Merge pull request #15013 from vespa-engine/bratseth/persist-metrics-rebased

Bratseth/persist metrics rebased

57 files changed, 1165 insertions, 718 deletions

diff --git a/node-repository/src/main/config/node-repository.xml b/node-repository/src/main/config/node-repository.xml
index 90e98d11ac0..a12e2a8b11c 100644
--- a/node-repository/src/main/config/node-repository.xml
+++ b/node-repository/src/main/config/node-repository.xml
@@ -1,8 +1,8 @@
 <!-- services.xml snippet for the node repository. Included in config server services.xml if the package is installed-->
 <!-- Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root. -->
 <component id="com.yahoo.vespa.hosted.provision.provisioning.InfraDeployerImpl" bundle="node-repository"/>
-<component id="com.yahoo.vespa.hosted.provision.autoscale.NodeMetricsFetcher" bundle="node-repository"/>
-<component id="com.yahoo.vespa.hosted.provision.autoscale.NodeMetricsDb" bundle="node-repository"/>
+<component id="com.yahoo.vespa.hosted.provision.autoscale.MetricsV2MetricsFetcher" bundle="node-repository"/>
+<component id="com.yahoo.vespa.hosted.provision.autoscale.QuestMetricsDb" bundle="node-repository"/>
 <component id="com.yahoo.vespa.hosted.provision.provisioning.NodeRepositoryProvisioner" bundle="node-repository" />
 <component id="NodeRepository" class="com.yahoo.vespa.hosted.provision.NodeRepository" bundle="node-repository"/>
 <component id="com.yahoo.vespa.hosted.provision.maintenance.NodeRepositoryMaintenance" bundle="node-repository"/>
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/NodeList.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/NodeList.java
index 5827d7a0f7d..17273344594 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/NodeList.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/NodeList.java
@@ -4,6 +4,7 @@ package com.yahoo.vespa.hosted.provision;
 import com.yahoo.collections.AbstractFilteringList;
 import com.yahoo.component.Version;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
 import com.yahoo.config.provision.NodeResources;
 import com.yahoo.config.provision.NodeType;
@@ -179,6 +180,15 @@ public class NodeList extends AbstractFilteringList<Node, NodeList> {
                                                        .findFirst());
     }
 
+    public ClusterResources toResources() {
+        if (isEmpty()) return new ClusterResources(0, 0, NodeResources.unspecified());
+        return new ClusterResources(size(),
+                                    (int)stream().map(node -> node.allocation().get().membership().cluster().group().get())
+                                                 .distinct()
+                                                 .count(),
+                                    first().get().resources());
+    }
+
     /** Returns the nodes of this as a stream */
     public Stream<Node> stream() { return asList().stream(); }
 
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/NodeRepository.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/NodeRepository.java
index fd7dbc9716b..3fdade27410 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/NodeRepository.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/NodeRepository.java
@@ -7,6 +7,7 @@ import com.yahoo.component.AbstractComponent;
 import com.yahoo.component.Version;
 import com.yahoo.concurrent.maintenance.JobControl;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.DockerImage;
 import com.yahoo.config.provision.Flavor;
 import com.yahoo.config.provision.NodeFlavors;
@@ -504,17 +505,17 @@ public class NodeRepository extends AbstractComponent {
     }
 
     /** Deactivate nodes owned by application guarded by given lock */
-    public void deactivate(NestedTransaction transaction, ProvisionLock lock) {
-        deactivate(db.readNodes(lock.application(), State.reserved, State.active), transaction, lock);
-        applications.remove(lock.application(), transaction, lock);
+    public void deactivate(ApplicationTransaction transaction) {
+        deactivate(db.readNodes(transaction.application(), State.reserved, State.active), transaction);
+        applications.remove(transaction);
     }
 
     /**
      * Deactivates these nodes in a transaction and returns the nodes in the new state which will hold if the
      * transaction commits.
      */
-    public List<Node> deactivate(List<Node> nodes, NestedTransaction transaction, @SuppressWarnings("unused") ProvisionLock lock) {
-        return db.writeTo(State.inactive, nodes, Agent.application, Optional.empty(), transaction);
+    public List<Node> deactivate(List<Node> nodes, ApplicationTransaction transaction) {
+        return db.writeTo(State.inactive, nodes, Agent.application, Optional.empty(), transaction.nested());
     }
 
     /** Move nodes to the dirty state */
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Application.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Application.java
index e9e91910281..fd92b5b0ca0 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Application.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Application.java
@@ -5,6 +5,7 @@ import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 import java.util.HashMap;
 import java.util.Optional;
@@ -56,7 +57,7 @@ public class Application {
     public Application withCluster(ClusterSpec.Id id, boolean exclusive, ClusterResources min, ClusterResources max) {
         Cluster cluster = clusters.get(id);
         if (cluster == null)
-            cluster = new Cluster(id, exclusive, min, max, Optional.empty(), Optional.empty());
+            cluster = new Cluster(id, exclusive, min, max, Optional.empty(), Optional.empty(), List.of());
         else
             cluster = cluster.withConfiguration(exclusive, min, max);
         return with(cluster);
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Applications.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Applications.java
index 9f45839f1c3..9db28652d0e 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Applications.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Applications.java
@@ -2,6 +2,7 @@
 package com.yahoo.vespa.hosted.provision.applications;
 
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.ProvisionLock;
 import com.yahoo.transaction.Mutex;
 import com.yahoo.transaction.NestedTransaction;
@@ -42,17 +43,16 @@ public class Applications {
     // TODO: Require ProvisionLock instead of Mutex
     public void put(Application application, Mutex applicationLock) {
         NestedTransaction transaction = new NestedTransaction();
-        put(application, transaction, applicationLock);
+        db.writeApplication(application, transaction);
         transaction.commit();
     }
 
-    // TODO: Require ProvisionLock instead of Mutex
-    public void put(Application application, NestedTransaction transaction, Mutex applicationLock) {
-        db.writeApplication(application, transaction);
+    public void put(Application application, ApplicationTransaction transaction) {
+        db.writeApplication(application, transaction.nested());
     }
 
-    public void remove(ApplicationId application, NestedTransaction transaction, @SuppressWarnings("unused") ProvisionLock lock) {
-        db.deleteApplication(application, transaction);
+    public void remove(ApplicationTransaction transaction) {
+        db.deleteApplication(transaction);
     }
 
 }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Cluster.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Cluster.java
index 3aae47a9088..a17ee081447 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Cluster.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/Cluster.java
@@ -6,6 +6,7 @@ import com.yahoo.config.provision.ClusterSpec;
 import com.yahoo.config.provision.NodeResources;
 import com.yahoo.vespa.hosted.provision.lb.LoadBalancer;
 
+import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 
@@ -23,13 +24,15 @@ public class Cluster {
     private final ClusterResources min, max;
     private final Optional<ClusterResources> suggested;
     private final Optional<ClusterResources> target;
+    private final List<ScalingEvent> scalingEvents;
 
     public Cluster(ClusterSpec.Id id,
                    boolean exclusive,
                    ClusterResources minResources,
                    ClusterResources maxResources,
                    Optional<ClusterResources> suggestedResources,
-                   Optional<ClusterResources> targetResources) {
+                   Optional<ClusterResources> targetResources,
+                   List<ScalingEvent> scalingEvents) {
         this.id = Objects.requireNonNull(id);
         this.exclusive = exclusive;
         this.min = Objects.requireNonNull(minResources);
@@ -40,6 +43,7 @@ public class Cluster {
             this.target = Optional.empty();
         else
             this.target = targetResources;
+        this.scalingEvents = scalingEvents;
     }
 
     public ClusterSpec.Id id() { return id; }
@@ -66,16 +70,24 @@ public class Cluster {
      */
     public Optional<ClusterResources> suggestedResources() { return suggested; }
 
+    /** Returns the recent scaling events in this cluster */
+    public List<ScalingEvent> scalingEvents() { return scalingEvents; }
+
     public Cluster withConfiguration(boolean exclusive, ClusterResources min, ClusterResources max) {
-        return new Cluster(id, exclusive, min, max, suggested, target);
+        return new Cluster(id, exclusive, min, max, suggested, target, scalingEvents);
     }
 
     public Cluster withSuggested(Optional<ClusterResources> suggested) {
-        return new Cluster(id, exclusive, min, max, suggested, target);
+        return new Cluster(id, exclusive, min, max, suggested, target, scalingEvents);
     }
 
     public Cluster withTarget(Optional<ClusterResources> target) {
-        return new Cluster(id, exclusive, min, max, suggested, target);
+        return new Cluster(id, exclusive, min, max, suggested, target, scalingEvents);
+    }
+
+    public Cluster with(ScalingEvent scalingEvent) {
+        // NOTE: We're just storing the latest scaling event so far
+        return new Cluster(id, exclusive, min, max, suggested, target, List.of(scalingEvent));
     }
 
     @Override
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/ScalingEvent.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/ScalingEvent.java
new file mode 100644
index 00000000000..68e65d10d69
--- /dev/null
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/applications/ScalingEvent.java
@@ -0,0 +1,59 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.applications;
+
+import com.yahoo.config.provision.ClusterResources;
+
+import java.time.Instant;
+import java.util.Objects;
+
+/**
+ * A recording of a change in resources for an application cluster
+ *
+ * @author bratseth
+ */
+public class ScalingEvent {
+
+    private final ClusterResources from, to;
+    private final long generation;
+    private final Instant at;
+
+    public ScalingEvent(ClusterResources from, ClusterResources to, long generation, Instant at) {
+        this.from = from;
+        this.to = to;
+        this.generation = generation;
+        this.at = at;
+    }
+
+    /** Returns the resources we changed from */
+    public ClusterResources from() { return from; }
+
+    /** Returns the resources we changed to */
+    public ClusterResources to() { return to; }
+
+    /** Returns the application config generation resulting from this deployment */
+    public long generation() { return generation; }
+
+    /** Returns the time of this deployment */
+    public Instant at() { return at; }
+
+    @Override
+    public int hashCode() { return Objects.hash(from, to, generation, at); }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == this) return true;
+        if ( ! (o instanceof ScalingEvent)) return true;
+        ScalingEvent other = (ScalingEvent)o;
+        if ( other.generation != this.generation) return false;
+        if ( ! other.at.equals(this.at)) return false;
+        if ( ! other.from.equals(this.from)) return false;
+        if ( ! other.to.equals(this.to)) return false;
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return "scaling event from " + from + " to " + to + ", generation " + generation + " at " + at;
+    }
+
+}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Autoscaler.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Autoscaler.java
index a267d59f1dc..c73a19bd9e2 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Autoscaler.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Autoscaler.java
@@ -24,11 +24,11 @@ public class Autoscaler {
     /** What difference factor for a resource is worth a reallocation? */
     private static final double resourceDifferenceWorthReallocation = 0.1;
 
-    private final NodeMetricsDb metricsDb;
+    private final MetricsDb metricsDb;
     private final NodeRepository nodeRepository;
     private final AllocationOptimizer allocationOptimizer;
 
-    public Autoscaler(NodeMetricsDb metricsDb, NodeRepository nodeRepository) {
+    public Autoscaler(MetricsDb metricsDb, NodeRepository nodeRepository) {
         this.metricsDb = metricsDb;
         this.nodeRepository = nodeRepository;
         this.allocationOptimizer = new AllocationOptimizer(nodeRepository);
@@ -42,7 +42,7 @@ public class Autoscaler {
      * @return a new suggested allocation for this cluster, or empty if it should not be rescaled at this time
      */
     public Optional<ClusterResources> suggest(Cluster cluster, List<Node> clusterNodes) {
-        return autoscale(clusterNodes, Limits.empty(), cluster.exclusive())
+        return autoscale(cluster, clusterNodes, Limits.empty(), cluster.exclusive())
                        .map(AllocatableClusterResources::toAdvertisedClusterResources);
 
     }
@@ -55,20 +55,21 @@ public class Autoscaler {
      */
     public Optional<ClusterResources> autoscale(Cluster cluster, List<Node> clusterNodes) {
         if (cluster.minResources().equals(cluster.maxResources())) return Optional.empty(); // Shortcut
-        return autoscale(clusterNodes, Limits.of(cluster), cluster.exclusive())
+        return autoscale(cluster, clusterNodes, Limits.of(cluster), cluster.exclusive())
                        .map(AllocatableClusterResources::toAdvertisedClusterResources);
     }
 
-    private Optional<AllocatableClusterResources> autoscale(List<Node> clusterNodes, Limits limits, boolean exclusive) {
+    private Optional<AllocatableClusterResources> autoscale(Cluster cluster,
+                                                            List<Node> clusterNodes, Limits limits, boolean exclusive) {
         if (unstable(clusterNodes)) return Optional.empty();
 
         AllocatableClusterResources currentAllocation = new AllocatableClusterResources(clusterNodes, nodeRepository);
 
-        MetricSnapshot metricSnapshot = new MetricSnapshot(clusterNodes, metricsDb, nodeRepository);
+        ClusterTimeseries clusterTimeseries = new ClusterTimeseries(cluster, clusterNodes, metricsDb, nodeRepository);
 
-        Optional<Double> cpuLoad    = metricSnapshot.averageLoad(Resource.cpu);
-        Optional<Double> memoryLoad = metricSnapshot.averageLoad(Resource.memory);
-        Optional<Double> diskLoad   = metricSnapshot.averageLoad(Resource.disk);
+        Optional<Double> cpuLoad    = clusterTimeseries.averageLoad(Resource.cpu);
+        Optional<Double> memoryLoad = clusterTimeseries.averageLoad(Resource.memory);
+        Optional<Double> diskLoad   = clusterTimeseries.averageLoad(Resource.disk);
         if (cpuLoad.isEmpty() || memoryLoad.isEmpty() || diskLoad.isEmpty()) return Optional.empty();
         var target = ResourceTarget.idealLoad(cpuLoad.get(), memoryLoad.get(), diskLoad.get(), currentAllocation);
 
@@ -100,6 +101,10 @@ public class Autoscaler {
         return Duration.ofHours(1);
     }
 
+    static Duration maxScalingWindow() {
+        return Duration.ofHours(12);
+    }
+
     /** Measurements are currently taken once a minute. See also scalingWindow */
     static int minimumMeasurementsPerNode(ClusterSpec.Type clusterType) {
         if (clusterType.isContent()) return 60;
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ClusterTimeseries.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ClusterTimeseries.java
new file mode 100644
index 00000000000..2123ecd0224
--- /dev/null
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ClusterTimeseries.java
@@ -0,0 +1,99 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.autoscale;
+
+import com.yahoo.config.provision.ClusterSpec;
+import com.yahoo.vespa.hosted.provision.Node;
+import com.yahoo.vespa.hosted.provision.NodeRepository;
+import com.yahoo.vespa.hosted.provision.applications.Cluster;
+
+import java.time.Instant;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+/**
+ * A series of metric snapshots for all nodes in a cluster
+ *
+ * @author bratseth
+ */
+public class ClusterTimeseries {
+
+    private final List<Node> clusterNodes;
+    private final Map<String, Instant> startTimePerNode;
+
+    /** The measurements for all hosts in this snapshot */
+    private final List<NodeTimeseries> nodeTimeseries;
+
+    public ClusterTimeseries(Cluster cluster, List<Node> clusterNodes, MetricsDb db, NodeRepository nodeRepository) {
+        this.clusterNodes = clusterNodes;
+        ClusterSpec.Type clusterType = clusterNodes.get(0).allocation().get().membership().cluster().type();
+        this.nodeTimeseries = db.getNodeTimeseries(nodeRepository.clock().instant().minus(Autoscaler.scalingWindow(clusterType)),
+                                                   clusterNodes.stream().map(Node::hostname).collect(Collectors.toSet()));
+        this.startTimePerNode = metricStartTimes(cluster, clusterNodes, nodeRepository);
+    }
+
+    /**
+     * Returns the instant of the oldest metric to consider for each node, or an empty map if metrics from the
+     * entire (max) window should be considered.
+     */
+    private Map<String, Instant> metricStartTimes(Cluster cluster,
+                                                  List<Node> clusterNodes,
+                                                  NodeRepository nodeRepository) {
+        Map<String, Instant> startTimePerHost = new HashMap<>();
+        if ( ! cluster.scalingEvents().isEmpty()) {
+            var deployment = cluster.scalingEvents().get(cluster.scalingEvents().size() - 1);
+            for (Node node : clusterNodes) {
+                startTimePerHost.put(node.hostname(), nodeRepository.clock().instant()); // Discard all unless we can prove otherwise
+                var nodeGenerationMeasurements =
+                        nodeTimeseries.stream().filter(m -> m.hostname().equals(node.hostname())).findAny();
+                if (nodeGenerationMeasurements.isPresent()) {
+                    var firstMeasurementOfCorrectGeneration =
+                            nodeGenerationMeasurements.get().asList().stream()
+                                                      .filter(m -> m.generation() >= deployment.generation())
+                                                      .findFirst();
+                    if (firstMeasurementOfCorrectGeneration.isPresent()) {
+                        startTimePerHost.put(node.hostname(), firstMeasurementOfCorrectGeneration.get().at());
+                    }
+                }
+            }
+        }
+        return startTimePerHost;
+    }
+
+    /**
+     * Returns the average load of this resource in the measurement window,
+     * or empty if we are not in a position to make decisions from these measurements at this time.
+     */
+    public Optional<Double> averageLoad(Resource resource) {
+        ClusterSpec.Type clusterType = clusterNodes.get(0).allocation().get().membership().cluster().type();
+
+        List<NodeTimeseries> currentMeasurements = filterStale(nodeTimeseries, startTimePerNode);
+
+        // Require a total number of measurements scaling with the number of nodes,
+        // but don't require that we have at least that many from every node
+        int measurementCount = currentMeasurements.stream().mapToInt(m -> m.size()).sum();
+        if (measurementCount / clusterNodes.size() < Autoscaler.minimumMeasurementsPerNode(clusterType)) return Optional.empty();
+        if (currentMeasurements.size() != clusterNodes.size()) return Optional.empty();
+
+        double measurementSum = currentMeasurements.stream().flatMap(m -> m.asList().stream()).mapToDouble(m -> value(resource, m)).sum();
+        return Optional.of(measurementSum / measurementCount);
+    }
+
+    private double value(Resource resource, MetricSnapshot snapshot) {
+        switch (resource) {
+            case cpu: return snapshot.cpu();
+            case memory: return snapshot.memory();
+            case disk: return snapshot.disk();
+            default: throw new IllegalArgumentException("Got an unknown resource " + resource);
+        }
+    }
+
+    private List<NodeTimeseries> filterStale(List<NodeTimeseries> timeseries,
+                                             Map<String, Instant> startTimePerHost) {
+        if (startTimePerHost.isEmpty()) return timeseries; // Map is either empty or complete
+        return timeseries.stream().map(m -> m.justAfter(startTimePerHost.get(m.hostname()))).collect(Collectors.toList());
+    }
+
+}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MemoryMetricsDb.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MemoryMetricsDb.java
new file mode 100644
index 00000000000..999acad7ab0
--- /dev/null
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MemoryMetricsDb.java
@@ -0,0 +1,87 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.autoscale;
+
+import com.yahoo.collections.Pair;
+import com.yahoo.vespa.hosted.provision.Node;
+import com.yahoo.vespa.hosted.provision.NodeRepository;
+
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * An in-memory implementation of the metrics Db.
+ * Thread model: One writer, many readers.
+ *
+ * @author bratseth
+ */
+public class MemoryMetricsDb implements MetricsDb {
+
+    private final NodeRepository nodeRepository;
+
+    /** Metric time seriest by node (hostname). Each list of metric snapshots is sorted by increasing timestamp */
+    private final Map<String, NodeTimeseries> db = new HashMap<>();
+
+    /** Lock all access for now since we modify lists inside a map */
+    private final Object lock = new Object();
+
+    public MemoryMetricsDb(NodeRepository nodeRepository) {
+        this.nodeRepository = nodeRepository;
+    }
+
+    @Override
+    public void add(Collection<Pair<String, MetricSnapshot>> nodeMetrics) {
+        synchronized (lock) {
+            for (var value : nodeMetrics) {
+                add(value.getFirst(), value.getSecond());
+            }
+        }
+    }
+
+    @Override
+    public List<NodeTimeseries> getNodeTimeseries(Instant startTime, Set<String> hostnames) {
+        synchronized (lock) {
+            return hostnames.stream()
+                            .map(hostname -> db.getOrDefault(hostname, new NodeTimeseries(hostname, List.of())).justAfter(startTime))
+                            .collect(Collectors.toList());
+        }
+    }
+
+    @Override
+    public void gc() {
+        synchronized (lock) {
+            // Each measurement is Object + long + float = 16 + 8 + 4 = 28 bytes
+            // 12 hours with 1k nodes and 3 resources and 1 measurement/sec is about 5Gb
+            for (String hostname : db.keySet()) {
+                var timeseries = db.get(hostname);
+                timeseries = timeseries.justAfter(nodeRepository.clock().instant().minus(Autoscaler.maxScalingWindow()));
+                if (timeseries.isEmpty())
+                    db.remove(hostname);
+                else
+                    db.put(hostname, timeseries);
+            }
+        }
+    }
+
+    @Override
+    public void close() {}
+
+    private void add(String hostname, MetricSnapshot snapshot) {
+        NodeTimeseries timeseries = db.get(hostname);
+        if (timeseries == null) { // new node
+            Optional<Node> node = nodeRepository.getNode(hostname);
+            if (node.isEmpty()) return;
+            if (node.get().allocation().isEmpty()) return;
+            timeseries = new NodeTimeseries(hostname, new ArrayList<>());
+            db.put(hostname, timeseries);
+        }
+        db.put(hostname, timeseries.add(snapshot));
+    }
+
+}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Metric.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Metric.java
deleted file mode 100644
index b98535f19c3..00000000000
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Metric.java
+++ /dev/null
@@ -1,46 +0,0 @@
-// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.hosted.provision.autoscale;
-
-/**
- * A kind of measurement we are making for autoscaling purposes
- *
- * @author bratseth
- */
-public enum Metric {
-
-    cpu { // a node resource
-        public String fullName() { return "cpu.util"; }
-        float valueFromMetric(double metricValue) { return (float)metricValue / 100; } // % to ratio
-    },
-    memory { // a node resource
-        public String fullName() { return "mem_total.util"; }
-        float valueFromMetric(double metricValue) { return (float)metricValue / 100; } // % to ratio
-    },
-    disk { // a node resource
-        public String fullName() { return "disk.util"; }
-        float valueFromMetric(double metricValue) { return (float)metricValue / 100; } // % to ratio
-    },
-    generation { // application config generation active on the node
-        public String fullName() { return "application_generation"; }
-        float valueFromMetric(double metricValue) { return (float)metricValue; } // Really an integer, ok up to 16M gens
-    };
-
-    /** The name of this metric as emitted from its source */
-    public abstract String fullName();
-
-    /** Convert from the emitted value of this metric to the value we want to use here */
-    abstract float valueFromMetric(double metricValue);
-
-    public static Metric fromFullName(String name) {
-        for (Metric metric : values())
-            if (metric.fullName().equals(name)) return metric;
-        throw new IllegalArgumentException("Metric '" + name + "' has no mapping");
-    }
-
-    public static Metric from(Resource resource) {
-        for (Metric metric : values())
-            if (metric.name().equals(resource.name())) return metric;
-        throw new IllegalArgumentException("Resource '" + resource + "' does not map to a metric");
-    }
-
-}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricSnapshot.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricSnapshot.java
index 46ba4351082..7861cf4698d 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricSnapshot.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricSnapshot.java
@@ -1,98 +1,42 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.autoscale;
 
-import com.yahoo.config.provision.ApplicationId;
-import com.yahoo.config.provision.ClusterSpec;
-import com.yahoo.vespa.hosted.provision.Node;
-import com.yahoo.vespa.hosted.provision.NodeRepository;
-
 import java.time.Instant;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-import java.util.stream.Collectors;
 
 /**
- * A snapshot which implements the questions we want to ask about metrics for one cluster at one point in time.
+ * A single measurement of all values we measure for one node.
  *
  * @author bratseth
  */
 public class MetricSnapshot {
 
-    private final List<Node> clusterNodes;
-    private final NodeMetricsDb db;
-    private final NodeRepository nodeRepository;
-    private final Map<String, Instant> startTimePerHost;
-
-    public MetricSnapshot(List<Node> clusterNodes, NodeMetricsDb db, NodeRepository nodeRepository) {
-        this.clusterNodes = clusterNodes;
-        this.db = db;
-        this.nodeRepository = nodeRepository;
-        this.startTimePerHost = metricStartTimes(clusterNodes, db, nodeRepository);
-    }
-
-    /**
-     * Returns the instant of the oldest metric to consider for each node, or an empty map if metrics from the
-     * entire (max) window should be considered.
-     */
-    private static Map<String, Instant> metricStartTimes(List<Node> clusterNodes,
-                                                         NodeMetricsDb db,
-                                                         NodeRepository nodeRepository) {
-        ApplicationId application = clusterNodes.get(0).allocation().get().owner();
-        List<NodeMetricsDb.AutoscalingEvent> deployments = db.getEvents(application);
-        Map<String, Instant> startTimePerHost = new HashMap<>();
-        if (!deployments.isEmpty()) {
-            var deployment = deployments.get(deployments.size() - 1);
-            List<NodeMetricsDb.NodeMeasurements> generationMeasurements =
-                    db.getMeasurements(deployment.time(),
-                                              Metric.generation,
-                                              clusterNodes.stream().map(Node::hostname).collect(Collectors.toList()));
-            for (Node node : clusterNodes) {
-                startTimePerHost.put(node.hostname(), nodeRepository.clock().instant()); // Discard all unless we can prove otherwise
-                var nodeGenerationMeasurements =
-                        generationMeasurements.stream().filter(m -> m.hostname().equals(node.hostname())).findAny();
-                if (nodeGenerationMeasurements.isPresent()) {
-                    var firstMeasurementOfCorrectGeneration =
-                            nodeGenerationMeasurements.get().asList().stream()
-                                                      .filter(m -> m.value() >= deployment.generation())
-                                                      .findFirst();
-                    if (firstMeasurementOfCorrectGeneration.isPresent()) {
-                        startTimePerHost.put(node.hostname(), firstMeasurementOfCorrectGeneration.get().at());
-                    }
-                }
-            }
-        }
-        return startTimePerHost;
-    }
-
-    /**
-     * Returns the average load of this resource in the measurement window,
-     * or empty if we are not in a position to make decisions from these measurements at this time.
-     */
-    public Optional<Double> averageLoad(Resource resource) {
-        ClusterSpec.Type clusterType = clusterNodes.get(0).allocation().get().membership().cluster().type();
+    // TODO: Order by timestamp
+    private final Instant at;
 
-        List<NodeMetricsDb.NodeMeasurements> measurements =
-                db.getMeasurements(nodeRepository.clock().instant().minus(Autoscaler.scalingWindow(clusterType)),
-                                          Metric.from(resource),
-                                          clusterNodes.stream().map(Node::hostname).collect(Collectors.toList()));
-        measurements = filterStale(measurements, startTimePerHost);
+    private final double cpu;
+    private final double memory;
+    private final double disk;
+    private final long generation;
 
-        // Require a total number of measurements scaling with the number of nodes,
-        // but don't require that we have at least that many from every node
-        int measurementCount = measurements.stream().mapToInt(m -> m.size()).sum();
-        if (measurementCount / clusterNodes.size() < Autoscaler.minimumMeasurementsPerNode(clusterType)) return Optional.empty();
-        if (measurements.size() != clusterNodes.size()) return Optional.empty();
-
-        double measurementSum = measurements.stream().flatMap(m -> m.asList().stream()).mapToDouble(m -> m.value()).sum();
-        return Optional.of(measurementSum / measurementCount);
+    public MetricSnapshot(Instant at, double cpu, double memory, double disk, long generation) {
+        this.at = at;
+        this.cpu = cpu;
+        this.memory = memory;
+        this.disk = disk;
+        this.generation = generation;
     }
 
-    private List<NodeMetricsDb.NodeMeasurements> filterStale(List<NodeMetricsDb.NodeMeasurements> measurements,
-                                                             Map<String, Instant> startTimePerHost) {
-        if (startTimePerHost.isEmpty()) return measurements; // Map is either empty or complete
-        return measurements.stream().map(m -> m.copyAfter(startTimePerHost.get(m.hostname()))).collect(Collectors.toList());
-    }
+    public Instant at() { return at; }
+    public double cpu() { return cpu; }
+    public double memory() { return memory; }
+    public double disk() { return disk; }
+    public long generation() { return generation; }
+
+    @Override
+    public String toString() { return "metrics at " + at + ":" +
+                                      " cpu: " + cpu +
+                                      " memory: " + memory +
+                                      " disk: " + disk +
+                                      " generation: " + generation; }
 
 }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsDb.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsDb.java
new file mode 100644
index 00000000000..ea4ce4b44de
--- /dev/null
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsDb.java
@@ -0,0 +1,38 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.autoscale;
+
+import com.yahoo.collections.Pair;
+import com.yahoo.vespa.hosted.provision.NodeRepository;
+
+import java.time.Clock;
+import java.time.Instant;
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * An in-memory time-series database of node metrics.
+ *
+ * @author bratseth
+ */
+public interface MetricsDb {
+
+    /** Adds snapshots to this. */
+    void add(Collection<Pair<String, MetricSnapshot>> nodeMetrics);
+
+    /**
+     * Returns a list with one entry for each hostname containing
+     * the snapshots recorded after the given time (or an empty snapshot if none).
+     */
+    List<NodeTimeseries> getNodeTimeseries(Instant startTime, Set<String> hostnames);
+
+    /** Must be called intermittently (as long as add is called) to gc old data */
+    void gc();
+
+    void close();
+
+    static MetricsDb createTestInstance(NodeRepository nodeRepository) {
+        return new MemoryMetricsDb(nodeRepository);
+    }
+
+}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsFetcher.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsFetcher.java
new file mode 100644
index 00000000000..70ac915f792
--- /dev/null
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsFetcher.java
@@ -0,0 +1,25 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.autoscale;
+
+import com.yahoo.collections.Pair;
+import com.yahoo.config.provision.ApplicationId;
+
+import java.time.Instant;
+import java.util.Collection;
+
+/**
+ * Interface to retrieve metrics on (tenant) nodes.
+ *
+ * @author bratseth
+ */
+public interface MetricsFetcher {
+
+    /**
+     * Fetches metrics for all hosts of an application. This call may be expensive.
+     *
+     * @param application the application to fetch metrics from
+     * @return a metric snapshot for each hostname of this application
+     */
+    Collection<Pair<String, MetricSnapshot>> fetchMetrics(ApplicationId application);
+
+}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsResponse.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsResponse.java
index b4195b4cdf1..1b24788c2a9 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsResponse.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsResponse.java
@@ -1,15 +1,17 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.autoscale;
 
+import com.yahoo.collections.Pair;
 import com.yahoo.slime.ArrayTraverser;
 import com.yahoo.slime.Inspector;
 import com.yahoo.slime.ObjectTraverser;
 import com.yahoo.slime.Slime;
 import com.yahoo.slime.SlimeUtils;
 
+import java.time.Instant;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 
 /**
@@ -19,17 +21,13 @@ import java.util.Map;
  */
 public class MetricsResponse {
 
-    private final List<NodeMetrics.MetricValue> metricValues = new ArrayList<>();
-
-    public MetricsResponse(byte[] response) {
-        this(SlimeUtils.jsonToSlime(response));
-    }
+    private final Collection<Pair<String, MetricSnapshot>> nodeMetrics = new ArrayList<>();
 
     public MetricsResponse(String response) {
         this(SlimeUtils.jsonToSlime(response));
     }
 
-    public List<NodeMetrics.MetricValue> metrics() { return metricValues; }
+    public Collection<Pair<String, MetricSnapshot>> metrics() { return nodeMetrics; }
 
     private MetricsResponse(Slime response) {
         Inspector root = response.get();
@@ -40,22 +38,17 @@ public class MetricsResponse {
     private void consumeNode(Inspector node) {
         String hostname = node.field("hostname").asString();
         consumeNodeMetrics(hostname, node.field("node"));
-        consumeServiceMetrics(hostname, node.field("services"));
+        // consumeServiceMetrics(hostname, node.field("services"));
     }
 
     private void consumeNodeMetrics(String hostname, Inspector node) {
         long timestampSecond = node.field("timestamp").asLong();
         Map<String, Double> values = consumeMetrics(node.field("metrics"));
-        for (Metric metric : Metric.values())
-            addMetricIfPresent(hostname, metric, timestampSecond, values);
-    }
-
-    private void addMetricIfPresent(String hostname, Metric metric, long timestampSecond, Map<String, Double> values) {
-        if (values.containsKey(metric.fullName()))
-            metricValues.add(new NodeMetrics.MetricValue(hostname,
-                                                         metric.fullName(),
-                                                         timestampSecond,
-                                                         values.get(metric.fullName())));
+        nodeMetrics.add(new Pair<>(hostname, new MetricSnapshot(Instant.ofEpochMilli(timestampSecond * 1000),
+                                                                Metric.cpu.from(values),
+                                                                Metric.memory.from(values),
+                                                                Metric.disk.from(values),
+                                                                (long)Metric.generation.from(values))));
     }
 
     private void consumeServiceMetrics(String hostname, Inspector node) {
@@ -74,4 +67,36 @@ public class MetricsResponse {
         item.field("values").traverse((ObjectTraverser)(name, value) -> values.put(name, value.asDouble()));
     }
 
+    /** The metrics this can read */
+    private enum Metric {
+
+        cpu { // a node resource
+            public String metricResponseName() { return "cpu.util"; }
+            double convertValue(double metricValue) { return (float)metricValue / 100; } // % to ratio
+        },
+        memory { // a node resource
+            public String metricResponseName() { return "mem_total.util"; }
+            double convertValue(double metricValue) { return (float)metricValue / 100; } // % to ratio
+        },
+        disk { // a node resource
+            public String metricResponseName() { return "disk.util"; }
+            double convertValue(double metricValue) { return (float)metricValue / 100; } // % to ratio
+        },
+        generation { // application config generation active on the node
+            public String metricResponseName() { return "application_generation"; }
+            double convertValue(double metricValue) { return (float)metricValue; } // Really a long
+        };
+
+        /** The name of this metric as emitted from its source */
+        public abstract String metricResponseName();
+
+        /** Convert from the emitted value of this metric to the value we want to use here */
+        abstract double convertValue(double metricValue);
+
+        public double from(Map<String, Double> values) {
+            return convertValue(values.getOrDefault(metricResponseName(), 0.0));
+        }
+
+    }
+
 }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetricsFetcher.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsV2MetricsFetcher.java
index 1361faba66c..b4a63175548 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetricsFetcher.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsV2MetricsFetcher.java
@@ -3,6 +3,7 @@ package com.yahoo.vespa.hosted.provision.autoscale;
 
 import ai.vespa.util.http.VespaHttpClientBuilder;
 import com.google.inject.Inject;
+import com.yahoo.collections.Pair;
 import com.yahoo.component.AbstractComponent;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.vespa.applicationmodel.HostName;
@@ -28,9 +29,9 @@ import java.util.logging.Logger;
  *
  * @author bratseth
  */
-public class NodeMetricsFetcher extends AbstractComponent implements NodeMetrics {
+public class MetricsV2MetricsFetcher extends AbstractComponent implements MetricsFetcher {
 
-    private static final Logger log = Logger.getLogger(NodeMetricsFetcher.class.getName());
+    private static final Logger log = Logger.getLogger(MetricsV2MetricsFetcher.class.getName());
 
     private static final String apiPath = "/metrics/v2/values";
 
@@ -40,18 +41,18 @@ public class NodeMetricsFetcher extends AbstractComponent implements NodeMetrics
 
     @Inject
     @SuppressWarnings("unused")
-    public NodeMetricsFetcher(NodeRepository nodeRepository, Orchestrator orchestrator) {
+    public MetricsV2MetricsFetcher(NodeRepository nodeRepository, Orchestrator orchestrator) {
         this(nodeRepository, orchestrator, new ApacheHttpClient());
     }
 
-    NodeMetricsFetcher(NodeRepository nodeRepository, Orchestrator orchestrator, HttpClient httpClient) {
+    MetricsV2MetricsFetcher(NodeRepository nodeRepository, Orchestrator orchestrator, HttpClient httpClient) {
         this.nodeRepository = nodeRepository;
         this.orchestrator = orchestrator;
         this.httpClient = httpClient;
     }
 
     @Override
-    public Collection<MetricValue> fetchMetrics(ApplicationId application) {
+    public Collection<Pair<String, MetricSnapshot>> fetchMetrics(ApplicationId application) {
         NodeList applicationNodes = nodeRepository.list(application).state(Node.State.active);
 
         // Do not try to draw conclusions from utilization while unstable
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetrics.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetrics.java
deleted file mode 100644
index daed5a34873..00000000000
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetrics.java
+++ /dev/null
@@ -1,49 +0,0 @@
-// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.hosted.provision.autoscale;
-
-import com.yahoo.config.provision.ApplicationId;
-
-import java.time.Instant;
-import java.util.Collection;
-
-/**
- * Interface to retrieve metrics on (tenant) nodes.
- *
- * @author bratseth
- */
-public interface NodeMetrics {
-
-    /**
-     * Fetches metrics for an application. This call may be expensive.
-     *
-     * @param application the application to fetch metrics from
-     */
-    Collection<MetricValue> fetchMetrics(ApplicationId application);
-
-    final class MetricValue {
-
-        private final String hostname;
-        private final String name;
-        private final long timestampSecond;
-        private final double value;
-
-        public MetricValue(String hostname, String name, long timestampSecond, double value) {
-            this.hostname = hostname;
-            this.name = name;
-            this.timestampSecond = timestampSecond;
-            this.value = value;
-        }
-
-        public String hostname() { return hostname; }
-        public String name() { return name; }
-        public long timestampSecond() { return timestampSecond; }
-        public double value() { return value; }
-
-        @Override
-        public String toString() {
-            return "metric value " + name + ": " + value + " at " + Instant.ofEpochSecond(timestampSecond) + " for " + hostname;
-        }
-
-    }
-
-}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetricsDb.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetricsDb.java
deleted file mode 100644
index 635f3ffc081..00000000000
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetricsDb.java
+++ /dev/null
@@ -1,236 +0,0 @@
-// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.hosted.provision.autoscale;
-
-import com.yahoo.config.provision.ApplicationId;
-import com.yahoo.config.provision.ClusterSpec;
-import com.yahoo.vespa.hosted.provision.Node;
-import com.yahoo.vespa.hosted.provision.NodeRepository;
-
-import java.time.Clock;
-import java.time.Instant;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
-import java.util.stream.Collectors;
-
-/**
- * An in-memory time-series "database" of node metrics.
- * Thread model: One writer, many readers.
- *
- * @author bratseth
- */
-public class NodeMetricsDb {
-
-    private final NodeRepository nodeRepository;
-
-    /** Measurements by key. Each list of measurements is sorted by increasing timestamp */
-    private final Map<NodeMeasurementsKey, NodeMeasurements> db = new HashMap<>();
-
-    /** Events */
-    private final List<AutoscalingEvent> events = new ArrayList<>();
-
-    /** Lock all access for now since we modify lists inside a map */
-    private final Object lock = new Object();
-
-    public NodeMetricsDb(NodeRepository nodeRepository) {
-        this.nodeRepository = nodeRepository;
-    }
-
-    /** Adds measurements to this. */
-    public void add(Collection<NodeMetrics.MetricValue> metricValues) {
-        synchronized (lock) {
-            for (var value : metricValues) {
-                Metric metric =  Metric.fromFullName(value.name());
-                NodeMeasurementsKey key = new NodeMeasurementsKey(value.hostname(), metric);
-                NodeMeasurements measurements = db.get(key);
-                if (measurements == null) { // new node
-                    Optional<Node> node = nodeRepository.getNode(value.hostname());
-                    if (node.isEmpty()) continue;
-                    if (node.get().allocation().isEmpty()) continue;
-                    measurements = new NodeMeasurements(value.hostname(),
-                                                        metric,
-                                                        node.get().allocation().get().membership().cluster().type(),
-                                                        new ArrayList<>());
-                    db.put(key, measurements);
-                }
-                measurements.add(new Measurement(value.timestampSecond() * 1000,
-                                                 metric.valueFromMetric(value.value())));
-            }
-        }
-    }
-
-    /** Adds an event to this */
-    public void add(AutoscalingEvent event) {
-        synchronized (lock) {
-            events.add(event);
-        }
-    }
-
-    /** Must be called intermittently (as long as any add methods are called) to gc old data */
-    public void gc(Clock clock) {
-        synchronized (lock) {
-            // Each measurement is Object + long + float = 16 + 8 + 4 = 28 bytes
-            // 12 hours with 1k nodes and 3 resources and 1 measurement/sec is about 5Gb
-            for (Iterator<NodeMeasurements> i = db.values().iterator(); i.hasNext(); ) {
-                var measurements = i.next();
-                measurements.removeOlderThan(clock.instant().minus(Autoscaler.scalingWindow(measurements.type)).toEpochMilli());
-                if (measurements.isEmpty())
-                    i.remove();
-            }
-
-            // TODO: gc events
-        }
-    }
-
-    /**
-     * Returns a list of measurements with one entry for each of the given host names
-     * which have any values after startTime, in the same order
-     */
-    public List<NodeMeasurements> getMeasurements(Instant startTime, Metric metric, List<String> hostnames) {
-        synchronized (lock) {
-            List<NodeMeasurements> measurementsList = new ArrayList<>(hostnames.size());
-            for (String hostname : hostnames) {
-                NodeMeasurements measurements = db.get(new NodeMeasurementsKey(hostname, metric));
-                if (measurements == null) continue;
-                measurements = measurements.copyAfter(startTime);
-                if (measurements.isEmpty()) continue;
-                measurementsList.add(measurements);
-            }
-            return measurementsList;
-        }
-    }
-
-    public List<AutoscalingEvent> getEvents(ApplicationId application) {
-        synchronized (lock) {
-            return events.stream().filter(event -> event.application().equals(application)).collect(Collectors.toList());
-        }
-    }
-
-    private static class NodeMeasurementsKey {
-
-        private final String hostname;
-        private final Metric metric;
-
-        public NodeMeasurementsKey(String hostname, Metric metric) {
-            this.hostname = hostname;
-            this.metric = metric;
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hash(hostname, metric);
-        }
-
-        @Override
-        public boolean equals(Object o) {
-            if (this == o) return true;
-            if ( ! (o instanceof NodeMeasurementsKey)) return false;
-            NodeMeasurementsKey other = (NodeMeasurementsKey)o;
-            if ( ! this.hostname.equals(other.hostname)) return false;
-            if ( ! this.metric.equals(other.metric)) return false;
-            return true;
-        }
-
-        @Override
-        public String toString() { return "key to measurements of " + metric + " for " + hostname; }
-
-    }
-
-    public static class NodeMeasurements {
-
-        private final String hostname;
-        private final Metric metric;
-        private final ClusterSpec.Type type;
-        private final List<Measurement> measurements;
-
-        // Note: This transfers ownership of the measurement list to this
-        private NodeMeasurements(String hostname, Metric metric, ClusterSpec.Type type, List<Measurement> measurements) {
-            this.hostname = hostname;
-            this.metric = metric;
-            this.type = type;
-            this.measurements = measurements;
-        }
-
-        // Public access
-
-        public boolean isEmpty() { return measurements.isEmpty(); }
-
-        public int size() { return measurements.size(); }
-
-        public Measurement get(int index) { return measurements.get(index); }
-
-        public List<Measurement> asList() { return Collections.unmodifiableList(measurements); }
-
-        public String hostname() { return hostname; }
-
-        public NodeMeasurements copyAfter(Instant oldestTime) {
-            long oldestTimestamp = oldestTime.toEpochMilli();
-            return new NodeMeasurements(hostname, metric, type,
-                                        measurements.stream()
-                                                    .filter(measurement -> measurement.timestamp >= oldestTimestamp)
-                                                    .collect(Collectors.toList()));
-        }
-
-        // Private mutation
-
-        private void add(Measurement measurement) { measurements.add(measurement); }
-
-        private void removeOlderThan(long oldestTimestamp) {
-            while (!measurements.isEmpty() && measurements.get(0).timestamp < oldestTimestamp)
-                measurements.remove(0);
-        }
-
-    }
-
-    public static class Measurement {
-
-        // TODO: Order by timestamp
-        /** The time of this measurement in epoch millis */
-        private final long timestamp;
-
-        /** The measured value */
-        private final double value;
-
-        public Measurement(long timestamp, float value) {
-            this.timestamp = timestamp;
-            this.value = value;
-        }
-
-        public double value() { return value; }
-        public Instant at() { return Instant.ofEpochMilli(timestamp); }
-
-        @Override
-        public String toString() { return "measurement at " + timestamp + ": " + value; }
-
-    }
-
-    public static class AutoscalingEvent {
-
-        private final ApplicationId application;
-        private final long generation;
-        private final long timestamp;
-
-        public AutoscalingEvent(ApplicationId application, long generation, Instant times) {
-            this.application = application;
-            this.generation = generation;
-            this.timestamp = times.toEpochMilli();
-        }
-
-        /** Returns the deployed application */
-        public ApplicationId application() { return application; }
-
-        /** Returns the application config generation resulting from this deployment */
-        public long generation() { return generation; }
-
-        /** Returns the time of this deployment */
-        public Instant time() { return Instant.ofEpochMilli(timestamp); }
-
-    }
-
-}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeTimeseries.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeTimeseries.java
new file mode 100644
index 00000000000..6cba3928b8f
--- /dev/null
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeTimeseries.java
@@ -0,0 +1,51 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.autoscale;
+
+import com.yahoo.config.provision.ClusterSpec;
+
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * A list of metric snapshots from a host
+ *
+ * @author bratseth
+ */
+public class NodeTimeseries {
+
+    private final String hostname;
+    private final List<MetricSnapshot> snapshots;
+
+    // Note: This transfers ownership of the snapshot list to this
+    NodeTimeseries(String hostname, List<MetricSnapshot> snapshots) {
+        this.hostname = hostname;
+        this.snapshots = snapshots;
+    }
+
+    public boolean isEmpty() { return snapshots.isEmpty(); }
+
+    public int size() { return snapshots.size(); }
+
+    public MetricSnapshot get(int index) { return snapshots.get(index); }
+
+    public List<MetricSnapshot> asList() { return Collections.unmodifiableList(snapshots); }
+
+    public String hostname() { return hostname; }
+
+    public NodeTimeseries add(MetricSnapshot snapshot) {
+        List<MetricSnapshot> list = new ArrayList<>(snapshots);
+        list.add(snapshot);
+        return new NodeTimeseries(hostname(), list);
+    }
+
+    public NodeTimeseries justAfter(Instant oldestTime) {
+        return new NodeTimeseries(hostname,
+                                  snapshots.stream()
+                                           .filter(snapshot -> snapshot.at().equals(oldestTime) || snapshot.at().isAfter(oldestTime))
+                                           .collect(Collectors.toList()));
+    }
+
+}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/QuestMetricsDb.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/QuestMetricsDb.java
new file mode 100644
index 00000000000..b1585922f38
--- /dev/null
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/QuestMetricsDb.java
@@ -0,0 +1,193 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.autoscale;
+
+import com.google.inject.Inject;
+import com.yahoo.collections.ListMap;
+import com.yahoo.collections.Pair;
+import com.yahoo.io.IOUtils;
+import com.yahoo.vespa.defaults.Defaults;
+import io.questdb.cairo.CairoConfiguration;
+import io.questdb.cairo.CairoEngine;
+import io.questdb.cairo.DefaultCairoConfiguration;
+import io.questdb.cairo.TableWriter;
+import io.questdb.cairo.sql.Record;
+import io.questdb.cairo.sql.RecordCursor;
+import io.questdb.cairo.sql.RecordCursorFactory;
+import io.questdb.griffin.SqlCompiler;
+import io.questdb.griffin.SqlException;
+import io.questdb.griffin.SqlExecutionContext;
+import io.questdb.griffin.SqlExecutionContextImpl;
+import io.questdb.std.str.Path;
+
+import java.io.File;
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+
+/**
+ * An implementation of the metrics Db backed by Quest:
+ * This provides local persistent storage of metrics with fast, multi-threaded lookup and write,
+ * suitable for production.
+ *
+ * @author bratseth
+ */
+public class QuestMetricsDb implements MetricsDb {
+
+    private static final Logger log = Logger.getLogger(QuestMetricsDb.class.getName());
+    private static final String tableName = "metrics";
+
+    private final Clock clock;
+    private final String dataDir;
+    private final CairoEngine engine;
+
+    @Inject
+    public QuestMetricsDb() {
+        this(Defaults.getDefaults().underVespaHome("var/db/vespa/autoscaling"), Clock.systemUTC());
+    }
+
+    public QuestMetricsDb(String dataDir, Clock clock) {
+        this.clock = clock;
+
+        if (dataDir.startsWith(Defaults.getDefaults().vespaHome())
+            && ! new File(Defaults.getDefaults().vespaHome()).exists())
+            dataDir = "data"; // We're injected, but not on a node with Vespa installed
+        this.dataDir = dataDir;
+
+        IOUtils.createDirectory(dataDir + "/" + tableName);
+
+        // silence Questdb's custom logging system
+        IOUtils.writeFile(new File(dataDir, "quest-log.conf"), new byte[0]);
+        System.setProperty("questdbLog", dataDir + "/quest-log.conf");
+
+        CairoConfiguration configuration = new DefaultCairoConfiguration(dataDir);
+        engine = new CairoEngine(configuration);
+        ensureExists(tableName);
+    }
+
+    @Override
+    public void add(Collection<Pair<String, MetricSnapshot>> snapshots) {
+        try (TableWriter writer = engine.getWriter(newContext().getCairoSecurityContext(), tableName)) {
+            for (var snapshot : snapshots) {
+                long atMillis = snapshot.getSecond().at().toEpochMilli();
+                TableWriter.Row row = writer.newRow(atMillis * 1000); // in microseconds
+                row.putStr(0, snapshot.getFirst());
+                row.putFloat(2, (float)snapshot.getSecond().cpu());
+                row.putFloat(3, (float)snapshot.getSecond().memory());
+                row.putFloat(4, (float)snapshot.getSecond().disk());
+                row.putLong(5, snapshot.getSecond().generation());
+                row.append();
+            }
+            writer.commit();
+        }
+    }
+
+    @Override
+    public List<NodeTimeseries> getNodeTimeseries(Instant startTime, Set<String> hostnames) {
+        try (SqlCompiler compiler = new SqlCompiler(engine)) {
+            SqlExecutionContext context = newContext();
+            var snapshots = getSnapshots(startTime, hostnames, compiler, context);
+            return snapshots.entrySet().stream()
+                            .map(entry -> new NodeTimeseries(entry.getKey(), entry.getValue()))
+                            .collect(Collectors.toList());
+        }
+        catch (SqlException e) {
+            throw new IllegalStateException("Could not read timeseries data in Quest stored in " + dataDir, e);
+        }
+    }
+
+    @Override
+    public void gc() {
+        // Since we remove full days at once we need to keep at least the scaling window + 1 day
+        Instant oldestToKeep = clock.instant().minus(Autoscaler.maxScalingWindow().plus(Duration.ofDays(1)));
+        SqlExecutionContext context = newContext();
+        try (SqlCompiler compiler = new SqlCompiler(engine)) {
+            File tableRoot = new File(dataDir, tableName);
+            List<String> removeList = new ArrayList<>();
+            for (String dirEntry : tableRoot.list()) {
+                File partitionDir = new File(tableRoot, dirEntry);
+                if ( ! partitionDir.isDirectory()) continue;
+                DateTimeFormatter formatter = DateTimeFormatter.ISO_DATE_TIME.withZone(ZoneId.of("UTC"));
+                Instant partitionDay = Instant.from(formatter.parse(dirEntry + "T00:00:00"));
+                if (partitionDay.isBefore(oldestToKeep))
+                    removeList.add(dirEntry);
+            }
+            if ( ! removeList.isEmpty())
+                compiler.compile("alter table " + tableName + " drop partition " +
+                                 removeList.stream().map(dir -> "'" + dir + "'").collect(Collectors.joining(",")),
+                                 context);
+        }
+        catch (SqlException e) {
+            log.log(Level.WARNING, "Failed to gc old metrics data in " + dataDir, e);
+        }
+    }
+
+    @Override
+    public void close() {
+        if (engine != null)
+            engine.close();
+    }
+
+    private void ensureExists(String tableName) {
+        SqlExecutionContext context = newContext();
+        if (0 == engine.getStatus(context.getCairoSecurityContext(), new Path(), tableName)) return;
+
+        try (SqlCompiler compiler = new SqlCompiler(engine)) {
+            compiler.compile("create table " + tableName +
+                             " (hostname string, at timestamp, cpu_util float, mem_total_util float, disk_util float, application_generation long)" +
+                             " timestamp(at)" +
+                             "PARTITION BY DAY;",
+                             context);
+            // We should do this if we get a version where selecting on stringhs work embedded, see below
+            // compiler.compile("alter table " + tableName + " alter column hostname add index", context);
+        }
+        catch (SqlException e) {
+            throw new IllegalStateException("Could not create Quest db table '" + tableName + "'", e);
+        }
+    }
+
+    private ListMap<String, MetricSnapshot> getSnapshots(Instant startTime,
+                                                         Set<String> hostnames,
+                                                         SqlCompiler compiler,
+                                                         SqlExecutionContext context)  throws SqlException {
+        DateTimeFormatter formatter = DateTimeFormatter.ISO_DATE_TIME.withZone(ZoneId.of("UTC"));
+        String from = formatter.format(startTime).substring(0, 19) + ".000000Z";
+        String to = formatter.format(clock.instant()).substring(0, 19) + ".000000Z";
+        String sql = "select * from " + tableName + " where at in('" + from + "', '" + to + "');";
+
+        // WHERE clauses does not work:
+        // String sql = "select * from " + tableName + " where hostname in('host1', 'host2', 'host3');";
+
+        try (RecordCursorFactory factory = compiler.compile(sql, context).getRecordCursorFactory()) {
+            ListMap<String, MetricSnapshot> snapshots = new ListMap<>();
+            try (RecordCursor cursor = factory.getCursor(context)) {
+                Record record = cursor.getRecord();
+                while (cursor.hasNext()) {
+                    String hostname = record.getStr(0).toString();
+                    if (hostnames.contains(hostname)) {
+                        snapshots.put(hostname,
+                                      new MetricSnapshot(Instant.ofEpochMilli(record.getTimestamp(1) / 1000),
+                                                         record.getFloat(2),
+                                                         record.getFloat(3),
+                                                         record.getFloat(4),
+                                                         record.getLong(5)));
+                    }
+                }
+            }
+            return snapshots;
+        }
+    }
+
+    private SqlExecutionContext newContext() {
+        return new SqlExecutionContextImpl(engine, 1);
+    }
+
+}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Resource.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Resource.java
index 7f1844efdbe..b6d75165340 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Resource.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Resource.java
@@ -33,10 +33,4 @@ public enum Resource {
 
     abstract double valueFrom(NodeResources resources);
 
-    public static Resource from(Metric metric) {
-        for (Resource resource : values())
-            if (resource.name().equals(metric.name())) return resource;
-        throw new IllegalArgumentException("Metric '" + metric + "' does not map to a resource");
-    }
-
 }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainer.java
index bdc16cadab6..3b01f678982 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainer.java
@@ -13,7 +13,7 @@ import com.yahoo.vespa.hosted.provision.applications.Applications;
 import com.yahoo.vespa.hosted.provision.applications.Cluster;
 import com.yahoo.vespa.hosted.provision.autoscale.AllocatableClusterResources;
 import com.yahoo.vespa.hosted.provision.autoscale.Autoscaler;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetricsDb;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricsDb;
 
 import java.time.Duration;
 import java.util.List;
@@ -28,13 +28,13 @@ import java.util.stream.Collectors;
  */
 public class AutoscalingMaintainer extends NodeRepositoryMaintainer {
 
-    private final NodeMetricsDb metricsDb;
+    private final MetricsDb metricsDb;
     private final Autoscaler autoscaler;
     private final Deployer deployer;
     private final Metric metric;
 
     public AutoscalingMaintainer(NodeRepository nodeRepository,
-                                 NodeMetricsDb metricsDb,
+                                 MetricsDb metricsDb,
                                  Deployer deployer,
                                  Metric metric,
                                  Duration interval) {
@@ -73,12 +73,7 @@ public class AutoscalingMaintainer extends NodeRepositoryMaintainer {
             applications().put(application.with(cluster.get().withTarget(target)), deployment.applicationLock().get());
             if (target.isPresent()) {
                 logAutoscaling(target.get(), applicationId, clusterId, clusterNodes);
-                Optional<Long> resultingGeneration = deployment.activate();
-                if (resultingGeneration.isEmpty()) return; // Failed to activate
-
-                metricsDb.add(new NodeMetricsDb.AutoscalingEvent(applicationId,
-                                                                 resultingGeneration.get(),
-                                                                 nodeRepository().clock().instant()));
+                deployment.activate();
             }
         }
     }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeFailer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeFailer.java
index 38511db6c4d..a651c4e52c2 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeFailer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeFailer.java
@@ -357,7 +357,7 @@ public class NodeFailer extends NodeRepositoryMaintainer {
     private boolean failActive(Node node, String reason) {
         Optional<Deployment> deployment =
             deployer.deployFromLocalActive(node.allocation().get().owner(), Duration.ofMinutes(30));
-        if (deployment.isEmpty()) return false; // this will be done at another config server
+        if (deployment.isEmpty()) return false;
 
         try (Mutex lock = nodeRepository().lock(node.allocation().get().owner())) {
             // If the active node that we are trying to fail is of type host, we need to successfully fail all
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeMetricsDbMaintainer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeMetricsDbMaintainer.java
index dd5a62f3167..5770564d23a 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeMetricsDbMaintainer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeMetricsDbMaintainer.java
@@ -4,8 +4,8 @@ package com.yahoo.vespa.hosted.provision.maintenance;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.jdisc.Metric;
 import com.yahoo.vespa.hosted.provision.NodeRepository;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetrics;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetricsDb;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricsFetcher;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricsDb;
 import com.yahoo.yolean.Exceptions;
 
 import java.time.Duration;
@@ -21,17 +21,17 @@ public class NodeMetricsDbMaintainer extends NodeRepositoryMaintainer {
 
     private static final int maxWarningsPerInvocation = 2;
 
-    private final NodeMetrics nodeMetrics;
-    private final NodeMetricsDb nodeMetricsDb;
+    private final MetricsFetcher nodeMetrics;
+    private final MetricsDb metricsDb;
 
     public NodeMetricsDbMaintainer(NodeRepository nodeRepository,
-                                   NodeMetrics nodeMetrics,
-                                   NodeMetricsDb nodeMetricsDb,
+                                   MetricsFetcher nodeMetrics,
+                                   MetricsDb metricsDb,
                                    Duration interval,
                                    Metric metric) {
         super(nodeRepository, interval, metric);
         this.nodeMetrics = nodeMetrics;
-        this.nodeMetricsDb = nodeMetricsDb;
+        this.metricsDb = metricsDb;
     }
 
     @Override
@@ -39,7 +39,7 @@ public class NodeMetricsDbMaintainer extends NodeRepositoryMaintainer {
         int warnings = 0;
         for (ApplicationId application : activeNodesByApplication().keySet()) {
             try {
-                nodeMetricsDb.add(nodeMetrics.fetchMetrics(application));
+                metricsDb.add(nodeMetrics.fetchMetrics(application));
             }
             catch (Exception e) {
                 // TODO: Don't warn if this only happens occasionally
@@ -47,7 +47,7 @@ public class NodeMetricsDbMaintainer extends NodeRepositoryMaintainer {
                     log.log(Level.WARNING, "Could not update metrics for " + application + ": " + Exceptions.toMessageString(e));
             }
         }
-        nodeMetricsDb.gc(nodeRepository().clock());
+        metricsDb.gc();
 
         // Suppress failures for manual zones for now to avoid noise
         if (nodeRepository().zone().environment().isManuallyDeployed()) return true;
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeRepositoryMaintenance.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeRepositoryMaintenance.java
index 529f3d9afa8..5e3584bfcd0 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeRepositoryMaintenance.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/NodeRepositoryMaintenance.java
@@ -11,8 +11,8 @@ import com.yahoo.config.provision.Zone;
 import com.yahoo.jdisc.Metric;
 import com.yahoo.vespa.flags.FlagSource;
 import com.yahoo.vespa.hosted.provision.NodeRepository;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetrics;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetricsDb;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricsFetcher;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricsDb;
 import com.yahoo.vespa.hosted.provision.provisioning.ProvisionServiceProvider;
 import com.yahoo.vespa.orchestrator.Orchestrator;
 import com.yahoo.vespa.service.monitor.ServiceMonitor;
@@ -56,16 +56,16 @@ public class NodeRepositoryMaintenance extends AbstractComponent {
                                      HostLivenessTracker hostLivenessTracker, ServiceMonitor serviceMonitor,
                                      Zone zone, Orchestrator orchestrator, Metric metric,
                                      ProvisionServiceProvider provisionServiceProvider, FlagSource flagSource,
-                                     NodeMetrics nodeMetrics, NodeMetricsDb nodeMetricsDb) {
+                                     MetricsFetcher nodeMetrics, MetricsDb metricsDb) {
         this(nodeRepository, deployer, infraDeployer, hostLivenessTracker, serviceMonitor, zone, Clock.systemUTC(),
-             orchestrator, metric, provisionServiceProvider, flagSource, nodeMetrics, nodeMetricsDb);
+             orchestrator, metric, provisionServiceProvider, flagSource, nodeMetrics, metricsDb);
     }
 
     public NodeRepositoryMaintenance(NodeRepository nodeRepository, Deployer deployer, InfraDeployer infraDeployer,
                                      HostLivenessTracker hostLivenessTracker, ServiceMonitor serviceMonitor,
                                      Zone zone, Clock clock, Orchestrator orchestrator, Metric metric,
                                      ProvisionServiceProvider provisionServiceProvider, FlagSource flagSource,
-                                     NodeMetrics nodeMetrics, NodeMetricsDb nodeMetricsDb) {
+                                     MetricsFetcher metricsFetcher, MetricsDb metricsDb) {
         DefaultTimes defaults = new DefaultTimes(zone, deployer);
 
         nodeFailer = new NodeFailer(deployer, hostLivenessTracker, serviceMonitor, nodeRepository, defaults.failGrace,
@@ -89,9 +89,9 @@ public class NodeRepositoryMaintenance extends AbstractComponent {
         spareCapacityMaintainer = new SpareCapacityMaintainer(deployer, nodeRepository, metric, defaults.spareCapacityMaintenanceInterval);
         osUpgradeActivator = new OsUpgradeActivator(nodeRepository, defaults.osUpgradeActivatorInterval, metric);
         rebalancer = new Rebalancer(deployer, nodeRepository, metric, defaults.rebalancerInterval);
-        nodeMetricsDbMaintainer = new NodeMetricsDbMaintainer(nodeRepository, nodeMetrics, nodeMetricsDb, defaults.nodeMetricsCollectionInterval, metric);
-        autoscalingMaintainer = new AutoscalingMaintainer(nodeRepository, nodeMetricsDb, deployer, metric, defaults.autoscalingInterval);
-        scalingSuggestionsMaintainer = new ScalingSuggestionsMaintainer(nodeRepository, nodeMetricsDb, defaults.scalingSuggestionsInterval, metric);
+        nodeMetricsDbMaintainer = new NodeMetricsDbMaintainer(nodeRepository, metricsFetcher, metricsDb, defaults.nodeMetricsCollectionInterval, metric);
+        autoscalingMaintainer = new AutoscalingMaintainer(nodeRepository, metricsDb, deployer, metric, defaults.autoscalingInterval);
+        scalingSuggestionsMaintainer = new ScalingSuggestionsMaintainer(nodeRepository, metricsDb, defaults.scalingSuggestionsInterval, metric);
         switchRebalancer = new SwitchRebalancer(nodeRepository, defaults.switchRebalancerInterval, metric, deployer);
 
         // The DuperModel is filled with infrastructure applications by the infrastructure provisioner, so explicitly run that now
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/ScalingSuggestionsMaintainer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/ScalingSuggestionsMaintainer.java
index db0e5f03097..c9538d878f2 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/ScalingSuggestionsMaintainer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/ScalingSuggestionsMaintainer.java
@@ -12,7 +12,7 @@ import com.yahoo.vespa.hosted.provision.applications.Application;
 import com.yahoo.vespa.hosted.provision.applications.Applications;
 import com.yahoo.vespa.hosted.provision.applications.Cluster;
 import com.yahoo.vespa.hosted.provision.autoscale.Autoscaler;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetricsDb;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricsDb;
 
 import java.time.Duration;
 import java.util.List;
@@ -30,7 +30,7 @@ public class ScalingSuggestionsMaintainer extends NodeRepositoryMaintainer {
     private final Autoscaler autoscaler;
 
     public ScalingSuggestionsMaintainer(NodeRepository nodeRepository,
-                                        NodeMetricsDb metricsDb,
+                                        MetricsDb metricsDb,
                                         Duration interval,
                                         Metric metric) {
         super(nodeRepository, interval, metric);
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/IP.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/IP.java
index 6b2e1da0432..955936931be 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/IP.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/IP.java
@@ -245,7 +245,7 @@ public class IP {
         /**
          * Finds all unused addresses in this pool
          *
-         * @param nodes Locked list of all nodes in the repository
+         * @param nodes a list of all nodes in the repository
          */
         public Set<String> findUnused(NodeList nodes) {
             var unusedAddresses = new LinkedHashSet<>(asSet());
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/ApplicationSerializer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/ApplicationSerializer.java
index 3464e9dd881..2ddbd6def6f 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/ApplicationSerializer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/ApplicationSerializer.java
@@ -11,13 +11,16 @@ import com.yahoo.slime.Slime;
 import com.yahoo.slime.SlimeUtils;
 import com.yahoo.vespa.hosted.provision.applications.Application;
 import com.yahoo.vespa.hosted.provision.applications.Cluster;
+import com.yahoo.vespa.hosted.provision.applications.ScalingEvent;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 import java.util.Optional;
+import java.util.stream.Collectors;
 
 /**
  * Application JSON serializer
@@ -43,6 +46,11 @@ public class ApplicationSerializer {
     private static final String nodesKey = "nodes";
     private static final String groupsKey = "groups";
     private static final String nodeResourcesKey = "resources";
+    private static final String scalingEventsKey = "scalingEvents";
+    private static final String fromKey = "from";
+    private static final String toKey = "to";
+    private static final String generationKey = "generation";
+    private static final String atKey = "at";
 
     public static byte[] toJson(Application application) {
         Slime slime = new Slime();
@@ -86,6 +94,7 @@ public class ApplicationSerializer {
         toSlime(cluster.maxResources(), clusterObject.setObject(maxResourcesKey));
         cluster.suggestedResources().ifPresent(suggested -> toSlime(suggested, clusterObject.setObject(suggestedResourcesKey)));
         cluster.targetResources().ifPresent(target -> toSlime(target, clusterObject.setObject(targetResourcesKey)));
+        scalingEventsToSlime(cluster.scalingEvents(), clusterObject.setArray(scalingEventsKey));
     }
 
     private static Cluster clusterFromSlime(String id, Inspector clusterObject) {
@@ -94,7 +103,8 @@ public class ApplicationSerializer {
                            clusterResourcesFromSlime(clusterObject.field(minResourcesKey)),
                            clusterResourcesFromSlime(clusterObject.field(maxResourcesKey)),
                            optionalClusterResourcesFromSlime(clusterObject.field(suggestedResourcesKey)),
-                           optionalClusterResourcesFromSlime(clusterObject.field(targetResourcesKey)));
+                           optionalClusterResourcesFromSlime(clusterObject.field(targetResourcesKey)),
+                           scalingEventsFromSlime(clusterObject.field(scalingEventsKey)));
     }
 
     private static void toSlime(ClusterResources resources, Cursor clusterResourcesObject) {
@@ -114,4 +124,26 @@ public class ApplicationSerializer {
                                               : Optional.empty();
     }
 
+    private static void scalingEventsToSlime(List<ScalingEvent> scalingEvents, Cursor eventArray) {
+        scalingEvents.forEach(event -> toSlime(event, eventArray.addObject()));
+    }
+
+    private static List<ScalingEvent> scalingEventsFromSlime(Inspector eventArray) {
+        return SlimeUtils.entriesStream(eventArray).map(item -> scalingEventFromSlime(item)).collect(Collectors.toList());
+    }
+
+    private static void toSlime(ScalingEvent event, Cursor object) {
+        toSlime(event.from(), object.setObject(fromKey));
+        toSlime(event.to(), object.setObject(toKey));
+        object.setLong(generationKey, event.generation());
+        object.setLong(atKey, event.at().toEpochMilli());
+    }
+
+    private static ScalingEvent scalingEventFromSlime(Inspector inspector) {
+        return new ScalingEvent(clusterResourcesFromSlime(inspector.field(fromKey)),
+                                clusterResourcesFromSlime(inspector.field(toKey)),
+                                inspector.field(generationKey).asLong(),
+                                Instant.ofEpochMilli(inspector.field(atKey).asLong()));
+    }
+
 }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabaseClient.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabaseClient.java
index e6564b52216..9e83960335d 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabaseClient.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabaseClient.java
@@ -5,6 +5,7 @@ import com.google.common.util.concurrent.UncheckedTimeoutException;
 import com.yahoo.component.Version;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.ApplicationLockException;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.DockerImage;
 import com.yahoo.config.provision.HostName;
 import com.yahoo.config.provision.NodeFlavors;
@@ -380,10 +381,10 @@ public class CuratorDatabaseClient {
                                         ApplicationSerializer.toJson(application)));
     }
 
-    public void deleteApplication(ApplicationId application, NestedTransaction transaction) {
-        if (db.exists(applicationPath(application)))
-            db.newCuratorTransactionIn(transaction)
-              .add(CuratorOperations.delete(applicationPath(application).getAbsolute()));
+    public void deleteApplication(ApplicationTransaction transaction) {
+        if (db.exists(applicationPath(transaction.application())))
+            db.newCuratorTransactionIn(transaction.nested())
+              .add(CuratorOperations.delete(applicationPath(transaction.application()).getAbsolute()));
     }
 
     private Path applicationPath(ApplicationId id) {
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/Activator.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/Activator.java
index b85862446a8..8e691b538a1 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/Activator.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/Activator.java
@@ -2,7 +2,9 @@
 package com.yahoo.vespa.hosted.provision.provisioning;
 
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.ClusterMembership;
+import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
 import com.yahoo.config.provision.Flavor;
 import com.yahoo.config.provision.HostSpec;
@@ -13,6 +15,8 @@ import com.yahoo.transaction.NestedTransaction;
 import com.yahoo.vespa.hosted.provision.Node;
 import com.yahoo.vespa.hosted.provision.NodeList;
 import com.yahoo.vespa.hosted.provision.NodeRepository;
+import com.yahoo.vespa.hosted.provision.applications.Application;
+import com.yahoo.vespa.hosted.provision.applications.ScalingEvent;
 import com.yahoo.vespa.hosted.provision.node.Allocation;
 
 import java.util.ArrayList;
@@ -39,9 +43,9 @@ class Activator {
     }
 
     /** Activate required resources for application guarded by given lock */
-    public void activate(Collection<HostSpec> hosts, NestedTransaction transaction, ProvisionLock lock) {
-        activateNodes(hosts, transaction, lock);
-        activateLoadBalancers(hosts, transaction, lock);
+    public void activate(Collection<HostSpec> hosts, long generation, ApplicationTransaction transaction) {
+        activateNodes(hosts, generation, transaction);
+        activateLoadBalancers(hosts, transaction);
     }
 
     /**
@@ -53,41 +57,69 @@ class Activator {
      * Post condition: Nodes in reserved which are present in <code>hosts</code> are moved to active.
      * Nodes in active which are not present in <code>hosts</code> are moved to inactive.
      *
-     * @param transaction Transaction with operations to commit together with any operations done within the repository.
      * @param hosts the hosts to make the set of active nodes of this
-     * @param lock provision lock that must be held when calling this
+     * @param generation the application config generation that is activated
+     * @param transaction transaction with operations to commit together with any operations done within the repository,
+     *                    while holding the node repository lock on this application
      */
-    private void activateNodes(Collection<HostSpec> hosts, NestedTransaction transaction, ProvisionLock lock) {
-        ApplicationId application = lock.application();
+    private void activateNodes(Collection<HostSpec> hosts, long generation, ApplicationTransaction transaction) {
+        ApplicationId application = transaction.application();
         Set<String> hostnames = hosts.stream().map(HostSpec::hostname).collect(Collectors.toSet());
         NodeList allNodes = nodeRepository.list();
         NodeList applicationNodes = allNodes.owner(application);
 
         List<Node> reserved = applicationNodes.state(Node.State.reserved).asList();
-        List<Node> reservedToActivate = retainHostsInList(hostnames, reserved);
-        List<Node> active = applicationNodes.state(Node.State.active).asList();
-        List<Node> continuedActive = retainHostsInList(hostnames, active);
-        List<Node> allActive = new ArrayList<>(continuedActive);
-        allActive.addAll(reservedToActivate);
-        if (!containsAll(hostnames, allActive))
+        List<Node> reservedToActivate = updatePortsFrom(hosts, retainHostsInList(hostnames, reserved));
+        List<Node> oldActive = applicationNodes.state(Node.State.active).asList(); // All nodes active now
+        List<Node> continuedActive = retainHostsInList(hostnames, oldActive);
+        List<Node> newActive = updateFrom(hosts, continuedActive); // All nodes that will be active when this is committed
+        newActive.addAll(reservedToActivate);
+        if ( ! containsAll(hostnames, newActive))
             throw new IllegalArgumentException("Activation of " + application + " failed. " +
                                                "Could not find all requested hosts." +
                                                "\nRequested: " + hosts +
                                                "\nReserved: " + toHostNames(reserved) +
-                                               "\nActive: " + toHostNames(active) +
+                                               "\nActive: " + toHostNames(oldActive) +
                                                "\nThis might happen if the time from reserving host to activation takes " +
                                                "longer time than reservation expiry (the hosts will then no longer be reserved)");
 
         validateParentHosts(application, allNodes, reservedToActivate);
 
-        List<Node> activeToRemove = removeHostsFromList(hostnames, active);
-        activeToRemove = activeToRemove.stream().map(Node::unretire).collect(Collectors.toList()); // only active nodes can be retired
-        nodeRepository.deactivate(activeToRemove, transaction, lock);
-        nodeRepository.activate(updateFrom(hosts, continuedActive), transaction); // update active with any changes
-        nodeRepository.activate(updatePortsFrom(hosts, reservedToActivate), transaction);
+        List<Node> activeToRemove = removeHostsFromList(hostnames, oldActive);
+        activeToRemove = activeToRemove.stream().map(Node::unretire).collect(Collectors.toList()); // only active nodes can be retired. TODO: Move this line to deactivate
+        nodeRepository.deactivate(activeToRemove, transaction);
+        nodeRepository.activate(newActive, transaction.nested()); // activate also continued active to update node state
+
+        rememberResourceChange(transaction, generation,
+                               NodeList.copyOf(oldActive).not().retired(),
+                               NodeList.copyOf(newActive).not().retired());
         unreserveParentsOf(reservedToActivate);
     }
 
+    private void rememberResourceChange(ApplicationTransaction transaction, long generation,
+                                        NodeList oldNodes, NodeList newNodes) {
+        Optional<Application> application = nodeRepository.applications().get(transaction.application());
+        if (application.isEmpty()) return; // infrastructure app, hopefully :-|
+
+        var currentNodesByCluster = newNodes.stream()
+                                            .collect(Collectors.groupingBy(node -> node.allocation().get().membership().cluster().id()));
+        Application modified = application.get();
+        for (var clusterEntry : currentNodesByCluster.entrySet()) {
+            var previousResources = oldNodes.cluster(clusterEntry.getKey()).toResources();
+            var currentResources = NodeList.copyOf(clusterEntry.getValue()).toResources();
+            if ( ! previousResources.equals(currentResources)) {
+                modified = modified.with(application.get().cluster(clusterEntry.getKey()).get()
+                                                          .with(new ScalingEvent(previousResources,
+                                                                                 currentResources,
+                                                                                 generation,
+                                                                                 nodeRepository.clock().instant())));
+            }
+        }
+
+        if (modified != application.get())
+            nodeRepository.applications().put(modified, transaction);
+    }
+
     /** When a tenant node is activated on a host, we can open up that host for use by others */
     private void unreserveParentsOf(List<Node> nodes) {
         for (Node node : nodes) {
@@ -104,8 +136,8 @@ class Activator {
     }
 
     /** Activate load balancers */
-    private void activateLoadBalancers(Collection<HostSpec> hosts, NestedTransaction transaction, ProvisionLock lock) {
-        loadBalancerProvisioner.ifPresent(provisioner -> provisioner.activate(transaction, allClustersOf(hosts), lock));
+    private void activateLoadBalancers(Collection<HostSpec> hosts, ApplicationTransaction transaction) {
+        loadBalancerProvisioner.ifPresent(provisioner -> provisioner.activate(allClustersOf(hosts), transaction));
     }
 
     private static Set<ClusterSpec> allClustersOf(Collection<HostSpec> hosts) {
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/GroupPreparer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/GroupPreparer.java
index 7f62eb8632c..99557cb0908 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/GroupPreparer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/GroupPreparer.java
@@ -67,7 +67,7 @@ public class GroupPreparer {
         {
             MutableInteger probePrepareHighestIndex = new MutableInteger(highestIndex.get());
             NodeAllocation probeAllocation = prepareAllocation(application, cluster, requestedNodes, surplusActiveNodes,
-                    probePrepareHighestIndex, wantedGroups, allocateFully, PROBE_LOCK);
+                                                               probePrepareHighestIndex, wantedGroups, allocateFully, PROBE_LOCK);
             if (probeAllocation.fulfilledAndNoChanges()) {
                 List<Node> acceptedNodes = probeAllocation.finalNodes();
                 surplusActiveNodes.removeAll(acceptedNodes);
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/InfraDeployerImpl.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/InfraDeployerImpl.java
index b3506a0c102..34ad8ef6b00 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/InfraDeployerImpl.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/InfraDeployerImpl.java
@@ -3,7 +3,9 @@ package com.yahoo.vespa.hosted.provision.provisioning;
 
 import com.google.inject.Inject;
 import com.yahoo.component.Version;
+import com.yahoo.config.provision.ActivationContext;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Deployment;
 import com.yahoo.config.provision.HostFilter;
 import com.yahoo.config.provision.HostName;
@@ -105,7 +107,7 @@ public class InfraDeployerImpl implements InfraDeployer {
                     removeApplication(application.getApplicationId());
                 } else {
                     NestedTransaction nestedTransaction = new NestedTransaction();
-                    provisioner.activate(nestedTransaction, hostSpecs, lock);
+                    provisioner.activate(hostSpecs, new ActivationContext(0), new ApplicationTransaction(lock, nestedTransaction));
                     nestedTransaction.commit();
 
                     duperModel.infraApplicationActivated(
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/LoadBalancerProvisioner.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/LoadBalancerProvisioner.java
index 634726f9d71..bb5498a2459 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/LoadBalancerProvisioner.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/LoadBalancerProvisioner.java
@@ -2,6 +2,7 @@
 package com.yahoo.vespa.hosted.provision.provisioning;
 
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.ClusterSpec;
 import com.yahoo.config.provision.HostName;
 import com.yahoo.config.provision.NodeType;
@@ -96,24 +97,24 @@ public class LoadBalancerProvisioner {
      *
      * Calling this when no load balancer has been prepared for given cluster is a no-op.
      */
-    public void activate(NestedTransaction transaction, Set<ClusterSpec> clusters, ProvisionLock lock) {
-        for (var cluster : loadBalancedClustersOf(lock.application()).entrySet()) {
+    public void activate(Set<ClusterSpec> clusters, ApplicationTransaction transaction) {
+        for (var cluster : loadBalancedClustersOf(transaction.application()).entrySet()) {
             // Provision again to ensure that load balancer instance is re-configured with correct nodes
-            provision(lock.application(), cluster.getKey(), cluster.getValue(), true, lock);
+            provision(transaction.application(), cluster.getKey(), cluster.getValue(), true, transaction.lock());
         }
         // Deactivate any surplus load balancers, i.e. load balancers for clusters that have been removed
-        var surplusLoadBalancers = surplusLoadBalancersOf(lock.application(), clusters.stream()
+        var surplusLoadBalancers = surplusLoadBalancersOf(transaction.application(), clusters.stream()
                                                                                       .map(LoadBalancerProvisioner::effectiveId)
                                                                                       .collect(Collectors.toSet()));
-        deactivate(surplusLoadBalancers, transaction);
+        deactivate(surplusLoadBalancers, transaction.nested());
     }
 
     /**
      * Deactivate all load balancers assigned to given application. This is a no-op if an application does not have any
      * load balancer(s).
      */
-    public void deactivate(NestedTransaction transaction, ProvisionLock lock) {
-        deactivate(nodeRepository.loadBalancers(lock.application()).asList(), transaction);
+    public void deactivate(ApplicationTransaction transaction) {
+        deactivate(nodeRepository.loadBalancers(transaction.application()).asList(), transaction.nested());
     }
 
     /** Returns load balancers of given application that are no longer referenced by given clusters */
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/NodeRepositoryProvisioner.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/NodeRepositoryProvisioner.java
index 3aa87348c73..1c71b528842 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/NodeRepositoryProvisioner.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/NodeRepositoryProvisioner.java
@@ -2,7 +2,9 @@
 package com.yahoo.vespa.hosted.provision.provisioning;
 
 import com.google.inject.Inject;
+import com.yahoo.config.provision.ActivationContext;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
@@ -122,14 +124,21 @@ public class NodeRepositoryProvisioner implements Provisioner {
     // TODO(mpolden): Remove
     public void activate(NestedTransaction transaction, ApplicationId application, Collection<HostSpec> hosts) {
         try (var lock = lock(application)) {
-            activate(transaction, hosts, lock);
+            activate(hosts, new ActivationContext(0), new ApplicationTransaction(lock, transaction));
         }
     }
 
     @Override
+    // TODO: Remove after November 2020
     public void activate(NestedTransaction transaction, Collection<HostSpec> hosts, ProvisionLock lock) {
         validate(hosts);
-        activator.activate(hosts, transaction, lock);
+        activator.activate(hosts, 0, new ApplicationTransaction(lock, transaction));
+    }
+
+    @Override
+    public void activate(Collection<HostSpec> hosts, ActivationContext context, ApplicationTransaction transaction) {
+        validate(hosts);
+        activator.activate(hosts, context.generation(), transaction);
     }
 
     @Override
@@ -137,18 +146,24 @@ public class NodeRepositoryProvisioner implements Provisioner {
         nodeRepository.restart(ApplicationFilter.from(application, NodeHostFilter.from(filter)));
     }
 
-    @Override
     // TODO(mpolden): Remove
+    @Override
     public void remove(NestedTransaction transaction, ApplicationId application) {
         try (var lock = lock(application)) {
-            remove(transaction, lock);
+            remove(new ApplicationTransaction(lock, transaction));
         }
     }
 
+    // TODO: Remove after November 2020
     @Override
     public void remove(NestedTransaction transaction, ProvisionLock lock) {
-        nodeRepository.deactivate(transaction, lock);
-        loadBalancerProvisioner.ifPresent(lbProvisioner -> lbProvisioner.deactivate(transaction, lock));
+        remove(new ApplicationTransaction(lock, transaction));
+    }
+
+    @Override
+    public void remove(ApplicationTransaction transaction) {
+        nodeRepository.deactivate(transaction);
+        loadBalancerProvisioner.ifPresent(lbProvisioner -> lbProvisioner.deactivate(transaction));
     }
 
     @Override
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/ContainerConfig.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/ContainerConfig.java
index d66bb7d6efb..5e40c0bd9ff 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/ContainerConfig.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/ContainerConfig.java
@@ -25,8 +25,8 @@ public class ContainerConfig {
                "  <component id='com.yahoo.vespa.hosted.provision.testutils.ServiceMonitorStub'/>\n" +
                "  <component id='com.yahoo.vespa.hosted.provision.testutils.MockDuperModel'/>\n" +
                "  <component id='com.yahoo.vespa.hosted.provision.testutils.MockNodeFlavors'/>\n" +
-               "  <component id='com.yahoo.vespa.hosted.provision.autoscale.NodeMetricsDb'/>\n" +
-               "  <component id='com.yahoo.vespa.hosted.provision.testutils.MockNodeMetrics'/>\n" +
+               "  <component id='com.yahoo.vespa.hosted.provision.autoscale.QuestMetricsDb'/>\n" +
+               "  <component id='com.yahoo.vespa.hosted.provision.testutils.MockMetricsFetcher'/>\n" +
                "  <component id='com.yahoo.vespa.hosted.provision.testutils.MockNodeRepository'/>\n" +
                "  <component id='com.yahoo.vespa.hosted.provision.testutils.MockProvisionServiceProvider'/>\n" +
                "  <component id='com.yahoo.vespa.hosted.provision.maintenance.NodeRepositoryMaintenance'/>\n" +
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockDeployer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockDeployer.java
index a5522a93a6e..8099b08ae89 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockDeployer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockDeployer.java
@@ -2,7 +2,9 @@
 package com.yahoo.vespa.hosted.provision.testutils;
 
 import com.google.inject.Inject;
+import com.yahoo.config.provision.ActivationContext;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterSpec;
 import com.yahoo.config.provision.Deployer;
@@ -36,7 +38,7 @@ public class MockDeployer implements Deployer {
     // For mock deploy anything, changing wantToRetire to retired only
     private final NodeRepository nodeRepository;
 
-    /** The number of redeployments done to this */
+    /** The number of redeployments done to this, which is also the config generation */
     public int redeployments = 0;
 
     private final Map<ApplicationId, Instant> lastDeployTimes = new HashMap<>();
@@ -159,14 +161,16 @@ public class MockDeployer implements Deployer {
                 prepare();
             if (failActivate)
                 throw new IllegalStateException("failActivate is true");
+
+            redeployments++;
             try (var lock = provisioner.lock(application.id)) {
                 try (NestedTransaction t = new NestedTransaction()) {
-                    provisioner.activate(t, preparedHosts, lock);
+                    provisioner.activate(preparedHosts, new ActivationContext(redeployments), new ApplicationTransaction(lock, t));
                     t.commit();
                     lastDeployTimes.put(application.id, clock.instant());
                 }
             }
-            return redeployments++;
+            return redeployments;
         }
 
         @Override
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockNodeMetrics.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockMetricsFetcher.java
index d5397aa421c..ed2d7eed9e4 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockNodeMetrics.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockMetricsFetcher.java
@@ -1,8 +1,10 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.testutils;
 
+import com.yahoo.collections.Pair;
 import com.yahoo.config.provision.ApplicationId;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetrics;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricSnapshot;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricsFetcher;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -10,10 +12,10 @@ import java.util.Collection;
 /**
  * @author bratseth
  */
-public class MockNodeMetrics implements NodeMetrics {
+public class MockMetricsFetcher implements MetricsFetcher {
 
     @Override
-    public Collection<MetricValue> fetchMetrics(ApplicationId application) {
+    public Collection<Pair<String, MetricSnapshot>>  fetchMetrics(ApplicationId application) {
         return new ArrayList<>();
     }
 
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockNodeRepository.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockNodeRepository.java
index 0509ccc81c1..fed0ab6a8ee 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockNodeRepository.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockNodeRepository.java
@@ -2,8 +2,10 @@
 package com.yahoo.vespa.hosted.provision.testutils;
 
 import com.yahoo.component.Version;
+import com.yahoo.config.provision.ActivationContext;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.ApplicationName;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
@@ -198,7 +200,7 @@ public class MockNodeRepository extends NodeRepository {
     private void activate(List<HostSpec> hosts, ApplicationId application, NodeRepositoryProvisioner provisioner) {
         try (var lock = provisioner.lock(application)) {
             NestedTransaction transaction = new NestedTransaction();
-            provisioner.activate(transaction, hosts, lock);
+            provisioner.activate(hosts, new ActivationContext(0), new ApplicationTransaction(lock, transaction));
             transaction.commit();
         }
     }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockProvisioner.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockProvisioner.java
index 3dc96e0011b..d5d3bb6c950 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockProvisioner.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockProvisioner.java
@@ -1,7 +1,9 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.testutils;
 
+import com.yahoo.config.provision.ActivationContext;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterSpec;
 import com.yahoo.config.provision.HostFilter;
@@ -25,29 +27,25 @@ public class MockProvisioner implements Provisioner {
     }
 
     @Override
-    public void activate(NestedTransaction transaction, ApplicationId application, Collection<HostSpec> hosts) {
-
-    }
+    public void activate(NestedTransaction transaction, ApplicationId application, Collection<HostSpec> hosts) { }
 
     @Override
-    public void activate(NestedTransaction transaction, Collection<HostSpec> hosts, ProvisionLock lock) {
-
-    }
+    public void activate(NestedTransaction transaction, Collection<HostSpec> hosts, ProvisionLock lock) { }
 
     @Override
-    public void remove(NestedTransaction transaction, ApplicationId application) {
-
-    }
+    public void activate(Collection<HostSpec> hosts, ActivationContext context, ApplicationTransaction transaction) { }
 
     @Override
-    public void remove(NestedTransaction transaction, ProvisionLock lock) {
+    public void remove(NestedTransaction transaction, ApplicationId application) { }
 
-    }
+    @Override
+    public void remove(NestedTransaction transaction, ProvisionLock lock) { }
 
     @Override
-    public void restart(ApplicationId application, HostFilter filter) {
+    public void remove(ApplicationTransaction transaction) { }
 
-    }
+    @Override
+    public void restart(ApplicationId application, HostFilter filter) { }
 
     @Override
     public ProvisionLock lock(ApplicationId application) {
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/applications/ApplicationsTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/applications/ApplicationsTest.java
index 2f331c53f74..cc988b2ec1e 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/applications/ApplicationsTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/applications/ApplicationsTest.java
@@ -2,6 +2,7 @@
 package com.yahoo.vespa.hosted.provision.applications;
 
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.ProvisionLock;
 import com.yahoo.transaction.NestedTransaction;
 import com.yahoo.vespa.hosted.provision.NodeRepositoryTester;
@@ -30,7 +31,7 @@ public class ApplicationsTest {
         assertEquals(app1, applications.get(app1).get().id());
         assertEquals(List.of(app1), applications.ids());
         NestedTransaction t = new NestedTransaction();
-        applications.remove(app1, t, provisionLock(app1));
+        applications.remove(new ApplicationTransaction(provisionLock(app1), t));
         t.commit();
         assertTrue(applications.get(app1).isEmpty());
         assertEquals(List.of(), applications.ids());
@@ -38,14 +39,14 @@ public class ApplicationsTest {
         applications.put(new Application(app1), () -> {});
         applications.put(new Application(app2), () -> {});
         t = new NestedTransaction();
-        applications.put(new Application(app3), t, () -> {});
+        applications.put(new Application(app3), new ApplicationTransaction(provisionLock(app1), t));
         assertEquals(List.of(app1, app2), applications.ids());
         t.commit();
         assertEquals(List.of(app1, app2, app3), applications.ids());
         t = new NestedTransaction();
-        applications.remove(app1, t, provisionLock(app1));
-        applications.remove(app2, t, provisionLock(app2));
-        applications.remove(app3, t, provisionLock(app3));
+        applications.remove(new ApplicationTransaction(provisionLock(app1), t));
+        applications.remove(new ApplicationTransaction(provisionLock(app2), t));
+        applications.remove(new ApplicationTransaction(provisionLock(app3), t));
         assertEquals(List.of(app1, app2, app3), applications.ids());
         t.commit();
         assertTrue(applications.get(app1).isEmpty());
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingIntegrationTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingIntegrationTest.java
index 343e8ca44d4..9332eb79f20 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingIntegrationTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingIntegrationTest.java
@@ -30,9 +30,9 @@ public class AutoscalingIntegrationTest {
         NodeResources hosts = new NodeResources(3, 20, 200, 1);
 
         AutoscalingTester tester = new AutoscalingTester(hosts);
-        NodeMetricsFetcher fetcher = new NodeMetricsFetcher(tester.nodeRepository(),
-                                                            new OrchestratorMock(),
-                                                            new MockHttpClient(tester.clock()));
+        MetricsV2MetricsFetcher fetcher = new MetricsV2MetricsFetcher(tester.nodeRepository(),
+                                                                      new OrchestratorMock(),
+                                                                      new MockHttpClient(tester.clock()));
         Autoscaler autoscaler = new Autoscaler(tester.nodeMetricsDb(), tester.nodeRepository());
 
         ApplicationId application1 = tester.applicationId("test1");
@@ -47,7 +47,7 @@ public class AutoscalingIntegrationTest {
             tester.clock().advance(Duration.ofSeconds(10));
             tester.nodeMetricsDb().add(fetcher.fetchMetrics(application1));
             tester.clock().advance(Duration.ofSeconds(10));
-            tester.nodeMetricsDb().gc(tester.clock());
+            tester.nodeMetricsDb().gc();
         }
 
         ClusterResources min = new ClusterResources(2, 1, nodes);
@@ -63,7 +63,7 @@ public class AutoscalingIntegrationTest {
         assertTrue(scaledResources.isPresent());
     }
 
-    private static class MockHttpClient implements NodeMetricsFetcher.HttpClient {
+    private static class MockHttpClient implements MetricsV2MetricsFetcher.HttpClient {
 
         private final ManualClock clock;
 
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingTest.java
index 791f223930d..df5a7bbf9b8 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingTest.java
@@ -45,10 +45,10 @@ public class AutoscalingTest {
 
         assertTrue("No measurements -> No change", tester.autoscale(application1, cluster1.id(), min, max).isEmpty());
 
-        tester.addMeasurements(Resource.cpu, 0.25f, 1f, 59, application1);
+        tester.addCpuMeasurements(0.25f, 1f, 59, application1);
         assertTrue("Too few measurements -> No change", tester.autoscale(application1, cluster1.id(), min, max).isEmpty());
 
-        tester.addMeasurements(Resource.cpu, 0.25f, 1f, 60, application1);
+        tester.addCpuMeasurements(0.25f, 1f, 60, application1);
         ClusterResources scaledResources = tester.assertResources("Scaling up since resource usage is too high",
                                                                   15, 1, 1.3,  28.6, 28.6,
                                                                   tester.autoscale(application1, cluster1.id(), min, max));
@@ -57,14 +57,14 @@ public class AutoscalingTest {
         assertTrue("Cluster in flux -> No further change", tester.autoscale(application1, cluster1.id(), min, max).isEmpty());
 
         tester.deactivateRetired(application1, cluster1, scaledResources);
-        tester.addMeasurements(Resource.cpu, 0.8f, 1f, 3, application1);
+        tester.addCpuMeasurements(0.8f, 1f, 3, application1);
         assertTrue("Load change is large, but insufficient measurements for new config -> No change",
                    tester.autoscale(application1, cluster1.id(), min, max).isEmpty());
 
-        tester.addMeasurements(Resource.cpu,  0.19f, 1f, 100, application1);
+        tester.addCpuMeasurements(0.19f, 1f, 100, application1);
         assertEquals("Load change is small -> No change", Optional.empty(), tester.autoscale(application1, cluster1.id(), min, max));
 
-        tester.addMeasurements(Resource.cpu,  0.1f, 1f, 120, application1);
+        tester.addCpuMeasurements(0.1f, 1f, 120, application1);
         tester.assertResources("Scaling down to minimum since usage has gone down significantly",
                                14, 1, 1.0, 30.8, 30.8,
                                tester.autoscale(application1, cluster1.id(), min, max));
@@ -84,7 +84,7 @@ public class AutoscalingTest {
         // deploy
         tester.deploy(application1, cluster1, 5, 1, resources);
 
-        tester.addMeasurements(Resource.cpu, 0.25f, 1f, 120, application1);
+        tester.addCpuMeasurements(0.25f, 1f, 120, application1);
         ClusterResources scaledResources = tester.assertResources("Scaling up since cpu usage is too high",
                                                                   7, 1, 2.5,  80.0, 80.0,
                                                                   tester.autoscale(application1, cluster1.id(), min, max));
@@ -92,7 +92,7 @@ public class AutoscalingTest {
         tester.deploy(application1, cluster1, scaledResources);
         tester.deactivateRetired(application1, cluster1, scaledResources);
 
-        tester.addMeasurements(Resource.cpu,  0.1f, 1f, 120, application1);
+        tester.addCpuMeasurements(0.1f, 1f, 120, application1);
         tester.assertResources("Scaling down since cpu usage has gone down",
                                4, 1, 2.5, 68.6, 68.6,
                                tester.autoscale(application1, cluster1.id(), min, max));
@@ -111,7 +111,7 @@ public class AutoscalingTest {
         tester.nodeRepository().getNodes(application1).stream()
               .allMatch(n -> n.allocation().get().requestedResources().diskSpeed() == NodeResources.DiskSpeed.slow);
 
-        tester.addMeasurements(Resource.cpu, 0.25f, 1f, 120, application1);
+        tester.addCpuMeasurements(0.25f, 1f, 120, application1);
         // Changing min and max from slow to any
         ClusterResources min = new ClusterResources( 2, 1,
                                                      new NodeResources(1, 1, 1, 1, NodeResources.DiskSpeed.any));
@@ -140,9 +140,7 @@ public class AutoscalingTest {
         // deploy
         tester.deploy(application1, cluster1, 5, 1,
                       new NodeResources(1.9, 70, 70, 1));
-        tester.addMeasurements(Resource.cpu,    0.25f, 120, application1);
-        tester.addMeasurements(Resource.memory, 0.95f, 120, application1);
-        tester.addMeasurements(Resource.disk,   0.95f, 120, application1);
+        tester.addMeasurements(0.25f, 0.95f, 0.95f, 0, 120, application1);
         tester.assertResources("Scaling up to limit since resource usage is too high",
                                6, 1, 2.4,  78.0, 79.0,
                                tester.autoscale(application1, cluster1.id(), min, max));
@@ -160,9 +158,7 @@ public class AutoscalingTest {
 
         // deploy
         tester.deploy(application1, cluster1, 5, 1, resources);
-        tester.addMeasurements(Resource.cpu,    0.05f, 120, application1);
-        tester.addMeasurements(Resource.memory, 0.05f, 120, application1);
-        tester.addMeasurements(Resource.disk,   0.05f, 120, application1);
+        tester.addMeasurements(0.05f, 0.05f, 0.05f,  0, 120, application1);
         tester.assertResources("Scaling down to limit since resource usage is low",
                                4, 1, 1.8,  7.4, 10.0,
                                tester.autoscale(application1, cluster1.id(), min, max));
@@ -180,7 +176,7 @@ public class AutoscalingTest {
 
         // deploy
         tester.deploy(application1, cluster1, 5, 5, new NodeResources(3.0, 10, 10, 1));
-        tester.addMeasurements(Resource.cpu,  0.3f, 1f, 240, application1);
+        tester.addCpuMeasurements( 0.3f, 1f, 240, application1);
         tester.assertResources("Scaling up since resource usage is too high",
                                6, 6, 3.6,  8.0, 10.0,
                                tester.autoscale(application1, cluster1.id(), min, max));
@@ -198,7 +194,7 @@ public class AutoscalingTest {
 
         // deploy
         tester.deploy(application1, cluster1, 5, 1, resources);
-        tester.addMeasurements(Resource.cpu,  0.25f, 1f, 120, application1);
+        tester.addCpuMeasurements(0.25f, 1f, 120, application1);
         assertTrue(tester.autoscale(application1, cluster1.id(), min, max).isEmpty());
     }
 
@@ -214,7 +210,7 @@ public class AutoscalingTest {
 
         // deploy
         tester.deploy(application1, cluster1, 5, 1, resources);
-        tester.addMeasurements(Resource.cpu,  0.25f, 1f, 120, application1);
+        tester.addCpuMeasurements(0.25f, 1f, 120, application1);
         tester.assertResources("Scaling up since resource usage is too high",
                                7, 1, 2.5,  80.0, 80.0,
                                tester.suggest(application1, cluster1.id(), min, max));
@@ -232,7 +228,7 @@ public class AutoscalingTest {
 
         // deploy
         tester.deploy(application1, cluster1, 5, 5, resources);
-        tester.addMeasurements(Resource.cpu,  0.25f, 1f, 120, application1);
+        tester.addCpuMeasurements(0.25f, 1f, 120, application1);
         tester.assertResources("Scaling up since resource usage is too high",
                                7, 7, 2.5,  80.0, 80.0,
                                tester.autoscale(application1, cluster1.id(), min, max));
@@ -250,7 +246,7 @@ public class AutoscalingTest {
 
         // deploy
         tester.deploy(application1, cluster1, 6, 2, resources);
-        tester.addMeasurements(Resource.cpu,  0.25f, 1f, 120, application1);
+        tester.addCpuMeasurements(0.25f, 1f, 120, application1);
         tester.assertResources("Scaling up since resource usage is too high, changing to 1 group is cheaper",
                                8, 1, 2.7,  83.3, 83.3,
                                tester.autoscale(application1, cluster1.id(), min, max));
@@ -268,7 +264,7 @@ public class AutoscalingTest {
 
         // deploy
         tester.deploy(application1, cluster1, 6, 2, new NodeResources(10, 100, 100, 1));
-        tester.addMeasurements(Resource.memory,  1.0f, 1f, 1000, application1);
+        tester.addMemMeasurements(1.0f, 1f, 1000, application1);
         tester.assertResources("Increase group size to reduce memory load",
                                8, 2, 12.9,  89.3, 62.5,
                                tester.autoscale(application1, cluster1.id(), min, max));
@@ -286,7 +282,7 @@ public class AutoscalingTest {
 
         // deploy
         tester.deploy(application1, cluster1, 6, 1, hostResources.withVcpu(hostResources.vcpu() / 2));
-        tester.addMeasurements(Resource.memory,  0.02f, 0.95f, 120, application1);
+        tester.addMemMeasurements(0.02f, 0.95f, 120, application1);
         tester.assertResources("Scaling down",
                                6, 1, 2.8, 4.0, 95.0,
                                tester.autoscale(application1, cluster1.id(), min, max));
@@ -305,9 +301,7 @@ public class AutoscalingTest {
             ClusterSpec cluster1 = tester.clusterSpec(ClusterSpec.Type.content, "cluster1");
 
             tester.deploy(application1, cluster1, min);
-            tester.addMeasurements(Resource.cpu, 1.0f, 1000, application1);
-            tester.addMeasurements(Resource.memory, 1.0f, 1000, application1);
-            tester.addMeasurements(Resource.disk, 0.7f, 1000, application1);
+            tester.addMeasurements(1.0f, 1.0f, 0.7f, 0, 1000, application1);
             tester.assertResources("Scaling up",
                                    4, 1, 7.0, 20, 200,
                                    tester.autoscale(application1, cluster1.id(), min, max));
@@ -320,9 +314,7 @@ public class AutoscalingTest {
             ClusterSpec cluster1 = tester.clusterSpec(ClusterSpec.Type.content, "cluster1");
 
             tester.deploy(application1, cluster1, min);
-            tester.addMeasurements(Resource.cpu, 1.0f, 1000, application1);
-            tester.addMeasurements(Resource.memory, 1.0f, 1000, application1);
-            tester.addMeasurements(Resource.disk, 0.7f, 1000, application1);
+            tester.addMeasurements(1.0f, 1.0f, 0.7f, 0, 1000, application1);
             tester.assertResources("Scaling up",
                                    4, 1, 7.0, 34, 200,
                                    tester.autoscale(application1, cluster1.id(), min, max));
@@ -351,7 +343,7 @@ public class AutoscalingTest {
         // deploy (Why 103 Gb memory? See AutoscalingTester.MockHostResourcesCalculator
         tester.deploy(application1, cluster1, 5, 1, new NodeResources(3, 103, 100, 1));
 
-        tester.addMeasurements(Resource.memory, 0.9f, 0.6f, 120, application1);
+        tester.addMemMeasurements(0.9f, 0.6f, 120, application1);
         ClusterResources scaledResources = tester.assertResources("Scaling up since resource usage is too high.",
                                                                   8, 1, 3,  83, 34.3,
                                                                   tester.autoscale(application1, cluster1.id(), min, max));
@@ -359,7 +351,7 @@ public class AutoscalingTest {
         tester.deploy(application1, cluster1, scaledResources);
         tester.deactivateRetired(application1, cluster1, scaledResources);
 
-        tester.addMeasurements(Resource.memory, 0.3f, 0.6f, 1000, application1);
+        tester.addMemMeasurements(0.3f, 0.6f, 1000, application1);
         tester.assertResources("Scaling down since resource usage has gone down",
                                5, 1, 3, 83, 36,
                                tester.autoscale(application1, cluster1.id(), min, max));
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingTester.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingTester.java
index bdcf969563c..999ceeccc58 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingTester.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/AutoscalingTester.java
@@ -1,6 +1,7 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.autoscale;
 
+import com.yahoo.collections.Pair;
 import com.yahoo.component.Version;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.Capacity;
@@ -40,7 +41,7 @@ class AutoscalingTester {
 
     private final ProvisioningTester provisioningTester;
     private final Autoscaler autoscaler;
-    private final NodeMetricsDb db;
+    private final MetricsDb db;
     private final MockHostResourcesCalculator hostResourcesCalculator;
 
     /** Creates an autoscaling tester with a single host type ready */
@@ -67,7 +68,7 @@ class AutoscalingTester {
                                                              .build();
 
         hostResourcesCalculator = new MockHostResourcesCalculator(zone);
-        db = new NodeMetricsDb(provisioningTester.nodeRepository());
+        db = MetricsDb.createTestInstance(provisioningTester.nodeRepository());
         autoscaler = new Autoscaler(db, nodeRepository());
     }
 
@@ -117,39 +118,68 @@ class AutoscalingTester {
      * (I.e we adjust to measure a bit lower load than "naively" wanted to offset for the autoscaler
      * wanting to see the ideal load with one node missing.)
      *
-     * @param resource the resource we are explicitly setting the value of
      * @param otherResourcesLoad the load factor relative to ideal to use for other resources
      * @param count the number of measurements
      * @param applicationId the application we're adding measurements for all nodes of
      */
-    public void addMeasurements(Resource resource, float value, float otherResourcesLoad,
-                                int count, ApplicationId applicationId) {
+    public void addCpuMeasurements(float value, float otherResourcesLoad,
+                                   int count, ApplicationId applicationId) {
         List<Node> nodes = nodeRepository().getNodes(applicationId, Node.State.active);
         float oneExtraNodeFactor = (float)(nodes.size() - 1.0) / (nodes.size());
         for (int i = 0; i < count; i++) {
             clock().advance(Duration.ofMinutes(1));
             for (Node node : nodes) {
-                for (Resource r : Resource.values()) {
-                    float effectiveValue = (r == resource ? value : (float) r.idealAverageLoad() * otherResourcesLoad)
-                                           * oneExtraNodeFactor;
-                    db.add(List.of(new NodeMetrics.MetricValue(node.hostname(),
-                                                               Metric.from(r).fullName(),
-                                                               clock().instant().toEpochMilli(),
-                                                               effectiveValue * 100))); // the metrics are in %
-                }
+                float cpu = value * oneExtraNodeFactor;
+                float memory  = (float) Resource.memory.idealAverageLoad() * otherResourcesLoad * oneExtraNodeFactor;
+                float disk = (float) Resource.disk.idealAverageLoad() * otherResourcesLoad * oneExtraNodeFactor;
+                db.add(List.of(new Pair<>(node.hostname(), new MetricSnapshot(clock().instant(),
+                                                                              cpu,
+                                                                              memory,
+                                                                              disk,
+                                                                              0))));
             }
         }
     }
 
-    public void addMeasurements(Resource resource, float value, int count, ApplicationId applicationId) {
+    /**
+     * Adds measurements with the given resource value and ideal values for the other resources,
+     * scaled to take one node redundancy into account.
+     * (I.e we adjust to measure a bit lower load than "naively" wanted to offset for the autoscaler
+     * wanting to see the ideal load with one node missing.)
+     *
+     * @param otherResourcesLoad the load factor relative to ideal to use for other resources
+     * @param count the number of measurements
+     * @param applicationId the application we're adding measurements for all nodes of
+     */
+    public void addMemMeasurements(float value, float otherResourcesLoad,
+                                   int count, ApplicationId applicationId) {
+        List<Node> nodes = nodeRepository().getNodes(applicationId, Node.State.active);
+        float oneExtraNodeFactor = (float)(nodes.size() - 1.0) / (nodes.size());
+        for (int i = 0; i < count; i++) {
+            clock().advance(Duration.ofMinutes(1));
+            for (Node node : nodes) {
+                float cpu  = (float) Resource.cpu.idealAverageLoad() * otherResourcesLoad * oneExtraNodeFactor;
+                float memory = value * oneExtraNodeFactor;
+                float disk = (float) Resource.disk.idealAverageLoad() * otherResourcesLoad * oneExtraNodeFactor;
+                db.add(List.of(new Pair<>(node.hostname(), new MetricSnapshot(clock().instant(),
+                                                                              cpu,
+                                                                              memory,
+                                                                              disk,
+                                                                              0))));
+            }
+        }
+    }
+
+    public void addMeasurements(float cpu, float memory, float disk, int generation, int count, ApplicationId applicationId) {
         List<Node> nodes = nodeRepository().getNodes(applicationId, Node.State.active);
         for (int i = 0; i < count; i++) {
             clock().advance(Duration.ofMinutes(1));
             for (Node node : nodes) {
-                db.add(List.of(new NodeMetrics.MetricValue(node.hostname(),
-                                                           Metric.from(resource).fullName(),
-                                                           clock().instant().toEpochMilli(),
-                                                           value * 100))); // the metrics are in %
+                db.add(List.of(new Pair<>(node.hostname(), new MetricSnapshot(clock().instant(),
+                                                                              cpu,
+                                                                              memory,
+                                                                              disk,
+                                                                              generation))));
             }
         }
     }
@@ -199,7 +229,7 @@ class AutoscalingTester {
         return provisioningTester.nodeRepository();
     }
 
-    public NodeMetricsDb nodeMetricsDb() { return db; }
+    public MetricsDb nodeMetricsDb() { return db; }
 
     private static class MockHostResourcesCalculator implements HostResourcesCalculator {
 
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetricsDbTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsFetcherDbTest.java
index c6809fd8369..bc5303e14b8 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetricsDbTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsFetcherDbTest.java
@@ -1,6 +1,7 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.autoscale;
 
+import com.yahoo.collections.Pair;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
@@ -12,14 +13,16 @@ import org.junit.Test;
 
 import java.time.Duration;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
+import java.util.Set;
 
 import static org.junit.Assert.assertEquals;
 
 /**
  * @author bratseth
  */
-public class NodeMetricsDbTest {
+public class MetricsFetcherDbTest {
 
     @Test
     public void testNodeMetricsDb() {
@@ -34,25 +37,23 @@ public class NodeMetricsDbTest {
         String node0 = hosts.iterator().next().hostname();
 
         ManualClock clock = tester.clock();
-        NodeMetricsDb db = new NodeMetricsDb(tester.nodeRepository());
-        List<NodeMetrics.MetricValue> values = new ArrayList<>();
+        MetricsDb db = MetricsDb.createTestInstance(tester.nodeRepository());
+        Collection<Pair<String, MetricSnapshot>> values = new ArrayList<>();
         for (int i = 0; i < 40; i++) {
-            values.add(new NodeMetrics.MetricValue(node0, "cpu.util", clock.instant().getEpochSecond(), 0.9f));
-            clock.advance(Duration.ofMinutes(10));
+            values.add(new Pair<>(node0, new MetricSnapshot(clock.instant(), 0.9f, 0.6f, 0.6f, 0)));
+            clock.advance(Duration.ofMinutes(120));
         }
         db.add(values);
 
         // Avoid off-by-one bug when the below windows starts exactly on one of the above getEpochSecond() timestamps.
         clock.advance(Duration.ofMinutes(1));
 
-        assertEquals(35, measurementCount(db.getMeasurements(clock.instant().minus(Duration.ofHours(6)), Metric.cpu, List.of(node0))));
-        assertEquals( 0, measurementCount(db.getMeasurements(clock.instant().minus(Duration.ofHours(6)), Metric.memory, List.of(node0))));
-        db.gc(clock);
-        assertEquals( 5, measurementCount(db.getMeasurements(clock.instant().minus(Duration.ofHours(6)), Metric.cpu, List.of(node0))));
-        assertEquals( 0, measurementCount(db.getMeasurements(clock.instant().minus(Duration.ofHours(6)), Metric.memory, List.of(node0))));
+        assertEquals(35, measurementCount(db.getNodeTimeseries(clock.instant().minus(Duration.ofHours(72)), Set.of(node0))));
+        db.gc();
+        assertEquals( 5, measurementCount(db.getNodeTimeseries(clock.instant().minus(Duration.ofHours(72)), Set.of(node0))));
     }
 
-    private int measurementCount(List<NodeMetricsDb.NodeMeasurements> measurements) {
+    private int measurementCount(List<NodeTimeseries> measurements) {
         return measurements.stream().mapToInt(m -> m.size()).sum();
     }
 
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetricsFetcherTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsV2MetricsFetcherTest.java
index ba3ab25f082..dfa78b1fd13 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetricsFetcherTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/MetricsV2MetricsFetcherTest.java
@@ -1,6 +1,7 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.autoscale;
 
+import com.yahoo.collections.Pair;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
@@ -18,7 +19,9 @@ import java.util.List;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
-public class NodeMetricsFetcherTest {
+public class MetricsV2MetricsFetcherTest {
+
+    private static final double delta = 0.00000001;
 
     @Test
     public void testMetricsFetch() {
@@ -26,7 +29,7 @@ public class NodeMetricsFetcherTest {
         ProvisioningTester tester = new ProvisioningTester.Builder().build();
         OrchestratorMock orchestrator = new OrchestratorMock();
         MockHttpClient httpClient = new MockHttpClient();
-        NodeMetricsFetcher fetcher = new NodeMetricsFetcher(tester.nodeRepository(), orchestrator, httpClient);
+        MetricsV2MetricsFetcher fetcher = new MetricsV2MetricsFetcher(tester.nodeRepository(), orchestrator, httpClient);
 
         tester.makeReadyNodes(4, resources); // Creates (in order) host-1.yahoo.com, host-2.yahoo.com, host-3.yahoo.com, host-4.yahoo.com
         tester.activateTenantHosts();
@@ -40,26 +43,33 @@ public class NodeMetricsFetcherTest {
 
         {
             httpClient.cannedResponse = cannedResponseForApplication1;
-            List<NodeMetrics.MetricValue> values = new ArrayList<>(fetcher.fetchMetrics(application1));
+            List<Pair<String, MetricSnapshot>> values = new ArrayList<>(fetcher.fetchMetrics(application1));
             assertEquals("http://host-1.yahoo.com:4080/metrics/v2/values?consumer=autoscaling",
                          httpClient.requestsReceived.get(0));
-            assertEquals(5, values.size());
-            assertEquals("metric value cpu.util: 16.2 at 1970-01-01T00:20:34Z for host-1.yahoo.com", values.get(0).toString());
-            assertEquals("metric value mem_total.util: 23.1 at 1970-01-01T00:20:34Z for host-1.yahoo.com", values.get(1).toString());
-            assertEquals("metric value disk.util: 82.0 at 1970-01-01T00:20:34Z for host-1.yahoo.com", values.get(2).toString());
-            assertEquals("metric value cpu.util: 20.0 at 1970-01-01T00:20:00Z for host-2.yahoo.com", values.get(3).toString());
-            assertEquals("metric value disk.util: 40.0 at 1970-01-01T00:20:00Z for host-2.yahoo.com", values.get(4).toString());
+            assertEquals(2, values.size());
+
+            assertEquals("host-1.yahoo.com", values.get(0).getFirst());
+            assertEquals(0.162, values.get(0).getSecond().cpu(), delta);
+            assertEquals(0.231, values.get(0).getSecond().memory(), delta);
+            assertEquals(0.820, values.get(0).getSecond().disk(), delta);
+
+            assertEquals("host-2.yahoo.com", values.get(1).getFirst());
+            assertEquals(0.2, values.get(1).getSecond().cpu(), delta);
+            assertEquals(0.0, values.get(1).getSecond().memory(), delta);
+            assertEquals(0.4, values.get(1).getSecond().disk(), delta);
         }
 
         {
             httpClient.cannedResponse = cannedResponseForApplication2;
-            List<NodeMetrics.MetricValue> values = new ArrayList<>(fetcher.fetchMetrics(application2));
+            List<Pair<String, MetricSnapshot>> values = new ArrayList<>(fetcher.fetchMetrics(application2));
             assertEquals("http://host-3.yahoo.com:4080/metrics/v2/values?consumer=autoscaling",
                          httpClient.requestsReceived.get(1));
-            assertEquals(3, values.size());
-            assertEquals("metric value cpu.util: 10.0 at 1970-01-01T00:21:40Z for host-3.yahoo.com", values.get(0).toString());
-            assertEquals("metric value mem_total.util: 15.0 at 1970-01-01T00:21:40Z for host-3.yahoo.com", values.get(1).toString());
-            assertEquals("metric value disk.util: 20.0 at 1970-01-01T00:21:40Z for host-3.yahoo.com", values.get(2).toString());
+            assertEquals(1, values.size());
+            assertEquals("host-3.yahoo.com", values.get(0).getFirst());
+            assertEquals(0.10, values.get(0).getSecond().cpu(), delta);
+            assertEquals(0.15, values.get(0).getSecond().memory(), delta);
+            assertEquals(0.20, values.get(0).getSecond().disk(), delta);
+            assertEquals(3, values.get(0).getSecond().generation(), delta);
         }
 
         {
@@ -71,11 +81,12 @@ public class NodeMetricsFetcherTest {
         }
     }
 
-    private static class MockHttpClient implements NodeMetricsFetcher.HttpClient {
+    private static class MockHttpClient implements MetricsV2MetricsFetcher.HttpClient {
 
         List<String> requestsReceived = new ArrayList<>();
 
         String cannedResponse = null;
+
         @Override
         public String get(String url) {
             requestsReceived.add(url);
@@ -143,7 +154,8 @@ public class NodeMetricsFetcherTest {
             "            \"values\": {\n" +
             "              \"cpu.util\": 10,\n" +
             "              \"mem_total.util\": 15,\n" +
-            "              \"disk.util\": 20\n" +
+            "              \"disk.util\": 20,\n" +
+            "              \"application_generation\": 3\n" +
             "            },\n" +
             "            \"dimensions\": {\n" +
             "              \"state\": \"active\"\n" +
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/QuestMetricsDbTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/QuestMetricsDbTest.java
new file mode 100644
index 00000000000..a1cc66ffa28
--- /dev/null
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/autoscale/QuestMetricsDbTest.java
@@ -0,0 +1,105 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.autoscale;
+
+import com.yahoo.collections.Pair;
+import com.yahoo.io.IOUtils;
+import com.yahoo.test.ManualClock;
+import org.junit.Test;
+
+import java.io.File;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Tests the Quest metrics db.
+ *
+ * @author bratseth
+ */
+public class QuestMetricsDbTest {
+
+    private static final double delta = 0.0000001;
+
+    @Test
+    public void testReadWrite() {
+        String dataDir = "data/QuestMetricsDbReadWrite";
+        IOUtils.recursiveDeleteDir(new File(dataDir));
+        IOUtils.createDirectory(dataDir + "/metrics");
+        ManualClock clock = new ManualClock("2020-10-01T00:00:00");
+        QuestMetricsDb db = new QuestMetricsDb(dataDir, clock);
+        Instant startTime = clock.instant();
+        clock.advance(Duration.ofSeconds(1));
+        db.add(timeseries(1000, Duration.ofSeconds(1), clock, "host1", "host2", "host3"));
+
+        clock.advance(Duration.ofSeconds(1));
+
+        // Read all of one host
+        List<NodeTimeseries> nodeTimeSeries1 = db.getNodeTimeseries(startTime, Set.of("host1"));
+        assertEquals(1, nodeTimeSeries1.size());
+        assertEquals("host1", nodeTimeSeries1.get(0).hostname());
+        assertEquals(1000, nodeTimeSeries1.get(0).size());
+        MetricSnapshot snapshot = nodeTimeSeries1.get(0).asList().get(0);
+        assertEquals(startTime.plus(Duration.ofSeconds(1)), snapshot.at());
+        assertEquals(0.1, snapshot.cpu(), delta);
+        assertEquals(0.2, snapshot.memory(), delta);
+        assertEquals(0.4, snapshot.disk(), delta);
+        assertEquals(1, snapshot.generation(), delta);
+
+        // Read all from 2 hosts
+        List<NodeTimeseries> nodeTimeSeries2 = db.getNodeTimeseries(startTime, Set.of("host2", "host3"));
+        assertEquals(2, nodeTimeSeries2.size());
+        assertEquals(Set.of("host2", "host3"), nodeTimeSeries2.stream().map(ts -> ts.hostname()).collect(Collectors.toSet()));
+        assertEquals(1000, nodeTimeSeries2.get(0).size());
+        assertEquals(1000, nodeTimeSeries2.get(1).size());
+
+        // Read a short interval from 3 hosts
+        List<NodeTimeseries> nodeTimeSeries3 = db.getNodeTimeseries(clock.instant().minus(Duration.ofSeconds(3)),
+                                                                    Set.of("host1", "host2", "host3"));
+        assertEquals(3, nodeTimeSeries3.size());
+        assertEquals(Set.of("host1", "host2", "host3"), nodeTimeSeries3.stream().map(ts -> ts.hostname()).collect(Collectors.toSet()));
+        assertEquals(2, nodeTimeSeries3.get(0).size());
+        assertEquals(2, nodeTimeSeries3.get(1).size());
+        assertEquals(2, nodeTimeSeries3.get(2).size());
+    }
+
+    @Test
+    public void testGc() {
+        String dataDir = "data/QuestMetricsDbGc";
+        IOUtils.recursiveDeleteDir(new File(dataDir));
+        IOUtils.createDirectory(dataDir + "/metrics");
+        ManualClock clock = new ManualClock("2020-10-01T00:00:00");
+        QuestMetricsDb db = new QuestMetricsDb(dataDir, clock);
+        Instant startTime = clock.instant();
+        int dayOffset = 3;
+        clock.advance(Duration.ofHours(dayOffset));
+        db.add(timeseries(24 * 10, Duration.ofHours(1), clock, "host1", "host2", "host3"));
+
+        assertEquals(24 * 10, db.getNodeTimeseries(startTime, Set.of("host1")).get(0).size());
+        db.gc();
+        assertEquals(24 * 1 + dayOffset, db.getNodeTimeseries(startTime, Set.of("host1")).get(0).size());
+        db.gc(); // no-op
+        assertEquals(24 * 1 + dayOffset, db.getNodeTimeseries(startTime, Set.of("host1")).get(0).size());
+    }
+
+    private Collection<Pair<String, MetricSnapshot>> timeseries(int countPerHost, Duration sampleRate, ManualClock clock,
+                                                                String ... hosts) {
+        Collection<Pair<String, MetricSnapshot>> timeseries = new ArrayList<>();
+        for (int i = 1; i <= countPerHost; i++) {
+            for (String host : hosts)
+                timeseries.add(new Pair<>(host, new MetricSnapshot(clock.instant(),
+                                                                   i * 0.1,
+                                                                   i * 0.2,
+                                                                   i * 0.4,
+                                                                   i % 100)));
+            clock.advance(sampleRate);
+        }
+        return timeseries;
+    }
+
+}
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainerTest.java
index 2635258956a..5e318e00288 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainerTest.java
@@ -6,12 +6,14 @@ import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
 import com.yahoo.config.provision.NodeResources;
-import com.yahoo.vespa.hosted.provision.autoscale.Metric;
+import com.yahoo.vespa.hosted.provision.applications.ScalingEvent;
 import com.yahoo.vespa.hosted.provision.testutils.MockDeployer;
 import org.junit.Test;
 
 import java.time.Duration;
 import java.time.Instant;
+import java.util.List;
+
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
@@ -55,12 +57,8 @@ public class AutoscalingMaintainerTest {
         assertTrue(tester.deployer().lastDeployTime(app1).isEmpty());
         assertTrue(tester.deployer().lastDeployTime(app2).isEmpty());
 
-        tester.addMeasurements(Metric.cpu,    0.9f, 500, app1);
-        tester.addMeasurements(Metric.memory, 0.9f, 500, app1);
-        tester.addMeasurements(Metric.disk,   0.9f, 500, app1);
-        tester.addMeasurements(Metric.cpu,    0.9f, 500, app2);
-        tester.addMeasurements(Metric.memory, 0.9f, 500, app2);
-        tester.addMeasurements(Metric.disk,   0.9f, 500, app2);
+        tester.addMeasurements(0.9f, 0.9f, 0.9f, 0, 500, app1);
+        tester.addMeasurements(0.9f, 0.9f, 0.9f, 0, 500, app2);
 
         tester.maintainer().maintain();
         assertTrue(tester.deployer().lastDeployTime(app1).isEmpty()); // since autoscaling is off
@@ -82,9 +80,7 @@ public class AutoscalingMaintainerTest {
 
         // Measure overload
         tester.clock().advance(Duration.ofSeconds(1));
-        tester.addMeasurements(Metric.cpu,    0.9f, 500, app1);
-        tester.addMeasurements(Metric.memory, 0.9f, 500, app1);
-        tester.addMeasurements(Metric.disk,   0.9f, 500, app1);
+        tester.addMeasurements(0.9f, 0.9f, 0.9f, 0, 500, app1);
 
         // Causes autoscaling
         tester.clock().advance(Duration.ofSeconds(1));
@@ -92,41 +88,36 @@ public class AutoscalingMaintainerTest {
         tester.maintainer().maintain();
         assertTrue(tester.deployer().lastDeployTime(app1).isPresent());
         assertEquals(firstMaintenanceTime.toEpochMilli(), tester.deployer().lastDeployTime(app1).get().toEpochMilli());
-        assertEquals(1, tester.nodeMetricsDb().getEvents(app1).size());
-        assertEquals(app1, tester.nodeMetricsDb().getEvents(app1).get(0).application());
-        assertEquals(0, tester.nodeMetricsDb().getEvents(app1).get(0).generation());
-        assertEquals(firstMaintenanceTime.toEpochMilli(), tester.nodeMetricsDb().getEvents(app1).get(0).time().toEpochMilli());
+        List<ScalingEvent> events = tester.nodeRepository().applications().get(app1).get().cluster(cluster1.id()).get().scalingEvents();
+        assertEquals(1, events.size());
+        assertEquals(2, events.get(0).from().nodes());
+        assertEquals(4, events.get(0).to().nodes());
+        assertEquals(1, events.get(0).generation());
+        assertEquals(firstMaintenanceTime.toEpochMilli(), events.get(0).at().toEpochMilli());
 
         // Measure overload still, since change is not applied, but metrics are discarded
         tester.clock().advance(Duration.ofSeconds(1));
-        tester.addMeasurements(Metric.cpu,    0.9f, 500, app1);
-        tester.addMeasurements(Metric.memory, 0.9f, 500, app1);
-        tester.addMeasurements(Metric.disk,   0.9f, 500, app1);
+        tester.addMeasurements(0.9f, 0.9f, 0.9f, 0, 500, app1);
         tester.clock().advance(Duration.ofSeconds(1));
         tester.maintainer().maintain();
         assertEquals(firstMaintenanceTime.toEpochMilli(), tester.deployer().lastDeployTime(app1).get().toEpochMilli());
 
-        // Measure underload, but no autoscaling since we haven't measured we're on the new config generation
+        // Measure underload, but no autoscaling since we still haven't measured we're on the new config generation
         tester.clock().advance(Duration.ofSeconds(1));
-        tester.addMeasurements(Metric.cpu,    0.1f, 500, app1);
-        tester.addMeasurements(Metric.memory, 0.1f, 500, app1);
-        tester.addMeasurements(Metric.disk,   0.1f, 500, app1);
+        tester.addMeasurements(0.1f, 0.1f, 0.1f, 0, 500, app1);
         tester.clock().advance(Duration.ofSeconds(1));
         tester.maintainer().maintain();
         assertEquals(firstMaintenanceTime.toEpochMilli(), tester.deployer().lastDeployTime(app1).get().toEpochMilli());
 
         // Add measurement of the expected generation, leading to rescaling
         tester.clock().advance(Duration.ofSeconds(1));
-        tester.addMeasurements(Metric.generation, 0, 1, app1);
-        tester.addMeasurements(Metric.cpu,    0.1f, 500, app1);
-        tester.addMeasurements(Metric.memory, 0.1f, 500, app1);
-        tester.addMeasurements(Metric.disk,   0.1f, 500, app1);
+        tester.addMeasurements(0.1f, 0.1f, 0.1f, 1, 500, app1);
         //tester.clock().advance(Duration.ofSeconds(1));
         Instant lastMaintenanceTime = tester.clock().instant();
         tester.maintainer().maintain();
         assertEquals(lastMaintenanceTime.toEpochMilli(), tester.deployer().lastDeployTime(app1).get().toEpochMilli());
-        assertEquals(2, tester.nodeMetricsDb().getEvents(app1).size());
-        assertEquals(1, tester.nodeMetricsDb().getEvents(app1).get(1).generation());
+        events = tester.nodeRepository().applications().get(app1).get().cluster(cluster1.id()).get().scalingEvents();
+        assertEquals(2, events.get(0).generation());
     }
 
     @Test
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainerTester.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainerTester.java
index 31af40b4377..6e8b75a9af5 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainerTester.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/AutoscalingMaintainerTester.java
@@ -1,13 +1,12 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.maintenance;
 
+import com.yahoo.collections.Pair;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.Capacity;
-import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
 import com.yahoo.config.provision.Environment;
 import com.yahoo.config.provision.Flavor;
-import com.yahoo.config.provision.NodeResources;
 import com.yahoo.config.provision.NodeType;
 import com.yahoo.config.provision.RegionName;
 import com.yahoo.config.provision.Zone;
@@ -15,9 +14,9 @@ import com.yahoo.config.provisioning.FlavorsConfig;
 import com.yahoo.test.ManualClock;
 import com.yahoo.vespa.hosted.provision.Node;
 import com.yahoo.vespa.hosted.provision.NodeRepository;
-import com.yahoo.vespa.hosted.provision.autoscale.Metric;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetrics;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetricsDb;
+import com.yahoo.vespa.hosted.provision.autoscale.MemoryMetricsDb;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricSnapshot;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricsDb;
 import com.yahoo.vespa.hosted.provision.provisioning.FlavorConfigBuilder;
 import com.yahoo.vespa.hosted.provision.provisioning.ProvisioningTester;
 import com.yahoo.vespa.hosted.provision.testutils.MockDeployer;
@@ -35,7 +34,7 @@ import java.util.stream.Collectors;
 public class AutoscalingMaintainerTester {
 
     private final ProvisioningTester provisioningTester;
-    private final NodeMetricsDb nodeMetricsDb;
+    private final MetricsDb metricsDb;
     private final AutoscalingMaintainer maintainer;
     private final MockDeployer deployer;
 
@@ -47,9 +46,9 @@ public class AutoscalingMaintainerTester {
         Map<ApplicationId, MockDeployer.ApplicationContext> apps = Arrays.stream(appContexts)
                                                                          .collect(Collectors.toMap(c -> c.id(), c -> c));
         deployer = new MockDeployer(provisioningTester.provisioner(), provisioningTester.clock(), apps);
-        nodeMetricsDb = new NodeMetricsDb(provisioningTester.nodeRepository());
+        metricsDb = MetricsDb.createTestInstance(provisioningTester.nodeRepository());
         maintainer = new AutoscalingMaintainer(provisioningTester.nodeRepository(),
-                                               nodeMetricsDb,
+                                               metricsDb,
                                                deployer,
                                                new TestMetric(),
                                                Duration.ofMinutes(1));
@@ -61,7 +60,7 @@ public class AutoscalingMaintainerTester {
     public ManualClock clock() { return provisioningTester.clock(); }
     public MockDeployer deployer() { return deployer; }
     public AutoscalingMaintainer maintainer() { return maintainer; }
-    public NodeMetricsDb nodeMetricsDb() { return nodeMetricsDb; }
+    public MetricsDb nodeMetricsDb() { return metricsDb; }
 
     public static ApplicationId makeApplicationId(String name) { return ProvisioningTester.makeApplicationId(name); }
     public static ClusterSpec containerClusterSpec() { return ProvisioningTester.containerClusterSpec(); }
@@ -70,14 +69,15 @@ public class AutoscalingMaintainerTester {
         return provisioningTester.deploy(application, cluster, capacity);
     }
 
-    public void addMeasurements(Metric metric, float value, int count, ApplicationId applicationId) {
+    public void addMeasurements(float cpu, float mem, float disk, int generation, int count, ApplicationId applicationId) {
         List<Node> nodes = nodeRepository().getNodes(applicationId, Node.State.active);
         for (int i = 0; i < count; i++) {
             for (Node node : nodes)
-                nodeMetricsDb.add(List.of(new NodeMetrics.MetricValue(node.hostname(),
-                                                           metric.fullName(),
-                                                           clock().instant().getEpochSecond(),
-                                                           value * 100))); // the metrics are in %
+                metricsDb.add(List.of(new Pair<>(node.hostname(), new MetricSnapshot(clock().instant(),
+                                                                                     cpu,
+                                                                                     mem,
+                                                                                     disk,
+                                                                                     generation))));
         }
     }
 
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/FailedExpirerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/FailedExpirerTest.java
index 58a8edb4631..ceedb41ab31 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/FailedExpirerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/FailedExpirerTest.java
@@ -1,8 +1,10 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.maintenance;
 
+import com.yahoo.config.provision.ActivationContext;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.ApplicationName;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
@@ -330,7 +332,7 @@ public class FailedExpirerTest {
                                                                (level, message) -> System.out.println(level + ": " + message) );
             try (var lock = provisioner.lock(applicationId)) {
                 NestedTransaction transaction = new NestedTransaction().add(new CuratorTransaction(curator));
-                provisioner.activate(transaction, Set.copyOf(preparedNodes), lock);
+                provisioner.activate(Set.copyOf(preparedNodes), new ActivationContext(0), new ApplicationTransaction(lock, transaction));
                 transaction.commit();
             }
             return this;
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/NodeFailTester.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/NodeFailTester.java
index 5117a7b7397..824ebe40ea8 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/NodeFailTester.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/NodeFailTester.java
@@ -1,7 +1,9 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.maintenance;
 
+import com.yahoo.config.provision.ActivationContext;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
@@ -250,7 +252,7 @@ public class NodeFailTester {
         List<HostSpec> hosts = provisioner.prepare(applicationId, cluster, capacity, null);
         try (var lock = provisioner.lock(applicationId)) {
             NestedTransaction transaction = new NestedTransaction().add(new CuratorTransaction(curator));
-            provisioner.activate(transaction, hosts, lock);
+            provisioner.activate(hosts, new ActivationContext(0), new ApplicationTransaction(lock, transaction));
             transaction.commit();
         }
     }
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/RebalancerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/RebalancerTest.java
index 35c8a9a9251..21003324696 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/RebalancerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/RebalancerTest.java
@@ -2,6 +2,7 @@
 package com.yahoo.vespa.hosted.provision.maintenance;
 
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
@@ -82,7 +83,8 @@ public class RebalancerTest {
 
         // --- Making the system stable enables rebalancing
         NestedTransaction tx = new NestedTransaction();
-        tester.nodeRepository().deactivate(List.of(cpuSkewedNode), tx, new ProvisionLock(cpuApp, () -> {}));
+        tester.nodeRepository().deactivate(List.of(cpuSkewedNode),
+                                           new ApplicationTransaction(new ProvisionLock(cpuApp, () -> {}), tx));
         tx.commit();
 
         //     ... if activation fails when trying, we clean up the state
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/RetiredExpirerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/RetiredExpirerTest.java
index aba5810784b..bdae9d28fe2 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/RetiredExpirerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/RetiredExpirerTest.java
@@ -1,8 +1,10 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.maintenance;
 
+import com.yahoo.config.provision.ActivationContext;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.ApplicationName;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/ScalingSuggestionsMaintainerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/ScalingSuggestionsMaintainerTest.java
index 05b2d1e9ec9..9c952cc605e 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/ScalingSuggestionsMaintainerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/ScalingSuggestionsMaintainerTest.java
@@ -1,6 +1,7 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.provision.maintenance;
 
+import com.yahoo.collections.Pair;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
@@ -14,10 +15,8 @@ import com.yahoo.config.provision.Zone;
 import com.yahoo.config.provisioning.FlavorsConfig;
 import com.yahoo.vespa.hosted.provision.Node;
 import com.yahoo.vespa.hosted.provision.NodeRepository;
-import com.yahoo.vespa.hosted.provision.autoscale.Metric;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetrics;
-import com.yahoo.vespa.hosted.provision.autoscale.NodeMetricsDb;
-import com.yahoo.vespa.hosted.provision.autoscale.Resource;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricSnapshot;
+import com.yahoo.vespa.hosted.provision.autoscale.MetricsDb;
 import com.yahoo.vespa.hosted.provision.provisioning.FlavorConfigBuilder;
 import com.yahoo.vespa.hosted.provision.provisioning.ProvisioningTester;
 import org.junit.Test;
@@ -45,7 +44,7 @@ public class ScalingSuggestionsMaintainerTest {
         ApplicationId app2 = ProvisioningTester.makeApplicationId("app2");
         ClusterSpec cluster2 = ProvisioningTester.contentClusterSpec();
 
-        NodeMetricsDb nodeMetricsDb = new NodeMetricsDb(tester.nodeRepository());
+        MetricsDb metricsDb = MetricsDb.createTestInstance(tester.nodeRepository());
 
         tester.makeReadyNodes(20, "flt", NodeType.host, 8);
         tester.activateTenantHosts();
@@ -57,15 +56,11 @@ public class ScalingSuggestionsMaintainerTest {
                                                     new ClusterResources(10, 1, new NodeResources(6.5, 5, 15, 0.1)),
                                                     false, true));
 
-        addMeasurements(Resource.cpu,    0.9f, 500, app1, tester.nodeRepository(), nodeMetricsDb);
-        addMeasurements(Resource.memory, 0.9f, 500, app1, tester.nodeRepository(), nodeMetricsDb);
-        addMeasurements(Resource.disk,   0.9f, 500, app1, tester.nodeRepository(), nodeMetricsDb);
-        addMeasurements(Resource.cpu,    0.99f, 500, app2, tester.nodeRepository(), nodeMetricsDb);
-        addMeasurements(Resource.memory, 0.99f, 500, app2, tester.nodeRepository(), nodeMetricsDb);
-        addMeasurements(Resource.disk,   0.99f, 500, app2, tester.nodeRepository(), nodeMetricsDb);
+        addMeasurements(0.90f, 0.90f, 0.90f, 0, 500, app1, tester.nodeRepository(), metricsDb);
+        addMeasurements(0.99f, 0.99f, 0.99f, 0, 500, app2, tester.nodeRepository(), metricsDb);
 
         ScalingSuggestionsMaintainer maintainer = new ScalingSuggestionsMaintainer(tester.nodeRepository(),
-                                                                                   nodeMetricsDb,
+                                                                                   metricsDb,
                                                                                    Duration.ofMinutes(1),
                                                                                    new TestMetric());
         maintainer.maintain();
@@ -76,15 +71,16 @@ public class ScalingSuggestionsMaintainerTest {
                      tester.nodeRepository().applications().get(app2).get().cluster(cluster2.id()).get().suggestedResources().get().toString());
     }
 
-    public void addMeasurements(Resource resource, float value, int count, ApplicationId applicationId,
-                                NodeRepository nodeRepository, NodeMetricsDb db) {
+    public void addMeasurements(float cpu, float memory, float disk, int generation, int count, ApplicationId applicationId,
+                                NodeRepository nodeRepository, MetricsDb db) {
         List<Node> nodes = nodeRepository.getNodes(applicationId, Node.State.active);
         for (int i = 0; i < count; i++) {
             for (Node node : nodes)
-                db.add(List.of(new NodeMetrics.MetricValue(node.hostname(),
-                                                           Metric.from(resource).fullName(),
-                                                           nodeRepository.clock().instant().toEpochMilli(),
-                                                          value * 100))); // the metrics are in %
+                db.add(List.of(new Pair<>(node.hostname(), new MetricSnapshot(nodeRepository.clock().instant(),
+                                                                              cpu,
+                                                                              memory,
+                                                                              disk,
+                                                                              generation))));
         }
     }
 
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/SwitchRebalancerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/SwitchRebalancerTest.java
index 8675b55a27a..3662aee474d 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/SwitchRebalancerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/SwitchRebalancerTest.java
@@ -2,6 +2,7 @@
 package com.yahoo.vespa.hosted.provision.maintenance;
 
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
@@ -84,7 +85,7 @@ public class SwitchRebalancerTest {
             // Retired node becomes inactive and makes zone stable
             try (var lock = tester.provisioner().lock(app)) {
                 NestedTransaction removeTransaction = new NestedTransaction();
-                tester.nodeRepository().deactivate(clusterNodes.retired().asList(), removeTransaction, lock);
+                tester.nodeRepository().deactivate(clusterNodes.retired().asList(), new ApplicationTransaction(lock, removeTransaction));
                 removeTransaction.commit();
             }
         }
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/ApplicationSerializerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/ApplicationSerializerTest.java
index 598831d1eeb..72f9e9597de 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/ApplicationSerializerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/ApplicationSerializerTest.java
@@ -7,8 +7,10 @@ import com.yahoo.config.provision.ClusterSpec;
 import com.yahoo.config.provision.NodeResources;
 import com.yahoo.vespa.hosted.provision.applications.Application;
 import com.yahoo.vespa.hosted.provision.applications.Cluster;
+import com.yahoo.vespa.hosted.provision.applications.ScalingEvent;
 import org.junit.Test;
 
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
@@ -30,13 +32,19 @@ public class ApplicationSerializerTest {
                                  new ClusterResources( 8, 4, new NodeResources(1, 2,  3,  4)),
                                  new ClusterResources(12, 6, new NodeResources(3, 6, 21, 24)),
                                  Optional.empty(),
-                                 Optional.empty()));
+                                 Optional.empty(),
+                                 List.of()));
+        var minResources = new NodeResources(1, 2, 3, 4);
         clusters.add(new Cluster(ClusterSpec.Id.from("c2"),
                                  true,
-                                 new ClusterResources( 8, 4, new NodeResources(1, 2, 3, 4)),
+                                 new ClusterResources( 8, 4, minResources),
                                  new ClusterResources(14, 7, new NodeResources(3, 6, 21, 24)),
                                  Optional.of(new ClusterResources(20, 10, new NodeResources(0.5, 4, 14, 16))),
-                                 Optional.of(new ClusterResources(10, 5, new NodeResources(2, 4, 14, 16)))));
+                                 Optional.of(new ClusterResources(10, 5, new NodeResources(2, 4, 14, 16))),
+                                 List.of(new ScalingEvent(new ClusterResources(10, 5, minResources),
+                                                          new ClusterResources(12, 6, minResources),
+                                                          7L,
+                                                          Instant.ofEpochMilli(12345L)))));
         Application original = new Application(ApplicationId.from("myTenant", "myApplication", "myInstance"),
                                                clusters);
 
@@ -56,6 +64,7 @@ public class ApplicationSerializerTest {
             assertEquals(originalCluster.maxResources(), serializedCluster.maxResources());
             assertEquals(originalCluster.suggestedResources(), serializedCluster.suggestedResources());
             assertEquals(originalCluster.targetResources(), serializedCluster.targetResources());
+            assertEquals(originalCluster.scalingEvents(), serializedCluster.scalingEvents());
         }
     }
 
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/InfraDeployerImplTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/InfraDeployerImplTest.java
index 4fae7cf0ab9..fb732c641b8 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/InfraDeployerImplTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/InfraDeployerImplTest.java
@@ -2,6 +2,7 @@
 package com.yahoo.vespa.hosted.provision.provisioning;
 
 import com.yahoo.component.Version;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.ClusterMembership;
 import com.yahoo.config.provision.ClusterSpec;
 import com.yahoo.config.provision.HostName;
@@ -50,7 +51,6 @@ import static org.mockito.Mockito.when;
 @RunWith(Parameterized.class)
 public class InfraDeployerImplTest {
 
-
     @Parameterized.Parameters(name = "application={0}")
     public static Iterable<Object[]> parameters() {
         return List.of(
@@ -136,15 +136,15 @@ public class InfraDeployerImplTest {
     private void verifyActivated(String... hostnames) {
         verify(duperModelInfraApi).infraApplicationActivated(
                 eq(application.getApplicationId()), eq(Stream.of(hostnames).map(HostName::from).collect(Collectors.toList())));
-        ArgumentMatcher<ProvisionLock> lockMatcher = lock -> {
-            assertEquals(application.getApplicationId(), lock.application());
+        ArgumentMatcher<ApplicationTransaction> transactionMatcher = t -> {
+            assertEquals(application.getApplicationId(), t.application());
             return true;
         };
         ArgumentMatcher<Collection<HostSpec>> hostsMatcher = hostSpecs -> {
             assertEquals(Set.of(hostnames), hostSpecs.stream().map(HostSpec::hostname).collect(Collectors.toSet()));
             return true;
         };
-        verify(provisioner).activate(any(), argThat(hostsMatcher), argThat(lockMatcher));
+        verify(provisioner).activate(argThat(hostsMatcher), any(), argThat(transactionMatcher));
     }
 
     private Node addNode(int id, Node.State state, Optional<Version> wantedVespaVersion) {
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/ProvisioningTester.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/ProvisioningTester.java
index 74f49ffa419..8d972cc8f40 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/ProvisioningTester.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/ProvisioningTester.java
@@ -2,8 +2,10 @@
 package com.yahoo.vespa.hosted.provision.provisioning;
 
 import com.yahoo.component.Version;
+import com.yahoo.config.provision.ActivationContext;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.ApplicationName;
+import com.yahoo.config.provision.ApplicationTransaction;
 import com.yahoo.config.provision.Capacity;
 import com.yahoo.config.provision.ClusterResources;
 import com.yahoo.config.provision.ClusterSpec;
@@ -209,7 +211,7 @@ public class ProvisioningTester {
         try (var lock = provisioner.lock(application)) {
             NestedTransaction transaction = new NestedTransaction();
             transaction.add(new CuratorTransaction(curator));
-            provisioner.activate(transaction, hosts, lock);
+            provisioner.activate(hosts, new ActivationContext(0), new ApplicationTransaction(lock, transaction));
             transaction.commit();
         }
         assertEquals(toHostNames(hosts), toHostNames(nodeRepository.getNodes(application, Node.State.active)));
@@ -239,7 +241,8 @@ public class ProvisioningTester {
     public void deactivate(ApplicationId applicationId) {
         try (var lock = nodeRepository.lock(applicationId)) {
             NestedTransaction deactivateTransaction = new NestedTransaction();
-            nodeRepository.deactivate(deactivateTransaction, new ProvisionLock(applicationId, lock));
+            nodeRepository.deactivate(new ApplicationTransaction(new ProvisionLock(applicationId, lock),
+                                                                 deactivateTransaction));
             deactivateTransaction.commit();
         }
     }