diff --git a/core/src/sdk/examples/grpcsimple/src/ClientTest.cpp b/core/src/sdk/examples/grpcsimple/src/ClientTest.cpp
index ce511714b2882312b6e417fa65b27ec3df61877d..069283200f4f17bb34ed94203073c09c6b783f68 100644
--- a/core/src/sdk/examples/grpcsimple/src/ClientTest.cpp
+++ b/core/src/sdk/examples/grpcsimple/src/ClientTest.cpp
@@ -40,8 +40,10 @@ constexpr int64_t BATCH_ROW_COUNT = 100000;
 constexpr int64_t NQ = 5;
 constexpr int64_t TOP_K = 10;
 constexpr int64_t SEARCH_TARGET = 5000;  // change this value, result is different
-constexpr int64_t ADD_VECTOR_LOOP = 1;
+constexpr int64_t ADD_VECTOR_LOOP = 5;
 constexpr int64_t SECONDS_EACH_HOUR = 3600;
+constexpr milvus::IndexType INDEX_TYPE = milvus::IndexType::gpu_ivfsq8;
+constexpr int32_t N_LIST = 15000;
 
 #define BLOCK_SPLITER std::cout << "===========================================" << std::endl;
 
@@ -311,8 +313,8 @@ ClientTest::Test(const std::string& address, const std::string& port) {
         std::cout << "Wait until create all index done" << std::endl;
         milvus::IndexParam index;
         index.table_name = TABLE_NAME;
-        index.index_type = milvus::IndexType::gpu_ivfsq8;
-        index.nlist = 16384;
+        index.index_type = INDEX_TYPE;
+        index.nlist = N_LIST;
         milvus::Status stat = conn->CreateIndex(index);
         std::cout << "CreateIndex function call status: " << stat.message() << std::endl;
 
@@ -344,8 +346,8 @@ ClientTest::Test(const std::string& address, const std::string& port) {
 
     {  // delete by range
         milvus::Range rg;
-        rg.start_value = CurrentTmDate(-2);
-        rg.end_value = CurrentTmDate(-3);
+        rg.start_value = CurrentTmDate(-3);
+        rg.end_value = CurrentTmDate(-2);
 
         milvus::Status stat = conn->DeleteByRange(rg, TABLE_NAME);
         std::cout << "DeleteByRange function call status: " << stat.message() << std::endl;
diff --git a/core/src/sdk/interface/Status.cpp b/core/src/sdk/interface/Status.cpp
index a5e89556f29900d4a66f97fb2fce61b3e48d3aa4..9ccbabfd209f37514fc65053251d551ee3b4e0d1 100644
--- a/core/src/sdk/interface/Status.cpp
+++ b/core/src/sdk/interface/Status.cpp
@@ -88,7 +88,7 @@ Status::MoveFrom(Status& s) {
 std::string
 Status::message() const {
     if (state_ == nullptr) {
-        return "";
+        return "OK";
     }
 
     std::string msg;
diff --git a/core/src/utils/Status.cpp b/core/src/utils/Status.cpp
index ad97717cf7190422bc6db09e13723bbc5130cbbe..9ac02798103cc13ac766bbc46c8bf696af8bad8c 100644
--- a/core/src/utils/Status.cpp
+++ b/core/src/utils/Status.cpp
@@ -88,7 +88,7 @@ Status::MoveFrom(Status& s) {
 std::string
 Status::message() const {
     if (state_ == nullptr) {
-        return "";
+        return "OK";
     }
 
     std::string msg;
diff --git a/core/unittest/server/test_rpc.cpp b/core/unittest/server/test_rpc.cpp
index 7d3e0b55112fe00806969ad52101479b06a38a49..d398660f01c39161f6a20b138f5db7fc51c3dee5 100644
--- a/core/unittest/server/test_rpc.cpp
+++ b/core/unittest/server/test_rpc.cpp
@@ -405,8 +405,8 @@ TEST_F(RpcHandlerTest, DELETE_BY_RANGE_TEST) {
     handler->DeleteByRange(&context, &request, &status);
 
     request.set_table_name(TABLE_NAME);
-    request.mutable_range()->set_start_value(CurrentTmDate(-2));
-    request.mutable_range()->set_end_value(CurrentTmDate(-3));
+    request.mutable_range()->set_start_value(CurrentTmDate(-3));
+    request.mutable_range()->set_end_value(CurrentTmDate(-2));
 
     ::grpc::Status grpc_status = handler->DeleteByRange(&context, &request, &status);
     int error_code = status.error_code();