diff --git a/cpp/CHANGELOG.md b/cpp/CHANGELOG.md
index e88a80fb33..04ca984858 100644
--- a/cpp/CHANGELOG.md
+++ b/cpp/CHANGELOG.md
@@ -11,6 +11,7 @@ Please mark all change in change log and use the ticket from JIRA.
 - MS-89 - Fix compile failed, libgpufaiss.a link missing
 - MS-90 - Fix arch match incorrect on ARM
 - MS-99 - Fix compilation bug
+- MS-110 - Avoid huge file size
 
 ## Improvement
 - MS-82 - Update server startup welcome message
diff --git a/cpp/src/db/DBImpl.cpp b/cpp/src/db/DBImpl.cpp
index 279c2a5636..17280b37d3 100644
--- a/cpp/src/db/DBImpl.cpp
+++ b/cpp/src/db/DBImpl.cpp
@@ -479,7 +479,7 @@ void DBImpl::StartCompactionTask() {
     }
 
     //serialize memory data
-    std::vector<std::string> temp_table_ids;
+    std::set<std::string> temp_table_ids;
     mem_mgr_->Serialize(temp_table_ids);
     for(auto& id : temp_table_ids) {
         compact_table_ids_.insert(id);
@@ -550,7 +550,8 @@ Status DBImpl::MergeFiles(const std::string& table_id, const meta::DateT& date,
     ENGINE_LOG_DEBUG << "New merged file " << table_file.file_id_ <<
         " of size=" << index->PhysicalSize()/(1024*1024) << " M";
 
-    index->Cache();
+    //current disable this line to avoid memory
+    //index->Cache();
 
     return status;
 }
@@ -670,7 +671,8 @@ Status DBImpl::BuildIndex(const meta::TableFileSchema& file) {
                    << index->PhysicalSize()/(1024*1024) << " M"
                    << " from file " << to_remove.file_id_;
 
-        index->Cache();
+        //current disable this line to avoid memory
+        //index->Cache();
 
     } catch (std::exception& ex) {
         return Status::Error("Build index encounter exception", ex.what());
@@ -709,7 +711,7 @@ Status DBImpl::Size(uint64_t& result) {
 DBImpl::~DBImpl() {
     shutting_down_.store(true, std::memory_order_release);
     bg_timer_thread_.join();
-    std::vector<std::string> ids;
+    std::set<std::string> ids;
     mem_mgr_->Serialize(ids);
 }
 
diff --git a/cpp/src/db/MemManager.cpp b/cpp/src/db/MemManager.cpp
index d7a2087ee0..fa7f3c54b0 100644
--- a/cpp/src/db/MemManager.cpp
+++ b/cpp/src/db/MemManager.cpp
@@ -20,36 +20,54 @@ namespace engine {
 
 MemVectors::MemVectors(const std::shared_ptr<meta::Meta>& meta_ptr,
         const meta::TableFileSchema& schema, const Options& options)
-  : pMeta_(meta_ptr),
+  : meta_(meta_ptr),
     options_(options),
     schema_(schema),
-    pIdGenerator_(new SimpleIDGenerator()),
-    pEE_(EngineFactory::Build(schema_.dimension_, schema_.location_, (EngineType)schema_.engine_type_)) {
+    id_generator_(new SimpleIDGenerator()),
+    active_engine_(EngineFactory::Build(schema_.dimension_, schema_.location_, (EngineType)schema_.engine_type_)) {
 }
 
 
-void MemVectors::Add(size_t n_, const float* vectors_, IDNumbers& vector_ids_) {
+Status MemVectors::Add(size_t n_, const float* vectors_, IDNumbers& vector_ids_) {
+    if(active_engine_ == nullptr) {
+        return Status::Error("index engine is null");
+    }
+
     auto start_time = METRICS_NOW_TIME;
-    pIdGenerator_->GetNextIDNumbers(n_, vector_ids_);
-    pEE_->AddWithIds(n_, vectors_, vector_ids_.data());
+    id_generator_->GetNextIDNumbers(n_, vector_ids_);
+    Status status = active_engine_->AddWithIds(n_, vectors_, vector_ids_.data());
     auto end_time = METRICS_NOW_TIME;
     auto total_time = METRICS_MICROSECONDS(start_time, end_time);
     server::Metrics::GetInstance().AddVectorsPerSecondGaugeSet(static_cast<int>(n_), static_cast<int>(schema_.dimension_), total_time);
+
+    return status;
 }
 
-size_t MemVectors::Total() const {
-    return pEE_->Count();
+size_t MemVectors::RowCount() const {
+    if(active_engine_ == nullptr) {
+        return 0;
+    }
+
+    return active_engine_->Count();
 }
 
-size_t MemVectors::ApproximateSize() const {
-    return pEE_->Size();
+size_t MemVectors::Size() const {
+    if(active_engine_ == nullptr) {
+        return 0;
+    }
+
+    return active_engine_->Size();
 }
 
 Status MemVectors::Serialize(std::string& table_id) {
+    if(active_engine_ == nullptr) {
+        return Status::Error("index engine is null");
+    }
+
     table_id = schema_.table_id_;
-    auto size = ApproximateSize();
+    auto size = Size();
     auto start_time = METRICS_NOW_TIME;
-    pEE_->Serialize();
+    active_engine_->Serialize();
     auto end_time = METRICS_NOW_TIME;
     auto total_time = METRICS_MICROSECONDS(start_time, end_time);
     schema_.size_ = size;
@@ -59,20 +77,20 @@ Status MemVectors::Serialize(std::string& table_id) {
     schema_.file_type_ = (size >= options_.index_trigger_size) ?
         meta::TableFileSchema::TO_INDEX : meta::TableFileSchema::RAW;
 
-    auto status = pMeta_->UpdateTableFile(schema_);
+    auto status = meta_->UpdateTableFile(schema_);
 
     LOG(DEBUG) << "New " << ((schema_.file_type_ == meta::TableFileSchema::RAW) ? "raw" : "to_index")
-        << " file " << schema_.file_id_ << " of size " << (double)(pEE_->Size()) / (double)meta::M << " M";
+        << " file " << schema_.file_id_ << " of size " << (double)(active_engine_->Size()) / (double)meta::M << " M";
 
-    pEE_->Cache();
+    active_engine_->Cache();
 
     return status;
 }
 
 MemVectors::~MemVectors() {
-    if (pIdGenerator_ != nullptr) {
-        delete pIdGenerator_;
-        pIdGenerator_ = nullptr;
+    if (id_generator_ != nullptr) {
+        delete id_generator_;
+        id_generator_ = nullptr;
     }
 }
 
@@ -81,20 +99,20 @@ MemVectors::~MemVectors() {
  */
 MemManager::MemVectorsPtr MemManager::GetMemByTable(
         const std::string& table_id) {
-    auto memIt = memMap_.find(table_id);
-    if (memIt != memMap_.end()) {
+    auto memIt = mem_id_map_.find(table_id);
+    if (memIt != mem_id_map_.end()) {
         return memIt->second;
     }
 
     meta::TableFileSchema table_file;
     table_file.table_id_ = table_id;
-    auto status = pMeta_->CreateTableFile(table_file);
+    auto status = meta_->CreateTableFile(table_file);
     if (!status.ok()) {
         return nullptr;
     }
 
-    memMap_[table_id] = MemVectorsPtr(new MemVectors(pMeta_, table_file, options_));
-    return memMap_[table_id];
+    mem_id_map_[table_id] = MemVectorsPtr(new MemVectors(meta_, table_file, options_));
+    return mem_id_map_[table_id];
 }
 
 Status MemManager::InsertVectors(const std::string& table_id_,
@@ -114,37 +132,44 @@ Status MemManager::InsertVectorsNoLock(const std::string& table_id,
     if (mem == nullptr) {
         return Status::NotFound("Group " + table_id + " not found!");
     }
-    mem->Add(n, vectors, vector_ids);
 
-    return Status::OK();
+    //makesure each file size less than index_trigger_size
+    if(mem->Size() > options_.index_trigger_size) {
+        std::unique_lock<std::mutex> lock(serialization_mtx_);
+        immu_mem_list_.push_back(mem);
+        mem_id_map_.erase(table_id);
+        return InsertVectorsNoLock(table_id, n, vectors, vector_ids);
+    } else {
+        return mem->Add(n, vectors, vector_ids);
+    }
 }
 
 Status MemManager::ToImmutable() {
     std::unique_lock<std::mutex> lock(mutex_);
-    for (auto& kv: memMap_) {
-        immMems_.push_back(kv.second);
+    for (auto& kv: mem_id_map_) {
+        immu_mem_list_.push_back(kv.second);
     }
 
-    memMap_.clear();
+    mem_id_map_.clear();
     return Status::OK();
 }
 
-Status MemManager::Serialize(std::vector<std::string>& table_ids) {
+Status MemManager::Serialize(std::set<std::string>& table_ids) {
     ToImmutable();
     std::unique_lock<std::mutex> lock(serialization_mtx_);
     std::string table_id;
     table_ids.clear();
-    for (auto& mem : immMems_) {
+    for (auto& mem : immu_mem_list_) {
         mem->Serialize(table_id);
-        table_ids.push_back(table_id);
+        table_ids.insert(table_id);
     }
-    immMems_.clear();
+    immu_mem_list_.clear();
     return Status::OK();
 }
 
 Status MemManager::EraseMemVector(const std::string& table_id) {
     std::unique_lock<std::mutex> lock(mutex_);
-    memMap_.erase(table_id);
+    mem_id_map_.erase(table_id);
 
     return Status::OK();
 }
diff --git a/cpp/src/db/MemManager.h b/cpp/src/db/MemManager.h
index 1b329f971b..2aa0183898 100644
--- a/cpp/src/db/MemManager.h
+++ b/cpp/src/db/MemManager.h
@@ -15,6 +15,7 @@
 #include <ctime>
 #include <memory>
 #include <mutex>
+#include <set>
 
 namespace zilliz {
 namespace milvus {
@@ -32,11 +33,11 @@ public:
     explicit MemVectors(const std::shared_ptr<meta::Meta>&,
             const meta::TableFileSchema&, const Options&);
 
-    void Add(size_t n_, const float* vectors_, IDNumbers& vector_ids_);
+    Status Add(size_t n_, const float* vectors_, IDNumbers& vector_ids_);
 
-    size_t Total() const;
+    size_t RowCount() const;
 
-    size_t ApproximateSize() const;
+    size_t Size() const;
 
     Status Serialize(std::string& table_id);
 
@@ -49,11 +50,11 @@ private:
     MemVectors(const MemVectors&) = delete;
     MemVectors& operator=(const MemVectors&) = delete;
 
-    MetaPtr pMeta_;
+    MetaPtr meta_;
     Options options_;
     meta::TableFileSchema schema_;
-    IDGenerator* pIdGenerator_;
-    ExecutionEnginePtr pEE_;
+    IDGenerator* id_generator_;
+    ExecutionEnginePtr active_engine_;
 
 }; // MemVectors
 
@@ -66,14 +67,14 @@ public:
     using Ptr = std::shared_ptr<MemManager>;
 
     MemManager(const std::shared_ptr<meta::Meta>& meta, const Options& options)
-        : pMeta_(meta), options_(options) {}
+        : meta_(meta), options_(options) {}
 
     MemVectorsPtr GetMemByTable(const std::string& table_id);
 
     Status InsertVectors(const std::string& table_id,
             size_t n, const float* vectors, IDNumbers& vector_ids);
 
-    Status Serialize(std::vector<std::string>& table_ids);
+    Status Serialize(std::set<std::string>& table_ids);
 
     Status EraseMemVector(const std::string& table_id);
 
@@ -82,11 +83,11 @@ private:
             size_t n, const float* vectors, IDNumbers& vector_ids);
     Status ToImmutable();
 
-    using MemMap = std::map<std::string, MemVectorsPtr>;
-    using ImmMemPool = std::vector<MemVectorsPtr>;
-    MemMap memMap_;
-    ImmMemPool immMems_;
-    MetaPtr pMeta_;
+    using MemIdMap = std::map<std::string, MemVectorsPtr>;
+    using MemList = std::vector<MemVectorsPtr>;
+    MemIdMap mem_id_map_;
+    MemList immu_mem_list_;
+    MetaPtr meta_;
     Options options_;
     std::mutex mutex_;
     std::mutex serialization_mtx_;