private Page extractOutput() {
// INVARIANT: pagesIndex contains the full grouped & sorted data for one or more partitions
// Iterate through the positions sequentially until we have one full page
while (!pageBuilder.isFull()) {
if (partition == null || !partition.hasNext()) {
int partitionStart = partition == null ? 0 : partition.getPartitionEnd();
if (partitionStart >= pagesIndex.getPositionCount()) {
// Finished all of the partitions in the current pagesIndex
partition = null;
pagesIndex.clear();
// Try to extract more partitions from the pendingInput
if (pendingInput != null && processPendingInput()) {
partitionStart = 0;
} else if (state == State.FINISHING) {
state = State.FINISHED;
// Output the remaining page if we have anything buffered
if (!pageBuilder.isEmpty()) {
Page page = pageBuilder.build();
pageBuilder.reset();
return page;
}
return null;
} else {
state = State.NEEDS_INPUT;
return null;
}
}
int partitionEnd = findGroupEnd(pagesIndex, unGroupedPartitionHashStrategy, partitionStart);
partition =
new WindowPartition(
pagesIndex,
partitionStart,
partitionEnd,
outputChannels,
windowFunctions,
frameInfo,
peerGroupHashStrategy);
}
partition.processNextRow(pageBuilder);
}
Page page = pageBuilder.build();
pageBuilder.reset();
return page;
}
public ListenableFuture<?> flush(boolean force) {
// add all full pages to output buffer
List<ListenableFuture<?>> blockedFutures = new ArrayList<>();
for (int partition = 0; partition < pageBuilders.size(); partition++) {
PageBuilder partitionPageBuilder = pageBuilders.get(partition);
if (!partitionPageBuilder.isEmpty() && (force || partitionPageBuilder.isFull())) {
Page pagePartition = partitionPageBuilder.build();
partitionPageBuilder.reset();
blockedFutures.add(outputBuffer.enqueue(partition, pagePartition));
pagesAdded.incrementAndGet();
rowsAdded.addAndGet(pagePartition.getPositionCount());
}
}
ListenableFuture<?> future = Futures.allAsList(blockedFutures);
if (future.isDone()) {
return NOT_BLOCKED;
}
return future;
}