diff --git a/config_metrics.go b/config_metrics.go
index 7b7ae581..3275a78f 100644
--- a/config_metrics.go
+++ b/config_metrics.go
@@ -14,4 +14,3 @@ package bleve
 import (
 	_ "github.com/blevesearch/bleve/index/store/metrics"
 )
-
diff --git a/index/store/metrics/metrics.go b/index/store/metrics/metrics.go
index c5757d7a..9b460af3 100644
--- a/index/store/metrics/metrics.go
+++ b/index/store/metrics/metrics.go
@@ -131,10 +131,18 @@ type Batch struct {
 	o store.KVBatch
 }
 
+func (s *Store) Open() error {
+	return s.o.Open()
+}
+
 func (s *Store) Close() error {
 	return s.o.Close()
 }
 
+func (s *Store) SetMergeOperator(mo store.MergeOperator) {
+	s.o.SetMergeOperator(mo)
+}
+
 func (s *Store) Reader() (store.KVReader, error) {
 	o, err := s.o.Reader()
 	if err != nil {
@@ -289,9 +297,9 @@ func (w *Batch) Delete(key []byte) {
 	w.o.Delete(key)
 }
 
-func (w *Batch) Merge(key []byte, oper store.AssociativeMerge) {
+func (w *Batch) Merge(key, val []byte) {
 	w.s.TimerBatchMerge.Time(func() {
-		w.o.Merge(key, oper)
+		w.o.Merge(key, val)
 	})
 }