ARTEMIS-4455 - Improve message redistribution balance for OFF_WITH_REDISTRIBUTION

Author: AntonRoskvist

artemis-server/src/main/java/org/apache/activemq/artemis/core/postoffice/impl/BindingsImpl.java

@@ -470,6 +470,11 @@ private Binding getNextBinding(final Message message,
          // if no bindings were found, we will apply a secondary level on the routing logic
          if (lastLowPriorityBinding != -1) {
             nextBinding = bindings[lastLowPriorityBinding];
+            if (nextBinding != null && loadBalancingType.equals(MessageLoadBalancingType.OFF_WITH_REDISTRIBUTION)) {
+               //return before changing bindingIndex, otherwise every incoming message sets the index to the same position.
+               //bindingIndex is shared with the redistributor
+               return nextBinding;
+            }
             nextPosition = moveNextPosition(lastLowPriorityBinding, bindingsCount);
          }
       }

tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/cluster/distribution/MessageRedistributionTest.java

@@ -1011,6 +1011,40 @@ public void testRedistributionToRemoteConsumerFromNewQueueLbOffWithRedistributio
 
    }
 
+   @Test
+   public void testEvenRedistributionLbOffWithRedistribution() throws Exception {
+      final int messageCount = 1000;
+      final String queue = "queues.test";
+
+      setupCluster(MessageLoadBalancingType.OFF_WITH_REDISTRIBUTION);
+      startServers(0, 1, 2);
+
+      setupSessionFactory(0, isNetty());
+      setupSessionFactory(1, isNetty());
+      setupSessionFactory(2, isNetty());
+
+      createQueue(0, queue, queue, null, false, RoutingType.ANYCAST);
+      createQueue(1, queue, queue, null, false, RoutingType.ANYCAST);
+      createQueue(2, queue, queue, null, false, RoutingType.ANYCAST);
+
+      addConsumer(0, 1, queue, null);
+      addConsumer(1, 2, queue, null);
+
+      waitForBindings(0, queue, 1, 0, true);
+      waitForBindings(1, queue, 1, 1, true);
+      waitForBindings(2, queue, 1, 1, true);
+
+      waitForBindings(0, queue, 2, 2, false);
+      waitForBindings(1, queue, 2, 1, false);
+      waitForBindings(2, queue, 2, 1, false);
+
+      send(0, queue, messageCount * 2, false, null);
+
+      Wait.assertEquals(0L, () -> servers[0].getTotalMessageCount(), 5000, 100);
+      Assert.assertEquals(messageCount, servers[1].getTotalMessageCount());
+      Assert.assertEquals(messageCount, servers[2].getTotalMessageCount());
+   }
+
    @Test
    public void testRedistributionToRemoteMulticastConsumerLbOffWithRedistribution() throws Exception {