diff --git a/cpp/src/core/include/knowhere/index/preprocessor/normalize.h b/cpp/src/core/include/knowhere/index/preprocessor/normalize.h
index 1d871b580d2bcb6b0d1dbe7b82b0e458dae7fbf9..399a5d349034ef0e7308448f646f22df26f8bb79 100644
--- a/cpp/src/core/include/knowhere/index/preprocessor/normalize.h
+++ b/cpp/src/core/include/knowhere/index/preprocessor/normalize.h
@@ -1,26 +1,26 @@
-#pragma once
-
-#include <memory>
-#include "preprocessor.h"
-
-
-namespace zilliz {
-namespace knowhere {
-
-class NormalizePreprocessor : public Preprocessor {
- public:
-    DatasetPtr
-    Preprocess(const DatasetPtr &input) override;
-
- private:
-
-    void
-    Normalize(float *arr, int64_t dimension);
-};
-
-
-using NormalizePreprocessorPtr = std::shared_ptr<NormalizePreprocessor>;
-
-
-} // namespace knowhere
-} // namespace zilliz
+//#pragma once
+//
+//#include <memory>
+//#include "preprocessor.h"
+//
+//
+//namespace zilliz {
+//namespace knowhere {
+//
+//class NormalizePreprocessor : public Preprocessor {
+// public:
+//    DatasetPtr
+//    Preprocess(const DatasetPtr &input) override;
+//
+// private:
+//
+//    void
+//    Normalize(float *arr, int64_t dimension);
+//};
+//
+//
+//using NormalizePreprocessorPtr = std::shared_ptr<NormalizePreprocessor>;
+//
+//
+//} // namespace knowhere
+//} // namespace zilliz
diff --git a/cpp/src/core/include/knowhere/index/vector_index/cpu_kdt_rng.h b/cpp/src/core/include/knowhere/index/vector_index/cpu_kdt_rng.h
index a00d6afe58aeb784011e278663d813bbfa5cb9bd..0e1cc55e5df4f4712d9a5633adcb7137a92f7d15 100644
--- a/cpp/src/core/include/knowhere/index/vector_index/cpu_kdt_rng.h
+++ b/cpp/src/core/include/knowhere/index/vector_index/cpu_kdt_rng.h
@@ -27,8 +27,8 @@ class CPUKDTRNG : public VectorIndex {
     Load(const BinarySet &index_array) override;
 
  public:
-    PreprocessorPtr
-    BuildPreprocessor(const DatasetPtr &dataset, const Config &config) override;
+    //PreprocessorPtr
+    //BuildPreprocessor(const DatasetPtr &dataset, const Config &config) override;
     int64_t Count() override;
     int64_t Dimension() override;
 
diff --git a/cpp/src/core/src/knowhere/index/preprocessor/normalize.cpp b/cpp/src/core/src/knowhere/index/preprocessor/normalize.cpp
index 9e9ae924dd05be072b3c8b838a28a46ac7647eb8..41f6ad37159ef27dc3b94dfab35cba86b7c0832c 100644
--- a/cpp/src/core/src/knowhere/index/preprocessor/normalize.cpp
+++ b/cpp/src/core/src/knowhere/index/preprocessor/normalize.cpp
@@ -1,14 +1,14 @@
-
-#include "knowhere/index/vector_index/definitions.h"
-#include "knowhere/common/config.h"
-#include "knowhere/index/preprocessor/normalize.h"
-
-
-namespace zilliz {
-namespace knowhere {
-
-DatasetPtr
-NormalizePreprocessor::Preprocess(const DatasetPtr &dataset) {
+//
+//#include "knowhere/index/vector_index/definitions.h"
+//#include "knowhere/common/config.h"
+//#include "knowhere/index/preprocessor/normalize.h"
+//
+//
+//namespace zilliz {
+//namespace knowhere {
+//
+//DatasetPtr
+//NormalizePreprocessor::Preprocess(const DatasetPtr &dataset) {
 //    // TODO: wrap dataset->tensor
 //    auto tensor = dataset->tensor()[0];
 //    auto p_data = (float *)tensor->raw_mutable_data();
@@ -19,24 +19,24 @@ NormalizePreprocessor::Preprocess(const DatasetPtr &dataset) {
 //    for (auto i = 0; i < rows; ++i) {
 //        Normalize(&(p_data[i * dimension]), dimension);
 //    }
-}
-
-void
-NormalizePreprocessor::Normalize(float *arr, int64_t dimension) {
-    //double vector_length = 0;
-    //for (auto j = 0; j < dimension; j++) {
-    //    double val = arr[j];
-    //    vector_length += val * val;
-    //}
-    //vector_length = std::sqrt(vector_length);
-    //if (vector_length < 1e-6) {
-    //    auto val = (float) (1.0 / std::sqrt((double) dimension));
-    //    for (int j = 0; j < dimension; j++) arr[j] = val;
-    //} else {
-    //    for (int j = 0; j < dimension; j++) arr[j] = (float) (arr[j] / vector_length);
-    //}
-}
-
-} // namespace knowhere
-} // namespace zilliz
+//}
+//
+//void
+//NormalizePreprocessor::Normalize(float *arr, int64_t dimension) {
+//    double vector_length = 0;
+//    for (auto j = 0; j < dimension; j++) {
+//        double val = arr[j];
+//        vector_length += val * val;
+//    }
+//    vector_length = std::sqrt(vector_length);
+//    if (vector_length < 1e-6) {
+//        auto val = (float) (1.0 / std::sqrt((double) dimension));
+//        for (int j = 0; j < dimension; j++) arr[j] = val;
+//    } else {
+//        for (int j = 0; j < dimension; j++) arr[j] = (float) (arr[j] / vector_length);
+//    }
+//}
+//
+//} // namespace knowhere
+//} // namespace zilliz
 
diff --git a/cpp/src/core/src/knowhere/index/vector_index/cpu_kdt_rng.cpp b/cpp/src/core/src/knowhere/index/vector_index/cpu_kdt_rng.cpp
index ddcd8d789816cb14925dcbf0bf3d384f17dba37b..0805398144e210b42374b1bcbb897e8c38368a5b 100644
--- a/cpp/src/core/src/knowhere/index/vector_index/cpu_kdt_rng.cpp
+++ b/cpp/src/core/src/knowhere/index/vector_index/cpu_kdt_rng.cpp
@@ -9,7 +9,7 @@
 
 #include "knowhere/index/vector_index/cpu_kdt_rng.h"
 #include "knowhere/index/vector_index/definitions.h"
-#include "knowhere/index/preprocessor/normalize.h"
+//#include "knowhere/index/preprocessor/normalize.h"
 #include "knowhere/index/vector_index/kdt_parameters.h"
 #include "knowhere/adapter/sptag.h"
 #include "knowhere/common/exception.h"
@@ -60,10 +60,10 @@ CPUKDTRNG::Load(const BinarySet &binary_set) {
     index_ptr_->LoadIndexFromMemory(index_blobs);
 }
 
-PreprocessorPtr
-CPUKDTRNG::BuildPreprocessor(const DatasetPtr &dataset, const Config &config) {
-    return std::make_shared<NormalizePreprocessor>();
-}
+//PreprocessorPtr
+//CPUKDTRNG::BuildPreprocessor(const DatasetPtr &dataset, const Config &config) {
+//    return std::make_shared<NormalizePreprocessor>();
+//}
 
 IndexModelPtr
 CPUKDTRNG::Train(const DatasetPtr &origin, const Config &train_config) {
@@ -72,7 +72,7 @@ CPUKDTRNG::Train(const DatasetPtr &origin, const Config &train_config) {
 
     //if (index_ptr_->GetDistCalcMethod() == SPTAG::DistCalcMethod::Cosine
     //    && preprocessor_) {
-        preprocessor_->Preprocess(dataset);
+    //    preprocessor_->Preprocess(dataset);
     //}
 
     auto vectorset = ConvertToVectorSet(dataset);
@@ -90,7 +90,7 @@ CPUKDTRNG::Add(const DatasetPtr &origin, const Config &add_config) {
 
     //if (index_ptr_->GetDistCalcMethod() == SPTAG::DistCalcMethod::Cosine
     //    && preprocessor_) {
-        preprocessor_->Preprocess(dataset);
+    //    preprocessor_->Preprocess(dataset);
     //}
 
     auto vectorset = ConvertToVectorSet(dataset);
diff --git a/cpp/src/core/test/test_kdt.cpp b/cpp/src/core/test/test_kdt.cpp
index 4236704cd8bfb038f305991561414bd9cee03788..34eeb9933b141e98246a80378fb8f49e25bc97eb 100644
--- a/cpp/src/core/test/test_kdt.cpp
+++ b/cpp/src/core/test/test_kdt.cpp
@@ -8,6 +8,7 @@
 
 #include <iostream>
 #include <sstream>
+#include "knowhere/common/exception.h"
 
 #include "knowhere/index/vector_index/cpu_kdt_rng.h"
 #include "knowhere/index/vector_index/definitions.h"
@@ -125,6 +126,10 @@ TEST_P(KDTTest, kdt_serialize) {
     auto result = new_index->Search(query_dataset, search_cfg);
     AssertAnns(result, nq, k);
     PrintResult(result, nq, k);
+    ASSERT_EQ(new_index->Count(), nb);
+    ASSERT_EQ(new_index->Dimension(), dim);
+    ASSERT_THROW({new_index->Clone();}, zilliz::knowhere::KnowhereException);
+    ASSERT_NO_THROW({new_index->Seal();});
 
     {
         int fileno = 0;