There is a common and uncommon path here, where we expect majority
of high-performance uses to short-circuit to no combining at all.
Split that simple case out, so that we aid JIT inlining and also
know in profiling runs which branches are usually taken.
Change-Id: I18aaa12837c472308b46b770551e606096f7c983
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>
private <T> Future<T> combineFutureWithPossiblePriorReadOnlyTxFutures(final Future<T> future,
final TransactionIdentifier txId) {
private <T> Future<T> combineFutureWithPossiblePriorReadOnlyTxFutures(final Future<T> future,
final TransactionIdentifier txId) {
- if (!priorReadOnlyTxPromises.containsKey(txId) && !priorReadOnlyTxPromises.isEmpty()) {
- Collection<Entry<TransactionIdentifier, Promise<Object>>> priorReadOnlyTxPromiseEntries =
- new ArrayList<>(priorReadOnlyTxPromises.entrySet());
- if (priorReadOnlyTxPromiseEntries.isEmpty()) {
- return future;
- }
+ return priorReadOnlyTxPromises.isEmpty() || priorReadOnlyTxPromises.containsKey(txId) ? future
+ // Tough luck, we need do some work
+ : combineWithPriorReadOnlyTxFutures(future, txId);
+ }
- List<Future<Object>> priorReadOnlyTxFutures = new ArrayList<>(priorReadOnlyTxPromiseEntries.size());
- for (Entry<TransactionIdentifier, Promise<Object>> entry: priorReadOnlyTxPromiseEntries) {
- LOG.debug("Tx: {} - waiting on future for prior read-only Tx {}", txId, entry.getKey());
- priorReadOnlyTxFutures.add(entry.getValue().future());
- }
+ // Split out of the common path
+ private <T> Future<T> combineWithPriorReadOnlyTxFutures(final Future<T> future, final TransactionIdentifier txId) {
+ // Take a stable snapshot, and check if we raced
+ final List<Entry<TransactionIdentifier, Promise<Object>>> priorReadOnlyTxPromiseEntries =
+ new ArrayList<>(priorReadOnlyTxPromises.entrySet());
+ if (priorReadOnlyTxPromiseEntries.isEmpty()) {
+ return future;
+ }
- Future<Iterable<Object>> combinedFutures = Futures.sequence(priorReadOnlyTxFutures,
- getActorUtils().getClientDispatcher());
+ final List<Future<Object>> priorReadOnlyTxFutures = new ArrayList<>(priorReadOnlyTxPromiseEntries.size());
+ for (Entry<TransactionIdentifier, Promise<Object>> entry: priorReadOnlyTxPromiseEntries) {
+ LOG.debug("Tx: {} - waiting on future for prior read-only Tx {}", txId, entry.getKey());
+ priorReadOnlyTxFutures.add(entry.getValue().future());
+ }
- final Promise<T> returnPromise = Futures.promise();
- final OnComplete<Iterable<Object>> onComplete = new OnComplete<Iterable<Object>>() {
- @Override
- public void onComplete(final Throwable failure, final Iterable<Object> notUsed) {
- LOG.debug("Tx: {} - prior read-only Tx futures complete", txId);
+ final Future<Iterable<Object>> combinedFutures = Futures.sequence(priorReadOnlyTxFutures,
+ getActorUtils().getClientDispatcher());
- // Complete the returned Promise with the original Future.
- returnPromise.completeWith(future);
- }
- };
+ final Promise<T> returnPromise = Futures.promise();
+ final OnComplete<Iterable<Object>> onComplete = new OnComplete<>() {
+ @Override
+ public void onComplete(final Throwable failure, final Iterable<Object> notUsed) {
+ LOG.debug("Tx: {} - prior read-only Tx futures complete", txId);
- combinedFutures.onComplete(onComplete, getActorUtils().getClientDispatcher());
- return returnPromise.future();
- } else {
- return future;
- }
+ // Complete the returned Promise with the original Future.
+ returnPromise.completeWith(future);
+ }
+ };
+
+ combinedFutures.onComplete(onComplete, getActorUtils().getClientDispatcher());
+ return returnPromise.future();