iamaleksey commented on code in PR #2982:
URL: https://github.com/apache/cassandra/pull/2982#discussion_r1444946818
##########
src/java/org/apache/cassandra/service/accord/AccordJournal.java:
##########
@@ -699,6 +1003,246 @@ private static int msVersion(int version)
}
}
+ /*
+ * Record framing logic
+ */
+
+ private final class FrameAggregator implements Interruptible.Task
+ {
+ /* external MPSC pending request queue */
+ private final ManyToOneConcurrentLinkedQueue<PendingRequest>
unframedRequests = new ManyToOneConcurrentLinkedQueue<>();
+
+ private final LongArrayList waitForEpochs = new LongArrayList();
+ private final Long2ObjectHashMap<ArrayList<PendingRequest>>
delayedRequests = new Long2ObjectHashMap<>();
+
+ private volatile Interruptible executor;
+
+ // a signal and flag that callers outside the aggregator thread can use
+ // to signal they want the aggregator to run again
+ private final Semaphore haveWork = newSemaphore(1);
+
+ void onWrite(Pointer pointer, RequestContext context)
+ {
+ unframedRequests.add(new PendingRequest(pointer, context));
+ haveWork.release(1);
+ }
+
+ void notifyOfEpoch()
+ {
+ haveWork.release(1);
+ }
+
+ void start()
+ {
+ executor =
executorFactory().infiniteLoop("AccordJournal#FrameAggregator", this, SAFE,
NON_DAEMON, SYNCHRONIZED);
+ }
+
+ void shutdown()
+ {
+ executor.shutdown();
+ }
+
+ /* internal reusable buffers used for frame generation */
+ private final ArrayList<PendingRequest> requestBuffer = new
ArrayList<>();
+ private final ArrayList<Pointer> pointersBuffer = new ArrayList<>();
+ private final ArrayList<RequestContext> contextsBuffer = new
ArrayList<>();
+
+ @Override
+ public void run(Interruptible.State state) throws InterruptedException
+ {
+ if (unframedRequests.isEmpty() && delayedRequests.isEmpty())
+ return;
+
+ try
+ {
+ doRun();
+ }
+ finally
+ {
+ requestBuffer.clear();
+ pointersBuffer.clear();
+ contextsBuffer.clear();
+ }
+
+ haveWork.acquire(1);
+ }
+
+ private void doRun()
+ {
+ /*
+ * Deal with delayed requests
+ */
+
+ waitForEpochs.sort(null);
+
+ for (int i = 0; i < waitForEpochs.size(); i++)
+ {
+ long waitForEpoch = waitForEpochs.getLong(i);
+ if (!node.topology().hasEpoch(waitForEpoch))
+ break;
+ requestBuffer.addAll(delayedRequests.remove(waitForEpoch));
+ }
+
+ waitForEpochs.removeIfLong(epoch ->
!delayedRequests.containsKey(epoch));
+
+ /*
+ * Deal with regular pending requests
+ */
+
+ PendingRequest request;
+ while (null != (request = unframedRequests.poll()))
+ {
+ long waitForEpoch = request.context.waitForEpoch;
+ if (!node.topology().hasEpoch(waitForEpoch))
+ {
+ delayedRequests.computeIfAbsent(waitForEpoch, ignore ->
new ArrayList<>()).add(request);
+ if (!waitForEpochs.containsLong(waitForEpoch))
+ {
+ waitForEpochs.addLong(waitForEpoch);
+ node.withEpoch(waitForEpoch, this::notifyOfEpoch);
+ }
+ }
+ else
+ {
+ requestBuffer.add(request);
+ }
+ }
+
+ for (PendingRequest req : requestBuffer)
+ {
+ pointersBuffer.add(req.pointer);
+ contextsBuffer.add(req.context);
+ }
+
+ if (!requestBuffer.isEmpty())
+ {
+ FrameRecord frame = new FrameRecord(node.uniqueNow(),
pointersBuffer.toArray(new Pointer[0]));
+ FrameContext context = new
FrameContext(contextsBuffer.toArray(new RequestContext[0]));
+ appendAuxiliaryRecord(frame, context);
+ }
+ }
+
+ private final class PendingRequest
+ {
+ final Pointer pointer;
+ final RequestContext context;
+
+ PendingRequest(Pointer pointer, RequestContext context)
+ {
+ this.pointer = pointer;
+ this.context = context;
+ }
+ }
+ }
+
+ private final class FrameApplicator implements Runnable
+ {
+ /** external SPSC written frame queue */
+ private final SpscLinkedQueue<PendingFrame> newFrames = new
SpscLinkedQueue<>();
+
+ /* single-thread accessed internal frame buffer */
+ private final ArrayList<PendingFrame> pendingFrames = new
ArrayList<>();
+
+ /* furthest flushed journal segment + position */
+ private volatile Pointer flushedUntil = null;
+
+ private volatile SequentialExecutorPlus executor;
+
+ /* invoked from FrameGenerator thread via appendAuxiliaryRecord() call
*/
+ void onWrite(Pointer start, int size, FrameContext context)
+ {
+ newFrames.add(new PendingFrame(start, new Pointer(start.segment,
start.position + size), context));
+ }
+
+ /* invoked only from Journal Flusher thread (single) */
+ void onFlush(long segment, int position)
+ {
+ flushedUntil = new Pointer(segment, position);
+ executor.submit(this);
+ }
+
+ void start()
+ {
+ executor =
executorFactory().sequential("AccordJournal#FrameApplicator");
+ }
+
+ void shutdown()
+ {
+ executor.shutdown();
+ }
+
+ @Override
+ public void run()
+ {
+ if (newFrames.drain(pendingFrames::add) > 0)
+ {
+ /* order by position in the journal, DESC */
+ pendingFrames.sort((f1, f2) -> f2.start.compareTo(f1.start));
+ }
+
+ Pointer flushedUntil = this.flushedUntil;
+ for (int i = pendingFrames.size() - 1; i >= 0; i--)
+ {
+ PendingFrame frame = pendingFrames.get(i);
+ if (frame.end.compareTo(flushedUntil) > 0)
+ break;
+ applyFrame((FrameRecord) cachedRecords.remove(frame.start),
frame.context);
+ pendingFrames.remove(i);
+ }
+ }
+
+ private void applyFrame(FrameRecord frame, FrameContext context)
+ {
+ Invariants.checkState(frame.pointers.length ==
context.requestContexts.length);
+ for (int i = 0; i < frame.pointers.length; i++)
+ applyRequest(frame.pointers[i], context.requestContexts[i]);
+ }
+
+ private void applyRequest(Pointer pointer, RequestContext context)
+ {
+ Request request = (Request) cachedRecords.remove(pointer);
Review Comment:
Yep.
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