diff --git a/cpp/src/core/src/knowhere/index/vector_index/gpu_ivf.cpp b/cpp/src/core/src/knowhere/index/vector_index/gpu_ivf.cpp
index 01c4908511d47df86676688f9ffad0b50933686a..c06c58c40c6167968eeeb8106ad70bef0b62abd3 100644
--- a/cpp/src/core/src/knowhere/index/vector_index/gpu_ivf.cpp
+++ b/cpp/src/core/src/knowhere/index/vector_index/gpu_ivf.cpp
@@ -123,6 +123,7 @@ void GPUIVF::search_impl(int64_t n,
                          int64_t *labels,
                          const Config &cfg) {
     if (auto device_index = std::static_pointer_cast<faiss::gpu::GpuIndexIVF>(index_)) {
+        // todo: allocate search memory
         auto nprobe = cfg.get_with_default("nprobe", size_t(1));
 
         std::lock_guard<std::mutex> lk(mutex_);
diff --git a/cpp/src/core/test/test_nsg/CMakeLists.txt b/cpp/src/core/test/test_nsg/CMakeLists.txt
index bd2db8072c3ea40d645695f4fd961530e3404a8e..0ec275d9eec87ef6a7e92759763dae48aeb79741 100644
--- a/cpp/src/core/test/test_nsg/CMakeLists.txt
+++ b/cpp/src/core/test/test_nsg/CMakeLists.txt
@@ -27,6 +27,8 @@ aux_source_directory(${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/nsg nsg
 set(interface_src
         ${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/ivf.cpp
         ${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/gpu_ivf.cpp
+        ${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/cloner.cpp
+        ${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/idmap.cpp
         ${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/nsg_index.cpp
         ${CMAKE_SOURCE_DIR}/src/knowhere/adapter/structure.cpp
         ${CMAKE_SOURCE_DIR}/src/knowhere/common/exception.cpp