Add the ability to disable the retrieval of the metadata fields

core/src/main/java/org/elasticsearch/action/search/SearchRequestBuilder.java

@@ -289,6 +289,11 @@ public SearchRequestBuilder setFetchSource(@Nullable String[] includes, @Nullabl
         return this;
     }
 
+    public SearchRequestBuilder setFetchMetadata(boolean fetch) {
+        sourceBuilder().fetchMetadata(fetch);
+        return this;
+    }
+
     /**
      * Adds a docvalue based field to load and return. The field does not have to be stored,
      * but its recommended to use non analyzed or numeric fields.

core/src/main/java/org/elasticsearch/search/SearchService.java

@@ -21,7 +21,6 @@
 
 import com.carrotsearch.hppc.ObjectFloatHashMap;
 import org.apache.lucene.search.FieldDoc;
-import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.TopDocs;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.ExceptionsHelper;
@@ -813,6 +812,24 @@ private void parseSource(DefaultSearchContext context, SearchSourceBuilder sourc
             }
             context.sliceBuilder(source.slice());
         }
+
+        if (source.fetchMetadata() != null) {
+            if (source.fetchMetadata() == false) {
+                if (context.version()) {
+                    throw new SearchContextException(context,
+                        "`fetch_metadata` is required when version is requested");
+                }
+                if (context.hasFieldNames()) {
+                    throw new SearchContextException(context,
+                        "`fetch_metadata` is required when stored fields are requested");
+                }
+                if (context.sourceRequested() ||
+                    (context.hasFetchSourceContext() == false && context.hasScriptFields())) {
+                    throw new SearchContextException(context, "`fetch_metadata` cannot be false if _source is requested");
+                }
+            }
+            context.fetchMetadata(source.fetchMetadata());
+        }
     }
 
     /**

core/src/main/java/org/elasticsearch/search/builder/SearchSourceBuilder.java

@@ -82,6 +82,7 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
     public static final ParseField VERSION_FIELD = new ParseField("version");
     public static final ParseField EXPLAIN_FIELD = new ParseField("explain");
     public static final ParseField _SOURCE_FIELD = new ParseField("_source");
+    public static final ParseField FETCH_METADATA_FIELD = new ParseField("fetch_metadata");
     public static final ParseField FIELDS_FIELD = new ParseField("fields");
     public static final ParseField STORED_FIELDS_FIELD = new ParseField("stored_fields");
     public static final ParseField DOCVALUE_FIELDS_FIELD = new ParseField("docvalue_fields", "fielddata_fields");
@@ -152,6 +153,7 @@ public static HighlightBuilder highlight() {
     private List<String> docValueFields;
     private List<ScriptField> scriptFields;
     private FetchSourceContext fetchSourceContext;
+    private Boolean fetchMetadata;
 
     private AggregatorFactories.Builder aggregations;
 
@@ -183,6 +185,7 @@ public SearchSourceBuilder(StreamInput in) throws IOException {
         aggregations = in.readOptionalWriteable(AggregatorFactories.Builder::new);
         explain = in.readOptionalBoolean();
         fetchSourceContext = in.readOptionalStreamable(FetchSourceContext::new);
+        fetchMetadata = in.readOptionalBoolean();
         docValueFields = (List<String>) in.readGenericValue();
         storedFieldNames = (List<String>) in.readGenericValue();
         from = in.readVInt();
@@ -243,6 +246,7 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalWriteable(aggregations);
         out.writeOptionalBoolean(explain);
         out.writeOptionalStreamable(fetchSourceContext);
+        out.writeOptionalBoolean(fetchMetadata);
         out.writeGenericValue(docValueFields);
         out.writeGenericValue(storedFieldNames);
         out.writeVInt(from);
@@ -705,6 +709,21 @@ public FetchSourceContext fetchSource() {
         return fetchSourceContext;
     }
 
+    /**
+     * Indicate if the metadata fields should be fetched
+     */
+    public SearchSourceBuilder fetchMetadata(boolean fetch) {
+        this.fetchMetadata = fetch;
+        return this;
+    }
+
+    /**
+     * Returns true if the metadata fields should be fetched
+     */
+    public Boolean fetchMetadata() {
+        return fetchMetadata;
+    }
+
     /**
      * Adds a stored field to load and return as part of the
      * search request. If none are specified, the source of the document will be
@@ -911,6 +930,7 @@ private SearchSourceBuilder shallowCopy(QueryBuilder queryBuilder, QueryBuilder
             rewrittenBuilder.explain = explain;
             rewrittenBuilder.ext = ext;
             rewrittenBuilder.fetchSourceContext = fetchSourceContext;
+            rewrittenBuilder.fetchMetadata = fetchMetadata;
             rewrittenBuilder.docValueFields = docValueFields;
             rewrittenBuilder.storedFieldNames = storedFieldNames;
             rewrittenBuilder.from = from;
@@ -972,6 +992,8 @@ public void parseXContent(QueryParseContext context, AggregatorParsers aggParser
                     trackScores = parser.booleanValue();
                 } else if (context.getParseFieldMatcher().match(currentFieldName, _SOURCE_FIELD)) {
                     fetchSourceContext = FetchSourceContext.parse(context);
+                } else if (context.getParseFieldMatcher().match(currentFieldName, FETCH_METADATA_FIELD)) {
+                    fetchMetadata = parser.booleanValue();
                 } else if (context.getParseFieldMatcher().match(currentFieldName, STORED_FIELDS_FIELD)) {
                     storedField(parser.text());
                 } else if (context.getParseFieldMatcher().match(currentFieldName, SORT_FIELD)) {
@@ -1141,6 +1163,10 @@ public void innerToXContent(XContentBuilder builder, Params params) throws IOExc
             builder.field(_SOURCE_FIELD.getPreferredName(), fetchSourceContext);
         }
 
+        if (fetchMetadata != null) {
+            builder.field(FETCH_METADATA_FIELD.getPreferredName(), fetchMetadata);
+        }
+
         if (storedFieldNames != null) {
             if (storedFieldNames.size() == 1) {
                 builder.field(STORED_FIELDS_FIELD.getPreferredName(), storedFieldNames.get(0));
@@ -1349,7 +1375,7 @@ public boolean equals(Object obj) {
 
     @Override
     public int hashCode() {
-        return Objects.hash(aggregations, explain, fetchSourceContext, docValueFields, storedFieldNames, from,
+        return Objects.hash(aggregations, explain, fetchSourceContext, fetchMetadata, docValueFields, storedFieldNames, from,
                 highlightBuilder, indexBoost, minScore, postQueryBuilder, queryBuilder, rescoreBuilders, scriptFields,
                 size, sorts, searchAfterBuilder, sliceBuilder, stats, suggestBuilder, terminateAfter, timeout, trackScores, version, profile);
     }
@@ -1366,6 +1392,7 @@ public boolean equals(Object obj) {
         return Objects.equals(aggregations, other.aggregations)
                 && Objects.equals(explain, other.explain)
                 && Objects.equals(fetchSourceContext, other.fetchSourceContext)
+                && Objects.equals(fetchMetadata, other.fetchMetadata)
                 && Objects.equals(docValueFields, other.docValueFields)
                 && Objects.equals(storedFieldNames, other.storedFieldNames)
                 && Objects.equals(from, other.from)

core/src/main/java/org/elasticsearch/search/fetch/FetchPhase.java

@@ -97,12 +97,21 @@ public void execute(SearchContext context) {
         List<String> fieldNamePatterns = null;
         if (!context.hasFieldNames()) {
             // no fields specified, default to return source if no explicit indication
-            if (!context.hasScriptFields() && !context.hasFetchSourceContext()) {
+            if (!context.hasScriptFields() && !context.hasFetchSourceContext() && context.fetchMetadata()) {
                 context.fetchSourceContext(new FetchSourceContext(true));
             }
-            fieldsVisitor = new FieldsVisitor(context.sourceRequested());
+            if (context.fetchMetadata() == false) {
+                assert context.sourceRequested() == false;
+                fieldsVisitor = null;
+            } else {
+              fieldsVisitor = new FieldsVisitor(context.sourceRequested());
+            }
         } else if (context.fieldNames().isEmpty()) {
-            fieldsVisitor = new FieldsVisitor(context.sourceRequested());
+            if (context.fetchMetadata() == false && context.sourceRequested() == false) {
+                fieldsVisitor = null;
+            } else {
+                fieldsVisitor = new FieldsVisitor(context.sourceRequested());
+            }
         } else {
             for (String fieldName : context.fieldNames()) {
                 if (fieldName.equals(SourceFieldMapper.NAME)) {
@@ -182,6 +191,9 @@ private int findRootDocumentIfNested(SearchContext context, LeafReaderContext su
     }
 
     private InternalSearchHit createSearchHit(SearchContext context, FieldsVisitor fieldsVisitor, int docId, int subDocId, LeafReaderContext subReaderContext) {
+        if (fieldsVisitor == null) {
+            return new InternalSearchHit(docId, null, null, null);
+        }
         loadStoredFields(context, subReaderContext, fieldsVisitor, subDocId);
         fieldsVisitor.postProcess(context.mapperService());
 
@@ -193,14 +205,18 @@ private InternalSearchHit createSearchHit(SearchContext context, FieldsVisitor f
             }
         }
 
-        DocumentMapper documentMapper = context.mapperService().documentMapper(fieldsVisitor.uid().type());
-        Text typeText;
-        if (documentMapper == null) {
-            typeText = new Text(fieldsVisitor.uid().type());
-        } else {
-            typeText = documentMapper.typeText();
+        Text typeText = null;
+        String id = null;
+        if (context.fetchMetadata()) {
+            DocumentMapper documentMapper = context.mapperService().documentMapper(fieldsVisitor.uid().type());
+            if (documentMapper == null) {
+                typeText = new Text(fieldsVisitor.uid().type());
+            } else {
+                typeText = documentMapper.typeText();
+            }
+            id = fieldsVisitor.uid().id();
         }
-        InternalSearchHit searchHit = new InternalSearchHit(docId, fieldsVisitor.uid().id(), typeText, searchFields);
+        InternalSearchHit searchHit = new InternalSearchHit(docId, id, typeText, searchFields);
         // Set _source if requested.
         SourceLookup sourceLookup = context.lookup().source();
         sourceLookup.setSegmentAndDocument(subReaderContext, subDocId);

core/src/main/java/org/elasticsearch/search/fetch/parent/ParentFieldSubFetchPhase.java

@@ -38,6 +38,9 @@ public final class ParentFieldSubFetchPhase implements FetchSubPhase {
 
     @Override
     public void hitExecute(SearchContext context, HitContext hitContext) {
+        if (context.fetchMetadata() == false) {
+            return ;
+        }
         ParentFieldMapper parentFieldMapper = context.mapperService().documentMapper(hitContext.hit().type()).parentFieldMapper();
         if (parentFieldMapper.active() == false) {
             return;

core/src/main/java/org/elasticsearch/search/internal/DefaultSearchContext.java

@@ -109,6 +109,7 @@ public class DefaultSearchContext extends SearchContext {
     private List<String> fieldNames;
     private ScriptFieldsContext scriptFields;
     private FetchSourceContext fetchSourceContext;
+    private boolean fetchMetadata = true;
     private int from = -1;
     private int size = -1;
     private SortAndFormats sort;
@@ -469,6 +470,18 @@ public SearchContext fetchSourceContext(FetchSourceContext fetchSourceContext) {
         return this;
     }
 
+    @Override
+    public boolean fetchMetadata() {
+        return fetchMetadata;
+    }
+
+    @Override
+    public SearchContext fetchMetadata(boolean fetch) {
+        this.fetchMetadata = fetch;
+        return this;
+    }
+
+
     @Override
     public ContextIndexSearcher searcher() {
         return this.searcher;

core/src/main/java/org/elasticsearch/search/internal/FilteredSearchContext.java

@@ -219,6 +219,16 @@ public SearchContext fetchSourceContext(FetchSourceContext fetchSourceContext) {
         return in.fetchSourceContext(fetchSourceContext);
     }
 
+    @Override
+    public boolean fetchMetadata() {
+        return in.fetchMetadata();
+    }
+
+    @Override
+    public SearchContext fetchMetadata(boolean fetch) {
+        return in.fetchMetadata(fetch);
+    }
+
     @Override
     public ContextIndexSearcher searcher() {
         return in.searcher();

core/src/main/java/org/elasticsearch/search/internal/InternalSearchHit.java

@@ -100,16 +100,16 @@ private InternalSearchHit() {
 
     }
 
-    public InternalSearchHit(int docId, String id, Text type, Map<String, SearchHitField> fields) {
+    public InternalSearchHit(int docId, @Nullable String id, @Nullable Text type, @Nullable Map<String, SearchHitField> fields) {
         this.docId = docId;
-        this.id = new Text(id);
+        this.id = id != null ? new Text(id) : null;
         this.type = type;
         this.fields = fields;
     }
 
     public InternalSearchHit(int nestedTopDocId, String id, Text type, InternalNestedIdentity nestedIdentity, Map<String, SearchHitField> fields) {
         this.docId = nestedTopDocId;
-        this.id = new Text(id);
+        this.id = id != null ? new Text(id) : null;
         this.type = type;
         this.nestedIdentity = nestedIdentity;
         this.fields = fields;
@@ -168,7 +168,7 @@ public String getIndex() {
 
     @Override
     public String id() {
-        return id.string();
+        return id != null ? id.string() : null;
     }
 
     @Override
@@ -178,7 +178,7 @@ public String getId() {
 
     @Override
     public String type() {
-        return type.string();
+        return type != null ? type.string() : null;
     }
 
     @Override
@@ -444,8 +444,12 @@ public XContentBuilder toInnerXContent(XContentBuilder builder, Params params) t
             if (shard != null) {
                 builder.field(Fields._INDEX, shard.indexText());
             }
-            builder.field(Fields._TYPE, type);
-            builder.field(Fields._ID, id);
+            if (type != null) {
+                builder.field(Fields._TYPE, type);
+            }
+            if (id != null) {
+                builder.field(Fields._ID, id);
+            }
         }
         if (version != -1) {
             builder.field(Fields._VERSION, version);
@@ -555,8 +559,8 @@ public void readFrom(StreamInput in) throws IOException {
 
     public void readFrom(StreamInput in, InternalSearchHits.StreamContext context) throws IOException {
         score = in.readFloat();
-        id = in.readText();
-        type = in.readText();
+        id = in.readOptionalText();
+        type = in.readOptionalText();
         nestedIdentity = in.readOptionalStreamable(InternalNestedIdentity::new);
         version = in.readLong();
         source = in.readBytesReference();
@@ -664,8 +668,8 @@ public void writeTo(StreamOutput out) throws IOException {
 
     public void writeTo(StreamOutput out, InternalSearchHits.StreamContext context) throws IOException {
         out.writeFloat(score);
-        out.writeText(id);
-        out.writeText(type);
+        out.writeOptionalText(id);
+        out.writeOptionalText(type);
         out.writeOptionalStreamable(nestedIdentity);
         out.writeLong(version);
         out.writeBytesReference(source);

core/src/main/java/org/elasticsearch/search/internal/SearchContext.java

@@ -64,7 +64,6 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.Callable;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 public abstract class SearchContext implements Releasable {
@@ -200,6 +199,10 @@ public InnerHitsContext innerHits() {
 
     public abstract SearchContext fetchSourceContext(FetchSourceContext fetchSourceContext);
 
+    public abstract boolean fetchMetadata();
+
+    public abstract SearchContext fetchMetadata(boolean fetch);
+
     public abstract ContextIndexSearcher searcher();
 
     public abstract IndexShard indexShard();