[Java] Set the time of last consumer position change to be construction of the publication and on transition from 0 to 1 subscribers for IPC. This should avoid the publisher getting unblocked unexpectedly. Issue #377.

Author: mjpt777

aeron-driver/src/main/java/io/aeron/driver/DriverConductor.java

@@ -1071,6 +1071,7 @@ private IpcPublication addIpcPublication(
             rawLog,
             publicationUnblockTimeoutNs,
             context.systemCounters(),
+            nanoClock,
             isExclusive);
 
         ipcPublications.add(publication);

aeron-driver/src/main/java/io/aeron/driver/IpcPublication.java

@@ -20,6 +20,7 @@
 import io.aeron.logbuffer.LogBufferDescriptor;
 import io.aeron.logbuffer.LogBufferUnblocker;
 import org.agrona.collections.ArrayUtil;
+import org.agrona.concurrent.NanoClock;
 import org.agrona.concurrent.UnsafeBuffer;
 import org.agrona.concurrent.status.AtomicCounter;
 import org.agrona.concurrent.status.Position;
@@ -50,12 +51,12 @@ enum Status
     private final int termWindowLength;
     private final int positionBitsToShift;
     private final int initialTermId;
-    private long tripLimit = 0;
-    private long consumerPosition = 0;
-    private long lastConsumerPosition = 0;
-    private long timeOfLastConsumerPositionChange = 0;
-    private long cleanPosition = 0;
-    private long timeOfLastStatusChange = 0;
+    private long tripLimit;
+    private long consumerPosition;
+    private long lastConsumerPosition;
+    private long timeOfLastConsumerPositionChangeNs;
+    private long cleanPosition;
+    private long timeOfLastStatusChangeNs;
     private int refCount = 0;
     private boolean reachedEndOfLife = false;
     private final boolean isExclusive;
@@ -64,6 +65,7 @@ enum Status
     private ReadablePosition[] subscriberPositions = EMPTY_POSITIONS;
     private final Position publisherLimit;
     private final UnsafeBuffer metaDataBuffer;
+    private final NanoClock nanoClock;
     private final RawLog rawLog;
     private final AtomicCounter unblockedPublications;
 
@@ -75,6 +77,7 @@ public IpcPublication(
         final RawLog rawLog,
         final long unblockTimeoutNs,
         final SystemCounters systemCounters,
+        final NanoClock nanoClock,
         final boolean isExclusive)
     {
         this.registrationId = registrationId;
@@ -83,6 +86,7 @@ public IpcPublication(
         this.isExclusive = isExclusive;
         this.termBuffers = rawLog.termBuffers();
         this.initialTermId = initialTermId(rawLog.metaData());
+        this.nanoClock = nanoClock;
 
         final int termLength = rawLog.termLength();
         this.termBufferLength = termLength;
@@ -98,6 +102,7 @@ public IpcPublication(
         consumerPosition = producerPosition();
         lastConsumerPosition = consumerPosition;
         cleanPosition = consumerPosition;
+        timeOfLastConsumerPositionChangeNs = nanoClock.nanoTime();
     }
 
     public int sessionId()
@@ -143,6 +148,11 @@ public void close()
 
     public void addSubscriber(final ReadablePosition subscriberPosition)
     {
+        if (subscriberPositions.length == 0)
+        {
+            timeOfLastConsumerPositionChangeNs = nanoClock.nanoTime();
+        }
+
         subscriberPositions = ArrayUtil.add(subscriberPositions, subscriberPosition);
     }
 
@@ -236,13 +246,13 @@ public void onTimeEvent(final long timeNs, final long timeMs, final DriverConduc
                 if (isDrained())
                 {
                     status = Status.LINGER;
-                    timeOfLastStatusChange = timeNs;
+                    timeOfLastStatusChangeNs = timeNs;
                     conductor.transitionToLinger(this);
                 }
                 break;
 
             case LINGER:
-                if (timeNs > (timeOfLastStatusChange + PUBLICATION_LINGER_NS))
+                if (timeNs > (timeOfLastStatusChangeNs + PUBLICATION_LINGER_NS))
                 {
                     reachedEndOfLife = true;
                     conductor.cleanupIpcPublication(this);
@@ -256,14 +266,14 @@ public boolean hasReachedEndOfLife()
         return reachedEndOfLife;
     }
 
-    public void timeOfLastStateChange(final long time)
+    public void timeOfLastStateChange(final long timeNs)
     {
-        timeOfLastStatusChange = time;
+        timeOfLastStatusChangeNs = timeNs;
     }
 
     public long timeOfLastStateChange()
     {
-        return timeOfLastStatusChange;
+        return timeOfLastStatusChangeNs;
     }
 
     public void delete()
@@ -318,8 +328,8 @@ private void checkForBlockedPublisher(final long timeNs)
     {
         if (consumerPosition == lastConsumerPosition)
         {
-            if (producerPosition() > consumerPosition &&
-                timeNs > (timeOfLastConsumerPositionChange + unblockTimeoutNs))
+            if (timeNs > (timeOfLastConsumerPositionChangeNs + unblockTimeoutNs) &&
+                producerPosition() > consumerPosition)
             {
                 if (LogBufferUnblocker.unblock(termBuffers, metaDataBuffer, consumerPosition))
                 {
@@ -329,7 +339,7 @@ private void checkForBlockedPublisher(final long timeNs)
         }
         else
         {
-            timeOfLastConsumerPositionChange = timeNs;
+            timeOfLastConsumerPositionChangeNs = timeNs;
             lastConsumerPosition = consumerPosition;
         }
     }

aeron-driver/src/main/java/io/aeron/driver/NetworkPublication.java

@@ -198,6 +198,7 @@ public NetworkPublication(
 
         lastSenderPosition = senderPosition.get();
         cleanPosition = lastSenderPosition;
+        timeOfLastActivityNs = nowNs;
     }
 
     public void close()
@@ -565,8 +566,8 @@ private void checkForBlockedPublisher(final long timeNs, final long senderPositi
     {
         if (senderPosition == lastSenderPosition)
         {
-            if (producerPosition() > senderPosition &&
-                timeNs > (timeOfLastActivityNs + unblockTimeoutNs))
+            if (timeNs > (timeOfLastActivityNs + unblockTimeoutNs) &&
+                producerPosition() > senderPosition)
             {
                 if (LogBufferUnblocker.unblock(termBuffers, metaDataBuffer, senderPosition))
                 {