Optimize Mongo bulk delete

mongo/graph.go

@@ -121,16 +121,30 @@ func (mg *Graph) BulkAdd(stream <-chan *gdbi.GraphElement) error {
 }
 
 func (mg *Graph) BulkDel(Data *gdbi.DeleteData) error {
-	for _, v := range Data.Edges {
-		if err := mg.DelEdge(v); err != nil {
-			return err
-		}
+	eCol := mg.ar.EdgeCollection(mg.graph)
+	_, err := eCol.DeleteMany(context.TODO(), bson.M{"_id": bson.M{"$in": Data.Edges}})
+	if err != nil {
+		return fmt.Errorf("failed to delete edge(s): %s", err)
 	}
-	for _, v := range Data.Vertices {
-		if err := mg.DelVertex(v); err != nil {
-			return err
-		}
+	mg.ts.Touch(mg.graph)
+
+	vCol := mg.ar.VertexCollection(mg.graph)
+	_, err = vCol.DeleteMany(context.TODO(), bson.M{"_id": bson.M{"$in": Data.Vertices}})
+	if err != nil {
+		return fmt.Errorf("failed to delete list of vertices: %s", err)
 	}
+	mg.ts.Touch(mg.graph)
+
+	_, err = eCol.DeleteMany(context.TODO(), bson.M{
+		"$or": []bson.M{
+			{FIELD_FROM: bson.M{"$in": Data.Vertices}},
+			{FIELD_TO: bson.M{"$in": Data.Vertices}},
+		}})
+	if err != nil {
+		return fmt.Errorf("failed to delete connected edge(s): %s", err)
+	}
+	mg.ts.Touch(mg.graph)
+
 	return nil
 }