Optimize ExpressionFieldPath

1 files changed, 2 insertions, 2 deletions

diff --git a/src/mongo/db/pipeline/field_path.h b/src/mongo/db/pipeline/field_path.h
index c3b9aa2a22c..4ff97817fbe 100755
--- a/src/mongo/db/pipeline/field_path.h
+++ b/src/mongo/db/pipeline/field_path.h
@@ -46,7 +46,7 @@ namespace mongo {
           @param i the zero based index of the path element.
           @returns the path element
          */
-        string getFieldName(size_t i) const;
+        const string& getFieldName(size_t i) const;
 
         /**
           Get the full path.
@@ -102,7 +102,7 @@ namespace mongo {
         return vFieldName.size();
     }
 
-    inline string FieldPath::getFieldName(size_t i) const {
+    inline const string& FieldPath::getFieldName(size_t i) const {
         verify(i < getPathLength());
         return vFieldName[i];
     }