import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.SettableFuture;
+import java.util.ArrayList;
+import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
* 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);
- } else {
- operation.invoke(transactionContext);
}
}
+
+ if(invokeOperation) {
+ operation.invoke(transactionContext);
+ }
}
}
}
- // Create the TransactionContext from the response or failure and execute delayed
- // TransactionOperations. This entire section is done atomically (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.
- synchronized(txOperationsOnComplete) {
- // 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.getMessage());
-
- 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(
+ // 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.getMessage());
+
+ 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);
+ 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<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();
}
- for(TransactionOperation oper: txOperationsOnComplete) {
+ // 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);
}
-
- txOperationsOnComplete.clear();
-
- // We're done invoking the TransactionOperations so we can now publish the
- // TransactionContext.
- transactionContext = localTransactionContext;
}
}
Code Review / controller.git / blobdiff