Build empty extended stats aggregation if no docs are collected for bucket #16812

core/src/main/java/org/elasticsearch/search/aggregations/metrics/stats/extended/ExtendedStatsAggregator.java

@@ -167,14 +167,12 @@ public class ExtendedStatsAggregator extends NumericMetricsAggregator.MultiValue
     }
 
     @Override
-    public InternalAggregation buildAggregation(long owningBucketOrdinal) {
-        if (valuesSource == null) {
-            return new InternalExtendedStats(name, 0, 0d, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY, 0d, 0d, formatter,
-                    pipelineAggregators(), metaData());
+    public InternalAggregation buildAggregation(long bucket) {
+        if (valuesSource == null || bucket >= counts.size()) {
+            return buildEmptyAggregation();
         }
-        assert owningBucketOrdinal < counts.size();
-        return new InternalExtendedStats(name, counts.get(owningBucketOrdinal), sums.get(owningBucketOrdinal),
-                mins.get(owningBucketOrdinal), maxes.get(owningBucketOrdinal), sumOfSqrs.get(owningBucketOrdinal), sigma, formatter,
+        return new InternalExtendedStats(name, counts.get(bucket), sums.get(bucket),
+                mins.get(bucket), maxes.get(bucket), sumOfSqrs.get(bucket), sigma, formatter,
                 pipelineAggregators(), metaData());
     }
 

modules/lang-groovy/src/test/java/org/elasticsearch/messy/tests/ExtendedStatsTests.java

@@ -26,6 +26,8 @@ import org.elasticsearch.script.ScriptService.ScriptType;
 import org.elasticsearch.script.groovy.GroovyPlugin;
 import org.elasticsearch.search.aggregations.bucket.global.Global;
 import org.elasticsearch.search.aggregations.bucket.histogram.Histogram;
+import org.elasticsearch.search.aggregations.bucket.missing.Missing;
+import org.elasticsearch.search.aggregations.bucket.terms.Terms;
 import org.elasticsearch.search.aggregations.metrics.AbstractNumericTestCase;
 import org.elasticsearch.search.aggregations.metrics.stats.extended.ExtendedStats;
 
@@ -38,6 +40,8 @@ import static org.elasticsearch.index.query.QueryBuilders.matchAllQuery;
 import static org.elasticsearch.search.aggregations.AggregationBuilders.extendedStats;
 import static org.elasticsearch.search.aggregations.AggregationBuilders.global;
 import static org.elasticsearch.search.aggregations.AggregationBuilders.histogram;
+import static org.elasticsearch.search.aggregations.AggregationBuilders.missing;
+import static org.elasticsearch.search.aggregations.AggregationBuilders.terms;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertHitCount;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
@@ -498,6 +502,42 @@ public class ExtendedStatsTests extends AbstractNumericTestCase {
         checkUpperLowerBounds(stats, sigma);
     }
 
+    public void testEmptySubAggregation() {
+        SearchResponse searchResponse = client().prepareSearch("idx")
+            .setQuery(matchAllQuery())
+            .addAggregation(terms("value").field("value")
+                .subAggregation(missing("values").field("values")
+                    .subAggregation(extendedStats("stats").field("value"))))
+            .execute().actionGet();
+
+        assertHitCount(searchResponse, 10);
+
+        Terms terms = searchResponse.getAggregations().get("value");
+        assertThat(terms, notNullValue());
+        assertThat(terms.getBuckets().size(), equalTo(10));
+
+        for (Terms.Bucket bucket : terms.getBuckets()) {
+            assertThat(bucket.getDocCount(), equalTo(1L));
+
+            Missing missing = bucket.getAggregations().get("values");
+            assertThat(missing, notNullValue());
+            assertThat(missing.getDocCount(), equalTo(0L));
+
+            ExtendedStats stats = missing.getAggregations().get("stats");
+            assertThat(stats, notNullValue());
+            assertThat(stats.getName(), equalTo("stats"));
+            assertThat(stats.getSumOfSquares(), equalTo(0.0));
+            assertThat(stats.getCount(), equalTo(0L));
+            assertThat(stats.getSum(), equalTo(0.0));
+            assertThat(stats.getMin(), equalTo(Double.POSITIVE_INFINITY));
+            assertThat(stats.getMax(), equalTo(Double.NEGATIVE_INFINITY));
+            assertThat(Double.isNaN(stats.getStdDeviation()), is(true));
+            assertThat(Double.isNaN(stats.getAvg()), is(true));
+            assertThat(Double.isNaN(stats.getStdDeviationBound(ExtendedStats.Bounds.UPPER)), is(true));
+            assertThat(Double.isNaN(stats.getStdDeviationBound(ExtendedStats.Bounds.LOWER)), is(true));
+        }
+    }
+
 
     private void assertShardExecutionState(SearchResponse response, int expectedFailures) throws Exception {
         ShardSearchFailure[] failures = response.getShardFailures();
@@ -515,4 +555,4 @@ public class ExtendedStatsTests extends AbstractNumericTestCase {
         assertThat(stats.getStdDeviationBound(ExtendedStats.Bounds.LOWER), equalTo(stats.getAvg() - (stats.getStdDeviation() * sigma)));
     }
 
-}
+}