Speed up terms agg when alone

rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/370_doc_count_field.yml

@@ -177,4 +177,4 @@ setup:
   - match: { aggregations.f.buckets.foo.doc_count: 8 }
   - match: { aggregations.f.buckets.xyz.doc_count: 5 }
   - match: { profile.shards.0.aggregations.0.type: FiltersAggregator.FilterByFilter }
-  - gte: { profile.shards.0.aggregations.0.debug.segments_with_doc_count: 1 }
+  - gte: { profile.shards.0.aggregations.0.debug.segments_with_doc_count_field: 1 }

server/src/internalClusterTest/java/org/elasticsearch/search/profile/aggregation/AggregationProfilerIT.java

@@ -41,6 +41,7 @@
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 import static org.hamcrest.Matchers.hasEntry;
+import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.notNullValue;
 
 @ESIntegTestCase.SuiteScopeTestCase
@@ -633,10 +634,15 @@ public void testFilterByFilter() throws InterruptedException, IOException {
             assertThat(delegate.get("delegate"), equalTo("FiltersAggregator.FilterByFilter"));
             Map<?, ?> delegateDebug = (Map<?, ?>) delegate.get("delegate_debug");
             assertThat(delegateDebug, hasEntry("segments_with_deleted_docs", 0));
-            assertThat(delegateDebug, hasEntry("segments_with_doc_count", 0));
+            assertThat(delegateDebug, hasEntry("segments_with_doc_count_field", 0));
             assertThat(delegateDebug, hasEntry("max_cost", (long) RangeAggregator.DOCS_PER_RANGE_TO_USE_FILTERS * 2));
             assertThat(delegateDebug, hasEntry("estimated_cost", (long) RangeAggregator.DOCS_PER_RANGE_TO_USE_FILTERS * 2));
             assertThat((long) delegateDebug.get("estimate_cost_time"), greaterThanOrEqualTo(0L));  // ~1,276,734 nanos is normal
+            List<?> filtersDebug = (List<?>) delegateDebug.get("filters");
+            assertThat(filtersDebug, hasSize(1));
+            Map<?, ?> queryDebug = (Map<?, ?>) filtersDebug.get(0);
+            assertThat(queryDebug, hasEntry("type", "query"));
+            assertThat(queryDebug, hasEntry("query", "ConstantScore(DocValuesFieldExistsQuery [field=date])"));
         }
     }
 }

server/src/main/java/org/elasticsearch/search/aggregations/bucket/filter/FiltersAggregatorFactory.java

@@ -8,7 +8,6 @@
 
 package org.elasticsearch.search.aggregations.bucket.filter;
 
-import org.apache.lucene.search.Query;
 import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.AggregatorFactory;
@@ -17,13 +16,13 @@
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
 public class FiltersAggregatorFactory extends AggregatorFactory {
 
-    private final String[] keys;
-    private final Query[] filters;
+    private final List<QueryToFilterAdapter<?>> filters;
     private final boolean keyed;
     private final boolean otherBucket;
     private final String otherBucketKey;
@@ -35,20 +34,17 @@ public FiltersAggregatorFactory(String name, List<KeyedFilter> filters, boolean
         this.keyed = keyed;
         this.otherBucket = otherBucket;
         this.otherBucketKey = otherBucketKey;
-        keys = new String[filters.size()];
-        this.filters = new Query[filters.size()];
-        for (int i = 0; i < filters.size(); ++i) {
-            KeyedFilter keyedFilter = filters.get(i);
-            this.keys[i] = keyedFilter.key();
-            this.filters[i] = context.buildQuery(keyedFilter.filter());
+        this.filters = new ArrayList<>(filters.size());
+        for (KeyedFilter f : filters) {
+            this.filters.add(QueryToFilterAdapter.build(context.searcher(), f.key(), context.buildQuery(f.filter())));
         }
     }
 
     @Override
     public Aggregator createInternal(Aggregator parent,
                                         CardinalityUpperBound cardinality,
                                         Map<String, Object> metadata) throws IOException {
-        return FiltersAggregator.build(name, factories, keys, filters, keyed,
+        return FiltersAggregator.build(name, factories, filters, keyed,
             otherBucket ? otherBucketKey : null, context, parent, cardinality, metadata);
     }
 }