diff --git a/internal/core/src/common/LoadInfo.h b/internal/core/src/common/LoadInfo.h
index 372a5527ac..40a387f476 100644
--- a/internal/core/src/common/LoadInfo.h
+++ b/internal/core/src/common/LoadInfo.h
@@ -33,7 +33,7 @@ struct FieldBinlogInfo {
 
 struct LoadFieldDataInfo {
     std::map<int64_t, FieldBinlogInfo> field_infos;
-    // Set null to disable mmap,
+    // Set empty to disable mmap,
     // mmap file path will be {mmap_dir_path}/{segment_id}/{field_id}
     std::string mmap_dir_path = "";
 };
diff --git a/internal/core/src/mmap/Column.h b/internal/core/src/mmap/Column.h
index f0e0ff76d7..65f9f8c875 100644
--- a/internal/core/src/mmap/Column.h
+++ b/internal/core/src/mmap/Column.h
@@ -16,29 +16,76 @@
 #pragma once
 
 #include <sys/mman.h>
-
+#include <algorithm>
 #include <cstddef>
-#include <ostream>
-#include <string_view>
-#include <type_traits>
-#include <vector>
-#include <string>
-#include <utility>
+#include <cstring>
+#include <filesystem>
 
+#include "common/FieldMeta.h"
+#include "common/Span.h"
+#include "exceptions/EasyAssert.h"
+#include "fmt/format.h"
 #include "mmap/Utils.h"
 
 namespace milvus {
 
-struct Entry {
-    char* data;
-    uint32_t length;
-};
+#ifdef MAP_POPULATE
+static int mmap_flags = MAP_PRIVATE | MAP_POPULATE;
+#else
+static int mmap_flags = MAP_PRIVATE;
+#endif
 
 class ColumnBase {
  public:
-    ColumnBase() = default;
+    // memory mode ctor
+    ColumnBase(size_t num_rows, const FieldMeta& field_meta) {
+        // simdjson requires a padding following the json data
+        padding_ = field_meta.get_data_type() == DataType::JSON
+                       ? simdjson::SIMDJSON_PADDING
+                       : 0;
+
+        if (datatype_is_variable(field_meta.get_data_type())) {
+            return;
+        }
+
+        size_ = field_meta.get_sizeof() * num_rows + padding_;
+        auto data_type = field_meta.get_data_type();
+
+        // use anon mapping so we are able to free these memory with munmap only
+        data_ = static_cast<char*>(mmap(nullptr,
+                                        size_,
+                                        PROT_READ | PROT_WRITE,
+                                        mmap_flags | MAP_ANON,
+                                        -1,
+                                        0));
+        AssertInfo(
+            data_ != MAP_FAILED,
+            fmt::format("failed to create anon map, err: {}", strerror(errno)));
+    }
+
+    // mmap mode ctor
+    ColumnBase(int fd, size_t size, const FieldMeta& field_meta) {
+        padding_ = field_meta.get_data_type() == DataType::JSON
+                       ? simdjson::SIMDJSON_PADDING
+                       : 0;
+
+        len_ = size;
+        size_ = size + padding_;
+        data_ = static_cast<char*>(
+            mmap(nullptr, size_, PROT_READ, mmap_flags, fd, 0));
+#ifndef MAP_POPULATE
+        // Manually access the mapping to populate it
+        const size_t page_size = getpagesize();
+        char* begin = (char*)data_;
+        char* end = begin + len_;
+        for (char* page = begin; page < end; page += page_size) {
+            char value = page[0];
+        }
+#endif
+    }
+
     virtual ~ColumnBase() {
-        if (data_ != nullptr && data_ != MAP_FAILED) {
+        if (data_ != nullptr) {
             if (munmap(data_, size_)) {
                 AssertInfo(true,
                            fmt::format("failed to unmap variable field, err={}",
@@ -54,47 +101,93 @@ class ColumnBase {
     }
 
     const char*
-    data() const {
+    Data() const {
         return data_;
     }
 
-    [[nodiscard]] size_t
-    size() const {
+    size_t
+    Size() const {
         return size_;
     }
 
     virtual SpanBase
-    span() const = 0;
+    Span() const = 0;
+
+    // build only
+    void
+    Append(const char* data, size_t size) {
+        size_t required_size = len_ + size;
+        if (required_size + padding_ > size_) {
+            Expand(required_size * 2 + padding_);
+        }
+
+        std::copy_n(data, size, data_ + len_);
+        len_ += size;
+    }
 
  protected:
+    // only for memory mode, not mmap
+    void
+    Expand(size_t size) {
+        auto data = static_cast<char*>(mmap(nullptr,
+                                            size,
+                                            PROT_READ | PROT_WRITE,
+                                            mmap_flags | MAP_ANON,
+                                            -1,
+                                            0));
+
+        AssertInfo(data != MAP_FAILED,
+                   fmt::format("failed to create map: {}", strerror(errno)));
+
+        if (data_ != nullptr) {
+            std::memcpy(data, data_, len_);
+            if (munmap(data_, size_)) {
+                AssertInfo(
+                    false,
+                    fmt::format("failed to unmap while expanding, err={}",
+                                strerror(errno)));
+            }
+        }
+
+        data_ = data;
+        size_ = size;
+    }
+
     char* data_{nullptr};
-    uint64_t size_{0};
+    size_t size_{0};
+    size_t padding_{0};
+
+    // build only
+    size_t len_{0};
 };
 
 class Column : public ColumnBase {
  public:
-    Column(int64_t segment_id,
-           const FieldMeta& field_meta,
-           const FieldDataInfo& info) {
-        data_ = static_cast<char*>(CreateMap(segment_id, field_meta, info));
-        size_ = field_meta.get_sizeof() * info.row_count;
-        row_count_ = info.row_count;
+    // memory mode ctor
+    Column(size_t num_rows, const FieldMeta& field_meta)
+        : ColumnBase(num_rows, field_meta), num_rows_(num_rows) {
+    }
+
+    // mmap mode ctor
+    Column(int fd, size_t size, const FieldMeta& field_meta)
+        : ColumnBase(fd, size, field_meta),
+          num_rows_(size / field_meta.get_sizeof()) {
     }
 
     Column(Column&& column) noexcept
-        : ColumnBase(std::move(column)), row_count_(column.row_count_) {
-        column.row_count_ = 0;
+        : ColumnBase(std::move(column)), num_rows_(column.num_rows_) {
+        column.num_rows_ = 0;
     }
 
     ~Column() override = default;
 
     SpanBase
-    span() const override {
-        return SpanBase(data_, row_count_, size_ / row_count_);
+    Span() const override {
+        return SpanBase(data_, num_rows_, size_ / num_rows_);
     }
 
  private:
-    int64_t row_count_{};
+    size_t num_rows_{};
 };
 
 template <typename T>
@@ -103,37 +196,31 @@ class VariableColumn : public ColumnBase {
     using ViewType =
         std::conditional_t<std::is_same_v<T, std::string>, std::string_view, T>;
 
-    VariableColumn(int64_t segment_id,
-                   const FieldMeta& field_meta,
-                   const FieldDataInfo& info) {
-        indices_.reserve(info.row_count);
-        for (auto data : info.datas) {
-            for (ssize_t idx = 0; idx < data->get_num_rows(); ++idx) {
-                indices_.emplace_back(size_);
-                size_ += data->Size(idx);
-            }
-        }
-
-        data_ = static_cast<char*>(CreateMap(segment_id, field_meta, info));
-        construct_views();
+    // memory mode ctor
+    VariableColumn(size_t num_rows, const FieldMeta& field_meta)
+        : ColumnBase(num_rows, field_meta) {
     }
 
-    VariableColumn(VariableColumn&& field) noexcept
-        : indices_(std::move(field.indices_)), views_(std::move(field.views_)) {
-        data_ = field.data();
-        size_ = field.size();
-        field.data_ = nullptr;
+    // mmap mode ctor
+    VariableColumn(int fd, size_t size, const FieldMeta& field_meta)
+        : ColumnBase(fd, size, field_meta) {
+    }
+
+    VariableColumn(VariableColumn&& column) noexcept
+        : ColumnBase(std::move(column)),
+          indices_(std::move(column.indices_)),
+          views_(std::move(column.views_)) {
     }
 
     ~VariableColumn() override = default;
 
     SpanBase
-    span() const override {
+    Span() const override {
         return SpanBase(views_.data(), views_.size(), sizeof(ViewType));
     }
 
     [[nodiscard]] const std::vector<ViewType>&
-    views() const {
+    Views() const {
         return views_;
     }
 
@@ -143,21 +230,35 @@ class VariableColumn : public ColumnBase {
     }
 
     std::string_view
-    raw_at(const int i) const {
-        size_t len = (i == indices_.size() - 1) ? size_ - indices_.back()
+    RawAt(const int i) const {
+        size_t len = (i == indices_.size() - 1) ? len_ - indices_.back()
                                                 : indices_[i + 1] - indices_[i];
         return std::string_view(data_ + indices_[i], len);
     }
 
+    void
+    Append(const char* data, size_t size) {
+        indices_.emplace_back(len_);
+        ColumnBase::Append(data, size);
+    }
+
+    void
+    Seal(std::vector<uint64_t> indices = {}) {
+        if (!indices.empty()) {
+            indices_ = std::move(indices);
+        }
+        ConstructViews();
+    }
+
  protected:
     void
-    construct_views() {
+    ConstructViews() {
         views_.reserve(indices_.size());
         for (size_t i = 0; i < indices_.size() - 1; i++) {
             views_.emplace_back(data_ + indices_[i],
                                 indices_[i + 1] - indices_[i]);
         }
-        views_.emplace_back(data_ + indices_.back(), size_ - indices_.back());
+        views_.emplace_back(data_ + indices_.back(), len_ - indices_.back());
     }
 
  private:
diff --git a/internal/core/src/segcore/SegmentSealedImpl.cpp b/internal/core/src/segcore/SegmentSealedImpl.cpp
index 97ccae7894..e526ff9b7c 100644
--- a/internal/core/src/segcore/SegmentSealedImpl.cpp
+++ b/internal/core/src/segcore/SegmentSealedImpl.cpp
@@ -14,13 +14,16 @@
 #include <fcntl.h>
 #include <fmt/core.h>
 
+#include <cstdint>
 #include <filesystem>
 #include <memory>
 #include <string>
 #include <string_view>
+#include <vector>
 
 #include "Utils.h"
 #include "Types.h"
+#include "common/Json.h"
 #include "mmap/Column.h"
 #include "common/Consts.h"
 #include "common/FieldMeta.h"
@@ -178,9 +181,15 @@ SegmentSealedImpl::LoadFieldData(const LoadFieldDataInfo& load_info) {
         int64_t num_rows = storage::GetTotalNumRowsForFieldDatas(field_datas);
         AssertInfo(num_rows == info.row_count,
                    "inconsistent field data row count with meta");
+
         auto field_data_info = FieldDataInfo{
             field_id.get(), num_rows, field_datas, load_info.mmap_dir_path};
-        LoadFieldData(field_id, field_data_info);
+        if (load_info.mmap_dir_path.empty() ||
+            SystemProperty::Instance().IsSystem(field_id)) {
+            LoadFieldData(field_id, field_data_info);
+        } else {
+            MapFieldData(field_id, field_data_info);
+        }
     }
 }
 
@@ -251,13 +260,37 @@ SegmentSealedImpl::LoadFieldData(FieldId field_id,
             switch (data_type) {
                 case milvus::DataType::STRING:
                 case milvus::DataType::VARCHAR: {
-                    column = std::make_unique<VariableColumn<std::string>>(
-                        get_segment_id(), field_meta, data_info);
+                    auto var_column =
+                        std::make_unique<VariableColumn<std::string>>(
+                            num_rows, field_meta);
+                    for (auto& data : data_info.datas) {
+                        for (auto i = 0; i < data->get_num_rows(); i++) {
+                            auto str = static_cast<const std::string*>(
+                                data->RawValue(i));
+                            var_column->Append(str->data(), str->size());
+                        }
+                    }
+                    var_column->Seal();
+                    column = std::move(var_column);
                     break;
                 }
                 case milvus::DataType::JSON: {
-                    column = std::make_unique<VariableColumn<Json>>(
-                        get_segment_id(), field_meta, data_info);
+                    auto var_column =
+                        std::make_unique<VariableColumn<milvus::Json>>(
+                            num_rows, field_meta);
+                    for (auto& data : data_info.datas) {
+                        for (auto i = 0; i < data->get_num_rows(); i++) {
+                            auto padded_string =
+                                static_cast<const milvus::Json*>(
+                                    data->RawValue(i))
+                                    ->data();
+                            var_column->Append(padded_string.data(),
+                                               padded_string.size());
+                        }
+                    }
+                    var_column->Seal();
+                    column = std::move(var_column);
+                    break;
                 }
                 default: {
                 }
@@ -266,8 +299,11 @@ SegmentSealedImpl::LoadFieldData(FieldId field_id,
             std::unique_lock lck(mutex_);
             variable_fields_.emplace(field_id, std::move(column));
         } else {
-            auto column = Column(get_segment_id(), field_meta, data_info);
-
+            auto column = Column(num_rows, field_meta);
+            for (auto& data : data_info.datas) {
+                column.Append(static_cast<const char*>(data->Data()),
+                              data->Size());
+            }
             std::unique_lock lck(mutex_);
             fixed_fields_.emplace(field_id, std::move(column));
         }
@@ -287,6 +323,106 @@ SegmentSealedImpl::LoadFieldData(FieldId field_id,
     update_row_count(num_rows);
 }
 
+void
+SegmentSealedImpl::MapFieldData(const FieldId field_id,
+                                const FieldDataInfo& data_info) {
+    auto filepath = std::filesystem::path(data_info.mmap_dir_path) /
+                    std::to_string(get_segment_id()) /
+                    std::to_string(field_id.get());
+    auto dir = filepath.parent_path();
+    std::filesystem::create_directories(dir);
+
+    int fd =
+        open(filepath.c_str(), O_CREAT | O_TRUNC | O_RDWR, S_IRUSR | S_IWUSR);
+    AssertInfo(fd != -1,
+               fmt::format("failed to create mmap file {}", filepath.c_str()));
+
+    auto& field_meta = (*schema_)[field_id];
+    auto data_type = field_meta.get_data_type();
+
+    // write the field data to disk
+    ssize_t total_written{0};
+    auto data_size = GetDataSize(data_info.datas);
+    std::vector<uint64_t> indices{};
+    for (auto& data : data_info.datas) {
+        auto written = WriteFieldData(fd, data_type, data);
+        if (written != data->Size()) {
+            break;
+        }
+        indices.emplace_back(total_written);
+        total_written += written;
+    }
+    AssertInfo(
+        total_written == data_size ||
+            total_written != -1 &&
+                datatype_is_variable(field_meta.get_data_type()),
+        fmt::format(
+            "failed to write data file {}, written {} but total {}, err: {}",
+            filepath.c_str(),
+            total_written,
+            data_size,
+            strerror(errno)));
+    int ok = fsync(fd);
+    AssertInfo(ok == 0,
+               fmt::format("failed to fsync mmap data file {}, err: {}",
+                           filepath.c_str(),
+                           strerror(errno)));
+
+    auto num_rows = data_info.row_count;
+    if (datatype_is_variable(data_type)) {
+        std::unique_ptr<ColumnBase> column{};
+        switch (data_type) {
+            case milvus::DataType::STRING:
+            case milvus::DataType::VARCHAR: {
+                auto var_column = std::make_unique<VariableColumn<std::string>>(
+                    fd, total_written, field_meta);
+                var_column->Seal(std::move(indices));
+                column = std::move(var_column);
+                break;
+            }
+            case milvus::DataType::JSON: {
+                auto var_column =
+                    std::make_unique<VariableColumn<milvus::Json>>(
+                        fd, total_written, field_meta);
+                var_column->Seal(std::move(indices));
+                column = std::move(var_column);
+                break;
+            }
+            default: {
+            }
+        }
+
+        std::unique_lock lck(mutex_);
+        variable_fields_.emplace(field_id, std::move(column));
+    } else {
+        auto column = Column(fd, total_written, field_meta);
+        std::unique_lock lck(mutex_);
+        fixed_fields_.emplace(field_id, std::move(column));
+    }
+
+    ok = unlink(filepath.c_str());
+    AssertInfo(ok == 0,
+               fmt::format("failed to unlink mmap data file {}, err: {}",
+                           filepath.c_str(),
+                           strerror(errno)));
+    ok = close(fd);
+    AssertInfo(ok == 0,
+               fmt::format("failed to close data file {}, err: {}",
+                           filepath.c_str(),
+                           strerror(errno)));
+
+    // set pks to offset
+    if (schema_->get_primary_field_id() == field_id) {
+        AssertInfo(field_id.get() != -1, "Primary key is -1");
+        AssertInfo(insert_record_.empty_pks(), "already exists");
+        insert_record_.insert_pks(data_info.datas);
+        insert_record_.seal_pks();
+    }
+
+    std::unique_lock lck(mutex_);
+    set_bit(field_data_ready_bitset_, field_id, true);
+}
+
 void
 SegmentSealedImpl::LoadDeletedRecord(const LoadDeletedRecordInfo& info) {
     AssertInfo(info.row_count > 0, "The row count of deleted record is 0");
@@ -340,12 +476,12 @@ SegmentSealedImpl::chunk_data_impl(FieldId field_id, int64_t chunk_id) const {
     auto element_sizeof = field_meta.get_sizeof();
     if (auto it = fixed_fields_.find(field_id); it != fixed_fields_.end()) {
         auto& field_data = it->second;
-        return field_data.span();
+        return field_data.Span();
     }
     if (auto it = variable_fields_.find(field_id);
         it != variable_fields_.end()) {
         auto& field = it->second;
-        return field->span();
+        return field->Span();
     }
     auto field_data = insert_record_.get_field_data_base(field_id);
     AssertInfo(field_data->num_chunk() == 1,
@@ -439,7 +575,7 @@ SegmentSealedImpl::vector_search(SearchInfo& search_info,
         auto row_count = row_count_opt_.value();
         auto& vec_data = fixed_fields_.at(field_id);
         query::SearchOnSealed(*schema_,
-                              vec_data.data(),
+                              vec_data.Data(),
                               search_info,
                               query_data,
                               query_count,
@@ -614,7 +750,7 @@ SegmentSealedImpl::bulk_subscript_impl(const ColumnBase* column,
     for (int64_t i = 0; i < count; ++i) {
         auto offset = seg_offsets[i];
         if (offset != INVALID_SEG_OFFSET) {
-            dst[i] = std::move(T(field->raw_at(offset)));
+            dst[i] = std::move(T(field->RawAt(offset)));
         }
     }
 }
@@ -706,7 +842,7 @@ SegmentSealedImpl::bulk_subscript(FieldId field_id,
         }
     }
 
-    auto src_vec = fixed_fields_.at(field_id).data();
+    auto src_vec = fixed_fields_.at(field_id).Data();
     switch (field_meta.get_data_type()) {
         case DataType::BOOL: {
             FixedVector<bool> output(count);
diff --git a/internal/core/src/segcore/SegmentSealedImpl.h b/internal/core/src/segcore/SegmentSealedImpl.h
index 9fdd70d6f8..f4a93e3c78 100644
--- a/internal/core/src/segcore/SegmentSealedImpl.h
+++ b/internal/core/src/segcore/SegmentSealedImpl.h
@@ -55,9 +55,13 @@ class SegmentSealedImpl : public SegmentSealed {
     HasIndex(FieldId field_id) const override;
     bool
     HasFieldData(FieldId field_id) const override;
+
     void
     LoadFieldData(FieldId field_id, const FieldDataInfo& data_info) override;
 
+    void
+    MapFieldData(const FieldId field_id, const FieldDataInfo& data);
+
     int64_t
     get_segment_id() const override {
         return id_;
diff --git a/internal/core/src/segcore/Utils.cpp b/internal/core/src/segcore/Utils.cpp
index 77e63d0da7..c624b18443 100644
--- a/internal/core/src/segcore/Utils.cpp
+++ b/internal/core/src/segcore/Utils.cpp
@@ -552,12 +552,12 @@ LoadFieldDatasFromRemote(std::vector<std::string>& remote_files) {
     std::sort(remote_files.begin(),
               remote_files.end(),
               [](const std::string& a, const std::string& b) {
-                  return std::stol(a.substr(a.find_last_of("/") + 1)) <
-                         std::stol(b.substr(b.find_last_of("/") + 1));
+                  return std::stol(a.substr(a.find_last_of('/') + 1)) <
+                         std::stol(b.substr(b.find_last_of('/') + 1));
               });
 
     auto parallel_degree =
-        uint64_t(DEFAULT_FIELD_MAX_MEMORY_LIMIT / FILE_SLICE_SIZE);
+        static_cast<uint64_t>(DEFAULT_FIELD_MAX_MEMORY_LIMIT / FILE_SLICE_SIZE);
     std::vector<std::string> batch_files;
     std::vector<storage::FieldDataPtr> field_datas;