X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-distributed-datastore%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Fdatastore%2FTransactionProxy.java;h=f447f3c718980285d32e79c5a9b2579e26309971;hp=74245c42592ca3d6743d0aef3b48bb2e6ace2b45;hb=08dd5c2c443ff53f56af88a0e8dc8f34e36d2245;hpb=7d753ff9887cb803bdcd222aec2ab2a0a9c87906 diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/TransactionProxy.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/TransactionProxy.java index 74245c4259..f1ba4eabb9 100644 --- a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/TransactionProxy.java +++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/TransactionProxy.java @@ -8,34 +8,50 @@ package org.opendaylight.controller.cluster.datastore; -import akka.actor.ActorPath; import akka.actor.ActorSelection; +import akka.dispatch.Mapper; +import akka.dispatch.OnComplete; +import com.google.common.annotations.VisibleForTesting; +import com.google.common.base.FinalizablePhantomReference; +import com.google.common.base.FinalizableReferenceQueue; import com.google.common.base.Optional; +import com.google.common.base.Preconditions; +import com.google.common.collect.Lists; +import com.google.common.util.concurrent.CheckedFuture; import com.google.common.util.concurrent.ListenableFuture; -import com.google.common.util.concurrent.ListenableFutureTask; +import com.google.common.util.concurrent.SettableFuture; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.Semaphore; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.atomic.AtomicLong; +import javax.annotation.concurrent.GuardedBy; +import org.opendaylight.controller.cluster.datastore.compat.PreLithiumTransactionContextImpl; +import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException; +import org.opendaylight.controller.cluster.datastore.identifiers.TransactionIdentifier; import org.opendaylight.controller.cluster.datastore.messages.CloseTransaction; import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction; import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply; -import org.opendaylight.controller.cluster.datastore.messages.DeleteData; -import org.opendaylight.controller.cluster.datastore.messages.MergeData; -import org.opendaylight.controller.cluster.datastore.messages.ReadData; -import org.opendaylight.controller.cluster.datastore.messages.ReadDataReply; -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.shardstrategy.ShardStrategyFactory; import org.opendaylight.controller.cluster.datastore.utils.ActorContext; +import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException; import org.opendaylight.controller.sal.core.spi.data.DOMStoreReadWriteTransaction; import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort; -import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier; +import org.opendaylight.yangtools.util.concurrent.MappingCheckedFuture; +import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier; import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode; - -import java.util.ArrayList; -import java.util.HashMap; -import java.util.List; -import java.util.Map; -import java.util.concurrent.Callable; -import java.util.concurrent.ExecutorService; -import java.util.concurrent.atomic.AtomicLong; +import org.opendaylight.yangtools.yang.model.api.SchemaContext; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; +import scala.concurrent.Future; +import scala.concurrent.Promise; +import scala.concurrent.duration.FiniteDuration; /** * TransactionProxy acts as a proxy for one or more transactions that were created on a remote shard @@ -50,104 +66,377 @@ import java.util.concurrent.atomic.AtomicLong; *

*/ public class TransactionProxy implements DOMStoreReadWriteTransaction { - public enum TransactionType { + + public static enum TransactionType { READ_ONLY, WRITE_ONLY, - READ_WRITE + READ_WRITE; + + public static TransactionType fromInt(int type) { + if(type == WRITE_ONLY.ordinal()) { + return WRITE_ONLY; + } else if(type == READ_WRITE.ordinal()) { + return READ_WRITE; + } else if(type == READ_ONLY.ordinal()) { + return READ_ONLY; + } else { + throw new IllegalArgumentException("In TransactionType enum value" + type); + } + } } + static final Mapper SAME_FAILURE_TRANSFORMER = + new Mapper() { + @Override + public Throwable apply(Throwable failure) { + return failure; + } + }; + private static final AtomicLong counter = new AtomicLong(); + private static final Logger LOG = LoggerFactory.getLogger(TransactionProxy.class); + + /** + * Time interval in between transaction create retries. + */ + private static final FiniteDuration CREATE_TX_TRY_INTERVAL = + FiniteDuration.create(1, TimeUnit.SECONDS); + + /** + * Used to enqueue the PhantomReferences for read-only TransactionProxy instances. The + * FinalizableReferenceQueue is safe to use statically in an OSGi environment as it uses some + * trickery to clean up its internal thread when the bundle is unloaded. + */ + private static final FinalizableReferenceQueue phantomReferenceQueue = + new FinalizableReferenceQueue(); + + /** + * This stores the TransactionProxyCleanupPhantomReference instances statically, This is + * necessary because PhantomReferences need a hard reference so they're not garbage collected. + * Once finalized, the TransactionProxyCleanupPhantomReference removes itself from this map + * and thus becomes eligible for garbage collection. + */ + private static final Map phantomReferenceCache = + new ConcurrentHashMap<>(); + + /** + * A PhantomReference that closes remote transactions for a TransactionProxy when it's + * garbage collected. This is used for read-only transactions as they're not explicitly closed + * by clients. So the only way to detect that a transaction is no longer in use and it's safe + * to clean up is when it's garbage collected. It's inexact as to when an instance will be GC'ed + * but TransactionProxy instances should generally be short-lived enough to avoid being moved + * to the old generation space and thus should be cleaned up in a timely manner as the GC + * runs on the young generation (eden, swap1...) space much more frequently. + */ + private static class TransactionProxyCleanupPhantomReference + extends FinalizablePhantomReference { + + private final List remoteTransactionActors; + private final AtomicBoolean remoteTransactionActorsMB; + private final ActorContext actorContext; + private final TransactionIdentifier identifier; + + protected TransactionProxyCleanupPhantomReference(TransactionProxy referent) { + super(referent, phantomReferenceQueue); + + // Note we need to cache the relevant fields from the TransactionProxy as we can't + // have a hard reference to the TransactionProxy instance itself. + + remoteTransactionActors = referent.remoteTransactionActors; + remoteTransactionActorsMB = referent.remoteTransactionActorsMB; + actorContext = referent.actorContext; + identifier = referent.identifier; + } + + @Override + public void finalizeReferent() { + LOG.trace("Cleaning up {} Tx actors for TransactionProxy {}", + remoteTransactionActors.size(), identifier); + + phantomReferenceCache.remove(this); + + // Access the memory barrier volatile to ensure all previous updates to the + // remoteTransactionActors list are visible to this thread. + + if(remoteTransactionActorsMB.get()) { + for(ActorSelection actor : remoteTransactionActors) { + LOG.trace("Sending CloseTransaction to {}", actor); + actorContext.sendOperationAsync(actor, CloseTransaction.INSTANCE.toSerializable()); + } + } + } + } + + /** + * Stores the remote Tx actors for each requested data store path to be used by the + * PhantomReference to close the remote Tx's. This is only used for read-only Tx's. The + * remoteTransactionActorsMB volatile serves as a memory barrier to publish updates to the + * remoteTransactionActors list so they will be visible to the thread accessing the + * PhantomReference. + */ + private List remoteTransactionActors; + private volatile AtomicBoolean remoteTransactionActorsMB; + + /** + * Stores the create transaction results per shard. + */ + private final Map txFutureCallbackMap = new HashMap<>(); + private final TransactionType transactionType; private final ActorContext actorContext; - private final Map remoteTransactionPaths = new HashMap<>(); - private final String identifier; - private final ExecutorService executor; + private final TransactionIdentifier identifier; + private final String transactionChainId; + private final SchemaContext schemaContext; + private boolean inReadyState; + + private volatile boolean initialized; + private Semaphore operationLimiter; + private OperationCompleter operationCompleter; + + public TransactionProxy(ActorContext actorContext, TransactionType transactionType) { + this(actorContext, transactionType, ""); + } - public TransactionProxy( - ActorContext actorContext, - TransactionType transactionType, - ExecutorService executor - ) { + public TransactionProxy(ActorContext actorContext, TransactionType transactionType, + String transactionChainId) { + this.actorContext = Preconditions.checkNotNull(actorContext, + "actorContext should not be null"); + this.transactionType = Preconditions.checkNotNull(transactionType, + "transactionType should not be null"); + this.schemaContext = Preconditions.checkNotNull(actorContext.getSchemaContext(), + "schemaContext should not be null"); + this.transactionChainId = transactionChainId; - this.identifier = "txn-" + counter.getAndIncrement(); - this.transactionType = transactionType; - this.actorContext = actorContext; - this.executor = executor; + String memberName = actorContext.getCurrentMemberName(); + if(memberName == null){ + memberName = "UNKNOWN-MEMBER"; + } + + this.identifier = new TransactionIdentifier(memberName, counter.getAndIncrement()); + + LOG.debug("Created txn {} of type {} on chain {}", identifier, transactionType, transactionChainId); + } - Object response = actorContext.executeShardOperation(Shard.DEFAULT_NAME, new CreateTransaction(identifier), ActorContext.ASK_DURATION); - if(response instanceof CreateTransactionReply){ - CreateTransactionReply reply = (CreateTransactionReply) response; - remoteTransactionPaths.put(Shard.DEFAULT_NAME, actorContext.actorSelection(reply.getTransactionPath())); + @VisibleForTesting + List> getRecordedOperationFutures() { + List> recordedOperationFutures = Lists.newArrayList(); + for(TransactionFutureCallback txFutureCallback : txFutureCallbackMap.values()) { + TransactionContext transactionContext = txFutureCallback.getTransactionContext(); + if(transactionContext != null) { + recordedOperationFutures.addAll(transactionContext.getRecordedOperationFutures()); + } } + + return recordedOperationFutures; + } + + @VisibleForTesting + boolean hasTransactionContext() { + for(TransactionFutureCallback txFutureCallback : txFutureCallbackMap.values()) { + TransactionContext transactionContext = txFutureCallback.getTransactionContext(); + if(transactionContext != null) { + return true; + } + } + + return false; } @Override - public ListenableFuture>> read(final InstanceIdentifier path) { - final ActorSelection remoteTransaction = remoteTransactionFromIdentifier(path); - - Callable>> call = new Callable() { - - @Override public Optional> call() throws Exception { - Object response = actorContext - .executeRemoteOperation(remoteTransaction, new ReadData(path), - ActorContext.ASK_DURATION); - if(response instanceof ReadDataReply){ - ReadDataReply reply = (ReadDataReply) response; - if(reply.getNormalizedNode() == null){ - return Optional.absent(); - } - //FIXME : A cast should not be required here ??? - return (Optional>) Optional.of(reply.getNormalizedNode()); - } + public CheckedFuture>, ReadFailedException> read(final YangInstanceIdentifier path) { - return Optional.absent(); + Preconditions.checkState(transactionType != TransactionType.WRITE_ONLY, + "Read operation on write-only transaction is not allowed"); + + LOG.debug("Tx {} read {}", identifier, path); + + throttleOperation(); + + final SettableFuture>> proxyFuture = SettableFuture.create(); + + TransactionFutureCallback txFutureCallback = getOrCreateTxFutureCallback(path); + txFutureCallback.enqueueTransactionOperation(new TransactionOperation() { + @Override + public void invoke(TransactionContext transactionContext) { + transactionContext.readData(path, proxyFuture); } - }; + }); + + return MappingCheckedFuture.create(proxyFuture, ReadFailedException.MAPPER); + } + + @Override + public CheckedFuture exists(final YangInstanceIdentifier path) { + + Preconditions.checkState(transactionType != TransactionType.WRITE_ONLY, + "Exists operation on write-only transaction is not allowed"); + + LOG.debug("Tx {} exists {}", identifier, path); + + throttleOperation(); - ListenableFutureTask>> - future = ListenableFutureTask.create(call); + final SettableFuture proxyFuture = SettableFuture.create(); - executor.submit(future); + TransactionFutureCallback txFutureCallback = getOrCreateTxFutureCallback(path); + txFutureCallback.enqueueTransactionOperation(new TransactionOperation() { + @Override + public void invoke(TransactionContext transactionContext) { + transactionContext.dataExists(path, proxyFuture); + } + }); + + return MappingCheckedFuture.create(proxyFuture, ReadFailedException.MAPPER); + } - return future; + private void checkModificationState() { + Preconditions.checkState(transactionType != TransactionType.READ_ONLY, + "Modification operation on read-only transaction is not allowed"); + Preconditions.checkState(!inReadyState, + "Transaction is sealed - further modifications are not allowed"); } + private void throttleOperation() { + throttleOperation(1); + } + + private void throttleOperation(int acquirePermits) { + if(!initialized) { + // Note : Currently mailbox-capacity comes from akka.conf and not from the config-subsystem + operationLimiter = new Semaphore(actorContext.getTransactionOutstandingOperationLimit()); + operationCompleter = new OperationCompleter(operationLimiter); + + // Make sure we write this last because it's volatile and will also publish the non-volatile writes + // above as well so they'll be visible to other threads. + initialized = true; + } + + try { + if(!operationLimiter.tryAcquire(acquirePermits, + actorContext.getDatastoreContext().getOperationTimeoutInSeconds(), TimeUnit.SECONDS)){ + LOG.warn("Failed to acquire operation permit for transaction {}", getIdentifier()); + } + } catch (InterruptedException e) { + if(LOG.isDebugEnabled()) { + LOG.debug("Interrupted when trying to acquire operation permit for transaction " + getIdentifier().toString(), e); + } else { + LOG.warn("Interrupted when trying to acquire operation permit for transaction {}", getIdentifier()); + } + } + } + + @Override - public void write(InstanceIdentifier path, NormalizedNode data) { - final ActorSelection remoteTransaction = remoteTransactionFromIdentifier(path); - remoteTransaction.tell(new WriteData(path, data), null); + public void write(final YangInstanceIdentifier path, final NormalizedNode data) { + + checkModificationState(); + + LOG.debug("Tx {} write {}", identifier, path); + + throttleOperation(); + + TransactionFutureCallback txFutureCallback = getOrCreateTxFutureCallback(path); + txFutureCallback.enqueueTransactionOperation(new TransactionOperation() { + @Override + public void invoke(TransactionContext transactionContext) { + transactionContext.writeData(path, data); + } + }); } @Override - public void merge(InstanceIdentifier path, NormalizedNode data) { - final ActorSelection remoteTransaction = remoteTransactionFromIdentifier(path); - remoteTransaction.tell(new MergeData(path, data), null); + public void merge(final YangInstanceIdentifier path, final NormalizedNode data) { + + checkModificationState(); + + LOG.debug("Tx {} merge {}", identifier, path); + + throttleOperation(); + + TransactionFutureCallback txFutureCallback = getOrCreateTxFutureCallback(path); + txFutureCallback.enqueueTransactionOperation(new TransactionOperation() { + @Override + public void invoke(TransactionContext transactionContext) { + transactionContext.mergeData(path, data); + } + }); } @Override - public void delete(InstanceIdentifier path) { - final ActorSelection remoteTransaction = remoteTransactionFromIdentifier(path); - remoteTransaction.tell(new DeleteData(path), null); + public void delete(final YangInstanceIdentifier path) { + + checkModificationState(); + + LOG.debug("Tx {} delete {}", identifier, path); + + throttleOperation(); + + TransactionFutureCallback txFutureCallback = getOrCreateTxFutureCallback(path); + txFutureCallback.enqueueTransactionOperation(new TransactionOperation() { + @Override + public void invoke(TransactionContext transactionContext) { + transactionContext.deleteData(path); + } + }); } @Override public DOMStoreThreePhaseCommitCohort ready() { - List cohortPaths = new ArrayList<>(); - for(ActorSelection remoteTransaction : remoteTransactionPaths.values()) { - Object result = actorContext.executeRemoteOperation(remoteTransaction, - new ReadyTransaction(), - ActorContext.ASK_DURATION - ); + checkModificationState(); - if(result instanceof ReadyTransactionReply){ - ReadyTransactionReply reply = (ReadyTransactionReply) result; - cohortPaths.add(reply.getCohortPath()); + inReadyState = true; + + LOG.debug("Tx {} Readying {} transactions for commit", identifier, + txFutureCallbackMap.size()); + + if(txFutureCallbackMap.size() == 0) { + onTransactionReady(Collections.>emptyList()); + TransactionRateLimitingCallback.adjustRateLimitForUnusedTransaction(actorContext); + return NoOpDOMStoreThreePhaseCommitCohort.INSTANCE; + } + + throttleOperation(txFutureCallbackMap.size()); + + List> cohortFutures = Lists.newArrayList(); + + for(TransactionFutureCallback txFutureCallback : txFutureCallbackMap.values()) { + + LOG.debug("Tx {} Readying transaction for shard {} chain {}", identifier, + txFutureCallback.getShardName(), transactionChainId); + + final TransactionContext transactionContext = txFutureCallback.getTransactionContext(); + final Future future; + if (transactionContext != null) { + // avoid the creation of a promise and a TransactionOperation + future = transactionContext.readyTransaction(); + } else { + final Promise promise = akka.dispatch.Futures.promise(); + txFutureCallback.enqueueTransactionOperation(new TransactionOperation() { + @Override + public void invoke(TransactionContext transactionContext) { + promise.completeWith(transactionContext.readyTransaction()); + } + }); + future = promise.future(); } + + cohortFutures.add(future); } - return new ThreePhaseCommitCohortProxy(actorContext, cohortPaths, identifier, executor); + onTransactionReady(cohortFutures); + + return new ThreePhaseCommitCohortProxy(actorContext, cohortFutures, + identifier.toString()); + } + + /** + * Method for derived classes to be notified when the transaction has been readied. + * + * @param cohortFutures the cohort Futures for each shard transaction. + */ + protected void onTransactionReady(List> cohortFutures) { } @Override @@ -157,17 +446,358 @@ public class TransactionProxy implements DOMStoreReadWriteTransaction { @Override public void close() { - for(ActorSelection remoteTransaction : remoteTransactionPaths.values()) { - remoteTransaction.tell(new CloseTransaction(), null); + for (TransactionFutureCallback txFutureCallback : txFutureCallbackMap.values()) { + txFutureCallback.enqueueTransactionOperation(new TransactionOperation() { + @Override + public void invoke(TransactionContext transactionContext) { + transactionContext.closeTransaction(); + } + }); + } + + txFutureCallbackMap.clear(); + + if(remoteTransactionActorsMB != null) { + remoteTransactionActors.clear(); + remoteTransactionActorsMB.set(true); } } - private ActorSelection remoteTransactionFromIdentifier(InstanceIdentifier path){ + private String shardNameFromIdentifier(YangInstanceIdentifier path){ + return ShardStrategyFactory.getStrategy(path).findShard(path); + } + + protected Future sendFindPrimaryShardAsync(String shardName) { + return actorContext.findPrimaryShardAsync(shardName); + } + + private TransactionFutureCallback getOrCreateTxFutureCallback(YangInstanceIdentifier path) { String shardName = shardNameFromIdentifier(path); - return remoteTransactionPaths.get(shardName); + TransactionFutureCallback txFutureCallback = txFutureCallbackMap.get(shardName); + if(txFutureCallback == null) { + Future findPrimaryFuture = sendFindPrimaryShardAsync(shardName); + + final TransactionFutureCallback newTxFutureCallback = new TransactionFutureCallback(shardName); + + txFutureCallback = newTxFutureCallback; + txFutureCallbackMap.put(shardName, txFutureCallback); + + findPrimaryFuture.onComplete(new OnComplete() { + @Override + public void onComplete(Throwable failure, ActorSelection primaryShard) { + if(failure != null) { + newTxFutureCallback.createTransactionContext(failure, null); + } else { + newTxFutureCallback.setPrimaryShard(primaryShard); + } + } + }, actorContext.getClientDispatcher()); + } + + return txFutureCallback; + } + + public String getTransactionChainId() { + return transactionChainId; + } + + protected ActorContext getActorContext() { + return actorContext; + } + + /** + * Interfaces for transaction operations to be invoked later. + */ + private static interface TransactionOperation { + void invoke(TransactionContext transactionContext); } - private String shardNameFromIdentifier(InstanceIdentifier path){ - return Shard.DEFAULT_NAME; + /** + * Implements a Future OnComplete callback for a CreateTransaction message. This class handles + * retries, up to a limit, if the shard doesn't have a leader yet. This is done by scheduling a + * retry task after a short delay. + *

+ * The end result from a completed CreateTransaction message is a TransactionContext that is + * used to perform transaction operations. Transaction operations that occur before the + * CreateTransaction completes are cache and executed once the CreateTransaction completes, + * successfully or not. + */ + private class TransactionFutureCallback extends OnComplete { + + /** + * The list of transaction operations to execute once the CreateTransaction completes. + */ + @GuardedBy("txOperationsOnComplete") + private final List txOperationsOnComplete = Lists.newArrayList(); + + /** + * The TransactionContext resulting from the CreateTransaction reply. + */ + private volatile TransactionContext transactionContext; + + /** + * The target primary shard. + */ + private volatile ActorSelection primaryShard; + + private volatile int createTxTries = (int) (actorContext.getDatastoreContext(). + getShardLeaderElectionTimeout().duration().toMillis() / + CREATE_TX_TRY_INTERVAL.toMillis()); + + private final String shardName; + + TransactionFutureCallback(String shardName) { + this.shardName = shardName; + } + + String getShardName() { + return shardName; + } + + TransactionContext getTransactionContext() { + return transactionContext; + } + + + /** + * Sets the target primary shard and initiates a CreateTransaction try. + */ + void setPrimaryShard(ActorSelection primaryShard) { + this.primaryShard = primaryShard; + + if(transactionType == TransactionType.WRITE_ONLY && + actorContext.getDatastoreContext().isWriteOnlyTransactionOptimizationsEnabled()) { + LOG.debug("Tx {} Primary shard {} found - creating WRITE_ONLY transaction context", + identifier, primaryShard); + + // For write-only Tx's we prepare the transaction modifications directly on the shard actor + // to avoid the overhead of creating a separate transaction actor. + // FIXME: can't assume the shard version is LITHIUM_VERSION - need to obtain it somehow. + executeTxOperatonsOnComplete(createValidTransactionContext(this.primaryShard, + this.primaryShard.path().toString(), DataStoreVersions.LITHIUM_VERSION)); + } else { + tryCreateTransaction(); + } + } + + /** + * Adds a TransactionOperation to be executed after the CreateTransaction completes. + */ + void addTxOperationOnComplete(TransactionOperation operation) { + boolean invokeOperation = true; + synchronized(txOperationsOnComplete) { + if(transactionContext == null) { + LOG.debug("Tx {} Adding operation on complete", identifier); + + invokeOperation = false; + txOperationsOnComplete.add(operation); + } + } + + if(invokeOperation) { + operation.invoke(transactionContext); + } + } + + void enqueueTransactionOperation(final TransactionOperation op) { + + if (transactionContext != null) { + op.invoke(transactionContext); + } else { + // The shard Tx hasn't been created yet so add the Tx operation to the Tx Future + // callback to be executed after the Tx is created. + addTxOperationOnComplete(op); + } + } + + /** + * Performs a CreateTransaction try async. + */ + private void tryCreateTransaction() { + if(LOG.isDebugEnabled()) { + LOG.debug("Tx {} Primary shard {} found - trying create transaction", identifier, primaryShard); + } + + Object serializedCreateMessage = new CreateTransaction(identifier.toString(), + TransactionProxy.this.transactionType.ordinal(), + getTransactionChainId()).toSerializable(); + + Future createTxFuture = actorContext.executeOperationAsync(primaryShard, serializedCreateMessage); + + createTxFuture.onComplete(this, actorContext.getClientDispatcher()); + } + + @Override + public void onComplete(Throwable failure, Object response) { + if(failure instanceof NoShardLeaderException) { + // There's no leader for the shard yet - schedule and try again, unless we're out + // of retries. Note: createTxTries is volatile as it may be written by different + // threads however not concurrently, therefore decrementing it non-atomically here + // is ok. + if(--createTxTries > 0) { + LOG.debug("Tx {} Shard {} has no leader yet - scheduling create Tx retry", + identifier, shardName); + + actorContext.getActorSystem().scheduler().scheduleOnce(CREATE_TX_TRY_INTERVAL, + new Runnable() { + @Override + public void run() { + tryCreateTransaction(); + } + }, actorContext.getClientDispatcher()); + return; + } + } + + createTransactionContext(failure, response); + } + + private void createTransactionContext(Throwable failure, Object response) { + // Mainly checking for state violation here to perform a volatile read of "initialized" to + // ensure updates to operationLimter et al are visible to this thread (ie we're doing + // "piggy-back" synchronization here). + Preconditions.checkState(initialized, "Tx was not propertly initialized."); + + // Create the TransactionContext from the response or failure. Store the new + // TransactionContext locally until we've completed invoking the + // TransactionOperations. This avoids thread timing issues which could cause + // out-of-order TransactionOperations. Eg, on a modification operation, if the + // TransactionContext is non-null, then we directly call the TransactionContext. + // However, at the same time, the code may be executing the cached + // TransactionOperations. So to avoid thus timing, we don't publish the + // TransactionContext until after we've executed all cached TransactionOperations. + TransactionContext localTransactionContext; + if(failure != null) { + LOG.debug("Tx {} Creating NoOpTransaction because of error", identifier, failure); + + localTransactionContext = new NoOpTransactionContext(failure, identifier, operationLimiter); + } else if (response.getClass().equals(CreateTransactionReply.SERIALIZABLE_CLASS)) { + localTransactionContext = createValidTransactionContext( + CreateTransactionReply.fromSerializable(response)); + } else { + IllegalArgumentException exception = new IllegalArgumentException(String.format( + "Invalid reply type %s for CreateTransaction", response.getClass())); + + localTransactionContext = new NoOpTransactionContext(exception, identifier, operationLimiter); + } + + executeTxOperatonsOnComplete(localTransactionContext); + } + + private void executeTxOperatonsOnComplete(TransactionContext localTransactionContext) { + while(true) { + // Access to txOperationsOnComplete and transactionContext must be protected and atomic + // (ie synchronized) with respect to #addTxOperationOnComplete to handle timing + // issues and ensure no TransactionOperation is missed and that they are processed + // in the order they occurred. + + // We'll make a local copy of the txOperationsOnComplete list to handle re-entrancy + // in case a TransactionOperation results in another transaction operation being + // queued (eg a put operation from a client read Future callback that is notified + // synchronously). + Collection operationsBatch = null; + synchronized(txOperationsOnComplete) { + if(txOperationsOnComplete.isEmpty()) { + // We're done invoking the TransactionOperations so we can now publish the + // TransactionContext. + transactionContext = localTransactionContext; + break; + } + + operationsBatch = new ArrayList<>(txOperationsOnComplete); + txOperationsOnComplete.clear(); + } + + // Invoke TransactionOperations outside the sync block to avoid unnecessary blocking. + // A slight down-side is that we need to re-acquire the lock below but this should + // be negligible. + for(TransactionOperation oper: operationsBatch) { + oper.invoke(localTransactionContext); + } + } + } + + private TransactionContext createValidTransactionContext(CreateTransactionReply reply) { + LOG.debug("Tx {} Received {}", identifier, reply); + + return createValidTransactionContext(actorContext.actorSelection(reply.getTransactionPath()), + reply.getTransactionPath(), reply.getVersion()); + } + + private TransactionContext createValidTransactionContext(ActorSelection transactionActor, + String transactionPath, short remoteTransactionVersion) { + + if (transactionType == TransactionType.READ_ONLY) { + // Read-only Tx's aren't explicitly closed by the client so we create a PhantomReference + // to close the remote Tx's when this instance is no longer in use and is garbage + // collected. + + if(remoteTransactionActorsMB == null) { + remoteTransactionActors = Lists.newArrayList(); + remoteTransactionActorsMB = new AtomicBoolean(); + + TransactionProxyCleanupPhantomReference cleanup = + new TransactionProxyCleanupPhantomReference(TransactionProxy.this); + phantomReferenceCache.put(cleanup, cleanup); + } + + // Add the actor to the remoteTransactionActors list for access by the + // cleanup PhantonReference. + remoteTransactionActors.add(transactionActor); + + // Write to the memory barrier volatile to publish the above update to the + // remoteTransactionActors list for thread visibility. + remoteTransactionActorsMB.set(true); + } + + // TxActor is always created where the leader of the shard is. + // Check if TxActor is created in the same node + boolean isTxActorLocal = actorContext.isPathLocal(transactionPath); + + if(remoteTransactionVersion < DataStoreVersions.LITHIUM_VERSION) { + return new PreLithiumTransactionContextImpl(transactionPath, transactionActor, identifier, + transactionChainId, actorContext, schemaContext, isTxActorLocal, remoteTransactionVersion, + operationCompleter); + } else if (transactionType == TransactionType.WRITE_ONLY && + actorContext.getDatastoreContext().isWriteOnlyTransactionOptimizationsEnabled()) { + return new WriteOnlyTransactionContextImpl(transactionActor, identifier, transactionChainId, + actorContext, schemaContext, isTxActorLocal, remoteTransactionVersion, operationCompleter); + } else { + return new TransactionContextImpl(transactionActor, identifier, transactionChainId, + actorContext, schemaContext, isTxActorLocal, remoteTransactionVersion, operationCompleter); + } + } + } + + private static class NoOpDOMStoreThreePhaseCommitCohort implements DOMStoreThreePhaseCommitCohort { + static NoOpDOMStoreThreePhaseCommitCohort INSTANCE = new NoOpDOMStoreThreePhaseCommitCohort(); + + private static final ListenableFuture IMMEDIATE_VOID_SUCCESS = + com.google.common.util.concurrent.Futures.immediateFuture(null); + private static final ListenableFuture IMMEDIATE_BOOLEAN_SUCCESS = + com.google.common.util.concurrent.Futures.immediateFuture(Boolean.TRUE); + + private NoOpDOMStoreThreePhaseCommitCohort() { + } + + @Override + public ListenableFuture canCommit() { + return IMMEDIATE_BOOLEAN_SUCCESS; + } + + @Override + public ListenableFuture preCommit() { + return IMMEDIATE_VOID_SUCCESS; + } + + @Override + public ListenableFuture abort() { + return IMMEDIATE_VOID_SUCCESS; + } + + @Override + public ListenableFuture commit() { + return IMMEDIATE_VOID_SUCCESS; + } } }