Updated the algorithm selection logic

Signed-off-by: Vinay Krishna Pudyodu <vinkrish.neo@gmail.com>

Author: vinaykpud

server/src/main/java/org/opensearch/search/aggregations/bucket/terms/NumericTermsAggregator.java

@@ -263,7 +263,7 @@ private InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws
 
                 // Use priority queue approach when request size is smaller than 10% of total buckets,
                 // or when key ordering is required
-                if ((size < 0.1 * bucketsInOrd) || isKeyOrder(order)) {
+                if ((size < 0.2 * bucketsInOrd) || isKeyOrder(order)) {
                     PriorityQueue<B> ordered = buildPriorityQueue(size);
                     while (ordsEnum.next()) {
                         long docCount = bucketDocCount(ordsEnum.ord());

server/src/test/java/org/opensearch/search/aggregations/bucket/terms/NumericTermsAggregatorTests.java

@@ -196,16 +196,16 @@ private void testSearchCase(
         }
     }
 
-    public void testHeapSortForSmallResultSets() throws IOException {
-        List<Long> highCardinalityDataset = new ArrayList<>();
+    public void testBuildAggregationsForHeapSort() throws IOException {
+        List<Long> dataSet = new ArrayList<>();
         for (long i = 0; i < 150; i++) {
-            highCardinalityDataset.add(i);
+            dataSet.add(i);
         }
 
         testSearchCase(
             new MatchAllDocsQuery(),
-            highCardinalityDataset,
-            aggregation -> aggregation.field(LONG_FIELD).size(2), // Small result set
+            dataSet,
+            aggregation -> aggregation.field(LONG_FIELD).size(2),
             agg -> {
                 assertEquals(2, agg.getBuckets().size());
                 for (int i = 0; i < 2; i++) {
@@ -218,13 +218,13 @@ public void testHeapSortForSmallResultSets() throws IOException {
         );
     }
 
-    public void testQuickSelectForLargeResultSets() throws IOException {
-        List<Long> highCardinalityDataset = new ArrayList<>();
+    public void testBuildAggregationsForQuickSelect() throws IOException {
+        List<Long> dataSet = new ArrayList<>();
         for (long i = 0; i < 150; i++) {
-            highCardinalityDataset.add(i);
+            dataSet.add(i);
         }
 
-        testSearchCase(new MatchAllDocsQuery(), highCardinalityDataset, aggregation -> aggregation.field(LONG_FIELD).size(50), agg -> {
+        testSearchCase(new MatchAllDocsQuery(), dataSet, aggregation -> aggregation.field(LONG_FIELD).size(50), agg -> {
             assertEquals(50, agg.getBuckets().size());
             for (int i = 0; i < agg.getBuckets().size(); i++) {
                 LongTerms.Bucket bucket = (LongTerms.Bucket) agg.getBuckets().get(i);