diff --git a/include/client/taos.h b/include/client/taos.h
index 5bb528bd7f..b4e5a41ccf 100644
--- a/include/client/taos.h
+++ b/include/client/taos.h
@@ -194,6 +194,7 @@ DLL_EXPORT int         taos_errno(TAOS_RES *tres);
 
 DLL_EXPORT void taos_query_a(TAOS *taos, const char *sql, __taos_async_fn_t fp, void *param);
 DLL_EXPORT void taos_fetch_rows_a(TAOS_RES *res, __taos_async_fn_t fp, void *param);
+DLL_EXPORT void taos_fetch_raw_block_a(TAOS_RES* res, __taos_async_fn_t fp, void* param);
 
 // Shuduo: temporary enable for app build
 #if 1
diff --git a/source/client/inc/clientInt.h b/source/client/inc/clientInt.h
index 3a6f3badc0..6aa83e9575 100644
--- a/source/client/inc/clientInt.h
+++ b/source/client/inc/clientInt.h
@@ -171,6 +171,7 @@ typedef struct SReqResultInfo {
   uint32_t       current;
   bool           completed;
   int32_t        precision;
+  bool           convertUcs4;
   int32_t        payloadLen;
 } SReqResultInfo;
 
@@ -222,7 +223,7 @@ typedef struct SSyncQueryParam {
   SRequestObj* pRequest;
 } SSyncQueryParam;
 
-void*   doAsyncFetchRow(SRequestObj* pRequest, bool setupOneRowPtr, bool convertUcs4);
+void*   doAsyncFetchRows(SRequestObj* pRequest, bool setupOneRowPtr, bool convertUcs4);
 void*   doFetchRows(SRequestObj* pRequest, bool setupOneRowPtr, bool convertUcs4);
 
 void    doSetOneRowPtr(SReqResultInfo* pResultInfo);
diff --git a/source/client/src/clientEnv.c b/source/client/src/clientEnv.c
index 75e1884360..171f06c257 100644
--- a/source/client/src/clientEnv.c
+++ b/source/client/src/clientEnv.c
@@ -191,6 +191,8 @@ void *createRequest(STscObj *pObj, int32_t type) {
   pRequest->requestId = generateRequestId();
   pRequest->metric.start = taosGetTimestampUs();
 
+  pRequest->body.resInfo.convertUcs4 = true;  // convert ucs4 by default
+
   pRequest->type = type;
   pRequest->pTscObj = pObj;
   pRequest->msgBuf = taosMemoryCalloc(1, ERROR_MSG_BUF_DEFAULT_SIZE);
diff --git a/source/client/src/clientImpl.c b/source/client/src/clientImpl.c
index e15624bc0d..9025121854 100644
--- a/source/client/src/clientImpl.c
+++ b/source/client/src/clientImpl.c
@@ -1114,7 +1114,7 @@ static void syncFetchFn(void* param, TAOS_RES* res, int32_t numOfRows) {
   tsem_post(&pParam->sem);
 }
 
-void* doAsyncFetchRow(SRequestObj* pRequest, bool setupOneRowPtr, bool convertUcs4) {
+void* doAsyncFetchRows(SRequestObj* pRequest, bool setupOneRowPtr, bool convertUcs4) {
   assert(pRequest != NULL);
 
   SReqResultInfo* pResultInfo = &pRequest->body.resInfo;
@@ -1126,6 +1126,10 @@ void* doAsyncFetchRow(SRequestObj* pRequest, bool setupOneRowPtr, bool convertUc
     }
 
     SSyncQueryParam* pParam = pRequest->body.param;
+
+    // convert ucs4 to native multi-bytes string
+    pResultInfo->convertUcs4 = convertUcs4;
+
     taos_fetch_rows_a(pRequest, syncFetchFn, pParam);
     tsem_wait(&pParam->sem);
   }
diff --git a/source/client/src/clientMain.c b/source/client/src/clientMain.c
index 1a1925e244..5e442c4bf1 100644
--- a/source/client/src/clientMain.c
+++ b/source/client/src/clientMain.c
@@ -219,14 +219,13 @@ TAOS_ROW taos_fetch_row(TAOS_RES *res) {
 
   if (TD_RES_QUERY(res)) {
     SRequestObj *pRequest = (SRequestObj *)res;
+#if SYNC_ON_TOP_OF_ASYNC
+    return doAsyncFetchRows(pRequest, true, true);
+#else
     if (pRequest->type == TSDB_SQL_RETRIEVE_EMPTY_RESULT || pRequest->type == TSDB_SQL_INSERT ||
         pRequest->code != TSDB_CODE_SUCCESS || taos_num_fields(res) == 0) {
       return NULL;
     }
-
-#if SYNC_ON_TOP_OF_ASYNC
-    return doAsyncFetchRow(pRequest, true, true);
-#else
     return doFetchRows(pRequest, true, true);
 #endif
 
@@ -489,6 +488,7 @@ int taos_fetch_block_s(TAOS_RES *res, int *numOfRows, TAOS_ROW *rows) {
   if (res == NULL) {
     return 0;
   }
+
   if (TD_RES_QUERY(res)) {
     SRequestObj *pRequest = (SRequestObj *)res;
 
@@ -501,7 +501,7 @@ int taos_fetch_block_s(TAOS_RES *res, int *numOfRows, TAOS_ROW *rows) {
     }
 
 #if SYNC_ON_TOP_OF_ASYNC
-    doAsyncFetchRow(pRequest, false, true);
+    doAsyncFetchRows(pRequest, false, true);
 #else
     doFetchRows(pRequest, true, true);
 #endif
@@ -552,7 +552,11 @@ int taos_fetch_raw_block(TAOS_RES *res, int *numOfRows, void **pData) {
     return 0;
   }
 
+#if SYNC_ON_TOP_OF_ASYNC
+  doAsyncFetchRows(pRequest, false, false);
+#else
   doFetchRows(pRequest, false, false);
+#endif
 
   SReqResultInfo *pResultInfo = &pRequest->body.resInfo;
 
@@ -771,11 +775,11 @@ static void fetchCallback(void* pResult, void* param, int32_t code) {
   }
 
   if (pRequest->code != TSDB_CODE_SUCCESS) {
-    pRequest->code = code;
     pRequest->body.fetchFp(pRequest->body.param, pRequest, 0);
+    return;
   }
 
-  pRequest->code = setQueryResultFromRsp(&pRequest->body.resInfo, (SRetrieveTableRsp*)pResultInfo->pData, true, false);
+  pRequest->code = setQueryResultFromRsp(pResultInfo, (SRetrieveTableRsp*)pResultInfo->pData, pResultInfo->convertUcs4, false);
   if (pRequest->code != TSDB_CODE_SUCCESS) {
     pResultInfo->numOfRows = 0;
     pRequest->code = code;
@@ -815,6 +819,13 @@ void taos_fetch_rows_a(TAOS_RES *res, __taos_async_fn_t fp, void *param) {
   schedulerAsyncFetchRows(pRequest->body.queryJob, fetchCallback, pRequest);
 }
 
+void taos_fetch_raw_block_a(TAOS_RES* res, __taos_async_fn_t fp, void* param) {
+  ASSERT(res != NULL && fp != NULL);
+  SRequestObj *pRequest = res;
+  pRequest->body.resInfo.convertUcs4 = false;
+  taos_fetch_rows_a(res, fp, param);
+}
+
 TAOS_SUB *taos_subscribe(TAOS *taos, int restart, const char *topic, const char *sql, TAOS_SUBSCRIBE_CALLBACK fp,
                          void *param, int interval) {
   // TODO