fix: bug when allAll bucket (apache#13467)

(cherry picked from commit 1235162)

managed-ledger/src/main/java/org/apache/bookkeeper/mledger/util/StatsBuckets.java

@@ -110,7 +110,7 @@ public void addAll(StatsBuckets other) {
             buckets[i].add(other.values[i]);
         }
 
-        sumCounter.add(other.count);
+        sumCounter.add(other.sum);
     }
 
     private boolean isSorted(long[] array) {

managed-ledger/src/test/java/org/apache/bookkeeper/mledger/util/TestStatsBuckets.java

@@ -99,4 +99,17 @@ public void test() {
         assertEquals(stats.getCount(), 3);
         assertEquals(stats.getBuckets(), new long[] { 1, 0, 1, 1 });
     }
+
+    @Test
+    public void testAddAll() {
+        StatsBuckets stats = new StatsBuckets(10, 20, 30);
+        stats.addValue(1);
+        stats.addValue(2);
+        stats.refresh();
+        StatsBuckets stats2 = new StatsBuckets(10, 20, 30);
+        stats2.addAll(stats);
+        stats2.refresh();
+        assertEquals(stats2.getSum(),3);
+        assertEquals(stats2.getCount(),2);
+    }
 }

pulsar-websocket/src/main/java/org/apache/pulsar/websocket/stats/StatsBuckets.java

@@ -61,7 +61,7 @@ public void addAll(StatsBuckets other) {
         for (int i = 0; i < buckets.length; i++) {
             buckets[i].add(other.values[i]);
         }
-        sumCounter.add(other.count);
+        sumCounter.add(other.sum);
     }