diff --git a/src/sql/das/ob_das_insert_op.cpp b/src/sql/das/ob_das_insert_op.cpp
index 3e6f86e9a5..6d7c40aa2a 100644
--- a/src/sql/das/ob_das_insert_op.cpp
+++ b/src/sql/das/ob_das_insert_op.cpp
@@ -473,6 +473,8 @@ int ObDASInsertResult::reuse()
   } else {
     affected_rows_ = 0;
     is_duplicated_ = false;
+    result_buffer_.~ObDASWriteBuffer();
+    new(&result_buffer_) ObDASWriteBuffer();
   }
   return ret;
 }
diff --git a/src/sql/das/ob_data_access_service.cpp b/src/sql/das/ob_data_access_service.cpp
index dffff1da62..52ac233a17 100644
--- a/src/sql/das/ob_data_access_service.cpp
+++ b/src/sql/das/ob_data_access_service.cpp
@@ -405,23 +405,29 @@ int ObDataAccessService::do_async_remote_das_task(
   }
   // prepare op result in advance avoiding racing condition.
   for (int64_t i = 0; OB_SUCC(ret) && i < task_ops.count(); i++) {
-    if (OB_UNLIKELY(NULL != (op_result = task_ops.at(i)->get_op_result()))) {
-      // currently, we either disable async mode or try async task once
-      // and fall back to sync mode in error
-      // thus, get_op_result() should always be null
+    if (OB_UNLIKELY(ObDasTaskStatus::UNSTART != task_ops.at(i)->get_task_status())) {
       ret = OB_ERR_UNEXPECTED;
-      LOG_WARN("op_result is not null", KR(ret), KP(op_result), KPC(task_ops.at(i)));
-    } else if (OB_FAIL(das_ref.get_das_factory().create_das_task_result(task_ops.at(i)->get_type(), op_result))) {
-      LOG_WARN("failed to create das task result", K(ret));
-    } else if (OB_ISNULL(op_result)) {
-      ret = OB_ERR_UNEXPECTED;
-      LOG_WARN("failed to get op result", K(ret));
-    } else if (OB_FAIL(das_async_cb->get_op_results().push_back(op_result))) {
-      LOG_WARN("failed to add task result", K(ret));
-    } else if (OB_FAIL(op_result->init(*task_ops.at(i), das_async_cb->get_result_alloc()))) {
-      LOG_WARN("failed to init task result", K(ret));
+      LOG_WARN("task status unexpected", KR(ret), K(task_ops.at(i)->get_task_status()), KPC(task_ops.at(i)));
+    } else if (NULL != (op_result = task_ops.at(i)->get_op_result())) {
+      if (OB_FAIL(op_result->reuse())) {
+        LOG_WARN("reuse task result failed", K(ret));
+      }
     } else {
-      task_ops.at(i)->set_op_result(op_result);
+      if (OB_FAIL(das_ref.get_das_factory().create_das_task_result(task_ops.at(i)->get_type(), op_result))) {
+            LOG_WARN("failed to create das task result", K(ret));
+      } else if (OB_ISNULL(op_result)) {
+        ret = OB_ERR_UNEXPECTED;
+        LOG_WARN("failed to get op result", K(ret));
+      }
+    }
+    if (OB_SUCC(ret)) {
+      if (OB_FAIL(das_async_cb->get_op_results().push_back(op_result))) {
+        LOG_WARN("failed to add task result", K(ret));
+      } else if (OB_FAIL(op_result->init(*task_ops.at(i), das_async_cb->get_result_alloc()))) {
+        LOG_WARN("failed to init task result", K(ret));
+      } else {
+        task_ops.at(i)->set_op_result(op_result);
+      }
     }
   }
   LOG_DEBUG("begin to do remote das task", K(task_arg));
@@ -491,7 +497,10 @@ int ObDataAccessService::do_sync_remote_das_task(
 
     // prepare op result in advance avoiding racing condition.
     for (int64_t i = 0; OB_SUCC(ret) && i < task_ops.count(); i++) {
-      if (NULL != (op_result = task_ops.at(i)->get_op_result())) {
+      if (OB_UNLIKELY(ObDasTaskStatus::UNSTART != task_ops.at(i)->get_task_status())) {
+        ret = OB_ERR_UNEXPECTED;
+        LOG_WARN("task status unexpected", KR(ret), K(task_ops.at(i)->get_task_status()), KPC(task_ops.at(i)));
+      } else if (NULL != (op_result = task_ops.at(i)->get_op_result())) {
         if (OB_FAIL(op_result->reuse())) {
           LOG_WARN("reuse task result failed", K(ret));
         }