Rewrite range queries with open bounds to exists query (#26160)

* Rewrite range queries with open bounds to exists query

This change rewrites range query with open bounds to an exists query that should be faster to execute.

Fixes #22640

Author: jimczi

core/src/main/java/org/elasticsearch/index/query/RangeQueryBuilder.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.index.query;
 
+import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermRangeQuery;
 import org.apache.lucene.util.BytesRef;
@@ -36,6 +37,7 @@
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.index.mapper.DateFieldMapper;
+import org.elasticsearch.index.mapper.FieldNamesFieldMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.RangeFieldMapper;
@@ -483,6 +485,21 @@ protected QueryBuilder doRewrite(QueryRewriteContext queryRewriteContext) throws
 
     @Override
     protected Query doToQuery(QueryShardContext context) throws IOException {
+        if (from == null && to == null) {
+            /**
+             * Open bounds on both side, we can rewrite to an exists query
+             * if the {@link FieldNamesFieldMapper} is enabled.
+             */
+            final FieldNamesFieldMapper.FieldNamesFieldType fieldNamesFieldType =
+                (FieldNamesFieldMapper.FieldNamesFieldType) context.getMapperService().fullName(FieldNamesFieldMapper.NAME);
+            if (fieldNamesFieldType == null) {
+                return new MatchNoDocsQuery("No mappings yet");
+            }
+            // Exists query would fail if the fieldNames field is disabled.
+            if (fieldNamesFieldType.isEnabled()) {
+                return ExistsQueryBuilder.newFilter(context, fieldName);
+            }
+        }
         Query query = null;
         MappedFieldType mapper = context.fieldMapper(this.fieldName);
         if (mapper != null) {

core/src/test/java/org/elasticsearch/index/query/RangeQueryBuilderTests.java

@@ -23,15 +23,20 @@
 
 import org.apache.lucene.document.IntPoint;
 import org.apache.lucene.document.LongPoint;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.search.ConstantScoreQuery;
 import org.apache.lucene.search.IndexOrDocValuesQuery;
+import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.PointRangeQuery;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TermRangeQuery;
 import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.common.ParsingException;
 import org.elasticsearch.common.geo.ShapeRelation;
 import org.elasticsearch.common.lucene.BytesRefs;
 import org.elasticsearch.index.mapper.DateFieldMapper;
+import org.elasticsearch.index.mapper.FieldNamesFieldMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.MappedFieldType.Relation;
 import org.elasticsearch.index.mapper.MapperService;
@@ -52,7 +57,6 @@
 import static org.hamcrest.Matchers.sameInstance;
 
 public class RangeQueryBuilderTests extends AbstractQueryTestCase<RangeQueryBuilder> {
-
     @Override
     protected RangeQueryBuilder doCreateTestQueryBuilder() {
         RangeQueryBuilder query;
@@ -122,7 +126,16 @@ protected Map<String, RangeQueryBuilder> getAlternateVersions() {
 
     @Override
     protected void doAssertLuceneQuery(RangeQueryBuilder queryBuilder, Query query, SearchContext context) throws IOException {
-        if (getCurrentTypes().length == 0 ||
+        if (queryBuilder.from() == null && queryBuilder.to() == null) {
+            final Query expectedQuery;
+            if (getCurrentTypes().length > 0) {
+                expectedQuery = new ConstantScoreQuery(new TermQuery(new Term(FieldNamesFieldMapper.NAME, queryBuilder.fieldName())));
+            } else {
+                expectedQuery = new MatchNoDocsQuery("no mappings yet");
+            }
+            assertThat(query, equalTo(expectedQuery));
+
+        } else if (getCurrentTypes().length == 0 ||
             (queryBuilder.fieldName().equals(DATE_FIELD_NAME) == false
                 && queryBuilder.fieldName().equals(INT_FIELD_NAME) == false
                 && queryBuilder.fieldName().equals(DATE_RANGE_FIELD_NAME) == false
@@ -425,6 +438,16 @@ protected MappedFieldType.Relation getRelation(QueryRewriteContext queryRewriteC
         assertThat(rewrittenRange.fieldName(), equalTo(fieldName));
         assertThat(rewrittenRange.from(), equalTo(null));
         assertThat(rewrittenRange.to(), equalTo(null));
+
+        // Range query with open bounds rewrite to an exists query
+        final Query luceneQuery = rewrittenRange.toQuery(queryShardContext);
+        final Query expectedQuery;
+        if (getCurrentTypes().length > 0) {
+            expectedQuery = new ConstantScoreQuery(new TermQuery(new Term(FieldNamesFieldMapper.NAME, query.fieldName())));
+        } else {
+            expectedQuery = new MatchNoDocsQuery("no mappings yet");
+        }
+        assertThat(luceneQuery, equalTo(expectedQuery));
     }
 
     public void testRewriteDateToMatchAllWithTimezoneAndFormat() throws IOException {