Use long in Centroid count (#99491) (#99534)

* Use long in Centroid count

Centroids currently use integers to track how many samples their mean
tracks. This can overflow in case the digest tracks billions of samples
or more.

TDigestState already serializes the count as VLong, so it can be read as
VInt without compatibility issues.

Fixes #80153

* Update docs/changelog/99491.yaml

* More test fixes

* Bump TransportVersion

* Revert TransportVersion change

Author: kkrik-es

docs/changelog/99491.yaml

@@ -0,0 +1,6 @@
+pr: 99491
+summary: Use long in Centroid count
+area: Aggregations
+type: bug
+issues:
+ - 80153

libs/tdigest/src/main/java/org/elasticsearch/tdigest/AVLGroupTree.java

@@ -31,10 +31,10 @@
 final class AVLGroupTree extends AbstractCollection<Centroid> {
     /* For insertions into the tree */
     private double centroid;
-    private int count;
+    private long count;
     private double[] centroids;
-    private int[] counts;
-    private int[] aggregatedCounts;
+    private long[] counts;
+    private long[] aggregatedCounts;
     private final IntAVLTree tree;
 
     AVLGroupTree() {
@@ -78,8 +78,8 @@ protected void fixAggregates(int node) {
 
         };
         centroids = new double[tree.capacity()];
-        counts = new int[tree.capacity()];
-        aggregatedCounts = new int[tree.capacity()];
+        counts = new long[tree.capacity()];
+        aggregatedCounts = new long[tree.capacity()];
     }
 
     /**
@@ -113,14 +113,14 @@ public double mean(int node) {
     /**
      * Return the count for the provided node.
      */
-    public int count(int node) {
+    public long count(int node) {
         return counts[node];
     }
 
     /**
      * Add the provided centroid to the tree.
      */
-    public void add(double centroid, int count) {
+    public void add(double centroid, long count) {
         this.centroid = centroid;
         this.count = count;
         tree.add();
@@ -135,7 +135,7 @@ public boolean add(Centroid centroid) {
     /**
      * Update values associated with a node, readjusting the tree if necessary.
      */
-    public void update(int node, double centroid, int count) {
+    public void update(int node, double centroid, long count) {
         // have to do full scale update
         this.centroid = centroid;
         this.count = count;
@@ -242,7 +242,7 @@ public void remove() {
     /**
      * Return the total count of points that have been added to the tree.
      */
-    public int sum() {
+    public long sum() {
         return aggregatedCounts[tree.root()];
     }
 

libs/tdigest/src/main/java/org/elasticsearch/tdigest/AVLTreeDigest.java

@@ -68,7 +68,7 @@ public int centroidCount() {
     }
 
     @Override
-    public void add(double x, int w) {
+    public void add(double x, long w) {
         checkValue(x);
         needsCompression = true;
 
@@ -84,7 +84,7 @@ public void add(double x, int w) {
         }
 
         if (start == NIL) { // empty summary
-            assert summary.size() == 0;
+            assert summary.isEmpty();
             summary.add(x, w);
             count = w;
         } else {
@@ -127,7 +127,7 @@ public void add(double x, int w) {
                 // if the nearest point was not unique, then we may not be modifying the first copy
                 // which means that ordering can change
                 double centroid = summary.mean(closest);
-                int count = summary.count(closest);
+                long count = summary.count(closest);
                 centroid = weightedAverage(centroid, count, x, w);
                 count += w;
                 summary.update(closest, centroid, count);
@@ -189,7 +189,7 @@ public long size() {
     @Override
     public double cdf(double x) {
         AVLGroupTree values = summary;
-        if (values.size() == 0) {
+        if (values.isEmpty()) {
             return Double.NaN;
         }
         if (values.size() == 1) {
@@ -272,7 +272,7 @@ public double quantile(double q) {
         }
 
         AVLGroupTree values = summary;
-        if (values.size() == 0) {
+        if (values.isEmpty()) {
             // no centroids means no data, no way to get a quantile
             return Double.NaN;
         } else if (values.size() == 1) {
@@ -293,7 +293,7 @@ public double quantile(double q) {
         }
 
         int currentNode = values.first();
-        int currentWeight = values.count(currentNode);
+        long currentWeight = values.count(currentNode);
 
         // Total mass to the left of the center of the current node.
         double weightSoFar = currentWeight / 2.0;
@@ -305,7 +305,7 @@ public double quantile(double q) {
 
         for (int i = 0; i < values.size() - 1; i++) {
             int nextNode = values.next(currentNode);
-            int nextWeight = values.count(nextNode);
+            long nextWeight = values.count(nextNode);
             // this is the mass between current center and next center
             double dw = (currentWeight + nextWeight) / 2.0;
 

libs/tdigest/src/main/java/org/elasticsearch/tdigest/Centroid.java

@@ -30,7 +30,7 @@ public class Centroid implements Comparable<Centroid> {
     private static final AtomicInteger uniqueCount = new AtomicInteger(1);
 
     private double centroid = 0;
-    private int count = 0;
+    private long count = 0;
 
     // The ID is transient because it must be unique within a given JVM. A new
     // ID should be generated from uniqueCount when a Centroid is deserialized.
@@ -45,22 +45,22 @@ public Centroid(double x) {
         start(x, 1, uniqueCount.getAndIncrement());
     }
 
-    public Centroid(double x, int w) {
+    public Centroid(double x, long w) {
         this();
         start(x, w, uniqueCount.getAndIncrement());
     }
 
-    public Centroid(double x, int w, int id) {
+    public Centroid(double x, long w, int id) {
         this();
         start(x, w, id);
     }
 
-    private void start(double x, int w, int id) {
+    private void start(double x, long w, int id) {
         this.id = id;
         add(x, w);
     }
 
-    public void add(double x, int w) {
+    public void add(double x, long w) {
         count += w;
         centroid += w * (x - centroid) / count;
     }
@@ -69,7 +69,7 @@ public double mean() {
         return centroid;
     }
 
-    public int count() {
+    public long count() {
         return count;
     }
 

libs/tdigest/src/main/java/org/elasticsearch/tdigest/HybridDigest.java

@@ -70,7 +70,7 @@ public class HybridDigest extends AbstractTDigest {
     }
 
     @Override
-    public void add(double x, int w) {
+    public void add(double x, long w) {
         reserve(w);
         if (mergingDigest != null) {
             mergingDigest.add(x, w);

libs/tdigest/src/main/java/org/elasticsearch/tdigest/MergingDigest.java

@@ -216,7 +216,7 @@ public MergingDigest(double compression, int bufferSize, int size) {
     }
 
     @Override
-    public void add(double x, int w) {
+    public void add(double x, long w) {
         checkValue(x);
         if (tempUsed >= tempWeight.length - lastUsedCell - 1) {
             mergeNewValues();
@@ -514,7 +514,7 @@ public boolean hasNext() {
 
                     @Override
                     public Centroid next() {
-                        Centroid rc = new Centroid(mean[i], (int) weight[i]);
+                        Centroid rc = new Centroid(mean[i], (long) weight[i]);
                         i++;
                         return rc;
                     }

libs/tdigest/src/main/java/org/elasticsearch/tdigest/SortingDigest.java

@@ -39,7 +39,7 @@ public class SortingDigest extends AbstractTDigest {
     private boolean isSorted = true;
 
     @Override
-    public void add(double x, int w) {
+    public void add(double x, long w) {
         checkValue(x);
         isSorted = isSorted && (values.isEmpty() || values.get(values.size() - 1) <= x);
         for (int i = 0; i < w; i++) {

libs/tdigest/src/main/java/org/elasticsearch/tdigest/TDigest.java

@@ -94,7 +94,7 @@ public static TDigest createHybridDigest(double compression) {
      * @param x The value to add.
      * @param w The weight of this point.
      */
-    public abstract void add(double x, int w);
+    public abstract void add(double x, long w);
 
     /**
      * Add a single sample to this TDigest.

libs/tdigest/src/test/java/org/elasticsearch/tdigest/MergingDigestTests.java

@@ -118,7 +118,7 @@ public void testSingletonsAtEnds() {
                 d.add(x);
             }
         }
-        int last = 0;
+        long last = 0;
         for (Centroid centroid : d.centroids()) {
             if (last == 0) {
                 assertEquals(1, centroid.count());

server/src/main/java/org/elasticsearch/search/aggregations/metrics/EmptyTDigestState.java

@@ -15,7 +15,7 @@ public EmptyTDigestState() {
     }
 
     @Override
-    public void add(double x, int w) {
+    public void add(double x, long w) {
         throw new UnsupportedOperationException("Immutable Empty TDigest");
     }