diff --git a/src/client/inc/tsclient.h b/src/client/inc/tsclient.h
index 1d06d38264..1726090e12 100644
--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@@ -252,7 +252,6 @@ typedef struct {
   uint32_t     allocSize;
   char *       payload;
   int          payloadLen;
-  int64_t      globalLimit;
   SQueryInfo **pQueryInfo;
   int32_t      numOfClause;
 
diff --git a/src/client/src/tscAsync.c b/src/client/src/tscAsync.c
index ad60635afe..7b1a1a6074 100644
--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -133,7 +133,7 @@ static void tscProcessAsyncFetchRowsProxy(void *param, TAOS_RES *tres, int numOf
   
   // local reducer has handle this situation during super table non-projection query.
   if (pCmd->command != TSDB_SQL_RETRIEVE_METRIC) {
-    pRes->numOfTotal += pRes->numOfRows;
+    pRes->numOfTotalInCurrentClause += pRes->numOfRows;
   }
 
   (*pSql->fetchFp)(param, tres, numOfRows);
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 70ebced203..06eb4a6088 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -521,18 +521,12 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       pCmd->command = pQueryInfo1->command;
   
       // if there is only one element, the limit of clause is the limit of global result.
-      if (pCmd->numOfClause == 1) {
-        pCmd->globalLimit = pQueryInfo1->clauseLimit;
-      } else { // check the output fields information, column name and column type
-        pCmd->globalLimit = -1;
+      for(int32_t i = 1; i < pCmd->numOfClause; ++i) {
+        SQueryInfo* pQueryInfo2 = tscGetQueryInfoDetail(pCmd, i);
         
-        for(int32_t i = 1; i < pCmd->numOfClause; ++i) {
-          SQueryInfo* pQueryInfo2 = tscGetQueryInfoDetail(pCmd, i);
-          
-          int32_t ret = tscFieldInfoCompare(&pQueryInfo1->fieldsInfo, &pQueryInfo2->fieldsInfo);
-          if (ret != 0) {
-            return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
-          }
+        int32_t ret = tscFieldInfoCompare(&pQueryInfo1->fieldsInfo, &pQueryInfo2->fieldsInfo);
+        if (ret != 0) {
+          return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
         }
       }
 
diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index b89c6e49b0..7d5d1d242f 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -543,12 +543,12 @@ static void **tscBuildResFromSubqueries(SSqlObj *pSql) {
       pRes->numOfTotalInCurrentClause++;
 
       break;
-    } else {                                              // continue retrieve data from vnode
-      if (!tscHashRemainDataInSubqueryResultSet(pSql)) {  // free all sub sqlobj
+    } else {// continue retrieve data from vnode
+      if (!tscHashRemainDataInSubqueryResultSet(pSql)) {
         tscTrace("%p at least one subquery exhausted, free all other %d subqueries", pSql, pSql->numOfSubs - 1);
-
         SSubqueryState *pState = NULL;
-
+  
+        // free all sub sqlobj
         for (int32_t i = 0; i < pSql->numOfSubs; ++i) {
           SSqlObj *pChildObj = pSql->pSubs[i];
           if (pChildObj == NULL) {
@@ -716,7 +716,7 @@ int taos_fetch_block(TAOS_RES *res, TAOS_ROW *rows) {
 }
 
 int taos_select_db(TAOS *taos, const char *db) {
-  char sql[64];
+  char sql[256] = {0};
 
   STscObj *pObj = (STscObj *)taos;
   if (pObj == NULL || pObj->signature != pObj) {
@@ -724,8 +724,7 @@ int taos_select_db(TAOS *taos, const char *db) {
     return TSDB_CODE_DISCONNECTED;
   }
 
-  sprintf(sql, "use %s", db);
-
+  snprintf(sql, tListLen(sql), "use %s", db);
   return taos_query(taos, sql);
 }
 
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index 19016497ac..037763afd7 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -2057,12 +2057,15 @@ void tscTryQueryNextVnode(SSqlObj *pSql, __async_cb_func_t fp) {
     
     // in case of async query, set the callback function
     void* fp1 = pSql->fp;
+    pSql->fp = fp;
+    
     if (fp1 != NULL) {
         assert(fp != NULL);
-       pSql->fp = fp;
     }
     
     int32_t ret = tscProcessSql(pSql);  // todo check for failure
+    
+    // in case of async query, return now
     if (fp != NULL) {
       return;
     }