diff --git a/src/client/src/tscAsync.c b/src/client/src/tscAsync.c
index 9f207936df234ec87a5f8e9c74b6aa2e3ef0db3e..8fba57790984c7fc1c8d2f3bda0c6ef42171ca77 100644
--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -145,7 +145,7 @@ static void tscAsyncFetchRowsProxy(void *param, TAOS_RES *tres, int numOfRows) {
     return;
   }
   
-  // local reducer has handle this situation during super table non-projection query.
+  // local merge has handle this situation during super table non-projection query.
   if (pCmd->command != TSDB_SQL_RETRIEVE_LOCALMERGE) {
     pRes->numOfTotalInCurrentClause += pRes->numOfRows;
   }
@@ -222,9 +222,30 @@ void taos_fetch_rows_a(TAOS_RES *taosa, void (*fp)(void *, TAOS_RES *, int), voi
   tscResetForNextRetrieve(pRes);
   
   // handle the sub queries of join query
-  if (pCmd->command == TSDB_SQL_METRIC_JOIN_RETRIEVE) {
+  if (pCmd->command == TSDB_SQL_TABLE_JOIN_RETRIEVE) {
     tscFetchDatablockFromSubquery(pSql);
-  } else {
+  } else if (pRes->completed && pCmd->command == TSDB_SQL_FETCH) {
+    if (hasMoreVnodesToTry(pSql)) { // sequentially retrieve data from remain vnodes.
+      tscTryQueryNextVnode(pSql, tscAsyncQueryRowsForNextVnode);
+      return;
+    } else {
+      /*
+       * all available virtual node has been checked already, now we need to check
+       * for the next subclause queries
+       */
+      if (pCmd->clauseIndex < pCmd->numOfClause - 1) {
+        tscTryQueryNextClause(pSql, tscAsyncQueryRowsForNextVnode);
+        return;
+      }
+    
+      /*
+       * 1. has reach the limitation
+       * 2. no remain virtual nodes to be retrieved anymore
+       */
+      (*pSql->fetchFp)(param, pSql, 0);
+    }
+    return;
+  } else { // current query is not completed, continue retrieve from node
     if (pCmd->command != TSDB_SQL_RETRIEVE_LOCALMERGE && pCmd->command < TSDB_SQL_LOCAL) {
       pCmd->command = (pCmd->command > TSDB_SQL_MGMT) ? TSDB_SQL_RETRIEVE : TSDB_SQL_FETCH;
     }
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index b958bbe15c3fcb5372e6b324d5780ed37ef758c1..889433770aace9561d54ea4b332a8577983aa63f 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -1444,8 +1444,9 @@ int tscProcessRetrieveLocalMergeRsp(SSqlObj *pSql) {
   }
 
   pRes->row = 0;
+  pRes->completed = (pRes->numOfRows == 0);
 
-  uint8_t code = pRes->code;
+  int32_t code = pRes->code;
   if (pRes->code == TSDB_CODE_SUCCESS) {
     (*pSql->fp)(pSql->param, pSql, pRes->numOfRows);
   } else {
diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index 14f0fa07caab1daac854cc9372fedc88e161ee12..87292f4fe659adf2c0d54ad08143fbcf2ba36126 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -463,11 +463,11 @@ TAOS_ROW taos_fetch_row(TAOS_RES *res) {
     return NULL;
   }
   
-  // current data are exhausted, fetch more data
-  if (pRes->row >= pRes->numOfRows && pRes->completed != true &&
+  // current data set are exhausted, fetch more data from node
+  if (pRes->row >= pRes->numOfRows && (pRes->completed != true || hasMoreVnodesToTry(pSql)) &&
       (pCmd->command == TSDB_SQL_RETRIEVE ||
        pCmd->command == TSDB_SQL_RETRIEVE_LOCALMERGE ||
-       pCmd->command == TSDB_SQL_METRIC_JOIN_RETRIEVE ||
+       pCmd->command == TSDB_SQL_TABLE_JOIN_RETRIEVE ||
        pCmd->command == TSDB_SQL_FETCH ||
        pCmd->command == TSDB_SQL_SHOW ||
        pCmd->command == TSDB_SQL_SELECT ||
diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index 1e4a142a906cb852dffdebca799f0cfbbab4dece..cf14525c491e94ea07ba255eb69bc9306bf7e087 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -1203,7 +1203,7 @@ int32_t tscHandleMasterJoinQuery(SSqlObj* pSql) {
     }
   }
   
-  pSql->cmd.command = (pSql->numOfSubs <= 0)? TSDB_SQL_RETRIEVE_EMPTY_RESULT:TSDB_SQL_METRIC_JOIN_RETRIEVE;
+  pSql->cmd.command = (pSql->numOfSubs <= 0)? TSDB_SQL_RETRIEVE_EMPTY_RESULT:TSDB_SQL_TABLE_JOIN_RETRIEVE;
   
   return TSDB_CODE_SUCCESS;
 }
@@ -1949,7 +1949,7 @@ void **doSetResultRowData(SSqlObj *pSql, bool finalResult) {
   
   assert(pRes->row >= 0 && pRes->row <= pRes->numOfRows);
   
-  if(pCmd->command == TSDB_SQL_METRIC_JOIN_RETRIEVE) {
+  if(pCmd->command == TSDB_SQL_TABLE_JOIN_RETRIEVE) {
     if (pRes->completed) {
       tfree(pRes->tsrow);
     }
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index 171d40b932e2570affeb4e42b27deaece7c9731a..f0bc8d975517051ff22b0568c26c47a1406803f6 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -386,7 +386,7 @@ void tscPartiallyFreeSqlObj(SSqlObj* pSql) {
 
   int32_t cmd = pCmd->command;
   if (cmd < TSDB_SQL_INSERT || cmd == TSDB_SQL_RETRIEVE_LOCALMERGE || cmd == TSDB_SQL_RETRIEVE_EMPTY_RESULT ||
-      cmd == TSDB_SQL_METRIC_JOIN_RETRIEVE) {
+      cmd == TSDB_SQL_TABLE_JOIN_RETRIEVE) {
     tscRemoveFromSqlList(pSql);
   }
   
@@ -1644,9 +1644,11 @@ void doRemoveTableMetaInfo(SQueryInfo* pQueryInfo, int32_t index, bool removeFro
 void clearAllTableMetaInfo(SQueryInfo* pQueryInfo, const char* address, bool removeFromCache) {
   tscTrace("%p deref the table meta in cache, numOfTables:%d", address, pQueryInfo->numOfTables);
   
-  int32_t index = pQueryInfo->numOfTables;
-  while (index >= 0) {
-    doRemoveTableMetaInfo(pQueryInfo, --index, removeFromCache);
+  for(int32_t i = 0; i < pQueryInfo->numOfTables; ++i) {
+    STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, i);
+  
+    tscClearTableMetaInfo(pTableMetaInfo, removeFromCache);
+    free(pTableMetaInfo);
   }
   
   tfree(pQueryInfo->pTableMetaInfo);
@@ -1698,16 +1700,8 @@ void tscClearTableMetaInfo(STableMetaInfo* pTableMetaInfo, bool removeFromCache)
   taosCacheRelease(tscCacheHandle, (void**)&(pTableMetaInfo->pTableMeta), removeFromCache);
   tfree(pTableMetaInfo->vgroupList);
   
-  if (pTableMetaInfo->tagColList != NULL) {
-    size_t numOfTags = taosArrayGetSize(pTableMetaInfo->tagColList);
-    for(int32_t i = 0; i < numOfTags; ++i) { // todo do NOT use the allocated object
-      SColumn* pCol = taosArrayGetP(pTableMetaInfo->tagColList, i);
-      tfree(pCol);
-    }
-    
-    taosArrayDestroy(pTableMetaInfo->tagColList);
-    pTableMetaInfo->tagColList = NULL;
-  }
+  tscColumnListDestroy(pTableMetaInfo->tagColList);
+  pTableMetaInfo->tagColList = NULL;
 }
 
 void tscResetForNextRetrieve(SSqlRes* pRes) {
@@ -1991,22 +1985,28 @@ char* tscGetErrorMsgPayload(SSqlCmd* pCmd) { return pCmd->payload; }
 
 /**
  *  If current vnode query does not return results anymore (pRes->numOfRows == 0), try the next vnode if exists,
- *  in case of multi-vnode super table projection query and the result does not reach the limitation.
+ *  while multi-vnode super table projection query and the result does not reach the limitation.
  */
 bool hasMoreVnodesToTry(SSqlObj* pSql) {
-//  SSqlCmd* pCmd = &pSql->cmd;
-//  SSqlRes* pRes = &pSql->res;
+  SSqlCmd* pCmd = &pSql->cmd;
+  SSqlRes* pRes = &pSql->res;
+  if (pCmd->command != TSDB_SQL_FETCH) {
+    return false;
+  }
 
-//  SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
+  SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
   
-//  STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
-//  if (!UTIL_TABLE_IS_SUPERTABLE(pTableMetaInfo) || (pTableMetaInfo->pMetricMeta == NULL)) {
+  STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
+  assert(pRes->completed);
+  
+  // for normal table, do not try any more if result are exhausted
+  if (!UTIL_TABLE_IS_SUPERTABLE(pTableMetaInfo) || (pTableMetaInfo->vgroupList == NULL)) {
     return false;
-//  }
+  }
   
-//  int32_t totalVnode = pTableMetaInfo->pMetricMeta->numOfVnodes;
-//  return pRes->numOfRows == 0 && tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) &&
-//         (!tscHasReachLimitation(pQueryInfo, pRes)) && (pTableMetaInfo->vgroupIndex < totalVnode - 1);
+  int32_t numOfVgroups = pTableMetaInfo->vgroupList->numOfVgroups;
+  return tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) &&
+         (!tscHasReachLimitation(pQueryInfo, pRes)) && (pTableMetaInfo->vgroupIndex < numOfVgroups - 1);
 }
 
 void tscTryQueryNextVnode(SSqlObj* pSql, __async_cb_func_t fp) {
@@ -2022,12 +2022,11 @@ void tscTryQueryNextVnode(SSqlObj* pSql, __async_cb_func_t fp) {
   assert(pRes->numOfRows == 0 && tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) && !tscHasReachLimitation(pQueryInfo, pRes));
 
   STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
-  int32_t totalVnode = 0;
-//  int32_t         totalVnode = pTableMetaInfo->pMetricMeta->numOfVnodes;
-
-  while (++pTableMetaInfo->vgroupIndex < totalVnode) {
+  
+  int32_t totalVgroups = pTableMetaInfo->vgroupList->numOfVgroups;
+  while (++pTableMetaInfo->vgroupIndex < totalVgroups) {
     tscTrace("%p current vnode:%d exhausted, try next:%d. total vnode:%d. current numOfRes:%d", pSql,
-             pTableMetaInfo->vgroupIndex - 1, pTableMetaInfo->vgroupIndex, totalVnode, pRes->numOfTotalInCurrentClause);
+             pTableMetaInfo->vgroupIndex - 1, pTableMetaInfo->vgroupIndex, totalVgroups, pRes->numOfTotalInCurrentClause);
 
     /*
      * update the limit and offset value for the query on the next vnode,
@@ -2043,10 +2042,10 @@ void tscTryQueryNextVnode(SSqlObj* pSql, __async_cb_func_t fp) {
     }
 
     pQueryInfo->limit.offset = pRes->offset;
-
     assert((pRes->offset >= 0 && pRes->numOfRows == 0) || (pRes->offset == 0 && pRes->numOfRows >= 0));
-    tscTrace("%p new query to next vnode, vnode index:%d, limit:%" PRId64 ", offset:%" PRId64 ", glimit:%" PRId64, pSql,
-             pTableMetaInfo->vgroupIndex, pQueryInfo->limit.limit, pQueryInfo->limit.offset, pQueryInfo->clauseLimit);
+    
+    tscTrace("%p new query to next vgroup, index:%d, limit:%" PRId64 ", offset:%" PRId64 ", glimit:%" PRId64,
+        pSql, pTableMetaInfo->vgroupIndex, pQueryInfo->limit.limit, pQueryInfo->limit.offset, pQueryInfo->clauseLimit);
 
     /*
      * For project query with super table join, the numOfSub is equalled to the number of all subqueries.
@@ -2060,43 +2059,46 @@ void tscTryQueryNextVnode(SSqlObj* pSql, __async_cb_func_t fp) {
     tscResetForNextRetrieve(pRes);
 
     // in case of async query, set the callback function
-    void* fp1 = pSql->fp;
+//    void* fp1 = pSql->fp;
     pSql->fp = fp;
 
-    if (fp1 != NULL) {
-      assert(fp != NULL);
-    }
-
-    int32_t ret = tscProcessSql(pSql);  // todo check for failure
+//    if (fp1 != NULL) {
+//      assert(fp != NULL);
+//    }
 
-    // in case of async query, return now
-    if (fp != NULL) {
-      return;
-    }
-
-    if (ret != TSDB_CODE_SUCCESS) {
-      pSql->res.code = ret;
+    int32_t ret = tscProcessSql(pSql);
+    if (ret == TSDB_CODE_SUCCESS) {
       return;
+    } else {// todo check for failure
     }
-
-    // retrieve data
-    assert(pCmd->command == TSDB_SQL_SELECT);
-    pCmd->command = TSDB_SQL_FETCH;
-
-    if ((ret = tscProcessSql(pSql)) != TSDB_CODE_SUCCESS) {
-      pSql->res.code = ret;
-      return;
-    }
-
-    // if the result from current virtual node are empty, try next if exists. otherwise, return the results.
-    if (pRes->numOfRows > 0) {
-      break;
-    }
+    // in case of async query, return now
+//    if (fp != NULL) {
+//      return;
+//    }
+//
+//    if (ret != TSDB_CODE_SUCCESS) {
+//      pSql->res.code = ret;
+//      return;
+//    }
+//
+//    // retrieve data
+//    assert(pCmd->command == TSDB_SQL_SELECT);
+//    pCmd->command = TSDB_SQL_FETCH;
+//
+//    if ((ret = tscProcessSql(pSql)) != TSDB_CODE_SUCCESS) {
+//      pSql->res.code = ret;
+//      return;
+//    }
+//
+//    // if the result from current virtual node are empty, try next if exists. otherwise, return the results.
+//    if (pRes->numOfRows > 0) {
+//      break;
+//    }
   }
 
-  if (pRes->numOfRows == 0) {
-    tscTrace("%p all vnodes exhausted, prj query completed. total res:%d", pSql, totalVnode, pRes->numOfTotal);
-  }
+//  if (pRes->numOfRows == 0) {
+//    tscTrace("%p all vnodes exhausted, prj query completed. total res:%d", pSql, totalVnode, pRes->numOfTotal);
+//  }
 }
 
 void tscTryQueryNextClause(SSqlObj* pSql, void (*queryFp)()) {
diff --git a/src/query/inc/qsqltype.h b/src/query/inc/qsqltype.h
index 08d30be925796654ec127de997e6a236ea39f6fc..4087be49eeac3042f04013b9e929fce30d323cea 100644
--- a/src/query/inc/qsqltype.h
+++ b/src/query/inc/qsqltype.h
@@ -61,7 +61,7 @@ enum _sql_type {
   TSDB_SQL_LOCAL,  // SQL below for client local
   TSDB_SQL_DESCRIBE_TABLE,
   TSDB_SQL_RETRIEVE_LOCALMERGE,
-  TSDB_SQL_METRIC_JOIN_RETRIEVE,
+  TSDB_SQL_TABLE_JOIN_RETRIEVE,
 
   /*
    * build empty result instead of accessing dnode to fetch result