diff --git a/cpp/include/milvus-storage/reader/common/combine_reader.h b/cpp/include/milvus-storage/reader/common/combine_reader.h
index 72e44597..ba4fd168 100644
--- a/cpp/include/milvus-storage/reader/common/combine_reader.h
+++ b/cpp/include/milvus-storage/reader/common/combine_reader.h
@@ -1,11 +1,11 @@
 // Copyright 2023 Zilliz
-// 
+//
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
-// 
+//
 //     http://www.apache.org/licenses/LICENSE-2.0
-// 
+//
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -16,7 +16,6 @@
 
 #include <memory>
 #include "arrow/record_batch.h"
-#include "common/result.h"
 #include "storage/schema.h"
 
 namespace milvus_storage {
@@ -24,24 +23,24 @@ namespace milvus_storage {
 // CombineReader merges scalar fields and vector fields to an entire record.
 class CombineReader : public arrow::RecordBatchReader {
   public:
-  static Result<std::shared_ptr<CombineReader>> Make(std::shared_ptr<arrow::RecordBatchReader> scalar_reader,
-                                                     std::shared_ptr<arrow::RecordBatchReader> vector_reader,
-                                                     std::shared_ptr<Schema> schema);
+  static std::unique_ptr<CombineReader> Make(std::unique_ptr<arrow::RecordBatchReader> scalar_reader,
+                                             std::unique_ptr<arrow::RecordBatchReader> vector_reader,
+                                             std::shared_ptr<Schema> schema);
 
   std::shared_ptr<arrow::Schema> schema() const override;
 
   arrow::Status ReadNext(std::shared_ptr<arrow::RecordBatch>* batch) override;
 
-  CombineReader(std::shared_ptr<arrow::RecordBatchReader> scalar_reader,
-                std::shared_ptr<arrow::RecordBatchReader> vector_reader,
+  CombineReader(std::unique_ptr<arrow::RecordBatchReader> scalar_reader,
+                std::unique_ptr<arrow::RecordBatchReader> vector_reader,
                 std::shared_ptr<Schema> schema)
       : scalar_reader_(std::move(scalar_reader)),
         vector_reader_(std::move(vector_reader)),
         schema_(std::move(schema)) {}
 
   private:
-  std::shared_ptr<arrow::RecordBatchReader> scalar_reader_;
-  std::shared_ptr<arrow::RecordBatchReader> vector_reader_;
+  std::unique_ptr<arrow::RecordBatchReader> scalar_reader_;
+  std::unique_ptr<arrow::RecordBatchReader> vector_reader_;
   std::shared_ptr<Schema> schema_;
 };
 }  // namespace milvus_storage
diff --git a/cpp/include/milvus-storage/reader/merge_record_reader.h b/cpp/include/milvus-storage/reader/merge_record_reader.h
index 045e5fcd..b370d7c2 100644
--- a/cpp/include/milvus-storage/reader/merge_record_reader.h
+++ b/cpp/include/milvus-storage/reader/merge_record_reader.h
@@ -44,8 +44,8 @@ class MergeRecordReader : public arrow::RecordBatchReader {
   std::shared_ptr<Schema> schema_;
   const ReadOptions options_;
 
-  std::shared_ptr<arrow::RecordBatchReader> scalar_reader_;
-  std::shared_ptr<arrow::RecordBatchReader> vector_reader_;
+  std::unique_ptr<arrow::RecordBatchReader> scalar_reader_;
+  std::unique_ptr<arrow::RecordBatchReader> vector_reader_;
   std::shared_ptr<arrow::RecordBatchReader> curr_reader_;
   const DeleteFragmentVector delete_fragments_;
 };
diff --git a/cpp/include/milvus-storage/reader/record_reader.h b/cpp/include/milvus-storage/reader/record_reader.h
index 81bc68df..7fafabf7 100644
--- a/cpp/include/milvus-storage/reader/record_reader.h
+++ b/cpp/include/milvus-storage/reader/record_reader.h
@@ -31,10 +31,10 @@ bool only_contain_vector_columns(std::shared_ptr<Schema> schema, const std::set<
 
 bool filters_only_contain_pk_and_version(std::shared_ptr<Schema> schema, const Filter::FilterSet& filters);
 
-Result<std::shared_ptr<arrow::RecordBatchReader>> MakeScanDataReader(std::shared_ptr<Manifest> manifest,
+std::unique_ptr<arrow::RecordBatchReader> MakeScanDataReader(std::shared_ptr<Manifest> manifest,
                                                                      std::shared_ptr<arrow::fs::FileSystem> fs);
 
-std::shared_ptr<arrow::RecordBatchReader> MakeScanDeleteReader(std::shared_ptr<Manifest> manifest,
+std::unique_ptr<arrow::RecordBatchReader> MakeScanDeleteReader(std::shared_ptr<Manifest> manifest,
                                                                       std::shared_ptr<arrow::fs::FileSystem> fs);
 }  // namespace internal
 }  // namespace milvus_storage
diff --git a/cpp/include/milvus-storage/storage/manifest.h b/cpp/include/milvus-storage/storage/manifest.h
index 194078b3..6b3e50a8 100644
--- a/cpp/include/milvus-storage/storage/manifest.h
+++ b/cpp/include/milvus-storage/storage/manifest.h
@@ -1,11 +1,11 @@
 // Copyright 2023 Zilliz
-// 
+//
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
-// 
+//
 //     http://www.apache.org/licenses/LICENSE-2.0
-// 
+//
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -25,7 +25,7 @@ class Manifest {
   Manifest() = default;
   explicit Manifest(std::shared_ptr<Schema> schema);
 
-  const std::shared_ptr<Schema> schema();
+  std::shared_ptr<Schema> schema();
 
   void add_scalar_fragment(Fragment&& fragment);
 
diff --git a/cpp/include/milvus-storage/storage/space.h b/cpp/include/milvus-storage/storage/space.h
index 3072222a..807fc200 100644
--- a/cpp/include/milvus-storage/storage/space.h
+++ b/cpp/include/milvus-storage/storage/space.h
@@ -27,17 +27,17 @@ class RecordReader;
 
 class Space {
   public:
-  Status Write(arrow::RecordBatchReader* reader, const WriteOption& option);
+  Status Write(arrow::RecordBatchReader& reader, const WriteOption& option);
 
   std::unique_ptr<arrow::RecordBatchReader> Read(const ReadOptions& option) const;
 
   // Scan delete files
-  Result<std::shared_ptr<arrow::RecordBatchReader>> ScanDelete() const;
+  std::unique_ptr<arrow::RecordBatchReader> ScanDelete() const;
 
   // Scan data files without filtering deleted data
-  Result<std::shared_ptr<arrow::RecordBatchReader>> ScanData() const;
+  std::unique_ptr<arrow::RecordBatchReader> ScanData() const;
 
-  Status Delete(arrow::RecordBatchReader* reader);
+  Status Delete(arrow::RecordBatchReader& reader);
 
   // Open opened a space or create if the space does not exist.
   // If space does not exist. schema should not be nullptr, or an error will be returned.
@@ -54,7 +54,7 @@ class Space {
   // Get the byte size of a blob.
   Result<int64_t> GetBlobByteSize(const std::string& name) const;
 
-  std::vector<Blob> StatisticsBlobs() const;
+  const std::vector<Blob>& StatisticsBlobs() const;
 
   std::shared_ptr<Schema> schema() const;
 
diff --git a/cpp/src/reader/common/combine_reader.cpp b/cpp/src/reader/common/combine_reader.cpp
index f554a9ac..5785e950 100644
--- a/cpp/src/reader/common/combine_reader.cpp
+++ b/cpp/src/reader/common/combine_reader.cpp
@@ -1,11 +1,11 @@
 // Copyright 2023 Zilliz
-// 
+//
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
-// 
+//
 //     http://www.apache.org/licenses/LICENSE-2.0
-// 
+//
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -13,16 +13,14 @@
 // limitations under the License.
 
 #include "reader/common/combine_reader.h"
-#include "common/macro.h"
+#include <memory>
 #include "arrow/type.h"
 namespace milvus_storage {
-Result<std::shared_ptr<CombineReader>> CombineReader::Make(std::shared_ptr<arrow::RecordBatchReader> scalar_reader,
-                                                           std::shared_ptr<arrow::RecordBatchReader> vector_reader,
-                                                           std::shared_ptr<Schema> schema) {
-  if (scalar_reader == nullptr || vector_reader == nullptr) {
-    return Status::InvalidArgument("null reader");
-  }
-  return std::make_shared<CombineReader>(scalar_reader, vector_reader, schema);
+std::unique_ptr<CombineReader> CombineReader::Make(std::unique_ptr<arrow::RecordBatchReader> scalar_reader,
+                                                   std::unique_ptr<arrow::RecordBatchReader> vector_reader,
+                                                   std::shared_ptr<Schema> schema) {
+  assert(scalar_reader != nullptr && vector_reader != nullptr);
+  return std::make_unique<CombineReader>(std::move(scalar_reader), std::move(vector_reader), schema);
 }
 
 std::shared_ptr<arrow::Schema> CombineReader::schema() const { return schema_->schema(); }
@@ -48,4 +46,5 @@ arrow::Status CombineReader::ReadNext(std::shared_ptr<arrow::RecordBatch>* batch
   *batch = arrow::RecordBatch::Make(schema(), scalar_batch->num_rows(), std::move(columns));
   return arrow::Status::OK();
 }
-}  // namespace milvus_storage
\ No newline at end of file
+
+}  // namespace milvus_storage
diff --git a/cpp/src/reader/merge_record_reader.cpp b/cpp/src/reader/merge_record_reader.cpp
index c3dc7eed..482066e5 100644
--- a/cpp/src/reader/merge_record_reader.cpp
+++ b/cpp/src/reader/merge_record_reader.cpp
@@ -1,11 +1,11 @@
 // Copyright 2023 Zilliz
-// 
+//
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
-// 
+//
 //     http://www.apache.org/licenses/LICENSE-2.0
-// 
+//
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -36,8 +36,8 @@ MergeRecordReader::MergeRecordReader(const ReadOptions& options,
                                      std::shared_ptr<arrow::fs::FileSystem> fs,
                                      std::shared_ptr<Schema> schema)
     : schema_(schema), fs_(fs), options_(options), delete_fragments_(delete_fragments) {
-  scalar_reader_ = std::make_shared<MultiFilesSequentialReader>(fs, scalar_fragments, schema->scalar_schema(), options);
-  vector_reader_ = std::make_shared<MultiFilesSequentialReader>(fs, vector_fragments, schema->vector_schema(), options);
+  scalar_reader_ = std::make_unique<MultiFilesSequentialReader>(fs, scalar_fragments, schema->scalar_schema(), options);
+  vector_reader_ = std::make_unique<MultiFilesSequentialReader>(fs, vector_fragments, schema->vector_schema(), options);
 }
 
 std::shared_ptr<arrow::Schema> MergeRecordReader::schema() const {
@@ -73,8 +73,8 @@ arrow::Status MergeRecordReader::ReadNext(std::shared_ptr<arrow::RecordBatch>* b
 }
 
 Result<std::shared_ptr<arrow::RecordBatchReader>> MergeRecordReader::MakeInnerReader() {
-  ASSIGN_OR_RETURN_NOT_OK(auto combine_reader, CombineReader::Make(scalar_reader_, vector_reader_, schema_));
-  auto delete_reader = DeleteMergeReader::Make(combine_reader, schema_->options(), delete_fragments_, options_);
+  auto combine_reader = CombineReader::Make(std::move(scalar_reader_), std::move(vector_reader_), schema_);
+  auto delete_reader = DeleteMergeReader::Make(std::move(combine_reader), schema_->options(), delete_fragments_, options_);
   ASSIGN_OR_RETURN_NOT_OK(auto res, ProjectionReader::Make(schema(), delete_reader, options_));
   return res;
 }
diff --git a/cpp/src/reader/record_reader.cpp b/cpp/src/reader/record_reader.cpp
index 914eceb6..abeaeca1 100644
--- a/cpp/src/reader/record_reader.cpp
+++ b/cpp/src/reader/record_reader.cpp
@@ -72,8 +72,7 @@ std::unique_ptr<arrow::RecordBatchReader> MakeRecordReader(std::shared_ptr<Manif
   return std::make_unique<FilterQueryRecordReader>(options, scalar_data, vector_data, delete_fragments, fs, schema);
 }
 
-bool only_contain_scalar_columns(const std::shared_ptr<Schema> schema,
-                                               const std::set<std::string>& related_columns) {
+bool only_contain_scalar_columns(const std::shared_ptr<Schema> schema, const std::set<std::string>& related_columns) {
   for (auto& column : related_columns) {
     if (schema->options()->vector_column == column) {
       return false;
@@ -82,8 +81,7 @@ bool only_contain_scalar_columns(const std::shared_ptr<Schema> schema,
   return true;
 }
 
-bool only_contain_vector_columns(const std::shared_ptr<Schema> schema,
-                                               const std::set<std::string>& related_columns) {
+bool only_contain_vector_columns(const std::shared_ptr<Schema> schema, const std::set<std::string>& related_columns) {
   for (auto& column : related_columns) {
     if (schema->options()->vector_column != column && schema->options()->primary_column != column &&
         schema->options()->version_column != column) {
@@ -93,8 +91,7 @@ bool only_contain_vector_columns(const std::shared_ptr<Schema> schema,
   return true;
 }
 
-bool filters_only_contain_pk_and_version(std::shared_ptr<Schema> schema,
-                                                       const Filter::FilterSet& filters) {
+bool filters_only_contain_pk_and_version(std::shared_ptr<Schema> schema, const Filter::FilterSet& filters) {
   for (auto& filter : filters) {
     if (filter->get_column_name() != schema->options()->primary_column &&
         filter->get_column_name() != schema->options()->version_column) {
@@ -104,22 +101,20 @@ bool filters_only_contain_pk_and_version(std::shared_ptr<Schema> schema,
   return true;
 }
 
-Result<std::shared_ptr<arrow::RecordBatchReader>> MakeScanDataReader(
-    std::shared_ptr<Manifest> manifest, std::shared_ptr<arrow::fs::FileSystem> fs) {
-  auto scalar_reader = std::make_shared<MultiFilesSequentialReader>(fs, manifest->scalar_fragments(),
+std::unique_ptr<arrow::RecordBatchReader> MakeScanDataReader(std::shared_ptr<Manifest> manifest,
+                                                             std::shared_ptr<arrow::fs::FileSystem> fs) {
+  auto scalar_reader = std::make_unique<MultiFilesSequentialReader>(fs, manifest->scalar_fragments(),
                                                                     manifest->schema()->scalar_schema(), ReadOptions());
-  auto vector_reader = std::make_shared<MultiFilesSequentialReader>(fs, manifest->vector_fragments(),
+  auto vector_reader = std::make_unique<MultiFilesSequentialReader>(fs, manifest->vector_fragments(),
                                                                     manifest->schema()->vector_schema(), ReadOptions());
 
-  ASSIGN_OR_RETURN_NOT_OK(auto combine_reader, CombineReader::Make(scalar_reader, vector_reader, manifest->schema()));
-  return std::static_pointer_cast<arrow::RecordBatchReader>(combine_reader);
+  return CombineReader::Make(std::move(scalar_reader), std::move(vector_reader), manifest->schema());
 }
 
-std::shared_ptr<arrow::RecordBatchReader> MakeScanDeleteReader(
-    std::shared_ptr<Manifest> manifest, std::shared_ptr<arrow::fs::FileSystem> fs) {
-  auto reader = std::make_shared<MultiFilesSequentialReader>(fs, manifest->delete_fragments(),
-                                                             manifest->schema()->delete_schema(), ReadOptions());
-  return reader;
+std::unique_ptr<arrow::RecordBatchReader> MakeScanDeleteReader(std::shared_ptr<Manifest> manifest,
+                                                               std::shared_ptr<arrow::fs::FileSystem> fs) {
+  return std::make_unique<MultiFilesSequentialReader>(fs, manifest->delete_fragments(),
+                                                      manifest->schema()->delete_schema(), ReadOptions());
 }
 }  // namespace internal
 }  // namespace milvus_storage
diff --git a/cpp/src/storage/manifest.cpp b/cpp/src/storage/manifest.cpp
index e8fd5c83..9def53fc 100644
--- a/cpp/src/storage/manifest.cpp
+++ b/cpp/src/storage/manifest.cpp
@@ -21,7 +21,7 @@ namespace milvus_storage {
 
 Manifest::Manifest(std::shared_ptr<Schema> schema) : schema_(std::move(schema)) {}
 
-const std::shared_ptr<Schema> Manifest::schema() { return schema_; }
+std::shared_ptr<Schema> Manifest::schema() { return schema_; }
 
 void Manifest::add_scalar_fragment(Fragment&& fragment) { scalar_fragments_.push_back(fragment); }
 
diff --git a/cpp/src/storage/space.cpp b/cpp/src/storage/space.cpp
index bffe3981..235213ac 100644
--- a/cpp/src/storage/space.cpp
+++ b/cpp/src/storage/space.cpp
@@ -29,7 +29,6 @@
 #include "common/log.h"
 #include "common/macro.h"
 #include "file/delete_fragment.h"
-#include "filter/constant_filter.h"
 #include "format/parquet/file_writer.h"
 #include "storage/space.h"
 #include "common/utils.h"
@@ -47,8 +46,8 @@ Status Space::Init() {
   return Status::OK();
 }
 
-Status Space::Write(arrow::RecordBatchReader* reader, const WriteOption& option) {
-  if (!reader->schema()->Equals(*this->manifest_->schema()->schema())) {
+Status Space::Write(arrow::RecordBatchReader& reader, const WriteOption& option) {
+  if (!reader.schema()->Equals(*this->manifest_->schema()->schema())) {
     return Status::InvalidArgument("Schema not match");
   }
 
@@ -65,7 +64,7 @@ Status Space::Write(arrow::RecordBatchReader* reader, const WriteOption& option)
   Fragment scalar_fragment;
   Fragment vector_fragment;
 
-  for (auto rec = reader->Next(); rec.ok(); rec = reader->Next()) {
+  for (auto rec = reader.Next(); rec.ok(); rec = reader.Next()) {
     auto batch = rec.ValueOrDie();
     if (batch == nullptr) {
       break;
@@ -140,12 +139,12 @@ Status Space::Write(arrow::RecordBatchReader* reader, const WriteOption& option)
   return Status::OK();
 }
 
-Status Space::Delete(arrow::RecordBatchReader* reader) {
+Status Space::Delete(arrow::RecordBatchReader& reader) {
   FileWriter* writer = nullptr;
   Fragment fragment;
   auto delete_fragment = std::make_shared<DeleteFragment>(fs_, manifest_->schema());
   std::string delete_file;
-  for (auto rec = reader->Next(); rec.ok(); rec = reader->Next()) {
+  for (auto rec = reader.Next(); rec.ok(); rec = reader.Next()) {
     auto batch = rec.ValueOrDie();
     if (batch == nullptr) {
       break;
@@ -307,13 +306,13 @@ Result<arrow::fs::FileInfoVector> Space::FindAllManifest(std::shared_ptr<arrow::
   return info_vec;
 }
 
-std::vector<Blob> Space::StatisticsBlobs() const { return manifest_->blobs(); }
+const std::vector<Blob>& Space::StatisticsBlobs() const { return manifest_->blobs(); }
 
-Result<std::shared_ptr<arrow::RecordBatchReader>> Space::ScanDelete() const {
+std::unique_ptr<arrow::RecordBatchReader> Space::ScanDelete() const {
   return internal::MakeScanDeleteReader(manifest_, fs_);
 }
 
-Result<std::shared_ptr<arrow::RecordBatchReader>> Space::ScanData() const {
+std::unique_ptr<arrow::RecordBatchReader> Space::ScanData() const {
   return internal::MakeScanDataReader(manifest_, fs_);
 }
 
diff --git a/cpp/test/space_test.cpp b/cpp/test/space_test.cpp
index 4761e483..e65b1070 100644
--- a/cpp/test/space_test.cpp
+++ b/cpp/test/space_test.cpp
@@ -72,7 +72,7 @@ TEST(SpaceTest, SpaceWriteReadTest) {
   auto reader = arrow::RecordBatchReader::Make({rec_batch}, arrow_schema).ValueOrDie();
 
   WriteOption write_option{10};
-  space->Write(reader.get(), write_option);
+  space->Write(*reader, write_option);
 
   ConstantFilter filter(EQUAL, "pk_field", Value::Int64(1));
   ReadOptions read_options;