diff --git a/cpp/src/db/Factories.cpp b/cpp/src/db/Factories.cpp
index 3cfb9a6eb3c6938c73cfcf232960b194a1096a3a..442dca297421eadbe2016430b646df7ff8848afb 100644
--- a/cpp/src/db/Factories.cpp
+++ b/cpp/src/db/Factories.cpp
@@ -26,8 +26,6 @@ namespace zilliz {
 namespace milvus {
 namespace engine {
 
-#define USE_NEW_MEM_MANAGER 1
-
 DBMetaOptions DBMetaOptionsFactory::Build(const std::string& path) {
     auto p = path;
     if(p == "") {