diff --git a/index/store/gtreap/gtreap.go b/index/store/gtreap/gtreap.go
index c1272dd1..5992ca66 100644
--- a/index/store/gtreap/gtreap.go
+++ b/index/store/gtreap/gtreap.go
@@ -53,13 +53,6 @@ type Reader struct {
 	t *gtreap.Treap
 }
 
-type Writer struct {
-	s *Store
-
-	m sync.Mutex
-	t *gtreap.Treap
-}
-
 type Iterator struct {
 	t *gtreap.Treap
 
@@ -75,19 +68,12 @@ func newIterator(t *gtreap.Treap) *Iterator {
 }
 
 type Batch struct {
-	w *Writer
-
-	m sync.Mutex
-
-	ks [][]byte
-	vs [][]byte
-	ms map[string]store.AssociativeMergeChain
+	s     *Store
+	items []*Item
+	ms    map[string]store.AssociativeMergeChain
 }
 
 func (s *Store) Close() error {
-	s.m.Lock()
-	s.t = nil
-	s.m.Unlock()
 	return nil
 }
 
@@ -99,10 +85,7 @@ func (s *Store) Reader() (store.KVReader, error) {
 }
 
 func (s *Store) Writer() (store.KVWriter, error) {
-	s.m.Lock()
-	t := s.t
-	s.m.Unlock()
-	return &Writer{s: s, t: t}, nil
+	return s, nil
 }
 
 func (w *Reader) Get(k []byte) (v []byte, err error) {
@@ -121,7 +104,7 @@ func (w *Reader) Close() error {
 	return nil
 }
 
-func (w *Writer) Get(k []byte) (v []byte, err error) {
+func (w *Store) Get(k []byte) (v []byte, err error) {
 	w.m.Lock()
 	t := w.t
 	w.m.Unlock()
@@ -133,41 +116,33 @@ func (w *Writer) Get(k []byte) (v []byte, err error) {
 	return nil, nil
 }
 
-func (w *Writer) Iterator(k []byte) store.KVIterator {
+func (w *Store) Iterator(k []byte) store.KVIterator {
 	w.m.Lock()
 	t := w.t
 	w.m.Unlock()
 	return newIterator(t).restart(&Item{k: k})
 }
 
-func (w *Writer) Close() error {
+func (w *Store) Set(k, v []byte) (err error) {
 	w.m.Lock()
-	w.t = nil
+	w.t = w.t.Upsert(&Item{k: k, v: v}, rand.Int())
 	w.m.Unlock()
 	return nil
 }
 
-func (w *Writer) Set(k, v []byte) (err error) {
-	w.s.m.Lock()
-	w.s.t = w.s.t.Upsert(&Item{k: k, v: v}, rand.Int())
-	t := w.s.t
-	w.s.m.Unlock()
-
-	w.m.Lock()
-	w.t = t
-	w.m.Unlock()
-	return nil
-}
-
-func (w *Writer) Delete(k []byte) (err error) {
+func (w *Store) Delete(k []byte) (err error) {
 	w.m.Lock()
 	w.t = w.t.Delete(&Item{k: k})
 	w.m.Unlock()
 	return nil
 }
 
-func (w *Writer) NewBatch() store.KVBatch {
-	return &Batch{w: w, ms: map[string]store.AssociativeMergeChain{}}
+func (w *Store) NewBatch() store.KVBatch {
+	return &Batch{
+		s:     w,
+		items: make([]*Item, 0, 100),
+		ms:    map[string]store.AssociativeMergeChain{},
+	}
 }
 
 func (w *Iterator) SeekFirst() {
@@ -268,44 +243,26 @@ func (w *Iterator) Close() error {
 }
 
 func (w *Batch) Set(k, v []byte) {
-	w.m.Lock()
-	w.ks = append(w.ks, k)
-	w.vs = append(w.vs, v)
-	w.m.Unlock()
+	w.items = append(w.items, &Item{k, v})
 }
 
 func (w *Batch) Delete(k []byte) {
-	w.m.Lock()
-	w.ks = append(w.ks, k)
-	w.vs = append(w.vs, nil)
-	w.m.Unlock()
+	w.items = append(w.items, &Item{k, nil})
 }
 
 func (w *Batch) Merge(k []byte, oper store.AssociativeMerge) {
-	key := string(k)
-	w.m.Lock()
-	w.ms[key] = append(w.ms[key], oper)
-	w.m.Unlock()
+	w.ms[string(k)] = append(w.ms[string(k)], oper)
 }
 
 func (w *Batch) Execute() (err error) {
-	w.m.Lock()
-	ks := w.ks
-	w.ks = nil
-	vs := w.vs
-	w.vs = nil
-	ms := w.ms
-	w.ms = map[string]store.AssociativeMergeChain{}
-	w.m.Unlock()
-
 	done := false
 	for !done {
-		w.w.s.m.Lock()
-		torig := w.w.s.t
-		w.w.s.m.Unlock()
+		w.s.m.Lock()
+		torig := w.s.t
+		w.s.m.Unlock()
 
 		t := torig
-		for key, mc := range ms {
+		for key, mc := range w.ms {
 			k := []byte(key)
 			itm := t.Get(&Item{k: k})
 			v := []byte(nil)
@@ -323,31 +280,26 @@ func (w *Batch) Execute() (err error) {
 			}
 		}
 
-		for i, k := range ks {
-			v := vs[i]
+		for _, item := range w.items {
+			v := item.v
 			if v != nil {
-				t = t.Upsert(&Item{k: k, v: v}, rand.Int())
+				t = t.Upsert(item, rand.Int())
 			} else {
-				t = t.Delete(&Item{k: k})
+				t = t.Delete(item)
 			}
 		}
 
-		w.w.s.m.Lock()
-		if w.w.s.t == torig {
-			w.w.s.t = t
+		w.s.m.Lock()
+		if w.s.t == torig {
+			w.s.t = t
 			done = true
 		}
-		w.w.s.m.Unlock()
+		w.s.m.Unlock()
 	}
 
 	return nil
 }
 
 func (w *Batch) Close() error {
-	w.m.Lock()
-	w.ks = nil
-	w.vs = nil
-	w.ms = nil
-	w.m.Unlock()
 	return nil
 }