diff --git a/cpp/src/server/grpc_impl/GrpcRequestScheduler.cpp b/cpp/src/server/grpc_impl/GrpcRequestScheduler.cpp
index ef60aba8a3..637b4c3b34 100644
--- a/cpp/src/server/grpc_impl/GrpcRequestScheduler.cpp
+++ b/cpp/src/server/grpc_impl/GrpcRequestScheduler.cpp
@@ -39,6 +39,9 @@ namespace {
                 {SERVER_INVALID_ROWRECORD,        ::milvus::grpc::ErrorCode::ILLEGAL_ROWRECORD},
                 {SERVER_INVALID_ROWRECORD_ARRAY,  ::milvus::grpc::ErrorCode::ILLEGAL_ROWRECORD},
                 {SERVER_INVALID_TOPK,             ::milvus::grpc::ErrorCode::ILLEGAL_TOPK},
+                {SERVER_INVALID_NPROBE,           ::milvus::grpc::ErrorCode::ILLEGAL_ARGUMENT},
+                {SERVER_INVALID_INDEX_NLIST,      ::milvus::grpc::ErrorCode::ILLEGAL_ARGUMENT},
+                {SERVER_INVALID_INDEX_METRIC_TYPE,::milvus::grpc::ErrorCode::ILLEGAL_ARGUMENT},
                 {SERVER_ILLEGAL_VECTOR_ID,        ::milvus::grpc::ErrorCode::ILLEGAL_VECTOR_ID},
                 {SERVER_ILLEGAL_SEARCH_RESULT,    ::milvus::grpc::ErrorCode::ILLEGAL_SEARCH_RESULT},
                 {SERVER_CACHE_ERROR,              ::milvus::grpc::ErrorCode::CACHE_FAILED},
diff --git a/cpp/unittest/server/util_test.cpp b/cpp/unittest/server/util_test.cpp
index c0b1c83cf8..290655f565 100644
--- a/cpp/unittest/server/util_test.cpp
+++ b/cpp/unittest/server/util_test.cpp
@@ -217,6 +217,21 @@ TEST(UtilTest, VALIDATE_INDEX_TEST) {
     ASSERT_EQ(server::ValidationUtil::ValidateTableIndexMetricType(2), server::SERVER_SUCCESS);
 }
 
+TEST(ValidationUtilTest, ValidateTopkTest) {
+    engine::meta::TableSchema schema;
+    ASSERT_EQ(server::ValidationUtil::ValidateSearchTopk(10, schema), server::SERVER_SUCCESS);
+    ASSERT_NE(server::ValidationUtil::ValidateSearchTopk(65536, schema), server::SERVER_SUCCESS);
+    ASSERT_NE(server::ValidationUtil::ValidateSearchTopk(0, schema), server::SERVER_SUCCESS);
+}
+
+TEST(ValidationUtilTest, ValidateNprobeTest) {
+    engine::meta::TableSchema schema;
+    schema.nlist_ = 100;
+    ASSERT_EQ(server::ValidationUtil::ValidateSearchNprobe(10, schema), server::SERVER_SUCCESS);
+    ASSERT_NE(server::ValidationUtil::ValidateSearchNprobe(0, schema), server::SERVER_SUCCESS);
+    ASSERT_NE(server::ValidationUtil::ValidateSearchNprobe(101, schema), server::SERVER_SUCCESS);
+}
+
 TEST(ValidationUtilTest, ValidateGpuTest) {
     ASSERT_EQ(server::ValidationUtil::ValidateGpuIndex(0), server::SERVER_SUCCESS);
     ASSERT_NE(server::ValidationUtil::ValidateGpuIndex(100), server::SERVER_SUCCESS);