Merge pull request #26125 from vespa-engine/bratseth/handle-zero-trafficv8.129.8

Handle zero traffic

2 files changed, 12 insertions, 2 deletions

diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ClusterModel.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ClusterModel.java
index 264664f91b2..4a4222cca6a 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ClusterModel.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ClusterModel.java
@@ -196,8 +196,10 @@ public class ClusterModel {
         if (! cluster.bcpGroupInfo().isEmpty()) {
             // Do a weighted sum of the ideal "vote" based on local and bcp group info.
             // This avoids any discontinuities with a near-zero local query rate.
-            double localInformationWeight = Math.min(1, averageQueryRate().orElse(0) /
-                                                        Math.min(queryRateGivingFullConfidence, cluster.bcpGroupInfo().queryRate()));
+            double localInformationWeight = cluster.bcpGroupInfo().queryRate() == 0
+                                            ? 1
+                                            : Math.min(1, averageQueryRate().orElse(0) /
+                                                          Math.min(queryRateGivingFullConfidence, cluster.bcpGroupInfo().queryRate()));
             Load bcpGroupIdeal = adjustQueryDependentIdealLoadByBcpGroupInfo(ideal);
             ideal = ideal.multiply(localInformationWeight).add(bcpGroupIdeal.multiply(1 - localInformationWeight));
         }
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingUsingBcpGroupInfoTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingUsingBcpGroupInfoTest.java
index 91de7209ac1..5cef4baadd4 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingUsingBcpGroupInfoTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingUsingBcpGroupInfoTest.java
@@ -54,6 +54,14 @@ public class AutoscalingUsingBcpGroupInfoTest {
         fixture.tester().assertResources("Scaling up cpu using bcp group cpu info",
                                          9, 1, 5.4,  6.1, 25.3,
                                          fixture.autoscale());
+
+        // Bcp elsewhere is 0 - use local only
+        fixture.tester().clock().advance(Duration.ofDays(2));
+        fixture.store(new BcpGroupInfo(0, 1.1, 0.45));
+        fixture.loader().addCpuMeasurements(0.7f, 10);
+        fixture.tester().assertResources("Scaling using local info",
+                                         8, 1, 1,  7.0, 29.0,
+                                         fixture.autoscale());
     }
 
     /** Tests with varying BCP group info parameters. */