Save memory on numeric sig terms when not top

docs/reference/search/profile.asciidoc

@@ -782,7 +782,7 @@ This yields the following aggregation profile output:
       {
         "aggregations" : [
           {
-            "type" : "LongTermsAggregator",
+            "type" : "NumericTermsAggregator",
             "description" : "my_scoped_agg",
             "time_in_nanos" : 195386,
             "breakdown" : {
@@ -796,6 +796,7 @@ This yields the following aggregation profile output:
               "collect_count" : 4
             },
             "debug": {
+              "result_strategy": "long_terms",
               "total_buckets": 4
             }
           },
@@ -815,7 +816,7 @@ This yields the following aggregation profile output:
             },
             "children" : [
               {
-                "type" : "LongTermsAggregator",
+                "type" : "NumericTermsAggregator",
                 "description" : "my_level_agg",
                 "time_in_nanos" : 160329,
                 "breakdown" : {
@@ -829,6 +830,7 @@ This yields the following aggregation profile output:
                   "collect_count" : 4,
                 },
                 "debug": {
+                  "result_strategy": "long_terms",
                   "total_buckets": 4
                 }
               }
@@ -845,10 +847,10 @@ This yields the following aggregation profile output:
 // TESTRESPONSE[s/"id": "\[P6-vulHtQRWuD4YnubWb7A\]\[test\]\[0\]"/"id": $body.profile.shards.0.id/]
 
 From the profile structure we can see that the `my_scoped_agg` is internally 
-being run as a `LongTermsAggregator` (because the field it is aggregating, 
+being run as a `NumericTermsAggregator` (because the field it is aggregating, 
 `likes`, is a numeric field). At the same level, we see a `GlobalAggregator` 
 which comes from `my_global_agg`. That aggregation then has a child 
-`LongTermsAggregator` which comes from the second term's aggregation on `likes`.
+`NumericTermsAggregator` which comes from the second term's aggregation on `likes`.
 
 The `time_in_nanos` field shows the time executed by each aggregation, and is 
 inclusive of all children.  While the overall time is useful, the `breakdown` 

rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/20_terms.yml

@@ -726,8 +726,8 @@ setup:
 ---
 "profiler":
   - skip:
-      version: " - 7.8.99"
-      reason: debug information added in 7.9.0
+      version: " - 7.99.99"
+      reason: debug information added in 7.9.0 (change backporting to 7.9.0)
   - do:
       bulk:
         index: test_1
@@ -782,7 +782,8 @@ setup:
                 field: number
   - match: { aggregations.n_terms.buckets.0.key: 1 }
   - match: { aggregations.n_terms.buckets.1.key: 3 }
-  - match: { profile.shards.0.aggregations.0.type: LongTermsAggregator }
+  - match: { profile.shards.0.aggregations.0.type: NumericTermsAggregator }
   - match: { profile.shards.0.aggregations.0.description: n_terms }
   - match: { profile.shards.0.aggregations.0.breakdown.collect_count: 4 }
+  - match: { profile.shards.0.aggregations.0.debug.result_strategy: long_terms }
   - match: { profile.shards.0.aggregations.0.debug.total_buckets: 2 }

server/src/internalClusterTest/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java

@@ -195,7 +195,7 @@ public void testXContentResponse() throws Exception {
 
     }
 
-    public void testDeletesIssue7951() throws Exception {
+    public void testPopularTermManyDeletedDocs() throws Exception {
         String settings = "{\"index.number_of_shards\": 1, \"index.number_of_replicas\": 0}";
         assertAcked(prepareCreate(INDEX_NAME).setSettings(settings, XContentType.JSON)
                 .setMapping("text", "type=keyword", CLASS_FIELD, "type=keyword"));
@@ -237,7 +237,7 @@ public void testDeletesIssue7951() throws Exception {
                                 significantTerms("sig_terms")
                                         .field(TEXT_FIELD)
                                         .minDocCount(1)));
-        }else
+        } else
         {
             request = client().prepareSearch(INDEX_NAME)
                     .addAggregation(
@@ -477,8 +477,7 @@ public void testScriptScore() throws ExecutionException, InterruptedException, I
                             .subAggregation(significantText("mySignificantTerms", TEXT_FIELD)
                             .significanceHeuristic(scriptHeuristic)
                             .minDocCount(1).shardSize(2).size(2)));
-        }else
-        {
+        } else {
             request = client().prepareSearch(INDEX_NAME)
                     .addAggregation(terms("class").field(CLASS_FIELD)
                             .subAggregation(significantTerms("mySignificantTerms")

server/src/main/java/org/elasticsearch/search/aggregations/bucket/terms/DoubleTerms.java

@@ -39,7 +39,7 @@ public class DoubleTerms extends InternalMappedTerms<DoubleTerms, DoubleTerms.Bu
     public static final String NAME = "dterms";
 
     static class Bucket extends InternalTerms.Bucket<Bucket> {
-        private final double term;
+        double term;
 
         Bucket(double term, long docCount, InternalAggregations aggregations, boolean showDocCountError, long docCountError,
                 DocValueFormat format) {