if we loaded source, use it when needing it in other fetch phases like extracting specific fields instead of loading it again

src/main/java/org/elasticsearch/index/get/ShardGetService.java

@@ -293,7 +293,7 @@ public class ShardGetService extends AbstractIndexShardComponent {
                             } else {
                                 if (searchLookup == null) {
                                     searchLookup = new SearchLookup(mapperService, indexCache.fieldData());
-                                    searchLookup.source().setNextSource(SourceLookup.sourceAsMap(source.source.bytes(), source.source.offset(), source.source.length()));
+                                    searchLookup.source().setNextSource(source.source.bytes(), source.source.offset(), source.source.length());
                                 }
 
                                 FieldMapper<?> x = docMapper.mappers().smartNameFieldMapper(field);

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

@@ -184,6 +184,9 @@ public class FetchPhase implements SearchPhase {
             // go over and extract fields that are not mapped / stored
             context.lookup().setNextReader(subReader);
             context.lookup().setNextDocId(subDoc);
+            if (source != null) {
+                context.lookup().source().setNextSource(source, 0, source.length);
+            }
             if (extractFieldNames != null) {
                 for (String extractFieldName : extractFieldNames) {
                     Object value = context.lookup().source().extractValue(extractFieldName);

src/main/java/org/elasticsearch/search/lookup/SourceLookup.java

@@ -25,7 +25,6 @@ import org.apache.lucene.document.Fieldable;
 import org.apache.lucene.index.IndexReader;
 import org.elasticsearch.ElasticSearchParseException;
 import org.elasticsearch.common.xcontent.XContentHelper;
-import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 import org.elasticsearch.index.mapper.internal.SourceFieldMapper;
 import org.elasticsearch.index.mapper.internal.SourceFieldSelector;
@@ -45,6 +44,9 @@ public class SourceLookup implements Map {
 
     private int docId = -1;
 
+    private byte[] sourceAsBytes;
+    private int sourceAsBytesOffset;
+    private int sourceAsBytesLength;
     private Map<String, Object> source;
 
     public Map<String, Object> source() {
@@ -55,7 +57,10 @@ public class SourceLookup implements Map {
         if (source != null) {
             return source;
         }
-        XContentParser parser = null;
+        if (sourceAsBytes != null) {
+            source = sourceAsMap(sourceAsBytes, sourceAsBytesOffset, sourceAsBytesLength);
+            return source;
+        }
         try {
             Document doc = reader.document(docId, SourceFieldSelector.INSTANCE);
             Fieldable sourceField = doc.getFieldable(SourceFieldMapper.NAME);
@@ -66,10 +71,6 @@ public class SourceLookup implements Map {
             }
         } catch (Exception e) {
             throw new ElasticSearchParseException("failed to parse / load source", e);
-        } finally {
-            if (parser != null) {
-                parser.close();
-            }
         }
         return this.source;
     }
@@ -84,6 +85,7 @@ public class SourceLookup implements Map {
         }
         this.reader = reader;
         this.source = null;
+        this.sourceAsBytes = null;
         this.docId = -1;
     }
 
@@ -92,9 +94,16 @@ public class SourceLookup implements Map {
             return;
         }
         this.docId = docId;
+        this.sourceAsBytes = null;
         this.source = null;
     }
 
+    public void setNextSource(byte[] source, int offset, int length) {
+        this.sourceAsBytes = source;
+        this.sourceAsBytesOffset = offset;
+        this.sourceAsBytesLength = length;
+    }
+
     public void setNextSource(Map<String, Object> source) {
         this.source = source;
     }