diff --git a/cpp/CMakeLists.txt b/cpp/CMakeLists.txt
index 90d92b1e2c..a8c49657c5 100644
--- a/cpp/CMakeLists.txt
+++ b/cpp/CMakeLists.txt
@@ -69,7 +69,7 @@ link_directories(${VECWISE_THIRD_PARTY_BUILD}/lib)
 #                WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/third_party)
 
 add_subdirectory(src)
-#add_subdirectory(test_client)
+add_subdirectory(test_client)
 
 if (BUILD_UNIT_TEST)
     add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/unittest)
diff --git a/cpp/src/db/DB.cpp b/cpp/src/db/DB.cpp
index 808c87ad1d..5baa09bd71 100644
--- a/cpp/src/db/DB.cpp
+++ b/cpp/src/db/DB.cpp
@@ -19,7 +19,14 @@ DB::~DB() {}
 
 void DB::Open(const Options& options, DB** dbptr) {
     *dbptr = nullptr;
-    *dbptr = DBFactory::Build(options);
+
+#ifdef GPU_VERSION
+    std::string default_index_type{"Faiss,IVF"};
+#else
+    std::string default_index_type{"Faiss,IDMap"};
+#endif
+
+    *dbptr = DBFactory::Build(options, default_index_type);
     return;
 }
 
diff --git a/cpp/unittest/server/CMakeLists.txt b/cpp/unittest/server/CMakeLists.txt
index dc79f8ed1b..7141c45ede 100644
--- a/cpp/unittest/server/CMakeLists.txt
+++ b/cpp/unittest/server/CMakeLists.txt
@@ -7,7 +7,7 @@ include_directories(../../src)
 include_directories(/usr/include)
 
 include_directories(/usr/local/cuda/include)
-find_library(cuda_library cudart cublas HINTS /usr/local/cuda/lib64)
+link_directories(/usr/local/cuda/lib64)
 
 aux_source_directory(../../src/config config_files)
 aux_source_directory(../../src/cache cache_srcs)