diff --git a/src/client/src/tscSecondaryMerge.c b/src/client/src/tscSecondaryMerge.c
index 0ca079bc6e0b6a460c140e154e36be886b2eecad..1d4ed51f32a68cb39d511f83c5ea1f47a3aeb4eb 100644
--- a/src/client/src/tscSecondaryMerge.c
+++ b/src/client/src/tscSecondaryMerge.c
@@ -636,10 +636,11 @@ int32_t tscLocalReducerEnvCreate(SSqlObj *pSql, tExtMemBuffer ***pMemBuffer, tOr
 
   pModel = createColumnModel(pSchema, pQueryInfo->exprsInfo.numOfExprs, capacity);
 
-//  for (int32_t i = 0; i < pTableMetaInfo->pMetricMeta->numOfVnodes; ++i) {
-//    (*pMemBuffer)[i] = createExtMemBuffer(nBufferSizes, rlen, pModel);
-//    (*pMemBuffer)[i]->flushModel = MULTIPLE_APPEND_MODEL;
-//  }
+  size_t numOfSubs = taosArrayGetSize(pTableMetaInfo->vgroupIdList);
+  for (int32_t i = 0; i < numOfSubs; ++i) {
+    (*pMemBuffer)[i] = createExtMemBuffer(nBufferSizes, rlen, pModel);
+    (*pMemBuffer)[i]->flushModel = MULTIPLE_APPEND_MODEL;
+  }
 
   if (createOrderDescriptor(pOrderDesc, pCmd, pModel) != TSDB_CODE_SUCCESS) {
     pRes->code = TSDB_CODE_CLI_OUT_OF_MEMORY;
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 498a33838966bd4de795f0ab9474cd71bc83988c..111ebc4e8c690cef9c52ea214dacde0cf5d58dfd 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -509,31 +509,31 @@ int tscBuildRetrieveMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
 }
 
 int tscBuildSubmitMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
-  SSubmitMsg *pShellMsg;
-  char *           pMsg, *pStart;
-
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(&pSql->cmd, 0);
   STableMeta* pTableMeta = tscGetMetaInfo(pQueryInfo, 0)->pTableMeta;
   
-  pStart = pSql->cmd.payload + tsRpcHeadSize;
-  pMsg = pStart;
+  char* pMsg = pSql->cmd.payload + tsRpcHeadSize;
+  
+  // NOTE: shell message size should not include SMsgDesc
+  int32_t size = pSql->cmd.payloadLen - sizeof(SMsgDesc);
   
   SMsgDesc* pMsgDesc = (SMsgDesc*) pMsg;
-  pMsgDesc->numOfVnodes = htonl(1);       //set the number of vnodes
+  
+  pMsgDesc->numOfVnodes = htonl(1);       //todo set the right number of vnodes
   pMsg += sizeof(SMsgDesc);
   
-  pShellMsg = (SSubmitMsg *)pMsg;
+  SSubmitMsg *pShellMsg = (SSubmitMsg *)pMsg;
+  
   pShellMsg->header.vgId = htonl(pTableMeta->vgId);
-  pShellMsg->header.contLen = htonl(pSql->cmd.payloadLen);
+  pShellMsg->header.contLen = htonl(size);
   pShellMsg->length = pShellMsg->header.contLen;
   
   pShellMsg->numOfBlocks = htonl(pSql->cmd.numOfTablesInSubmit);  // number of meters to be inserted
 
-  // pSql->cmd.payloadLen is set during parse sql routine, so we do not use it here
+  // pSql->cmd.payloadLen is set during copying data into paylaod
   pSql->cmd.msgType = TSDB_MSG_TYPE_SUBMIT;
+  tscTrace("%p build submit msg, vgId:%d numOfVnodes:%d", pSql, pTableMeta->vgId, htons(pMsgDesc->numOfVnodes));
   
-//  tscTrace("%p update submit msg vnode:%s:%d", pSql, taosIpStr(pTableMeta->vpeerDesc[pTableMeta->index].ip),
-//           htons(pShellMsg->vnode));
   return TSDB_CODE_SUCCESS;
 }
 
diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index ccf187ac649578f026eb952e87ad45715279edd3..b0c7b68ab4cfc263f6728d4ff8e95c224ec988cf 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -1006,14 +1006,12 @@ int32_t tscHandleMasterSTableQuery(SSqlObj *pSql) {
   
   pRes->qhandle = 1;  // hack the qhandle check
   
-  const uint32_t nBufferSize = (1 << 16);  // 64KB
+  const uint32_t nBufferSize = (1u << 16);  // 64KB
   
   SQueryInfo *    pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
   STableMetaInfo *pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
   
-  int32_t numOfSubQueries = 1;
-//  int32_t numOfSubQueries = pTableMetaInfo->pMetricMeta->numOfVnodes;
-  
+  int32_t numOfSubQueries = taosArrayGetSize(pTableMetaInfo->vgroupIdList);
   assert(numOfSubQueries > 0);
   
   int32_t ret = tscLocalReducerEnvCreate(pSql, &pMemoryBuf, &pDesc, &pModel, nBufferSize);
@@ -1119,7 +1117,7 @@ static void tscFreeSubSqlObj(SRetrieveSupport *trsupport, SSqlObj *pSql) {
   tfree(trsupport);
 }
 
-static void tscRetrieveFromVnodeCallBack(void *param, TAOS_RES *tres, int numOfRows);
+static void tscRetrieveFromDnodeCallBack(void *param, TAOS_RES *tres, int numOfRows);
 
 static void tscAbortFurtherRetryRetrieval(SRetrieveSupport *trsupport, TAOS_RES *tres, int32_t errCode) {
 // set no disk space error info
@@ -1141,7 +1139,7 @@ static void tscAbortFurtherRetryRetrieval(SRetrieveSupport *trsupport, TAOS_RES
   
   pthread_mutex_unlock(&trsupport->queryMutex);
   
-  tscRetrieveFromVnodeCallBack(trsupport, tres, trsupport->pState->code);
+  tscRetrieveFromDnodeCallBack(trsupport, tres, trsupport->pState->code);
 }
 
 static void tscHandleSubRetrievalError(SRetrieveSupport *trsupport, SSqlObj *pSql, int numOfRows) {
@@ -1236,7 +1234,86 @@ static void tscHandleSubRetrievalError(SRetrieveSupport *trsupport, SSqlObj *pSq
   }
 }
 
-static void tscRetrieveFromVnodeCallBack(void *param, TAOS_RES *tres, int numOfRows) {
+static void tscAllDataRetrievedFromDnode(SRetrieveSupport *trsupport, SSqlObj* pSql) {
+  int32_t           idx = trsupport->subqueryIndex;
+  SSqlObj *         pPObj = trsupport->pParentSqlObj;
+  tOrderDescriptor *pDesc = trsupport->pOrderDescriptor;
+  
+  SSubqueryState* pState = trsupport->pState;
+  SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(&pSql->cmd, 0);
+  
+  // data in from current vnode is stored in cache and disk
+  uint32_t numOfRowsFromSubquery = trsupport->pExtMemBuffer[idx]->numOfTotalElems + trsupport->localBuffer->numOfElems;
+//    tscTrace("%p sub:%p all data retrieved from ip:%u,vid:%d, numOfRows:%d, orderOfSub:%d", pPObj, pSql, pSvd->ip,
+//             pSvd->vnode, numOfRowsFromSubquery, idx);
+  
+  tColModelCompact(pDesc->pColumnModel, trsupport->localBuffer, pDesc->pColumnModel->capacity);
+
+#ifdef _DEBUG_VIEW
+  printf("%" PRIu64 " rows data flushed to disk:\n", trsupport->localBuffer->numOfElems);
+    SSrcColumnInfo colInfo[256] = {0};
+    tscGetSrcColumnInfo(colInfo, pQueryInfo);
+    tColModelDisplayEx(pDesc->pColumnModel, trsupport->localBuffer->data, trsupport->localBuffer->numOfElems,
+                       trsupport->localBuffer->numOfElems, colInfo);
+#endif
+  
+  if (tsTotalTmpDirGB != 0 && tsAvailTmpDirGB < tsMinimalTmpDirGB) {
+    tscError("%p sub:%p client disk space remain %.3f GB, need at least %.3f GB, stop query", pPObj, pSql,
+             tsAvailTmpDirGB, tsMinimalTmpDirGB);
+    tscAbortFurtherRetryRetrieval(trsupport, pSql, TSDB_CODE_CLI_NO_DISKSPACE);
+    return;
+  }
+  
+  // each result for a vnode is ordered as an independant list,
+  // then used as an input of loser tree for disk-based merge routine
+  int32_t ret = tscFlushTmpBuffer(trsupport->pExtMemBuffer[idx], pDesc, trsupport->localBuffer,
+                                  pQueryInfo->groupbyExpr.orderType);
+  if (ret != 0) { // set no disk space error info, and abort retry
+    return tscAbortFurtherRetryRetrieval(trsupport, pSql, TSDB_CODE_CLI_NO_DISKSPACE);
+  }
+  
+  // keep this value local variable, since the pState variable may be released by other threads, if atomic_add opertion
+  // increases the finished value up to pState->numOfTotal value, which means all subqueries are completed.
+  // In this case, the comparsion between finished value and released pState->numOfTotal is not safe.
+  int32_t numOfTotal = pState->numOfTotal;
+  
+  int32_t finished = atomic_add_fetch_32(&pState->numOfCompleted, 1);
+  if (finished < numOfTotal) {
+    tscTrace("%p sub:%p orderOfSub:%d freed, finished subqueries:%d", pPObj, pSql, trsupport->subqueryIndex, finished);
+    return tscFreeSubSqlObj(trsupport, pSql);
+  }
+  
+  // all sub-queries are returned, start to local merge process
+  pDesc->pColumnModel->capacity = trsupport->pExtMemBuffer[idx]->numOfElemsPerPage;
+  
+  tscTrace("%p retrieve from %d vnodes completed.final NumOfRows:%d,start to build loser tree", pPObj,
+           pState->numOfTotal, pState->numOfRetrievedRows);
+  
+  SQueryInfo *pPQueryInfo = tscGetQueryInfoDetail(&pPObj->cmd, 0);
+  tscClearInterpInfo(pPQueryInfo);
+  
+  tscCreateLocalReducer(trsupport->pExtMemBuffer, pState->numOfTotal, pDesc, trsupport->pFinalColModel,
+                        &pPObj->cmd, &pPObj->res);
+  tscTrace("%p build loser tree completed", pPObj);
+  
+  pPObj->res.precision = pSql->res.precision;
+  pPObj->res.numOfRows = 0;
+  pPObj->res.row = 0;
+  
+  // only free once
+  tfree(trsupport->pState);
+  tscFreeSubSqlObj(trsupport, pSql);
+  
+  // set the command flag must be after the semaphore been correctly set.
+  pPObj->cmd.command = TSDB_SQL_RETRIEVE_METRIC;
+  if (pPObj->res.code == TSDB_CODE_SUCCESS) {
+    (*pPObj->fp)(pPObj->param, pPObj, 0);
+  } else {
+    tscQueueAsyncRes(pPObj);
+  }
+}
+
+static void tscRetrieveFromDnodeCallBack(void *param, TAOS_RES *tres, int numOfRows) {
   SRetrieveSupport *trsupport = (SRetrieveSupport *)param;
   int32_t           idx = trsupport->subqueryIndex;
   SSqlObj *         pPObj = trsupport->pParentSqlObj;
@@ -1265,15 +1342,15 @@ static void tscRetrieveFromVnodeCallBack(void *param, TAOS_RES *tres, int numOfR
   STableMetaInfo *pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
   
 //  SVnodeSidList *vnodeInfo = tscGetVnodeSidList(pTableMetaInfo->pMetricMeta, idx);
-  SVnodeSidList *vnodeInfo = 0;
-  SVnodeDesc *   pSvd = &vnodeInfo->vpeerDesc[vnodeInfo->index];
+//  SVnodeSidList *vnodeInfo = 0;
+//  SVnodeDesc *   pSvd = &vnodeInfo->vpeerDesc[vnodeInfo->index];
   
   if (numOfRows > 0) {
     assert(pRes->numOfRows == numOfRows);
     int64_t num = atomic_add_fetch_64(&pState->numOfRetrievedRows, numOfRows);
     
-    tscTrace("%p sub:%p retrieve numOfRows:%d totalNumOfRows:%d from ip:%u,vid:%d,orderOfSub:%d", pPObj, pSql,
-             pRes->numOfRows, pState->numOfRetrievedRows, pSvd->ip, pSvd->vnode, idx);
+//    tscTrace("%p sub:%p retrieve numOfRows:%d totalNumOfRows:%d from ip:%u,vid:%d,orderOfSub:%d", pPObj, pSql,
+//             pRes->numOfRows, pState->numOfRetrievedRows, pSvd->ip, pSvd->vnode, idx);
     
     if (num > tsMaxNumOfOrderedResults && tscIsProjectionQueryOnSTable(pQueryInfo, 0)) {
       tscError("%p sub:%p num of OrderedRes is too many, max allowed:%" PRId64 " , current:%" PRId64,
@@ -1299,85 +1376,16 @@ static void tscRetrieveFromVnodeCallBack(void *param, TAOS_RES *tres, int numOfR
     
     int32_t ret = saveToBuffer(trsupport->pExtMemBuffer[idx], pDesc, trsupport->localBuffer, pRes->data,
                                pRes->numOfRows, pQueryInfo->groupbyExpr.orderType);
-    if (ret < 0) {
-      // set no disk space error info, and abort retry
+    if (ret < 0) { // set no disk space error info, and abort retry
       tscAbortFurtherRetryRetrieval(trsupport, tres, TSDB_CODE_CLI_NO_DISKSPACE);
-    } else {
+    } else if (pRes->completed) {
+      tscAllDataRetrievedFromDnode(trsupport, pSql);
+    } else { // continue fetch data from dnode
       pthread_mutex_unlock(&trsupport->queryMutex);
-      taos_fetch_rows_a(tres, tscRetrieveFromVnodeCallBack, param);
-    }
-    
-  } else {  // all data has been retrieved to client
-    /* data in from current vnode is stored in cache and disk */
-    uint32_t numOfRowsFromVnode = trsupport->pExtMemBuffer[idx]->numOfTotalElems + trsupport->localBuffer->numOfElems;
-    tscTrace("%p sub:%p all data retrieved from ip:%u,vid:%d, numOfRows:%d, orderOfSub:%d", pPObj, pSql, pSvd->ip,
-             pSvd->vnode, numOfRowsFromVnode, idx);
-    
-    tColModelCompact(pDesc->pColumnModel, trsupport->localBuffer, pDesc->pColumnModel->capacity);
-
-#ifdef _DEBUG_VIEW
-    printf("%" PRIu64 " rows data flushed to disk:\n", trsupport->localBuffer->numOfElems);
-    SSrcColumnInfo colInfo[256] = {0};
-    tscGetSrcColumnInfo(colInfo, pQueryInfo);
-    tColModelDisplayEx(pDesc->pColumnModel, trsupport->localBuffer->data, trsupport->localBuffer->numOfElems,
-                       trsupport->localBuffer->numOfElems, colInfo);
-#endif
-    
-    if (tsTotalTmpDirGB != 0 && tsAvailTmpDirGB < tsMinimalTmpDirGB) {
-      tscError("%p sub:%p client disk space remain %.3f GB, need at least %.3f GB, stop query", pPObj, pSql,
-               tsAvailTmpDirGB, tsMinimalTmpDirGB);
-      tscAbortFurtherRetryRetrieval(trsupport, tres, TSDB_CODE_CLI_NO_DISKSPACE);
-      return;
-    }
-    
-    // each result for a vnode is ordered as an independant list,
-    // then used as an input of loser tree for disk-based merge routine
-    int32_t ret = tscFlushTmpBuffer(trsupport->pExtMemBuffer[idx], pDesc, trsupport->localBuffer,
-                                    pQueryInfo->groupbyExpr.orderType);
-    if (ret != 0) {
-      /* set no disk space error info, and abort retry */
-      return tscAbortFurtherRetryRetrieval(trsupport, tres, TSDB_CODE_CLI_NO_DISKSPACE);
-    }
-    
-    // keep this value local variable, since the pState variable may be released by other threads, if atomic_add opertion
-    // increases the finished value up to pState->numOfTotal value, which means all subqueries are completed.
-    // In this case, the comparsion between finished value and released pState->numOfTotal is not safe.
-    int32_t numOfTotal = pState->numOfTotal;
-    
-    int32_t finished = atomic_add_fetch_32(&pState->numOfCompleted, 1);
-    if (finished < numOfTotal) {
-      tscTrace("%p sub:%p orderOfSub:%d freed, finished subqueries:%d", pPObj, pSql, trsupport->subqueryIndex, finished);
-      return tscFreeSubSqlObj(trsupport, pSql);
-    }
-    
-    // all sub-queries are returned, start to local merge process
-    pDesc->pColumnModel->capacity = trsupport->pExtMemBuffer[idx]->numOfElemsPerPage;
-    
-    tscTrace("%p retrieve from %d vnodes completed.final NumOfRows:%d,start to build loser tree", pPObj,
-             pState->numOfTotal, pState->numOfRetrievedRows);
-    
-    SQueryInfo *pPQueryInfo = tscGetQueryInfoDetail(&pPObj->cmd, 0);
-    tscClearInterpInfo(pPQueryInfo);
-    
-    tscCreateLocalReducer(trsupport->pExtMemBuffer, pState->numOfTotal, pDesc, trsupport->pFinalColModel,
-                          &pPObj->cmd, &pPObj->res);
-    tscTrace("%p build loser tree completed", pPObj);
-    
-    pPObj->res.precision = pSql->res.precision;
-    pPObj->res.numOfRows = 0;
-    pPObj->res.row = 0;
-    
-    // only free once
-    tfree(trsupport->pState);
-    tscFreeSubSqlObj(trsupport, pSql);
-    
-    // set the command flag must be after the semaphore been correctly set.
-    pPObj->cmd.command = TSDB_SQL_RETRIEVE_METRIC;
-    if (pPObj->res.code == TSDB_CODE_SUCCESS) {
-      (*pPObj->fp)(pPObj->param, pPObj, 0);
-    } else {
-      tscQueueAsyncRes(pPObj);
+      taos_fetch_rows_a(tres, tscRetrieveFromDnodeCallBack, param);
     }
+  } else { // all data has been retrieved to client
+    tscAllDataRetrievedFromDnode(trsupport, pSql);
   }
 }
 
@@ -1437,7 +1445,7 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
   
   /*
    * if a query on a vnode is failed, all retrieve operations from vnode that occurs later
-   * than this one are actually not necessary, we simply call the tscRetrieveFromVnodeCallBack
+   * than this one are actually not necessary, we simply call the tscRetrieveFromDnodeCallBack
    * function to abort current and remain retrieve process.
    *
    * NOTE: threadsafe is required.
@@ -1475,7 +1483,7 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
                trsupport->subqueryIndex, pState->code);
     }
     
-    tscRetrieveFromVnodeCallBack(param, tres, pState->code);
+    tscRetrieveFromDnodeCallBack(param, tres, pState->code);
   } else {  // success, proceed to retrieve data from dnode
     if (vnodeInfo != NULL) {
       tscTrace("%p sub:%p query complete,ip:%u,vid:%d,orderOfSub:%d,retrieve data", trsupport->pParentSqlObj, pSql,
@@ -1486,7 +1494,7 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
                trsupport->subqueryIndex);
     }
     
-    taos_fetch_rows_a(tres, tscRetrieveFromVnodeCallBack, param);
+    taos_fetch_rows_a(tres, tscRetrieveFromDnodeCallBack, param);
   }
 }
 
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index 18f491aa9edaaa60efbc6cbca6bfc54e532f8b9c..ec6881db3f5ae4f1e32dbf790bfb662ae3df84c5 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -608,7 +608,7 @@ int32_t tscCopyDataBlockToPayload(SSqlObj* pSql, STableDataBlocks* pDataBlock) {
    * the payloadLen should be actual message body size
    * the old value of payloadLen is the allocated payload size
    */
-  pCmd->payloadLen = pDataBlock->nAllocSize - tsRpcHeadSize - sizeof(SMsgDesc);
+  pCmd->payloadLen = pDataBlock->nAllocSize - tsRpcHeadSize;
 
   assert(pCmd->allocSize >= pCmd->payloadLen + tsRpcHeadSize + 100 && pCmd->payloadLen > 0);
   return TSDB_CODE_SUCCESS;
diff --git a/src/query/src/queryExecutor.c b/src/query/src/queryExecutor.c
index 224512f0ae8f409bd6dae69dcfa07d8b0eebc28a..83cbae42664407d1245adfc9740fa31be5af1de0 100644
--- a/src/query/src/queryExecutor.c
+++ b/src/query/src/queryExecutor.c
@@ -2204,7 +2204,7 @@ static int32_t getInitialPageNum(SQInfo *pQInfo) {
     size_t s = taosArrayGetSize(pQInfo->pTableIdList);
     num = MAX(s, INITIAL_RESULT_ROWS_VALUE);
   } else {  // for super table query, one page for each subset
-            //    num = pQInfo->pSidSet->numOfSubSet;
+    num = 1;//pQInfo->pSidSet->numOfSubSet;
   }
 
   assert(num > 0);
@@ -3873,7 +3873,7 @@ static int32_t getNumOfSubset(SQInfo *pQInfo) {
   if (isGroupbyNormalCol(pQuery->pGroupbyExpr) || (isIntervalQuery(pQuery))) {
     totalSubset = numOfClosedTimeWindow(&pQInfo->runtimeEnv.windowResInfo);
   } else {
-    //    totalSubset = pQInfo->pSidSet->numOfSubSet;
+    totalSubset = 1;//pQInfo->pSidSet->numOfSubSet;
   }
 
   return totalSubset;
@@ -3909,19 +3909,18 @@ static int32_t doCopyToSData(SQInfo *pQInfo, SWindowResult *result, int32_t orde
 
     int32_t numOfRowsToCopy = result[i].numOfRows - pQInfo->offset;
     int32_t oldOffset = pQInfo->offset;
-    assert(0);
 
     /*
      * current output space is not enough to keep all the result data of this group, only copy partial results
      * to SQuery object's result buffer
      */
-    //    if (numOfRowsToCopy > pQuery->pointsToRead - numOfResult) {
-    //      numOfRowsToCopy = pQuery->pointsToRead - numOfResult;
-    //      pQInfo->offset += numOfRowsToCopy;
-    //    } else {
-    //      pQInfo->offset = 0;
-    //      pQInfo->subgroupIdx += 1;
-    //    }
+    if (numOfRowsToCopy > pQuery->rec.capacity - numOfResult) {
+      numOfRowsToCopy = pQuery->rec.capacity - numOfResult;
+      pQInfo->offset += numOfRowsToCopy;
+    } else {
+      pQInfo->offset = 0;
+      pQInfo->subgroupIdx += 1;
+    }
 
     for (int32_t j = 0; j < pQuery->numOfOutputCols; ++j) {
       int32_t size = pRuntimeEnv->pCtx[j].outputBytes;
@@ -3932,13 +3931,12 @@ static int32_t doCopyToSData(SQInfo *pQInfo, SWindowResult *result, int32_t orde
     }
 
     numOfResult += numOfRowsToCopy;
-    assert(0);
-    //    if (numOfResult == pQuery->rec.pointsToRead) {
-    //      break;
-    //    }
+    if (numOfResult == pQuery->rec.capacity) {
+      break;
+    }
   }
 
-  dTrace("QInfo:%p copy data to SQuery buf completed", GET_QINFO_ADDR(pQuery));
+  dTrace("QInfo:%p copy data to SQuery buf completed", pQInfo);
 
 #ifdef _DEBUG_VIEW
   displayInterResult(pQuery->sdata, pQuery, numOfResult);
@@ -4135,10 +4133,11 @@ int32_t vnodeQueryResultInterpolate(SQInfo *pQInfo, tFilePage **pDst, tFilePage
 }
 
 void vnodePrintQueryStatistics(SQInfo *pQInfo) {
+#if 0
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
 
   SQuery *pQuery = pRuntimeEnv->pQuery;
-#if 0
+
   SQueryCostSummary *pSummary = &pRuntimeEnv->summary;
   if (pRuntimeEnv->pResultBuf == NULL) {
     pSummary->tmpBufferInDisk = 0;
@@ -4179,41 +4178,30 @@ void vnodePrintQueryStatistics(SQInfo *pQInfo) {
 #endif
 }
 
-int32_t initQInfo(SQInfo *pQInfo, void *param, void* tsdb) {
+int32_t doInitializeQInfo(SQInfo *pQInfo, void *param, void* tsdb, bool isSTableQuery) {
+  SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
+  
   SQuery *pQuery = pQInfo->runtimeEnv.pQuery;
   int32_t code = TSDB_CODE_SUCCESS;
 
-  // only the successful complete requries the sem_post/over = 1 operations.
-  if ((QUERY_IS_ASC_QUERY(pQuery) && (pQuery->window.skey > pQuery->window.ekey)) ||
-      (!QUERY_IS_ASC_QUERY(pQuery) && (pQuery->window.ekey > pQuery->window.skey))) {
-    dTrace("QInfo:%p no result in time range %" PRId64 "-%" PRId64 ", order %d", pQInfo, pQuery->window.skey,
-           pQuery->window.ekey, pQuery->order.order);
-
-    sem_post(&pQInfo->dataReady);
-    setQueryStatus(pQuery, QUERY_COMPLETED);
-    return TSDB_CODE_SUCCESS;
-  }
-
   setScanLimitationByResultBuffer(pQuery);
   changeExecuteScanOrder(pQuery, false);
 
   // dataInCache requires lastKey value
   pQuery->lastKey = pQuery->window.skey;
 
-  STsdbQueryCond cond = {0};
-
-  cond.twindow = (STimeWindow){.skey = pQuery->window.skey, .ekey = pQuery->window.ekey};
-  cond.order = pQuery->order.order;
-  cond.colList = *pQuery->colList;
+  STsdbQueryCond cond = {
+    .twindow = pQuery->window,
+    .order   = pQuery->order.order,
+    .colList = *pQuery->colList,
+  };
 
   SArray *cols = taosArrayInit(pQuery->numOfCols, sizeof(pQuery->colList[0]));
   for (int32_t i = 0; i < pQuery->numOfCols; ++i) {
     taosArrayPush(cols, &pQuery->colList[i]);
   }
-
-  pQInfo->runtimeEnv.pQueryHandle = tsdbQueryByTableId(tsdb, &cond, pQInfo->pTableIdList, cols);
-
-  SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
+  
+  pRuntimeEnv->pQueryHandle = tsdbQueryByTableId(tsdb, &cond, pQInfo->pTableIdList, cols);
   pRuntimeEnv->pQuery = pQuery;
 
   pRuntimeEnv->pTSBuf = param;
@@ -4224,15 +4212,34 @@ int32_t initQInfo(SQInfo *pQInfo, void *param, void* tsdb) {
   }
 
   // create runtime environment
-  code = setupQueryRuntimeEnv(&pQInfo->runtimeEnv, NULL, pQuery->order.order, false);
+  code = setupQueryRuntimeEnv(pRuntimeEnv, NULL, pQuery->order.order, isSTableQuery);
   if (code != TSDB_CODE_SUCCESS) {
     return code;
   }
 
-  pRuntimeEnv->numOfRowsPerPage = getNumOfRowsInResultPage(pQuery, false);
-  if (isGroupbyNormalCol(pQuery->pGroupbyExpr) || isIntervalQuery(pQuery)) {
+  pRuntimeEnv->numOfRowsPerPage = getNumOfRowsInResultPage(pQuery, isSTableQuery);
+  
+  if (isSTableQuery) {
+    int32_t rows = getInitialPageNum(pQInfo);
+    code = createDiskbasedResultBuffer(&pRuntimeEnv->pResultBuf, rows, pQuery->rowSize);
+    if (code != TSDB_CODE_SUCCESS) {
+      return code;
+    }
+  
+    if (pQuery->intervalTime == 0) {
+      int16_t type = TSDB_DATA_TYPE_NULL;
+    
+      if (isGroupbyNormalCol(pQuery->pGroupbyExpr)) {  // group by columns not tags;
+        type = getGroupbyColumnType(pQuery, pQuery->pGroupbyExpr);
+      } else {
+        type = TSDB_DATA_TYPE_INT;  // group id
+      }
+    
+      initWindowResInfo(&pRuntimeEnv->windowResInfo, pRuntimeEnv, 512, 4096, type);
+    }
+  
+  } else if (isGroupbyNormalCol(pQuery->pGroupbyExpr) || isIntervalQuery(pQuery)) {
     int32_t rows = getInitialPageNum(pQInfo);
-
     code = createDiskbasedResultBuffer(&pRuntimeEnv->pResultBuf, rows, pQuery->rowSize);
     if (code != TSDB_CODE_SUCCESS) {
       return code;
@@ -4349,6 +4356,7 @@ static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
     for(int32_t i = 0; i < numOfTables; ++i) {
       if (pQInfo->pTableDataInfo[i].pTableQInfo->tid == blockInfo.sid) {
         pTableDataInfo = &pQInfo->pTableDataInfo[i];
+        break;
       }
     }
 
@@ -4361,7 +4369,7 @@ static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
     SArray *     pDataBlock = loadDataBlockOnDemand(pRuntimeEnv, &blockInfo, &pStatis);
 
     TSKEY nextKey = blockInfo.window.ekey;
-    if (pQuery->intervalTime == 0) {
+    if (!isIntervalQuery(pQuery)) {
       setExecutionContext(pQInfo, pTableQueryInfo, pTableDataInfo->tableIndex, pTableDataInfo->groupIdx, nextKey);
     } else {  // interval query
       setIntervalQueryRange(pTableQueryInfo, pQInfo, nextKey);
@@ -4487,9 +4495,10 @@ static int64_t doCheckMetersInGroup(SQInfo *pQInfo, int32_t index, int32_t start
  */
 static void vnodeSTableSeqProcessor(SQInfo *pQInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
-
-#if 0
   SQuery* pQuery = pRuntimeEnv->pQuery;
+  setQueryStatus(pQuery, QUERY_COMPLETED);
+  
+#if 0
 //  tSidSet *pTableIdList = pSupporter->pSidSet;
   
   int32_t vid = getMeterObj(pSupporter->pMetersHashTable, pMeterSidExtInfo[0]->sid)->vnode;
@@ -4876,9 +4885,10 @@ static void multiTableQueryProcess(SQInfo *pQInfo) {
     doRestoreContext(pQInfo);
   } else {
     dTrace("QInfo:%p no need to do reversed scan, query completed", pQInfo);
-    return;
   }
   
+  setQueryStatus(pQuery, QUERY_COMPLETED);
+  
   if (pQInfo->code != TSDB_CODE_SUCCESS || isQueryKilled(pQInfo)) {
     dTrace("QInfo:%p query killed or error occurred, code:%d, abort", pQInfo, pQInfo->code);
     return;
@@ -5245,14 +5255,16 @@ static int32_t validateQueryMsg(SQueryTableMsg *pQueryMsg) {
 static char* createTableIdList(SQueryTableMsg* pQueryMsg, char* pMsg, SArray** pTableIdList) {
   assert(pQueryMsg->numOfTables > 0);
   
-  *pTableIdList = taosArrayInit(pQueryMsg->numOfTables, sizeof(STableIdInfo));
+  *pTableIdList = taosArrayInit(pQueryMsg->numOfTables, sizeof(STableId));
   
   STableIdInfo *pTableIdInfo = (STableIdInfo *)pMsg;
   pTableIdInfo->sid = htonl(pTableIdInfo->sid);
   pTableIdInfo->uid = htobe64(pTableIdInfo->uid);
   pTableIdInfo->key = htobe64(pTableIdInfo->key);
   
-  taosArrayPush(*pTableIdList, pTableIdInfo);
+  STableId id = {.uid = pTableIdInfo->uid, .tid = pTableIdInfo->sid};
+  taosArrayPush(*pTableIdList, &id);
+  
   pMsg += sizeof(STableIdInfo);
   
   for (int32_t j = 1; j < pQueryMsg->numOfTables; ++j) {
@@ -5820,7 +5832,18 @@ static SQInfo *createQInfoImpl(SQueryTableMsg *pQueryMsg, SSqlGroupbyExpr *pGrou
 
   pQuery->pos = -1;
   
-  dTrace("QInfo %p is allocated", pQInfo);
+  pQuery->window.skey = pQueryMsg->window.skey;
+  pQuery->window.ekey = pQueryMsg->window.ekey;
+  pQuery->lastKey     = pQuery->window.skey;
+  
+  if (sem_init(&pQInfo->dataReady, 0, 0) != 0) {
+    dError("QInfo:%p init dataReady sem failed, reason:%s", pQInfo, strerror(errno));
+    goto _clean_memory;
+  }
+  
+  vnodeParametersSafetyCheck(pQuery);
+  
+  dTrace("qmsg:%p create QInfo:%p, QInfo created", pQueryMsg, pQInfo);
   return pQInfo;
 
 _clean_memory:
@@ -5859,57 +5882,42 @@ static bool isValidQInfo(void *param) {
 }
 
 static void freeQInfo(SQInfo *pQInfo);
-static int32_t createQInfo(SQueryTableMsg *pQueryMsg, SSqlGroupbyExpr *pGroupbyExpr, SSqlFunctionExpr *pSqlExprs,
-                           SArray *pTableIdList, void* tsdb, SQInfo **pQInfo) {
+static int32_t initializeQInfo(SQueryTableMsg *pQueryMsg, void* tsdb, SQInfo *pQInfo, bool isSTable) {
   int32_t code = TSDB_CODE_SUCCESS;
+  SQuery *pQuery = pQInfo->runtimeEnv.pQuery;
   
-  (*pQInfo) = createQInfoImpl(pQueryMsg, pGroupbyExpr, pSqlExprs, pTableIdList);
-  if ((*pQInfo) == NULL) {
-    code = TSDB_CODE_SERV_OUT_OF_MEMORY;
-    goto _error;
-  }
-
-  SQuery *pQuery = (*pQInfo)->runtimeEnv.pQuery;
-  dTrace("qmsg:%p create QInfo:%p, QInfo created", pQueryMsg, pQInfo);
-
-  pQuery->window.skey = pQueryMsg->window.skey;
-  pQuery->window.ekey = pQueryMsg->window.ekey;
-  pQuery->lastKey     = pQuery->window.skey;
-
-  if (sem_init(&(*pQInfo)->dataReady, 0, 0) != 0) {
-    dError("QInfo:%p init dataReady sem failed, reason:%s", pQInfo, strerror(errno));
-    code = TSDB_CODE_APP_ERROR;
-    goto _error;
-  }
-
-  vnodeParametersSafetyCheck(pQuery);
-
   STSBuf *pTSBuf = NULL;
   if (pQueryMsg->tsLen > 0) {  // open new file to save the result
     char *tsBlock = (char *)pQueryMsg + pQueryMsg->tsOffset;
     pTSBuf = tsBufCreateFromCompBlocks(tsBlock, pQueryMsg->tsNumOfBlocks, pQueryMsg->tsLen, pQueryMsg->tsOrder);
-
+    
     tsBufResetPos(pTSBuf);
     tsBufNextPos(pTSBuf);
   }
+  
+  // only the successful complete requries the sem_post/over = 1 operations.
+  if ((QUERY_IS_ASC_QUERY(pQuery) && (pQuery->window.skey > pQuery->window.ekey)) ||
+      (!QUERY_IS_ASC_QUERY(pQuery) && (pQuery->window.ekey > pQuery->window.skey))) {
+    dTrace("QInfo:%p no result in time range %" PRId64 "-%" PRId64 ", order %d", pQInfo, pQuery->window.skey,
+           pQuery->window.ekey, pQuery->order.order);
+    
+    sem_post(&pQInfo->dataReady);
+    setQueryStatus(pQuery, QUERY_COMPLETED);
+    return TSDB_CODE_SUCCESS;
+  }
 
   // filter the qualified
-  if ((code = initQInfo(*pQInfo, pTSBuf, tsdb)) != TSDB_CODE_SUCCESS) {
+  if ((code = doInitializeQInfo(pQInfo, pTSBuf, tsdb, isSTable)) != TSDB_CODE_SUCCESS) {
     goto _error;
   }
 
-  //  if (pQInfo->over == 1) {
-  //    vnodeAddRefCount(pQInfo);  // for retrieve procedure
-  //    return pQInfo;
-  //  }
-
   // dTrace("QInfo:%p set query flag and prepare runtime environment completed, ref:%d, wait for schedule", pQInfo,
   //       pQInfo->refCount);
   return code;
 
 _error:
   // table query ref will be decrease during error handling
-  freeQInfo(*pQInfo);
+  freeQInfo(pQInfo);
   return code;
 }
 
@@ -6068,7 +6076,10 @@ int32_t qCreateQueryInfo(void* tsdb, SQueryTableMsg *pQueryMsg, SQInfo **pQInfo)
   
   // super table query
   SArray* res = NULL;
+  bool isSTableQuery = false;
   if ((pQueryMsg->queryType & TSDB_QUERY_TYPE_STABLE_QUERY) != 0) {
+    isSTableQuery = true;
+    
     STableId* id = taosArrayGet(pTableIdList, 0);
     id->uid = -1;
     
@@ -6081,8 +6092,13 @@ int32_t qCreateQueryInfo(void* tsdb, SQueryTableMsg *pQueryMsg, SQInfo **pQInfo)
     res = pTableIdList;
   }
   
-  code = createQInfo(pQueryMsg, pGroupbyExpr, pExprs, res, tsdb, pQInfo);
-
+  (*pQInfo) = createQInfoImpl(pQueryMsg, pGroupbyExpr, pExprs, res);
+  if ((*pQInfo) == NULL) {
+    code = TSDB_CODE_SERV_OUT_OF_MEMORY;
+  }
+  
+  code = initializeQInfo(pQueryMsg, tsdb, *pQInfo, isSTableQuery);
+  
 _query_over:
   if (code != TSDB_CODE_SUCCESS) {
     taosArrayDestroy(pTableIdList);
diff --git a/src/vnode/tsdb/src/tsdbRead.c b/src/vnode/tsdb/src/tsdbRead.c
index 3119fdc7ccc9287fea28b4364cad75e7faa08784..7b996c8f7a170fdf278c1cb844ca85686f65fa6a 100644
--- a/src/vnode/tsdb/src/tsdbRead.c
+++ b/src/vnode/tsdb/src/tsdbRead.c
@@ -73,7 +73,7 @@ typedef struct SQueryFilesInfo {
   char dbFilePathPrefix[PATH_MAX];
 } SQueryFilesInfo;
 
-typedef struct STableQueryInfo {
+typedef struct STableCheckInfo {
   STableId    tableId;
   TSKEY       lastKey;
   STable *    pTableObj;
@@ -81,7 +81,8 @@ typedef struct STableQueryInfo {
   int32_t     numOfBlocks;
   int32_t     start;
   SCompBlock *pBlock;
-} STableQueryInfo;
+  SSkipListIterator* iter;
+} STableCheckInfo;
 
 typedef struct {
   SCompBlock *compBlock;
@@ -90,14 +91,19 @@ typedef struct {
 
 typedef struct STableDataBlockInfoEx {
   SCompBlockFields pBlock;
-  STableQueryInfo* pMeterDataInfo;
+  STableCheckInfo* pMeterDataInfo;
   int32_t          blockIndex;
   int32_t          groupIdx; /* number of group is less than the total number of meters */
 } STableDataBlockInfoEx;
 
+enum {
+  SINGLE_TABLE_MODEL = 1,
+  MULTI_TABLE_MODEL = 2,
+};
+
 typedef struct STsdbQueryHandle {
   struct STsdbRepo* pTsdb;
-  
+  int8_t          model;  // access model, single table model or multi-table model
   SQueryHandlePos cur;    // current position
   SQueryHandlePos start;  // the start position, used for secondary/third iteration
   int32_t         unzipBufSize;
@@ -120,14 +126,13 @@ typedef struct STsdbQueryHandle {
   bool        locateStart;
   int32_t     realNumOfRows;
   bool        loadDataAfterSeek;  // load data after seek.
-  SArray*     pTableQueryInfo;
+  SArray*     pTableCheckInfo;
   int32_t     activeIndex;
   
   int32_t     tableIndex;
   bool        isFirstSlot;
   void *      qinfo;              // query info handle, for debug purpose
   
-  SSkipListIterator*     memIter;
   STableDataBlockInfoEx *pDataBlockInfoEx;
 } STsdbQueryHandle;
 
@@ -271,19 +276,21 @@ tsdb_query_handle_t *tsdbQueryByTableId(tsdb_repo_t* tsdb, STsdbQueryCond *pCond
   size_t size = taosArrayGetSize(idList);
   assert(size >= 1);
 
-  pQueryHandle->pTableQueryInfo = taosArrayInit(size, sizeof(STableQueryInfo));
+  pQueryHandle->pTableCheckInfo = taosArrayInit(size, sizeof(STableCheckInfo));
   for(int32_t i = 0; i < size; ++i) {
     STableId id = *(STableId*) taosArrayGet(idList, i);
     
-    STableQueryInfo info = {
+    STableCheckInfo info = {
       .lastKey = pQueryHandle->window.skey,
       .tableId = id,
       .pTableObj = tsdbGetTableByUid(tsdbGetMeta(tsdb), id.uid),  //todo this may be failed
     };
     
-    taosArrayPush(pQueryHandle->pTableQueryInfo, &info);
+    taosArrayPush(pQueryHandle->pTableCheckInfo, &info);
   }
   
+  pQueryHandle->model = (size > 1)? MULTI_TABLE_MODEL:SINGLE_TABLE_MODEL;
+  
   pQueryHandle->activeIndex = 0;
   
   // malloc buffer in order to load data from file
@@ -314,11 +321,13 @@ tsdb_query_handle_t *tsdbQueryByTableId(tsdb_repo_t* tsdb, STsdbQueryCond *pCond
   return (tsdb_query_handle_t)pQueryHandle;
 }
 
-bool tsdbNextDataBlock(tsdb_query_handle_t *pQueryHandle) {
-  STsdbQueryHandle* pHandle = (STsdbQueryHandle*) pQueryHandle;
-  STableQueryInfo* pTableQInfo = taosArrayGet(pHandle->pTableQueryInfo, pHandle->activeIndex);
+static bool hasMoreDataInCacheForSingleModel(STsdbQueryHandle* pHandle) {
+  assert(pHandle->activeIndex == 0 && taosArrayGetSize(pHandle->pTableCheckInfo) == 1);
   
-  STable *pTable = pTableQInfo->pTableObj;
+  STableCheckInfo* pTableCheckInfo = taosArrayGet(pHandle->pTableCheckInfo, pHandle->activeIndex);
+  
+  STable *pTable = pTableCheckInfo->pTableObj;
+  assert(pTable != NULL);
   
   // no data in cache, abort
   if (pTable->mem == NULL && pTable->imem == NULL) {
@@ -326,13 +335,49 @@ bool tsdbNextDataBlock(tsdb_query_handle_t *pQueryHandle) {
   }
   
   // all data in mem are checked already.
-  if (pTableQInfo->lastKey > pTable->mem->keyLast) {
+  if (pTableCheckInfo->lastKey > pTable->mem->keyLast) {
     return false;
   }
   
   return true;
 }
 
+static bool hasMoreDataInCacheForMultiModel(STsdbQueryHandle* pHandle) {
+  size_t numOfTables = taosArrayGetSize(pHandle->pTableCheckInfo);
+  assert(numOfTables > 0);
+  
+  while(pHandle->activeIndex < numOfTables) {
+    STableCheckInfo* pTableCheckInfo = taosArrayGet(pHandle->pTableCheckInfo, pHandle->activeIndex);
+  
+    STable *pTable = pTableCheckInfo->pTableObj;
+    if (pTable->mem == NULL && pTable->imem == NULL) {
+      pHandle->activeIndex += 1;  // try next table if exits
+      continue;
+    }
+  
+    // all data in mem are checked already.
+    if (pTableCheckInfo->lastKey > pTable->mem->keyLast) {
+      pHandle->activeIndex += 1;  // try next table if exits
+      continue;
+    }
+    
+    return true;
+  }
+  
+  // all tables has checked already
+  return false;
+}
+
+// handle data in cache situation
+bool tsdbNextDataBlock(tsdb_query_handle_t *pQueryHandle) {
+  STsdbQueryHandle* pHandle = (STsdbQueryHandle*) pQueryHandle;
+  if (pHandle->model == SINGLE_TABLE_MODEL) {
+    return hasMoreDataInCacheForSingleModel(pHandle);
+  } else {
+    return hasMoreDataInCacheForMultiModel(pHandle);
+  }
+}
+
 static int tsdbReadRowsFromCache(SSkipListIterator *pIter, TSKEY maxKey, int maxRowsToRead,
     TSKEY* skey, TSKEY* ekey, STsdbQueryHandle* pHandle) {
   int numOfRows = 0;
@@ -370,7 +415,7 @@ static int tsdbReadRowsFromCache(SSkipListIterator *pIter, TSKEY maxKey, int max
 SDataBlockInfo tsdbRetrieveDataBlockInfo(tsdb_query_handle_t *pQueryHandle) {
   STsdbQueryHandle* pHandle = (STsdbQueryHandle*) pQueryHandle;
   
-  STableQueryInfo* pTableQInfo = taosArrayGet(pHandle->pTableQueryInfo, pHandle->activeIndex);
+  STableCheckInfo* pTableQInfo = taosArrayGet(pHandle->pTableCheckInfo, pHandle->activeIndex);
   STable *pTable = pTableQInfo->pTableObj;
   
   TSKEY skey = 0, ekey = 0;
@@ -379,11 +424,11 @@ SDataBlockInfo tsdbRetrieveDataBlockInfo(tsdb_query_handle_t *pQueryHandle) {
   if (pTable->mem != NULL) {
     
     // create mem table iterator if it is not created yet
-    if (pHandle->memIter == NULL) {
-      pHandle->memIter = tSkipListCreateIter(pTable->mem->pData);
+    if (pTableQInfo->iter == NULL) {
+      pTableQInfo->iter = tSkipListCreateIter(pTable->mem->pData);
     }
     
-    rows = tsdbReadRowsFromCache(pHandle->memIter, INT64_MAX, 2, &skey, &ekey, pHandle);
+    rows = tsdbReadRowsFromCache(pTableQInfo->iter, INT64_MAX, 2, &skey, &ekey, pHandle);
   }
   
   SDataBlockInfo blockInfo = {