diff --git a/posting/list.go b/posting/list.go
index c029721f167..0ed73feae78 100644
--- a/posting/list.go
+++ b/posting/list.go
@@ -312,14 +312,19 @@ func (l *List) updateMutationLayer(mpost *pb.Posting) {
 	if hasDeleteAll(mpost) {
 		plist := &pb.PostingList{}
 		plist.Postings = append(plist.Postings, mpost)
+		if l.mutationMap == nil {
+			l.mutationMap = make(map[uint64]*pb.PostingList)
+		}
 		l.mutationMap[mpost.StartTs] = plist
 		return
 	}
-
 	plist, ok := l.mutationMap[mpost.StartTs]
 	if !ok {
 		plist := &pb.PostingList{}
 		plist.Postings = append(plist.Postings, mpost)
+		if l.mutationMap == nil {
+			l.mutationMap = make(map[uint64]*pb.PostingList)
+		}
 		l.mutationMap[mpost.StartTs] = plist
 		return
 	}
@@ -511,6 +516,9 @@ func (l *List) setMutation(startTs uint64, data []byte) {
 	x.Check(pl.Unmarshal(data))
 
 	l.Lock()
+	if l.mutationMap == nil {
+		l.mutationMap = make(map[uint64]*pb.PostingList)
+	}
 	l.mutationMap[startTs] = pl
 	l.Unlock()
 }
diff --git a/posting/lists.go b/posting/lists.go
index 9f8ec721301..9a2ecfa242e 100644
--- a/posting/lists.go
+++ b/posting/lists.go
@@ -246,9 +246,8 @@ func (lc *LocalCache) getInternal(key []byte, readFromDisk bool) (*List, error)
 		}
 	} else {
 		pl = &List{
-			key:         key,
-			mutationMap: make(map[uint64]*pb.PostingList),
-			plist:       new(pb.PostingList),
+			key:   key,
+			plist: new(pb.PostingList),
 		}
 	}
 
diff --git a/posting/mvcc.go b/posting/mvcc.go
index 33432535101..1b7dd489ae9 100644
--- a/posting/mvcc.go
+++ b/posting/mvcc.go
@@ -143,7 +143,6 @@ func unmarshalOrCopy(plist *pb.PostingList, item *badger.Item) error {
 func ReadPostingList(key []byte, it *badger.Iterator) (*List, error) {
 	l := new(List)
 	l.key = key
-	l.mutationMap = make(map[uint64]*pb.PostingList)
 	l.plist = new(pb.PostingList)
 
 	// Iterates from highest Ts to lowest Ts
@@ -180,6 +179,9 @@ func ReadPostingList(key []byte, it *badger.Iterator) (*List, error) {
 					// stored on disk.
 					mpost.CommitTs = item.Version()
 				}
+				if l.mutationMap == nil {
+					l.mutationMap = make(map[uint64]*pb.PostingList)
+				}
 				l.mutationMap[pl.CommitTs] = pl
 				return nil
 			})