diff --git a/cpp/conf/server_config.yaml b/cpp/conf/server_config.yaml
index aa654e0b2304fe865cd10e6eb547a2fda6cae16d..4c2ce3119fa4a049845113f0828769983f4915c2 100644
--- a/cpp/conf/server_config.yaml
+++ b/cpp/conf/server_config.yaml
@@ -3,6 +3,8 @@ server_config:
   port: 33001
   transfer_protocol: json   #optional: binary, compact, json, debug
   server_mode: thread_pool    #optional: simple, thread_pool
+  db_backend_url: http://127.0.0.1
+  db_name: vecwise
 
 log_config:
   global:
diff --git a/cpp/src/CMakeLists.txt b/cpp/src/CMakeLists.txt
index b635b17e3b74bdb4618818f76904bf368ce2b4bc..0c6b2a569e6813c4b0bd69d926aeefcc51da86c3 100644
--- a/cpp/src/CMakeLists.txt
+++ b/cpp/src/CMakeLists.txt
@@ -8,6 +8,7 @@ aux_source_directory(cache cache_files)
 aux_source_directory(config config_files)
 aux_source_directory(server server_files)
 aux_source_directory(utils utils_files)
+aux_source_directory(db db_files)
 aux_source_directory(wrapper wrapper_files)
 
 set(service_files
@@ -18,6 +19,7 @@ set(service_files
 set(vecwise_engine_src
         ${CMAKE_CURRENT_SOURCE_DIR}/main.cpp
         ${cache_files}
+        ${db_files}
         ${wrapper_files})
 
 include_directories(/usr/local/cuda/include)
@@ -42,5 +44,6 @@ set(dependency_libs
         thrift
         pthread
         faiss
+        vecwise_engine
         )
 target_link_libraries(vecwise_engine_server ${dependency_libs} ${cuda_library})
\ No newline at end of file
diff --git a/cpp/src/server/ServerConfig.h b/cpp/src/server/ServerConfig.h
index 3be7a0914eb1703500545f57462e017cbde6ed0a..5ee282fc4448c7214a4e4c9689e7be225c4abe75 100644
--- a/cpp/src/server/ServerConfig.h
+++ b/cpp/src/server/ServerConfig.h
@@ -19,6 +19,8 @@ static const std::string CONFIG_SERVER_ADDRESS = "address";
 static const std::string CONFIG_SERVER_PORT = "port";
 static const std::string CONFIG_SERVER_PROTOCOL = "transfer_protocol";
 static const std::string CONFIG_SERVER_MODE = "server_mode";
+static const std::string CONFIG_SERVER_DB_URL = "db_backend_url";
+static const std::string CONFIG_SERVER_DB_NAME = "db_name";
 
 static const std::string CONFIG_LOG = "log_config";
 
diff --git a/cpp/src/server/VecServiceHandler.cpp b/cpp/src/server/VecServiceHandler.cpp
index 2b757da3482ba3d3c31e117ad4c729f79dac08a0..eda05db9bf6e2f0766861b8339404d0d3c393af8 100644
--- a/cpp/src/server/VecServiceHandler.cpp
+++ b/cpp/src/server/VecServiceHandler.cpp
@@ -1,15 +1,40 @@
-//
-// Created by yhmo on 19-4-16.
-//
-
+/*******************************************************************************
+ * Copyright 上海赜睿信息科技有限公司(Zilliz) - All Rights Reserved
+ * Unauthorized copying of this file, via any medium is strictly prohibited.
+ * Proprietary and confidential.
+ ******************************************************************************/
 #include "VecServiceHandler.h"
+#include "ServerConfig.h"
 #include "utils/Log.h"
+#include "utils/CommonUtil.h"
+
+#include "db/DB.h"
+#include "db/Env.h"
 
 namespace zilliz {
 namespace vecwise {
 namespace server {
 
+namespace {
+    static engine::DB* DB() {
+        static engine::DB* s_db = nullptr;
+        if(s_db == nullptr) {
+            engine::Options opt;
+
+            ConfigNode& config = ServerConfig::GetInstance().GetConfig(CONFIG_SERVER);
+            opt.meta.backend_uri = config.GetValue(CONFIG_SERVER_DB_URL);
+            opt.meta.dbname = config.GetValue(CONFIG_SERVER_DB_NAME);
+
+            std::string db_path = "/tmp/test";
+            CommonUtil::CreateDirectory(db_path);
+            s_db = engine::DB::Open(opt, db_path);
+        }
+        return s_db;
+    }
+}
+
 VecServiceHandler::VecServiceHandler() {
+
 }
 
 void
@@ -19,7 +44,16 @@ VecServiceHandler::add_group(const VecGroup &group) {
                         << ", group.index_type = " << group.index_type;
 
     try {
-
+        engine::GroupOptions gopt;
+        gopt.dimension = (size_t)group.dimension;
+        gopt.has_id = !group.id.empty();
+        engine::meta::GroupSchema group_info;
+        engine::Status stat = DB()->add_group(gopt, group.id, group_info);
+        if(!stat.ok()) {
+            SERVER_LOG_ERROR << "Engine failed: " << stat.ToString();
+        }
+
+        SERVER_LOG_INFO << "add_group() finished";
     } catch (std::exception& ex) {
         SERVER_LOG_ERROR << ex.what();
     }
@@ -31,7 +65,16 @@ VecServiceHandler::get_group(VecGroup &_return, const std::string &group_id) {
     SERVER_LOG_TRACE << "group_id = " << group_id;
 
     try {
-
+        engine::meta::GroupSchema group_info;
+        engine::Status stat = DB()->get_group(group_id, group_info);
+        if(!stat.ok()) {
+            SERVER_LOG_ERROR << "Engine failed: " << stat.ToString();
+        } else {
+            _return.id = group_info.group_id;
+            _return.dimension = (int32_t)group_info.dimension;
+        }
+
+        SERVER_LOG_INFO << "get_group() finished";
     } catch (std::exception& ex) {
         SERVER_LOG_ERROR << ex.what();
     }
@@ -44,19 +87,29 @@ VecServiceHandler::del_group(const std::string &group_id) {
 
     try {
 
+        SERVER_LOG_INFO << "del_group() not implemented";
     } catch (std::exception& ex) {
         SERVER_LOG_ERROR << ex.what();
     }
 }
 
 
-int64_t
-VecServiceHandler::add_vector(const std::string &group_id, const VecTensor &tensor) {
+void
+VecServiceHandler::add_vector(VecTensorIdList& _return, const std::string &group_id, const VecTensor &tensor) {
     SERVER_LOG_INFO << "add_vector() called";
     SERVER_LOG_TRACE << "group_id = " << group_id << ", vector size = " << tensor.tensor.size();
 
     try {
-
+        engine::IDNumbers vector_ids;
+        std::vector<float> vec_f(tensor.tensor.begin(), tensor.tensor.end());
+        engine::Status stat = DB()->add_vectors(group_id, 1, vec_f.data(), vector_ids);
+        if(!stat.ok()) {
+            SERVER_LOG_ERROR << "Engine failed: " << stat.ToString();
+        } else {
+            _return.id_list.swap(vector_ids);
+        }
+
+        SERVER_LOG_INFO << "add_vector() finished";
     } catch (std::exception& ex) {
         SERVER_LOG_ERROR << ex.what();
     }
@@ -71,7 +124,20 @@ VecServiceHandler::add_vector_batch(VecTensorIdList &_return,
                      << tensor_list.tensor_list.size();
 
     try {
-
+        std::vector<float> vec_f;
+        for(const VecTensor& tensor : tensor_list.tensor_list) {
+            vec_f.insert(vec_f.begin(), tensor.tensor.begin(), tensor.tensor.end());
+        }
+
+        engine::IDNumbers vector_ids;
+        engine::Status stat = DB()->add_vectors(group_id, tensor_list.tensor_list.size(), vec_f.data(), vector_ids);
+        if(!stat.ok()) {
+            SERVER_LOG_ERROR << "Engine failed: " << stat.ToString();
+        } else {
+            _return.id_list.swap(vector_ids);
+        }
+
+        SERVER_LOG_INFO << "add_vector_batch() finished";
     } catch (std::exception& ex) {
         SERVER_LOG_ERROR << ex.what();
     }
@@ -90,7 +156,18 @@ VecServiceHandler::search_vector(VecSearchResult &_return,
                         << ", time range list size = " << time_range_list.range_list.size();
 
     try {
-
+        engine::QueryResults results;
+        std::vector<float> vec_f(tensor.tensor.begin(), tensor.tensor.end());
+        engine::Status stat = DB()->search(group_id, (size_t)top_k, 1, vec_f.data(), results);
+        if(!stat.ok()) {
+            SERVER_LOG_ERROR << "Engine failed: " << stat.ToString();
+        } else {
+            if(results.size() > 0) {
+                _return.id_list.swap(results[0]);
+            }
+        }
+
+        SERVER_LOG_INFO << "search_vector() finished";
     } catch (std::exception& ex) {
         SERVER_LOG_ERROR << ex.what();
     }
@@ -108,7 +185,24 @@ VecServiceHandler::search_vector_batch(VecSearchResultList &_return,
                      << ", time range list size = " << time_range_list.range_list.size();
 
     try {
-
+        std::vector<float> vec_f;
+        for(const VecTensor& tensor : tensor_list.tensor_list) {
+            vec_f.insert(vec_f.begin(), tensor.tensor.begin(), tensor.tensor.end());
+        }
+
+        engine::QueryResults results;
+        engine::Status stat = DB()->search(group_id, (size_t)top_k, tensor_list.tensor_list.size(), vec_f.data(), results);
+        if(!stat.ok()) {
+            SERVER_LOG_ERROR << "Engine failed: " << stat.ToString();
+        } else {
+            for(engine::QueryResult& res : results){
+                VecSearchResult v_res;
+                v_res.id_list.swap(res);
+                _return.result_list.push_back(v_res);
+            }
+        }
+
+        SERVER_LOG_INFO << "search_vector_batch() finished";
     } catch (std::exception& ex) {
         SERVER_LOG_ERROR << ex.what();
     }
diff --git a/cpp/src/server/VecServiceHandler.h b/cpp/src/server/VecServiceHandler.h
index 74b684709ce3a56ebab3e01ff98b8607b25616c1..2a6df564a900a5594db29fd548518f6e1ec4e3b2 100644
--- a/cpp/src/server/VecServiceHandler.h
+++ b/cpp/src/server/VecServiceHandler.h
@@ -4,7 +4,11 @@
  * Proprietary and confidential.
  ******************************************************************************/
 #pragma once
-
+/*******************************************************************************
+ * Copyright 上海赜睿信息科技有限公司(Zilliz) - All Rights Reserved
+ * Unauthorized copying of this file, via any medium is strictly prohibited.
+ * Proprietary and confidential.
+ ******************************************************************************/
 #include "utils/Error.h"
 #include "thrift/gen-cpp/VecService.h"
 
@@ -37,7 +41,7 @@ public:
      * @param group_id
      * @param tensor
      */
-    int64_t add_vector(const std::string& group_id, const VecTensor& tensor);
+    void add_vector(VecTensorIdList& _return, const std::string& group_id, const VecTensor& tensor);
 
     void add_vector_batch(VecTensorIdList& _return, const std::string& group_id, const VecTensorList& tensor_list);
 
diff --git a/cpp/src/thrift/VectorService.thrift b/cpp/src/thrift/VectorService.thrift
index 7008ebd54c2ee46e26964acf8e701939dc3c7b96..9892e95370128be8c0c23599d76f0260e03ddeae 100644
--- a/cpp/src/thrift/VectorService.thrift
+++ b/cpp/src/thrift/VectorService.thrift
@@ -78,7 +78,7 @@ service VecService {
      * vector interfaces
      *
      */
-    i64 add_vector(2: string group_id, 3: VecTensor tensor) throws(1: VecException e);
+    VecTensorIdList add_vector(2: string group_id, 3: VecTensor tensor) throws(1: VecException e);
     VecTensorIdList add_vector_batch(2: string group_id, 3: VecTensorList tensor_list) throws(1: VecException e);
 
     /**
diff --git a/cpp/src/thrift/gen-cpp/VecService.cpp b/cpp/src/thrift/gen-cpp/VecService.cpp
index 6374f947eee49aa150ddab7fbd55773813393a38..fcd28a204be6a966df6c609b00f6a3174efebec7 100644
--- a/cpp/src/thrift/gen-cpp/VecService.cpp
+++ b/cpp/src/thrift/gen-cpp/VecService.cpp
@@ -711,8 +711,8 @@ uint32_t VecService_add_vector_result::read(::apache::thrift::protocol::TProtoco
     switch (fid)
     {
       case 0:
-        if (ftype == ::apache::thrift::protocol::T_I64) {
-          xfer += iprot->readI64(this->success);
+        if (ftype == ::apache::thrift::protocol::T_STRUCT) {
+          xfer += this->success.read(iprot);
           this->__isset.success = true;
         } else {
           xfer += iprot->skip(ftype);
@@ -745,8 +745,8 @@ uint32_t VecService_add_vector_result::write(::apache::thrift::protocol::TProtoc
   xfer += oprot->writeStructBegin("VecService_add_vector_result");
 
   if (this->__isset.success) {
-    xfer += oprot->writeFieldBegin("success", ::apache::thrift::protocol::T_I64, 0);
-    xfer += oprot->writeI64(this->success);
+    xfer += oprot->writeFieldBegin("success", ::apache::thrift::protocol::T_STRUCT, 0);
+    xfer += this->success.write(oprot);
     xfer += oprot->writeFieldEnd();
   } else if (this->__isset.e) {
     xfer += oprot->writeFieldBegin("e", ::apache::thrift::protocol::T_STRUCT, 1);
@@ -785,8 +785,8 @@ uint32_t VecService_add_vector_presult::read(::apache::thrift::protocol::TProtoc
     switch (fid)
     {
       case 0:
-        if (ftype == ::apache::thrift::protocol::T_I64) {
-          xfer += iprot->readI64((*(this->success)));
+        if (ftype == ::apache::thrift::protocol::T_STRUCT) {
+          xfer += (*(this->success)).read(iprot);
           this->__isset.success = true;
         } else {
           xfer += iprot->skip(ftype);
@@ -1718,10 +1718,10 @@ void VecServiceClient::recv_del_group()
   return;
 }
 
-int64_t VecServiceClient::add_vector(const std::string& group_id, const VecTensor& tensor)
+void VecServiceClient::add_vector(VecTensorIdList& _return, const std::string& group_id, const VecTensor& tensor)
 {
   send_add_vector(group_id, tensor);
-  return recv_add_vector();
+  recv_add_vector(_return);
 }
 
 void VecServiceClient::send_add_vector(const std::string& group_id, const VecTensor& tensor)
@@ -1739,7 +1739,7 @@ void VecServiceClient::send_add_vector(const std::string& group_id, const VecTen
   oprot_->getTransport()->flush();
 }
 
-int64_t VecServiceClient::recv_add_vector()
+void VecServiceClient::recv_add_vector(VecTensorIdList& _return)
 {
 
   int32_t rseqid = 0;
@@ -1764,7 +1764,6 @@ int64_t VecServiceClient::recv_add_vector()
     iprot_->readMessageEnd();
     iprot_->getTransport()->readEnd();
   }
-  int64_t _return;
   VecService_add_vector_presult result;
   result.success = &_return;
   result.read(iprot_);
@@ -1772,7 +1771,8 @@ int64_t VecServiceClient::recv_add_vector()
   iprot_->getTransport()->readEnd();
 
   if (result.__isset.success) {
-    return _return;
+    // _return pointer has now been filled
+    return;
   }
   if (result.__isset.e) {
     throw result.e;
@@ -2181,7 +2181,7 @@ void VecServiceProcessor::process_add_vector(int32_t seqid, ::apache::thrift::pr
 
   VecService_add_vector_result result;
   try {
-    result.success = iface_->add_vector(args.group_id, args.tensor);
+    iface_->add_vector(result.success, args.group_id, args.tensor);
     result.__isset.success = true;
   } catch (VecException &e) {
     result.e = e;
@@ -2645,10 +2645,10 @@ void VecServiceConcurrentClient::recv_del_group(const int32_t seqid)
   } // end while(true)
 }
 
-int64_t VecServiceConcurrentClient::add_vector(const std::string& group_id, const VecTensor& tensor)
+void VecServiceConcurrentClient::add_vector(VecTensorIdList& _return, const std::string& group_id, const VecTensor& tensor)
 {
   int32_t seqid = send_add_vector(group_id, tensor);
-  return recv_add_vector(seqid);
+  recv_add_vector(_return, seqid);
 }
 
 int32_t VecServiceConcurrentClient::send_add_vector(const std::string& group_id, const VecTensor& tensor)
@@ -2670,7 +2670,7 @@ int32_t VecServiceConcurrentClient::send_add_vector(const std::string& group_id,
   return cseqid;
 }
 
-int64_t VecServiceConcurrentClient::recv_add_vector(const int32_t seqid)
+void VecServiceConcurrentClient::recv_add_vector(VecTensorIdList& _return, const int32_t seqid)
 {
 
   int32_t rseqid = 0;
@@ -2708,7 +2708,6 @@ int64_t VecServiceConcurrentClient::recv_add_vector(const int32_t seqid)
         using ::apache::thrift::protocol::TProtocolException;
         throw TProtocolException(TProtocolException::INVALID_DATA);
       }
-      int64_t _return;
       VecService_add_vector_presult result;
       result.success = &_return;
       result.read(iprot_);
@@ -2716,8 +2715,9 @@ int64_t VecServiceConcurrentClient::recv_add_vector(const int32_t seqid)
       iprot_->getTransport()->readEnd();
 
       if (result.__isset.success) {
+        // _return pointer has now been filled
         sentry.commit();
-        return _return;
+        return;
       }
       if (result.__isset.e) {
         sentry.commit();
diff --git a/cpp/src/thrift/gen-cpp/VecService.h b/cpp/src/thrift/gen-cpp/VecService.h
index 5cccdfa03b7bd1e9424d378f09ccc98ff1192867..3d7fa98e7aa2bba551efd83351b3652efc0c93e2 100644
--- a/cpp/src/thrift/gen-cpp/VecService.h
+++ b/cpp/src/thrift/gen-cpp/VecService.h
@@ -38,7 +38,7 @@ class VecServiceIf {
    * @param group_id
    * @param tensor
    */
-  virtual int64_t add_vector(const std::string& group_id, const VecTensor& tensor) = 0;
+  virtual void add_vector(VecTensorIdList& _return, const std::string& group_id, const VecTensor& tensor) = 0;
   virtual void add_vector_batch(VecTensorIdList& _return, const std::string& group_id, const VecTensorList& tensor_list) = 0;
 
   /**
@@ -90,9 +90,8 @@ class VecServiceNull : virtual public VecServiceIf {
   void del_group(const std::string& /* group_id */) {
     return;
   }
-  int64_t add_vector(const std::string& /* group_id */, const VecTensor& /* tensor */) {
-    int64_t _return = 0;
-    return _return;
+  void add_vector(VecTensorIdList& /* _return */, const std::string& /* group_id */, const VecTensor& /* tensor */) {
+    return;
   }
   void add_vector_batch(VecTensorIdList& /* _return */, const std::string& /* group_id */, const VecTensorList& /* tensor_list */) {
     return;
@@ -492,16 +491,16 @@ class VecService_add_vector_result {
 
   VecService_add_vector_result(const VecService_add_vector_result&);
   VecService_add_vector_result& operator=(const VecService_add_vector_result&);
-  VecService_add_vector_result() : success(0) {
+  VecService_add_vector_result() {
   }
 
   virtual ~VecService_add_vector_result() throw();
-  int64_t success;
+  VecTensorIdList success;
   VecException e;
 
   _VecService_add_vector_result__isset __isset;
 
-  void __set_success(const int64_t val);
+  void __set_success(const VecTensorIdList& val);
 
   void __set_e(const VecException& val);
 
@@ -535,7 +534,7 @@ class VecService_add_vector_presult {
 
 
   virtual ~VecService_add_vector_presult() throw();
-  int64_t* success;
+  VecTensorIdList* success;
   VecException e;
 
   _VecService_add_vector_presult__isset __isset;
@@ -963,9 +962,9 @@ class VecServiceClient : virtual public VecServiceIf {
   void del_group(const std::string& group_id);
   void send_del_group(const std::string& group_id);
   void recv_del_group();
-  int64_t add_vector(const std::string& group_id, const VecTensor& tensor);
+  void add_vector(VecTensorIdList& _return, const std::string& group_id, const VecTensor& tensor);
   void send_add_vector(const std::string& group_id, const VecTensor& tensor);
-  int64_t recv_add_vector();
+  void recv_add_vector(VecTensorIdList& _return);
   void add_vector_batch(VecTensorIdList& _return, const std::string& group_id, const VecTensorList& tensor_list);
   void send_add_vector_batch(const std::string& group_id, const VecTensorList& tensor_list);
   void recv_add_vector_batch(VecTensorIdList& _return);
@@ -1063,13 +1062,14 @@ class VecServiceMultiface : virtual public VecServiceIf {
     ifaces_[i]->del_group(group_id);
   }
 
-  int64_t add_vector(const std::string& group_id, const VecTensor& tensor) {
+  void add_vector(VecTensorIdList& _return, const std::string& group_id, const VecTensor& tensor) {
     size_t sz = ifaces_.size();
     size_t i = 0;
     for (; i < (sz - 1); ++i) {
-      ifaces_[i]->add_vector(group_id, tensor);
+      ifaces_[i]->add_vector(_return, group_id, tensor);
     }
-    return ifaces_[i]->add_vector(group_id, tensor);
+    ifaces_[i]->add_vector(_return, group_id, tensor);
+    return;
   }
 
   void add_vector_batch(VecTensorIdList& _return, const std::string& group_id, const VecTensorList& tensor_list) {
@@ -1141,9 +1141,9 @@ class VecServiceConcurrentClient : virtual public VecServiceIf {
   void del_group(const std::string& group_id);
   int32_t send_del_group(const std::string& group_id);
   void recv_del_group(const int32_t seqid);
-  int64_t add_vector(const std::string& group_id, const VecTensor& tensor);
+  void add_vector(VecTensorIdList& _return, const std::string& group_id, const VecTensor& tensor);
   int32_t send_add_vector(const std::string& group_id, const VecTensor& tensor);
-  int64_t recv_add_vector(const int32_t seqid);
+  void recv_add_vector(VecTensorIdList& _return, const int32_t seqid);
   void add_vector_batch(VecTensorIdList& _return, const std::string& group_id, const VecTensorList& tensor_list);
   int32_t send_add_vector_batch(const std::string& group_id, const VecTensorList& tensor_list);
   void recv_add_vector_batch(VecTensorIdList& _return, const int32_t seqid);
diff --git a/cpp/src/thrift/gen-cpp/VecService_server.skeleton.cpp b/cpp/src/thrift/gen-cpp/VecService_server.skeleton.cpp
index 81726ee8fe5eadc5607af8732d5e235deb957367..b4c1277f0bd2f151e8b447287aa1e220fb51badc 100644
--- a/cpp/src/thrift/gen-cpp/VecService_server.skeleton.cpp
+++ b/cpp/src/thrift/gen-cpp/VecService_server.skeleton.cpp
@@ -45,7 +45,7 @@ class VecServiceHandler : virtual public VecServiceIf {
    * @param group_id
    * @param tensor
    */
-  int64_t add_vector(const std::string& group_id, const VecTensor& tensor) {
+  void add_vector(VecTensorIdList& _return, const std::string& group_id, const VecTensor& tensor) {
     // Your implementation goes here
     printf("add_vector\n");
   }
diff --git a/cpp/test_client/src/ClientApp.cpp b/cpp/test_client/src/ClientApp.cpp
index e6d1518ff7ce76952dde87f91a840176a05d024f..5eb2573b9bb12308759db9c098fbec187ffd5f24 100644
--- a/cpp/test_client/src/ClientApp.cpp
+++ b/cpp/test_client/src/ClientApp.cpp
@@ -68,13 +68,19 @@ void ClientApp::Run(const std::string &config_file) {
         transport_ptr->open();
         VecServiceClient client(protocol_ptr);
         try {
+            const int32_t dim = 256;
             VecGroup group;
             group.id = "test_group";
-            group.dimension = 256;
+            group.dimension = dim;
             group.index_type = 0;
             client.add_group(group);
 
-
+            VecTensor tensor;
+            for(int32_t i = 0; i < dim; i++) {
+                tensor.tensor.push_back((double)i);
+            }
+            VecTensorIdList result;
+            client.add_vector(result, group.id, tensor);
 
         } catch (apache::thrift::TException& ex) {
             printf("%s", ex.what());