diff --git a/cpp/src/server/VecServiceScheduler.cpp b/cpp/src/server/VecServiceScheduler.cpp
index 5826ff5be2594bf76b5e7a6274ebd9a49471abcb..7a78e8232314e2e970288425d16bae5f0cfcb3d1 100644
--- a/cpp/src/server/VecServiceScheduler.cpp
+++ b/cpp/src/server/VecServiceScheduler.cpp
@@ -11,10 +11,11 @@ namespace vecwise {
 namespace server {
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-BaseTask::BaseTask(const std::string& task_group)
-        : task_group_(task_group),
-          done_(false),
-          error_code_(SERVER_SUCCESS) {
+BaseTask::BaseTask(const std::string& task_group, bool async)
+    : task_group_(task_group),
+      async_(async),
+      done_(false),
+      error_code_(SERVER_SUCCESS) {
 
 }
 
@@ -73,14 +74,6 @@ void VecServiceScheduler::Stop() {
     stopped_ = true;
 }
 
-ServerError VecServiceScheduler::PushTask(const BaseTaskPtr& task_ptr) {
-    if(task_ptr == nullptr) {
-        return SERVER_NULL_POINTER;
-    }
-
-    return PutTaskToQueue(task_ptr);
-}
-
 ServerError VecServiceScheduler::ExecuteTask(const BaseTaskPtr& task_ptr) {
     if(task_ptr == nullptr) {
         return SERVER_NULL_POINTER;
@@ -91,7 +84,11 @@ ServerError VecServiceScheduler::ExecuteTask(const BaseTaskPtr& task_ptr) {
         return err;
     }
 
-    return task_ptr->WaitToFinish();
+    if(task_ptr->IsAsync()) {
+        return SERVER_SUCCESS;//async execution, caller need to call WaitToFinish at somewhere
+    }
+
+    return task_ptr->WaitToFinish();//sync execution
 }
 
 namespace {
diff --git a/cpp/src/server/VecServiceScheduler.h b/cpp/src/server/VecServiceScheduler.h
index d3fec4cc80758e093c401b6589aebbe0e532a058..ffcecbce5b379343544b249dcaa0d3060a85720f 100644
--- a/cpp/src/server/VecServiceScheduler.h
+++ b/cpp/src/server/VecServiceScheduler.h
@@ -17,7 +17,7 @@ namespace server {
 
 class BaseTask {
 protected:
-    BaseTask(const std::string& task_group);
+    BaseTask(const std::string& task_group, bool async = false);
     virtual ~BaseTask();
 
 public:
@@ -27,6 +27,9 @@ public:
     std::string TaskGroup() const { return task_group_; }
 
     ServerError ErrorCode() const { return error_code_; }
+
+    bool IsAsync() const { return async_; }
+
 protected:
     virtual ServerError OnExecute() = 0;
 
@@ -35,6 +38,7 @@ protected:
     std::condition_variable finish_cond_;
 
     std::string task_group_;
+    bool async_;
     bool done_;
     ServerError error_code_;
 };
@@ -54,9 +58,6 @@ public:
     void Start();
     void Stop();
 
-    //async
-    ServerError PushTask(const BaseTaskPtr& task_ptr);
-    //sync
     ServerError ExecuteTask(const BaseTaskPtr& task_ptr);
 
 protected:
diff --git a/cpp/src/server/VecServiceTask.cpp b/cpp/src/server/VecServiceTask.cpp
index 7254a69aa6659d76019710b3d172e28892a24c79..b5c0f4c66820f3d1e2965b04aeefb1f51b17de1a 100644
--- a/cpp/src/server/VecServiceTask.cpp
+++ b/cpp/src/server/VecServiceTask.cpp
@@ -16,8 +16,8 @@ namespace zilliz {
 namespace vecwise {
 namespace server {
 
-static const std::string NORMAL_TASK_GROUP = "normal";
-static const std::string SEARCH_TASK_GROUP = "search";
+static const std::string DQL_TASK_GROUP = "dql";
+static const std::string DDL_DML_TASK_GROUP = "ddl_dml";
 
 namespace {
     class DBWrapper {
@@ -53,7 +53,7 @@ namespace {
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 AddGroupTask::AddGroupTask(int32_t dimension,
                            const std::string& group_id)
-: BaseTask(NORMAL_TASK_GROUP),
+: BaseTask(DDL_DML_TASK_GROUP),
   dimension_(dimension),
   group_id_(group_id) {
 
@@ -81,7 +81,7 @@ ServerError AddGroupTask::OnExecute() {
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 GetGroupTask::GetGroupTask(const std::string& group_id, int32_t&  dimension)
-    : BaseTask(NORMAL_TASK_GROUP),
+    : BaseTask(DDL_DML_TASK_GROUP),
       group_id_(group_id),
       dimension_(dimension) {
 
@@ -111,7 +111,7 @@ ServerError GetGroupTask::OnExecute() {
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 DeleteGroupTask::DeleteGroupTask(const std::string& group_id)
-    : BaseTask(NORMAL_TASK_GROUP),
+    : BaseTask(DDL_DML_TASK_GROUP),
       group_id_(group_id) {
 
 }
@@ -132,7 +132,7 @@ ServerError DeleteGroupTask::OnExecute() {
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 AddSingleVectorTask::AddSingleVectorTask(const std::string& group_id,
                                          const VecTensor &tensor)
-    : BaseTask(NORMAL_TASK_GROUP),
+    : BaseTask(DDL_DML_TASK_GROUP),
       group_id_(group_id),
       tensor_(tensor) {
 
@@ -169,7 +169,7 @@ ServerError AddSingleVectorTask::OnExecute() {
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 AddBatchVectorTask::AddBatchVectorTask(const std::string& group_id,
                              const VecTensorList &tensor_list)
-    : BaseTask(NORMAL_TASK_GROUP),
+    : BaseTask(DDL_DML_TASK_GROUP),
       group_id_(group_id),
       tensor_list_(tensor_list) {
 
@@ -233,7 +233,7 @@ SearchVectorTask::SearchVectorTask(const std::string& group_id,
                                    const VecTensorList& tensor_list,
                                    const VecTimeRangeList& time_range_list,
                                    VecSearchResultList& result)
-    : BaseTask(SEARCH_TASK_GROUP),
+    : BaseTask(DQL_TASK_GROUP),
       group_id_(group_id),
       top_k_(top_k),
       tensor_list_(tensor_list),