOperation(new TransactionProxyOperation() {
             @Override
             public void run(TransactionProxy transactionProxy) {
-                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqDeleteData());
+                expectBatchedModifications(2);
 
                 transactionProxy.delete(TestModel.TEST_PATH);
 
@@ -1564,13 +1118,26 @@ public class TransactionProxyTest {
         }, false);
     }
 
+    @Test
+    public void testDeleteCompletionForLocalShard(){
+        completeOperationLocal(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+
+                transactionProxy.delete(TestModel.TEST_PATH);
+
+                transactionProxy.delete(TestModel.TEST_PATH);
+            }
+        }, createDataTree());
+
+    }
+
     @Test
     public void testDeleteCompletion(){
         completeOperation(new TransactionProxyOperation() {
             @Override
             public void run(TransactionProxy transactionProxy) {
-                doReturn(deleteDataReply()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqDeleteData());
+                expectBatchedModifications(2);
 
                 transactionProxy.delete(TestModel.TEST_PATH);
 
@@ -1631,6 +1198,33 @@ public class TransactionProxyTest {
 
     }
 
+    @Test
+    public void testReadCompletionForLocalShard(){
+        final NormalizedNode nodeToRead = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+        completeOperationLocal(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                transactionProxy.read(TestModel.TEST_PATH);
+
+                transactionProxy.read(TestModel.TEST_PATH);
+            }
+        }, createDataTree(nodeToRead));
+
+    }
+
+    @Test
+    public void testReadCompletionForLocalShardWhenExceptionOccurs(){
+        completeOperationLocal(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                transactionProxy.read(TestModel.TEST_PATH);
+
+                transactionProxy.read(TestModel.TEST_PATH);
+            }
+        }, createDataTree());
+
+    }
+
     @Test
     public void testExistsThrottlingWhenShardFound(){
 
@@ -1680,6 +1274,32 @@ public class TransactionProxyTest {
 
     }
 
+    @Test
+    public void testExistsCompletionForLocalShard(){
+        final NormalizedNode nodeToRead = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+        completeOperationLocal(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                transactionProxy.exists(TestModel.TEST_PATH);
+
+                transactionProxy.exists(TestModel.TEST_PATH);
+            }
+        }, createDataTree(nodeToRead));
+
+    }
+
+    @Test
+    public void testExistsCompletionForLocalShardWhenExceptionOccurs(){
+        completeOperationLocal(new TransactionProxyOperation() {
+            @Override
+            public void run(TransactionProxy transactionProxy) {
+                transactionProxy.exists(TestModel.TEST_PATH);
+
+                transactionProxy.exists(TestModel.TEST_PATH);
+            }
+        }, createDataTree());
+
+    }
     @Test
     public void testReadyThrottling(){
 
@@ -1688,11 +1308,7 @@ public class TransactionProxyTest {
             public void run(TransactionProxy transactionProxy) {
                 NormalizedNode<?, ?> nodeToWrite = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 
-                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqWriteData(nodeToWrite));
-
-                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), any(ReadyTransaction.class));
+                expectBatchedModifications(1);
 
                 transactionProxy.write(TestModel.TEST_PATH, nodeToWrite);
 
@@ -1703,28 +1319,260 @@ public class TransactionProxyTest {
 
     @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);
 
-                doReturn(writeDataReply()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqWriteData(nodeToWrite));
-
-                doReturn(incompleteFuture()).when(mockActorContext).executeOperationAsync(
-                        any(ActorSelection.class), eqWriteData(carsNode));
+                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);
+                // Trying to write to Cars will cause another transaction context to get created
+                transactionProxy.write(CarsModel.BASE_PATH, carsNode);
 
+                // Now ready should block for both transaction contexts
                 transactionProxy.ready();
             }
-        }, 2, true);
+        }, 1, true, TimeUnit.MILLISECONDS.toNanos(mockActorContext.getDatastoreContext().getOperationTimeoutInMillis()) * 2);
+    }
+
+    private void testModificationOperationBatching(TransactionType type) throws Exception {
+        int shardBatchedModificationCount = 3;
+        dataStoreContextBuilder.shardBatchedModificationCount(shardBatchedModificationCount);
+
+        ActorRef actorRef = setupActorContextWithInitialCreateTransaction(getSystem(), type);
+
+        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 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(mockComponentFactory, type);
+
+        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), false, new WriteModification(writePath1, writeNode1),
+                new WriteModification(writePath2, writeNode2), new DeleteModification(deletePath1));
+
+        verifyBatchedModifications(batchedModifications.get(1), false, new MergeModification(mergePath1, mergeNode1),
+                new MergeModification(mergePath2, mergeNode2), new WriteModification(writePath3, writeNode3));
+
+        verifyBatchedModifications(batchedModifications.get(2), true, true,
+                new MergeModification(mergePath3, mergeNode3), new DeleteModification(deletePath2));
+
+        assertEquals("getTotalMessageCount", 3, batchedModifications.get(2).getTotalMessagesSent());
+    }
+
+    @Test
+    public void testReadWriteModificationOperationBatching() throws Throwable {
+        testModificationOperationBatching(READ_WRITE);
+    }
+
+    @Test
+    public void testWriteOnlyModificationOperationBatching() throws Throwable {
+        testModificationOperationBatching(WRITE_ONLY);
+    }
+
+    @Test
+    public void testOptimizedWriteOnlyModificationOperationBatching() throws Throwable {
+        dataStoreContextBuilder.writeOnlyTransactionOptimizationsEnabled(true);
+        testModificationOperationBatching(WRITE_ONLY);
+    }
+
+    @Test
+    public void testModificationOperationBatchingWithInterleavedReads() throws Throwable {
+
+        int shardBatchedModificationCount = 10;
+        dataStoreContextBuilder.shardBatchedModificationCount(shardBatchedModificationCount);
+
+        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(mockComponentFactory, 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), false, new WriteModification(writePath1, writeNode1),
+                new WriteModification(writePath2, writeNode2));
+
+        verifyBatchedModifications(batchedModifications.get(1), false, new MergeModification(mergePath1, mergeNode1),
+                new MergeModification(mergePath2, mergeNode2));
+
+        verifyBatchedModifications(batchedModifications.get(2), false, 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());
+    }
+
+    @Test
+    public void testReadRoot() throws ReadFailedException, InterruptedException, ExecutionException, java.util.concurrent.TimeoutException {
+
+        SchemaContext schemaContext = SchemaContextHelper.full();
+        Configuration configuration = mock(Configuration.class);
+        doReturn(configuration).when(mockActorContext).getConfiguration();
+        doReturn(schemaContext).when(mockActorContext).getSchemaContext();
+        doReturn(Sets.newHashSet("test", "cars")).when(configuration).getAllShardNames();
+
+        NormalizedNode<?, ?> expectedNode1 = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
+        NormalizedNode<?, ?> expectedNode2 = ImmutableNodes.containerNode(CarsModel.CARS_QNAME);
+
+        setUpReadData("test", NormalizedNodeAggregatorTest.getRootNode(expectedNode1, schemaContext));
+        setUpReadData("cars", NormalizedNodeAggregatorTest.getRootNode(expectedNode2, schemaContext));
+
+        doReturn(memberName).when(mockActorContext).getCurrentMemberName();
+
+        doReturn(getSystem().dispatchers().defaultGlobalDispatcher()).when(mockActorContext).getClientDispatcher();
+
+        TransactionProxy transactionProxy = new TransactionProxy(mockComponentFactory, READ_ONLY);
+
+        Optional<NormalizedNode<?, ?>> readOptional = transactionProxy.read(
+                YangInstanceIdentifier.builder().build()).get(5, TimeUnit.SECONDS);
+
+        assertEquals("NormalizedNode isPresent", true, readOptional.isPresent());
+
+        NormalizedNode<?, ?> normalizedNode = readOptional.get();
+
+        assertTrue("Expect value to be a Collection", normalizedNode.getValue() instanceof Collection);
+
+        Collection<NormalizedNode<?,?>> collection = (Collection<NormalizedNode<?,?>>) normalizedNode.getValue();
+
+        for(NormalizedNode<?,?> node : collection){
+            assertTrue("Expected " + node + " to be a ContainerNode", node instanceof ContainerNode);
+        }
+
+        assertTrue("Child with QName = " + TestModel.TEST_QNAME + " not found",
+                NormalizedNodeAggregatorTest.findChildWithQName(collection, TestModel.TEST_QNAME) != null);
+
+        assertEquals(expectedNode1, NormalizedNodeAggregatorTest.findChildWithQName(collection, TestModel.TEST_QNAME));
+
+        assertTrue("Child with QName = " + CarsModel.BASE_QNAME + " not found",
+                NormalizedNodeAggregatorTest.findChildWithQName(collection, CarsModel.BASE_QNAME) != null);
+
+        assertEquals(expectedNode2, NormalizedNodeAggregatorTest.findChildWithQName(collection, CarsModel.BASE_QNAME));
+    }
+
+
+    private void setUpReadData(String shardName, NormalizedNode<?, ?> expectedNode) {
+        ActorSystem actorSystem = getSystem();
+        ActorRef shardActorRef = getSystem().actorOf(Props.create(DoNothingActor.class));
+
+        doReturn(getSystem().actorSelection(shardActorRef.path())).
+                when(mockActorContext).actorSelection(shardActorRef.path().toString());
+
+        doReturn(primaryShardInfoReply(getSystem(), shardActorRef)).
+                when(mockActorContext).findPrimaryShardAsync(eq(shardName));
+
+        doReturn(true).when(mockActorContext).isPathLocal(shardActorRef.path().toString());
+
+        ActorRef txActorRef = actorSystem.actorOf(Props.create(DoNothingActor.class));
+
+        doReturn(actorSystem.actorSelection(txActorRef.path())).
+                when(mockActorContext).actorSelection(txActorRef.path().toString());
+
+        doReturn(Futures.successful(createTransactionReply(txActorRef, DataStoreVersions.CURRENT_VERSION))).when(mockActorContext).
+                executeOperationAsync(eq(actorSystem.actorSelection(shardActorRef.path())),
+                        eqCreateTransaction(memberName, TransactionType.READ_ONLY), any(Timeout.class));
+
+        doReturn(readSerializedDataReply(expectedNode)).when(mockActorContext).executeOperationAsync(
+                eq(actorSelection(txActorRef)), eqSerializedReadData(YangInstanceIdentifier.builder().build()));
     }
 }