Make NodeTimeseries immutable

3 files changed, 20 insertions, 22 deletions

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
index 49dea25f8a8..52f6a5bbabc 100644
--- 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
@@ -93,7 +93,7 @@ public class ClusterTimeseries {
     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.copyAfter(startTimePerHost.get(m.hostname()))).collect(Collectors.toList());
+        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/NodeMetricsDb.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/NodeMetricsDb.java
index c4aacb63de6..271f8601ae2 100644
--- 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
@@ -10,10 +10,10 @@ import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.stream.Collectors;
 
 /**
  * An in-memory time-series "database" of node metrics.
@@ -55,7 +55,7 @@ public class NodeMetricsDb {
                                               new ArrayList<>());
             db.put(hostname, timeseries);
         }
-        timeseries.add(snapshot);
+        db.put(hostname, timeseries.add(snapshot));
     }
 
     /** Must be called intermittently (as long as any add methods are called) to gc old data */
@@ -63,11 +63,13 @@ public class NodeMetricsDb {
         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<NodeTimeseries> i = db.values().iterator(); i.hasNext(); ) {
-                var snapshot = i.next();
-                snapshot.removeOlderThan(clock.instant().minus(Autoscaler.scalingWindow(snapshot.type())).toEpochMilli());
-                if (snapshot.isEmpty())
-                    i.remove();
+            for (String hostname : db.keySet()) {
+                var timeseries = db.get(hostname);
+                timeseries = timeseries.justAfter(clock.instant().minus(Autoscaler.scalingWindow(timeseries.type())));
+                if (timeseries.isEmpty())
+                    db.remove(hostname);
+                else
+                    db.put(hostname, timeseries);
             }
         }
     }
@@ -82,7 +84,7 @@ public class NodeMetricsDb {
             for (String hostname : hostnames) {
                 NodeTimeseries measurements = db.get(hostname);
                 if (measurements == null) continue;
-                measurements = measurements.copyAfter(startTime);
+                measurements = measurements.justAfter(startTime);
                 if (measurements.isEmpty()) continue;
                 measurementsList.add(measurements);
             }
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
index e6f786f55aa..778a2110d2c 100644
--- 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
@@ -4,6 +4,7 @@ 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;
@@ -26,8 +27,6 @@ public class NodeTimeseries {
         this.snapshots = snapshots;
     }
 
-    // Public access
-
     public boolean isEmpty() { return snapshots.isEmpty(); }
 
     public int size() { return snapshots.size(); }
@@ -40,20 +39,17 @@ public class NodeTimeseries {
 
     public String hostname() { return hostname; }
 
-    public NodeTimeseries copyAfter(Instant oldestTime) {
+    public NodeTimeseries add(MetricSnapshot snapshot) {
+        List<MetricSnapshot> list = new ArrayList<>(snapshots);
+        list.add(snapshot);
+        return new NodeTimeseries(hostname(), type(), list);
+    }
+
+    public NodeTimeseries justAfter(Instant oldestTime) {
         return new NodeTimeseries(hostname, type,
                                   snapshots.stream()
-                                           .filter(measurement -> measurement.at().equals(oldestTime) || measurement.at().isAfter(oldestTime))
+                                           .filter(snapshot -> snapshot.at().equals(oldestTime) || snapshot.at().isAfter(oldestTime))
                                            .collect(Collectors.toList()));
     }
 
-    // Restricted mutation
-
-    void add(MetricSnapshot snapshot) { snapshots.add(snapshot); }
-
-    void removeOlderThan(long oldestTimestamp) {
-        while (!snapshots.isEmpty() && snapshots.get(0).at().toEpochMilli() < oldestTimestamp)
-            snapshots.remove(0);
-    }
-
 }