Ensure we can not pick the same candidate twice. This make it react a lot faster especially with few nodes.

2 files changed, 15 insertions, 12 deletions

diff --git a/documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/AdaptiveLoadBalancer.java b/documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/AdaptiveLoadBalancer.java
index 9d5ccf9f71d..6a68a6e122b 100644
--- a/documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/AdaptiveLoadBalancer.java
+++ b/documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/AdaptiveLoadBalancer.java
@@ -30,14 +30,17 @@ class AdaptiveLoadBalancer extends LoadBalancer {
             entry = choices.get(0);
             metrics = getNodeMetrics(entry);
         } else {
-            int candidateA = 0;
-            int candidateB = 1;
+            int candA = 0;
+            int candB = 1;
             if (choices.size() > 2) {
-                candidateA = random.nextInt(choices.size());
-                candidateB = random.nextInt(choices.size());
+                candA = random.nextInt(choices.size());
+                candB = random.nextInt(choices.size());
+                while (candB == candA) {
+                    candB = random.nextInt(choices.size());
+                }
             }
-            entry = choices.get(candidateA);
-            Mirror.Entry entryB = choices.get(candidateB);
+            entry = choices.get(candA);
+            Mirror.Entry entryB = choices.get(candB);
             metrics = getNodeMetrics(entry);
             NodeMetrics metricsB = getNodeMetrics(entryB);
             if (metrics.pending() > metricsB.pending()) {
diff --git a/documentapi/src/test/java/com/yahoo/documentapi/messagebus/protocol/LoadBalancerTestCase.java b/documentapi/src/test/java/com/yahoo/documentapi/messagebus/protocol/LoadBalancerTestCase.java
index 9afbeecec83..088259b74ac 100644
--- a/documentapi/src/test/java/com/yahoo/documentapi/messagebus/protocol/LoadBalancerTestCase.java
+++ b/documentapi/src/test/java/com/yahoo/documentapi/messagebus/protocol/LoadBalancerTestCase.java
@@ -101,13 +101,13 @@ public class LoadBalancerTestCase {
             sumPending += metrics.pending();
         }
         assertEquals(9999, sentSum);
-        assertEquals(2636, sumPending);
-        assertEquals(1781, weights.get(0).sent());
-        assertEquals(5585, weights.get(1).sent());
-        assertEquals(2633, weights.get(2).sent());
-        assertEquals(1318, weights.get(0).pending());
+        assertEquals(2039, sumPending);
+        assertEquals(1332, weights.get(0).sent());
+        assertEquals(6645, weights.get(1).sent());
+        assertEquals(2022, weights.get(2).sent());
+        assertEquals(1020, weights.get(0).pending());
         assertEquals(0, weights.get(1).pending());
-        assertEquals(1318, weights.get(2).pending());
+        assertEquals(1019, weights.get(2).pending());
     }
 
     @Test