- /**
- * 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",
- getIdentifier(), 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", getIdentifier());
-
- 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", getIdentifier(), primaryShard);
- }
-
- Object serializedCreateMessage = new CreateTransaction(getIdentifier().toString(),
- TransactionProxy.this.transactionType.ordinal(),
- getTransactionChainId()).toSerializable();
-
- Future<Object> 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",
- getIdentifier(), 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", getIdentifier(), failure);
-
- localTransactionContext = new NoOpTransactionContext(failure, getIdentifier(), operationLimiter);
- } else if (CreateTransactionReply.SERIALIZABLE_CLASS.equals(response.getClass())) {
- localTransactionContext = createValidTransactionContext(
- CreateTransactionReply.fromSerializable(response));
- } else {
- IllegalArgumentException exception = new IllegalArgumentException(String.format(
- "Invalid reply type %s for CreateTransaction", response.getClass()));
-
- localTransactionContext = new NoOpTransactionContext(exception, getIdentifier(), 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<TransactionOperation> 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);
- }
- }
- }