Don't avoid group blocking feed when groups = 1

2 files changed, 18 insertions, 5 deletions

diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/Dispatcher.java b/container-search/src/main/java/com/yahoo/search/dispatch/Dispatcher.java
index 869ea6436de..9b42ce03e6d 100644
--- a/container-search/src/main/java/com/yahoo/search/dispatch/Dispatcher.java
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/Dispatcher.java
@@ -249,11 +249,12 @@ public class Dispatcher extends AbstractComponent {
      * We want to avoid groups blocking feed because their data may be out of date.
      * If there is a single group blocking feed, we want to reject it.
      * If multiple groups are blocking feed we should use them anyway as we may not have remaining
-     * capacity otherwise.
+     * capacity otherwise. Same if there are no other groups.
      *
      * @return a modifiable set containing the single group to reject, or null otherwise
      */
     private Set<Integer> rejectGroupBlockingFeed(List<Group> groups) {
+        if (groups.size() == 1) return null;
         List<Group> groupsRejectingFeed = groups.stream().filter(Group::isBlockingWrites).collect(Collectors.toList());
         if (groupsRejectingFeed.size() != 1) return null;
         Set<Integer> rejected = new HashSet<>();
diff --git a/container-search/src/test/java/com/yahoo/search/dispatch/DispatcherTest.java b/container-search/src/test/java/com/yahoo/search/dispatch/DispatcherTest.java
index aa7a0c6b4f4..eaafb2d8b8a 100644
--- a/container-search/src/test/java/com/yahoo/search/dispatch/DispatcherTest.java
+++ b/container-search/src/test/java/com/yahoo/search/dispatch/DispatcherTest.java
@@ -93,7 +93,7 @@ public class DispatcherTest {
     }
 
     @Test
-    public void testGroup1IsSelected() {
+    public void testGroup0IsSelected() {
         SearchCluster cluster = new MockSearchCluster("1", 3, 1);
         Dispatcher dispatcher = new Dispatcher(new ClusterMonitor(cluster, false), cluster, createDispatchConfig(), new MockInvokerFactory(cluster, (n, a) -> true), new MockMetric());
         cluster.pingIterationCompleted();
@@ -103,7 +103,7 @@ public class DispatcherTest {
     }
 
     @Test
-    public void testGroup1IsSkippedWhenItIsBlockingFeed() {
+    public void testGroup0IsSkippedWhenItIsBlockingFeed() {
         SearchCluster cluster = new MockSearchCluster("1", 3, 1);
         Dispatcher dispatcher = new Dispatcher(new ClusterMonitor(cluster, false), cluster, createDispatchConfig(), new MockInvokerFactory(cluster, (n, a) -> true), new MockMetric());
         cluster.group(0).get().nodes().get(0).setBlockingWrites(true);
@@ -115,8 +115,8 @@ public class DispatcherTest {
     }
 
     @Test
-    public void testGroup1IsSelectedWhenMoreAreBlockingFeed() {
-        SearchCluster cluster = new MockSearchCluster("1", 2, 1);
+    public void testGroup0IsSelectedWhenMoreAreBlockingFeed() {
+        SearchCluster cluster = new MockSearchCluster("1", 3, 1);
         Dispatcher dispatcher = new Dispatcher(new ClusterMonitor(cluster, false), cluster, createDispatchConfig(), new MockInvokerFactory(cluster, (n, a) -> true), new MockMetric());
         cluster.group(0).get().nodes().get(0).setBlockingWrites(true);
         cluster.group(1).get().nodes().get(0).setBlockingWrites(true);
@@ -127,6 +127,18 @@ public class DispatcherTest {
         dispatcher.deconstruct();
     }
 
+    @Test
+    public void testGroup0IsSelectedWhenItIsBlockingFeedWhenNoOthers() {
+        SearchCluster cluster = new MockSearchCluster("1", 1, 1);
+        Dispatcher dispatcher = new Dispatcher(new ClusterMonitor(cluster, false), cluster, createDispatchConfig(), new MockInvokerFactory(cluster, (n, a) -> true), new MockMetric());
+        cluster.group(0).get().nodes().get(0).setBlockingWrites(true);
+        cluster.pingIterationCompleted();
+        assertEquals("Blocking group is used when there is no alternative",
+                     0,
+                     (dispatcher.getSearchInvoker(new Query(), null).distributionKey().get()).longValue());
+        dispatcher.deconstruct();
+    }
+
     interface FactoryStep {
         boolean returnInvoker(List<Node> nodes, boolean acceptIncompleteCoverage);
     }