diff --git a/src/client/src/tscAsync.c b/src/client/src/tscAsync.c
index 97b962e53acc27f5a5f5e09adf97dc9bc0ef1801..ad7041db10e489a43fb4b931424fc1f7fe678d31 100644
--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -388,10 +388,10 @@ void tscQueueAsyncRes(SSqlObj *pSql) {
     return;
   }
 
+  assert(pSql->res.code != TSDB_CODE_SUCCESS);
   tscError("%p add into queued async res, code:%s", pSql, tstrerror(pSql->res.code));
 
   SSqlRes *pRes = &pSql->res;
-
   if (pSql->fp == NULL || pSql->fetchFp == NULL){
     return;
   }
diff --git a/src/client/src/tscFunctionImpl.c b/src/client/src/tscFunctionImpl.c
index f313d355f118a4357960868b912872c4124b218b..6afc5ba223ac9766f5c1529d6882f888886a18d0 100644
--- a/src/client/src/tscFunctionImpl.c
+++ b/src/client/src/tscFunctionImpl.c
@@ -2597,14 +2597,23 @@ static void percentile_next_step(SQLFunctionCtx *pCtx) {
 }
 
 //////////////////////////////////////////////////////////////////////////////////
+static void buildHistogramInfo(SAPercentileInfo* pInfo) {
+  pInfo->pHisto = (SHistogramInfo*) ((char*) pInfo + sizeof(SAPercentileInfo));
+  pInfo->pHisto->elems = (SHistBin*) ((char*)pInfo->pHisto + sizeof(SHistogramInfo));
+}
+
 static SAPercentileInfo *getAPerctInfo(SQLFunctionCtx *pCtx) {
   SResultRowCellInfo *pResInfo = GET_RES_INFO(pCtx);
-  
+  SAPercentileInfo* pInfo = NULL;
+
   if (pCtx->stableQuery && pCtx->currentStage != SECONDARY_STAGE_MERGE) {
-    return (SAPercentileInfo*) pCtx->aOutputBuf;
+    pInfo = (SAPercentileInfo*) pCtx->aOutputBuf;
   } else {
-    return GET_ROWCELL_INTERBUF(pResInfo);
+    pInfo = GET_ROWCELL_INTERBUF(pResInfo);
   }
+
+  buildHistogramInfo(pInfo);
+  return pInfo;
 }
 
 static bool apercentile_function_setup(SQLFunctionCtx *pCtx) {
@@ -2616,6 +2625,7 @@ static bool apercentile_function_setup(SQLFunctionCtx *pCtx) {
   
   char *tmp = (char *)pInfo + sizeof(SAPercentileInfo);
   pInfo->pHisto = tHistogramCreateFrom(tmp, MAX_HISTOGRAM_BIN);
+  printf("%p, %p\n", pInfo->pHisto, pInfo->pHisto->elems);
   return true;
 }
 
@@ -2624,6 +2634,8 @@ static void apercentile_function(SQLFunctionCtx *pCtx) {
   
   SResultRowCellInfo *     pResInfo = GET_RES_INFO(pCtx);
   SAPercentileInfo *pInfo = getAPerctInfo(pCtx);
+
+  assert(pInfo->pHisto->elems != NULL);
   
   for (int32_t i = 0; i < pCtx->size; ++i) {
     char *data = GET_INPUT_CHAR_INDEX(pCtx, i);
diff --git a/src/query/inc/qExecutor.h b/src/query/inc/qExecutor.h
index d1278e2eee173dd819c0aae582d5ddef2a5543af..201b3b2abc5df629135cb3daac61b55e2e64cd21 100644
--- a/src/query/inc/qExecutor.h
+++ b/src/query/inc/qExecutor.h
@@ -33,13 +33,6 @@ struct SColumnFilterElem;
 typedef bool (*__filter_func_t)(struct SColumnFilterElem* pFilter, char* val1, char* val2);
 typedef int32_t (*__block_search_fn_t)(char* data, int32_t num, int64_t key, int32_t order);
 
-typedef struct SGroupResInfo {
-  int32_t  groupId;
-  int32_t  numOfDataPages;
-  int32_t  pageId;
-  int32_t  rowId;
-} SGroupResInfo;
-
 typedef struct SResultRowPool {
   int32_t elemSize;
   int32_t blockSize;
@@ -72,6 +65,12 @@ typedef struct SResultRow {
   union {STimeWindow win; char* key;};  // start key of current time window
 } SResultRow;
 
+typedef struct SGroupResInfo {
+  int32_t rowId;
+  int32_t index;
+  SArray* pRows;      // SArray<SResultRow*>
+} SGroupResInfo;
+
 /**
  * If the number of generated results is greater than this value,
  * query query will be halt and return results to client immediate.
@@ -89,7 +88,6 @@ typedef struct SResultRowInfo {
   int32_t      size:24;    // number of result set
   int32_t      capacity;   // max capacity
   int32_t      curIndex;   // current start active index
-  int64_t      startTime;  // start time of the first time window for sliding query
   int64_t      prevSKey;   // previous (not completed) sliding window start key
 } SResultRowInfo;
 
diff --git a/src/query/inc/qHistogram.h b/src/query/inc/qHistogram.h
index 442e61750b06d269ef48c5e74ede7646f7ac62e1..c904d0ec9b0d6f6dc9404222a64d29dd878c9407 100644
--- a/src/query/inc/qHistogram.h
+++ b/src/query/inc/qHistogram.h
@@ -67,7 +67,7 @@ void tHistogramDestroy(SHistogramInfo** pHisto);
 
 void tHistogramPrint(SHistogramInfo* pHisto);
 
-int32_t vnodeHistobinarySearch(SHistBin* pEntry, int32_t len, double val);
+//int32_t histoBinarySearch(SHistBin* pEntry, int32_t len, double val);
 
 SHeapEntry* tHeapCreate(int32_t numOfEntries);
 void tHeapSort(SHeapEntry* pEntry, int32_t len);
diff --git a/src/query/inc/qUtil.h b/src/query/inc/qUtil.h
index dde2e398459ebef7f870cd5f4482f5755247ecf9..974d93f89c9cdceced88eb96d1d5654c157ddf46 100644
--- a/src/query/inc/qUtil.h
+++ b/src/query/inc/qUtil.h
@@ -77,7 +77,6 @@ void* destroyResultRowPool(SResultRowPool* p);
 int32_t getNumOfAllocatedResultRows(SResultRowPool* p);
 int32_t getNumOfUsedResultRows(SResultRowPool* p);
 
-uint64_t getResultInfoUId(SQueryRuntimeEnv* pRuntimeEnv);
 bool isPointInterpoQuery(SQuery *pQuery);
 
 
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index b0c7cd3a6225949ab19b180d2829a979f404e688..c22764697bde1e7a430f81bc5073881971062f6a 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -178,11 +178,10 @@ static void getNextTimeWindow(SQuery* pQuery, STimeWindow* tw) {
 #define IS_STASBLE_QUERY_OVER(_q) ((_q)->tableIndex >= (int32_t)((_q)->tableqinfoGroupInfo.numOfTables))
 
 // todo move to utility
-static int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *group);
+static int32_t mergeIntoGroupResultImpl(SGroupResInfo* pGroupResInfo, SArray *pTableList, SQInfo* pQInfo);
 
 static void setResultOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, SResultRow *pResult);
 static void setResultRowOutputBufInitCtx(SQueryRuntimeEnv *pRuntimeEnv, SResultRow *pResult);
-static void resetMergeResultBuf(SQueryRuntimeEnv* pRuntimeEnv, SQLFunctionCtx *pCtx, SResultRow *pRow);
 static bool functionNeedToExecute(SQueryRuntimeEnv *pRuntimeEnv, SQLFunctionCtx *pCtx, int32_t functionId);
 
 static void setExecParams(SQuery *pQuery, SQLFunctionCtx *pCtx, void* inputData, TSKEY *tsCol, SDataBlockInfo* pBlockInfo,
@@ -195,7 +194,6 @@ static bool hasMainOutput(SQuery *pQuery);
 static void buildTagQueryResult(SQInfo *pQInfo);
 
 static int32_t setAdditionalInfo(SQInfo *pQInfo, void *pTable, STableQueryInfo *pTableQueryInfo);
-static int32_t flushFromResultBuf(SQueryRuntimeEnv* pRuntimeEnv, SGroupResInfo* pGroupResInfo);
 static int32_t checkForQueryBuf(size_t numOfTables);
 static void releaseQueryBuf(size_t numOfTables);
 static int32_t binarySearchForKey(char *pValue, int num, TSKEY key, int order);
@@ -291,7 +289,7 @@ void updateNumOfResult(SQueryRuntimeEnv *pRuntimeEnv, int32_t numOfRes) {
   }
 }
 
-static int32_t getMergeResultGroupId(int32_t groupIndex) {
+static UNUSED_FUNC int32_t getMergeResultGroupId(int32_t groupIndex) {
   int32_t base = 50000000;
   return base + (groupIndex * 10000);
 }
@@ -466,16 +464,34 @@ static bool hasNullValue(SColIndex* pColIndex, SDataStatis *pStatis, SDataStatis
 
 static SResultRow *doPrepareResultRowFromKey(SQueryRuntimeEnv *pRuntimeEnv, SResultRowInfo *pResultRowInfo, char *pData,
                                              int16_t bytes, bool masterscan, uint64_t uid) {
+  bool existed = false;
   SET_RES_WINDOW_KEY(pRuntimeEnv->keyBuf, pData, bytes, uid);
-  int32_t *p1 =
-      (int32_t *)taosHashGet(pRuntimeEnv->pResultRowHashTable, pRuntimeEnv->keyBuf, GET_RES_WINDOW_KEY_LEN(bytes));
-  if (p1 != NULL) {
-    pResultRowInfo->curIndex = *p1;
+
+  SResultRow **p1 =
+      (SResultRow **)taosHashGet(pRuntimeEnv->pResultRowHashTable, pRuntimeEnv->keyBuf, GET_RES_WINDOW_KEY_LEN(bytes));
+
+  // in case of repeat scan/reverse scan, no new time window added.
+  if (QUERY_IS_INTERVAL_QUERY(pRuntimeEnv->pQuery)) {
+    if (!masterscan) {  // the *p1 may be NULL in case of sliding+offset exists.
+      return (p1 != NULL)? *p1:NULL;
+    }
+
+    if (p1 != NULL) {
+      for(int32_t i = pResultRowInfo->size - 1; i >= 0; --i) {
+        if (pResultRowInfo->pResult[i] == (*p1)) {
+          pResultRowInfo->curIndex = i;
+          existed = true;
+          break;
+        }
+      }
+    }
   } else {
-    if (!masterscan) {  // not master scan, do not add new timewindow
-      return NULL;
+    if (p1 != NULL) {  // group by column query
+      return *p1;
     }
+  }
 
+  if (!existed) {
     // TODO refactor
     // more than the capacity, reallocate the resources
     if (pResultRowInfo->size >= pResultRowInfo->capacity) {
@@ -499,17 +515,23 @@ static SResultRow *doPrepareResultRowFromKey(SQueryRuntimeEnv *pRuntimeEnv, SRes
       pResultRowInfo->capacity = (int32_t)newCapacity;
     }
 
-    SResultRow *pResult = getNewResultRow(pRuntimeEnv->pool);
-    pResultRowInfo->pResult[pResultRowInfo->size] = pResult;
-    int32_t ret = initResultRow(pResult);
-    if (ret != TSDB_CODE_SUCCESS) {
-      longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_OUT_OF_MEMORY);
+    SResultRow *pResult = NULL;
+
+    if (p1 == NULL) {
+      pResult = getNewResultRow(pRuntimeEnv->pool);
+      int32_t ret = initResultRow(pResult);
+      if (ret != TSDB_CODE_SUCCESS) {
+        longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_OUT_OF_MEMORY);
+      }
+
+      // add a new result set for a new group
+      taosHashPut(pRuntimeEnv->pResultRowHashTable, pRuntimeEnv->keyBuf, GET_RES_WINDOW_KEY_LEN(bytes), &pResult, POINTER_BYTES);
+    } else {
+      pResult = *p1;
     }
 
-    // add a new result set for a new group
+    pResultRowInfo->pResult[pResultRowInfo->size] = pResult;
     pResultRowInfo->curIndex = pResultRowInfo->size++;
-    taosHashPut(pRuntimeEnv->pResultRowHashTable, pRuntimeEnv->keyBuf, GET_RES_WINDOW_KEY_LEN(bytes),
-                (char *)&pResultRowInfo->curIndex, sizeof(int32_t));
   }
 
   // too many time window in query
@@ -591,7 +613,6 @@ static int32_t addNewWindowResultBuf(SResultRow *pWindowRes, SDiskbasedResultBuf
     if (pData->num >= numOfRowsPerPage) {
       // release current page first, and prepare the next one
       releaseResBufPageInfo(pResultBuf, pi);
-
       pData = getNewDataBuf(pResultBuf, tid, &pageId);
       if (pData != NULL) {
         assert(pData->num == 0);  // number of elements must be 0 for new allocated buffer
@@ -614,24 +635,20 @@ static int32_t addNewWindowResultBuf(SResultRow *pWindowRes, SDiskbasedResultBuf
   return 0;
 }
 
-static int32_t setWindowOutputBufByKey(SQueryRuntimeEnv *pRuntimeEnv, SResultRowInfo *pResultRowInfo, SDataBlockInfo* pBockInfo,
-                                       STimeWindow *win, bool masterscan, bool* newWind, SResultRow** pResult) {
+static int32_t setWindowOutputBufByKey(SQueryRuntimeEnv *pRuntimeEnv, SResultRowInfo *pResultRowInfo, STimeWindow *win,
+    bool masterscan, SResultRow** pResult, int64_t groupId) {
   assert(win->skey <= win->ekey);
   SDiskbasedResultBuf *pResultBuf = pRuntimeEnv->pResultBuf;
 
-  // todo refactor
-  int64_t uid = getResultInfoUId(pRuntimeEnv);
-  SResultRow *pResultRow = doPrepareResultRowFromKey(pRuntimeEnv, pResultRowInfo, (char *)&win->skey, TSDB_KEYSIZE, masterscan, uid);
+  SResultRow *pResultRow = doPrepareResultRowFromKey(pRuntimeEnv, pResultRowInfo, (char *)&win->skey, TSDB_KEYSIZE, masterscan, groupId);
   if (pResultRow == NULL) {
-    *newWind = false;
-    return masterscan? -1:0;   // no master scan, no result generated means error occurs
+    *pResult = NULL;
+    return TSDB_CODE_SUCCESS;
   }
 
-  *newWind = true;
-
   // not assign result buffer yet, add new result buffer
   if (pResultRow->pageId == -1) {
-    int32_t ret = addNewWindowResultBuf(pResultRow, pResultBuf, pBockInfo->tid, pRuntimeEnv->numOfRowsPerPage);
+    int32_t ret = addNewWindowResultBuf(pResultRow, pResultBuf, groupId, pRuntimeEnv->numOfRowsPerPage);
     if (ret != TSDB_CODE_SUCCESS) {
       return -1;
     }
@@ -701,81 +718,47 @@ static FORCE_INLINE int32_t getForwardStepsInBlock(int32_t numOfRows, __block_se
   return forwardStep;
 }
 
-static int32_t updateResultRowCurrentIndex(SResultRowInfo* pWindowResInfo, TSKEY lastKey, bool ascQuery) {
-  int32_t i = 0;
+static void doUpdateResultRowIndex(SResultRowInfo*pResultRowInfo, TSKEY lastKey, bool ascQuery) {
   int64_t skey = TSKEY_INITIAL_VAL;
-
-  int32_t numOfClosed = 0;
-  for (i = 0; i < pWindowResInfo->size; ++i) {
-    SResultRow *pResult = pWindowResInfo->pResult[i];
+  int32_t i = 0;
+  for (i = pResultRowInfo->size - 1; i >= 0; --i) {
+    SResultRow *pResult = pResultRowInfo->pResult[i];
     if (pResult->closed) {
-      numOfClosed += 1;
-      continue;
+      break;
     }
 
-    TSKEY ekey = pResult->win.ekey;
-    if ((ekey <= lastKey && ascQuery) || (pResult->win.skey >= lastKey && !ascQuery)) {
-      closeResultRow(pWindowResInfo, i);
+    // new closed result rows
+    if ((pResult->win.ekey <= lastKey && ascQuery) || (pResult->win.skey >= lastKey && !ascQuery)) {
+      closeResultRow(pResultRowInfo, i);
     } else {
       skey = pResult->win.skey;
-      break;
     }
   }
 
-  // all windows are closed, set the last one to be the skey
+  // all result rows are closed, set the last one to be the skey
   if (skey == TSKEY_INITIAL_VAL) {
-    assert(i == pWindowResInfo->size);
-    pWindowResInfo->curIndex = pWindowResInfo->size - 1;
+    pResultRowInfo->curIndex = pResultRowInfo->size - 1;
   } else {
-    pWindowResInfo->curIndex = i;
-    pWindowResInfo->prevSKey = pWindowResInfo->pResult[pWindowResInfo->curIndex]->win.skey;
-  }
-
-  return numOfClosed;
-}
 
-/**
- * NOTE: the query status only set for the first scan of master scan.
- */
-static int32_t doCheckQueryCompleted(SQueryRuntimeEnv *pRuntimeEnv, TSKEY lastKey, SResultRowInfo *pWindowResInfo) {
-  SQuery *pQuery = pRuntimeEnv->pQuery;
-  if (pRuntimeEnv->scanFlag != MASTER_SCAN || pWindowResInfo->size == 0) {
-    return pWindowResInfo->size;
-  }
-
-  // no qualified results exist, abort check
-  int32_t numOfClosed = 0;
-  bool ascQuery = QUERY_IS_ASC_QUERY(pQuery);
-
-  // query completed
-  if ((lastKey >= pQuery->current->win.ekey && ascQuery) || (lastKey <= pQuery->current->win.ekey && (!ascQuery))) {
-    closeAllResultRows(pWindowResInfo);
-
-    pWindowResInfo->curIndex = pWindowResInfo->size - 1;
-    setQueryStatus(pQuery, QUERY_COMPLETED | QUERY_RESBUF_FULL);
-  } else {  // set the current index to be the last unclosed window
-    numOfClosed = updateResultRowCurrentIndex(pWindowResInfo, lastKey, ascQuery);
-
-    // the number of completed slots are larger than the threshold, return current generated results to client.
-    if (numOfClosed > pQuery->rec.threshold) {
-      qDebug("QInfo:%p total result window:%d closed:%d, reached the output threshold %d, return",
-          GET_QINFO_ADDR(pRuntimeEnv), pWindowResInfo->size, numOfClosed, pQuery->rec.threshold);
-
-      setQueryStatus(pQuery, QUERY_RESBUF_FULL);
-    } else {
-      qDebug("QInfo:%p total result window:%d already closed:%d", GET_QINFO_ADDR(pRuntimeEnv), pWindowResInfo->size,
-             numOfClosed);
+    for (i = pResultRowInfo->size - 1; i >= 0; --i) {
+      SResultRow *pResult = pResultRowInfo->pResult[i];
+      if (pResult->closed) {
+        break;
+      }
     }
-  }
 
-  // output has reached the limitation, set query completed
-  if (pQuery->limit.limit > 0 && (pQuery->limit.limit + pQuery->limit.offset) <= numOfClosed &&
-      pRuntimeEnv->scanFlag == MASTER_SCAN) {
-    setQueryStatus(pQuery, QUERY_COMPLETED);
+    pResultRowInfo->curIndex = i + 1;  // current not closed result object
+    pResultRowInfo->prevSKey = pResultRowInfo->pResult[pResultRowInfo->curIndex]->win.skey;
   }
+}
 
-  assert(pWindowResInfo->prevSKey != TSKEY_INITIAL_VAL);
-  return numOfClosed;
+static void updateResultRowIndex(SResultRowInfo* pResultRowInfo, STableQueryInfo* pTableQueryInfo, bool ascQuery) {
+  if ((pTableQueryInfo->lastKey >= pTableQueryInfo->win.ekey && ascQuery) || (pTableQueryInfo->lastKey <= pTableQueryInfo->win.ekey && (!ascQuery))) {
+    closeAllResultRows(pResultRowInfo);
+    pResultRowInfo->curIndex = pResultRowInfo->size - 1;
+  } else {
+    doUpdateResultRowIndex(pResultRowInfo, pTableQueryInfo->lastKey, ascQuery);
+  }
 }
 
 static int32_t getNumOfRowsInTimeWindow(SQuery *pQuery, SDataBlockInfo *pDataBlockInfo, TSKEY *pPrimaryColumn,
@@ -818,52 +801,47 @@ static int32_t getNumOfRowsInTimeWindow(SQuery *pQuery, SDataBlockInfo *pDataBlo
   return num;
 }
 
-static void doBlockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, bool closed, STimeWindow *pWin, int32_t offset,
-                                      int32_t forwardStep, TSKEY *tsCol, int32_t numOfTotal) {
-  SQuery *        pQuery = pRuntimeEnv->pQuery;
+static void doBlockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, STimeWindow *pWin, int32_t offset, int32_t forwardStep, TSKEY *tsCol, int32_t numOfTotal) {
+  SQuery         *pQuery = pRuntimeEnv->pQuery;
   SQLFunctionCtx *pCtx = pRuntimeEnv->pCtx;
 
   bool hasPrev = pCtx[0].preAggVals.isSet;
 
-  if (IS_MASTER_SCAN(pRuntimeEnv) || closed) {
-    for (int32_t k = 0; k < pQuery->numOfOutput; ++k) {
-      pCtx[k].nStartQueryTimestamp = pWin->skey;
-      pCtx[k].size = forwardStep;
-      pCtx[k].startOffset = (QUERY_IS_ASC_QUERY(pQuery)) ? offset : offset - (forwardStep - 1);
-
-      int32_t functionId = pQuery->pExpr1[k].base.functionId;
-      if ((aAggs[functionId].nStatus & TSDB_FUNCSTATE_SELECTIVITY) != 0) {
-        pCtx[k].ptsList = &tsCol[pCtx[k].startOffset];
-      }
+  for (int32_t k = 0; k < pQuery->numOfOutput; ++k) {
+    pCtx[k].nStartQueryTimestamp = pWin->skey;
+    pCtx[k].size = forwardStep;
+    pCtx[k].startOffset = (QUERY_IS_ASC_QUERY(pQuery)) ? offset : offset - (forwardStep - 1);
 
-      // not a whole block involved in query processing, statistics data can not be used
-      // NOTE: the original value of isSet have been changed here
-      if (pCtx[k].preAggVals.isSet && forwardStep < numOfTotal) {
-        pCtx[k].preAggVals.isSet = false;
-      }
+    int32_t functionId = pQuery->pExpr1[k].base.functionId;
+    if ((aAggs[functionId].nStatus & TSDB_FUNCSTATE_SELECTIVITY) != 0) {
+      pCtx[k].ptsList = &tsCol[pCtx[k].startOffset];
+    }
 
-      if (functionNeedToExecute(pRuntimeEnv, &pCtx[k], functionId)) {
-        aAggs[functionId].xFunction(&pCtx[k]);
-      }
+    // not a whole block involved in query processing, statistics data can not be used
+    // NOTE: the original value of isSet have been changed here
+    if (pCtx[k].preAggVals.isSet && forwardStep < numOfTotal) {
+      pCtx[k].preAggVals.isSet = false;
+    }
 
-      // restore it
-      pCtx[k].preAggVals.isSet = hasPrev;
+    if (functionNeedToExecute(pRuntimeEnv, &pCtx[k], functionId)) {
+      aAggs[functionId].xFunction(&pCtx[k]);
     }
+
+    // restore it
+    pCtx[k].preAggVals.isSet = hasPrev;
   }
 }
 
-static void doRowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, bool closed, STimeWindow *pWin, int32_t offset) {
-  SQuery *        pQuery = pRuntimeEnv->pQuery;
+static void doRowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, STimeWindow *pWin, int32_t offset) {
+  SQuery         *pQuery = pRuntimeEnv->pQuery;
   SQLFunctionCtx *pCtx = pRuntimeEnv->pCtx;
 
-  if (IS_MASTER_SCAN(pRuntimeEnv) || closed) {
-    for (int32_t k = 0; k < pQuery->numOfOutput; ++k) {
-      pCtx[k].nStartQueryTimestamp = pWin->skey;
+  for (int32_t k = 0; k < pQuery->numOfOutput; ++k) {
+    pCtx[k].nStartQueryTimestamp = pWin->skey;
 
-      int32_t functionId = pQuery->pExpr1[k].base.functionId;
-      if (functionNeedToExecute(pRuntimeEnv, &pCtx[k], functionId)) {
-        aAggs[functionId].xFunctionF(&pCtx[k], offset);
-      }
+    int32_t functionId = pQuery->pExpr1[k].base.functionId;
+    if (functionNeedToExecute(pRuntimeEnv, &pCtx[k], functionId)) {
+      aAggs[functionId].xFunctionF(&pCtx[k], offset);
     }
   }
 }
@@ -1178,7 +1156,9 @@ static void blockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *
   SQLFunctionCtx *pCtx = pRuntimeEnv->pCtx;
   bool            masterScan = IS_MASTER_SCAN(pRuntimeEnv);
 
-  SQuery *pQuery = pRuntimeEnv->pQuery;
+  SQuery *pQuery  = pRuntimeEnv->pQuery;
+  int64_t groupId = pQuery->current->groupIndex;
+
   TSKEY  *tsCols = NULL;
   if (pDataBlock != NULL) {
     SColumnInfoData *pColInfo = taosArrayGet(pDataBlock, 0);
@@ -1203,56 +1183,46 @@ static void blockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *
     TSKEY ts = getStartTsKey(pQuery, pDataBlockInfo, tsCols, step);
     STimeWindow win = getActiveTimeWindow(pWindowResInfo, ts, pQuery);
 
-    bool hasTimeWindow  = false;
     SResultRow* pResult = NULL;
-    int32_t ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, pDataBlockInfo, &win, masterScan, &hasTimeWindow, &pResult);
-    if (ret != TSDB_CODE_SUCCESS) {
-      tfree(sasArray);
-      return;
+    int32_t ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, &win, masterScan, &pResult, groupId);
+    if (ret != TSDB_CODE_SUCCESS || pResult == NULL) {
+      goto _end;
     }
 
     int32_t forwardStep = 0;
     int32_t startPos = pQuery->pos;
 
-    // in case of repeat scan/reverse scan, no new time window added.
-    if (hasTimeWindow) {
-      TSKEY ekey = reviseWindowEkey(pQuery, &win);
-      forwardStep = getNumOfRowsInTimeWindow(pQuery, pDataBlockInfo, tsCols, pQuery->pos, ekey, searchFn, true);
-
-      // prev time window not interpolation yet.
-      int32_t curIndex = curTimeWindowIndex(pWindowResInfo);
-      if (prevIndex != -1 && prevIndex < curIndex && pRuntimeEnv->timeWindowInterpo) {
-        for(int32_t j = prevIndex; j < curIndex; ++j) {
-          SResultRow *pRes = pWindowResInfo->pResult[j];
+    TSKEY ekey = reviseWindowEkey(pQuery, &win);
+    forwardStep = getNumOfRowsInTimeWindow(pQuery, pDataBlockInfo, tsCols, pQuery->pos, ekey, searchFn, true);
 
-          STimeWindow w = pRes->win;
-          ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, pDataBlockInfo, &w, masterScan, &hasTimeWindow, &pResult);
-          assert(ret == TSDB_CODE_SUCCESS && !resultRowInterpolated(pResult, RESULT_ROW_END_INTERP));
+    // prev time window not interpolation yet.
+    int32_t curIndex = curTimeWindowIndex(pWindowResInfo);
+    if (prevIndex != -1 && prevIndex < curIndex && pRuntimeEnv->timeWindowInterpo) {
+      for(int32_t j = prevIndex; j < curIndex; ++j) {
+        SResultRow *pRes = pWindowResInfo->pResult[j];
 
-          int32_t p = QUERY_IS_ASC_QUERY(pQuery)? 0:pDataBlockInfo->rows-1;
-          doRowwiseTimeWindowInterpolation(pRuntimeEnv, pDataBlock, *(TSKEY*) pRuntimeEnv->prevRow[0], -1,  tsCols[0], p, w.ekey, RESULT_ROW_END_INTERP);
-          setResultRowInterpo(pResult, RESULT_ROW_END_INTERP);
-          setNotInterpoWindowKey(pRuntimeEnv->pCtx, pQuery->numOfOutput, RESULT_ROW_START_INTERP);
+        STimeWindow w = pRes->win;
+        ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, &w, masterScan, &pResult, groupId);
+        assert(ret == TSDB_CODE_SUCCESS && !resultRowInterpolated(pResult, RESULT_ROW_END_INTERP));
 
-          bool closed = getResultRowStatus(pWindowResInfo, curTimeWindowIndex(pWindowResInfo));
-          doBlockwiseApplyFunctions(pRuntimeEnv, closed, &w, startPos, 0, tsCols, pDataBlockInfo->rows);
-        }
+        int32_t p = QUERY_IS_ASC_QUERY(pQuery)? 0:pDataBlockInfo->rows-1;
+        doRowwiseTimeWindowInterpolation(pRuntimeEnv, pDataBlock, *(TSKEY*) pRuntimeEnv->prevRow[0], -1,  tsCols[0], p, w.ekey, RESULT_ROW_END_INTERP);
+        setResultRowInterpo(pResult, RESULT_ROW_END_INTERP);
+        setNotInterpoWindowKey(pRuntimeEnv->pCtx, pQuery->numOfOutput, RESULT_ROW_START_INTERP);
 
-        // restore current time window
-        ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, pDataBlockInfo, &win, masterScan, &hasTimeWindow, &pResult);
-        assert (ret == TSDB_CODE_SUCCESS);  // null data, too many state code
+        doBlockwiseApplyFunctions(pRuntimeEnv, &w, startPos, 0, tsCols, pDataBlockInfo->rows);
       }
 
-      // window start key interpolation
-      doWindowBorderInterpolation(pRuntimeEnv, pDataBlockInfo, pDataBlock, pResult, &win, pQuery->pos, forwardStep);
-
-      bool pStatus = getResultRowStatus(pWindowResInfo, curTimeWindowIndex(pWindowResInfo));
-      doBlockwiseApplyFunctions(pRuntimeEnv, pStatus, &win, startPos, forwardStep, tsCols, pDataBlockInfo->rows);
+      // restore current time window
+      ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, &win, masterScan, &pResult, groupId);
+      assert (ret == TSDB_CODE_SUCCESS);
     }
 
-    int32_t     index = pWindowResInfo->curIndex;
-    STimeWindow nextWin = win;
+    // window start key interpolation
+    doWindowBorderInterpolation(pRuntimeEnv, pDataBlockInfo, pDataBlock, pResult, &win, pQuery->pos, forwardStep);
+    doBlockwiseApplyFunctions(pRuntimeEnv, &win, startPos, forwardStep, tsCols, pDataBlockInfo->rows);
 
+    STimeWindow nextWin = win;
     while (1) {
       int32_t prevEndPos = (forwardStep - 1) * step + startPos;
       startPos = getNextQualifiedWindow(pRuntimeEnv, &nextWin, pDataBlockInfo, tsCols, searchFn, prevEndPos);
@@ -1261,27 +1231,19 @@ static void blockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *
       }
 
       // null data, failed to allocate more memory buffer
-      hasTimeWindow = false;
-      if (setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, pDataBlockInfo, &nextWin, masterScan, &hasTimeWindow, &pResult) !=
-          TSDB_CODE_SUCCESS) {
+      int32_t code = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, &nextWin, masterScan, &pResult, groupId);
+      if (code != TSDB_CODE_SUCCESS || pResult == NULL) {
         break;
       }
 
-      if (!hasTimeWindow) {
-        continue;
-      }
-
-      TSKEY ekey = reviseWindowEkey(pQuery, &nextWin);
+      ekey = reviseWindowEkey(pQuery, &nextWin);
       forwardStep = getNumOfRowsInTimeWindow(pQuery, pDataBlockInfo, tsCols, startPos, ekey, searchFn, true);
 
       // window start(end) key interpolation
       doWindowBorderInterpolation(pRuntimeEnv, pDataBlockInfo, pDataBlock, pResult, &nextWin, startPos, forwardStep);
-
-      bool closed = getResultRowStatus(pWindowResInfo, curTimeWindowIndex(pWindowResInfo));
-      doBlockwiseApplyFunctions(pRuntimeEnv, closed, &nextWin, startPos, forwardStep, tsCols, pDataBlockInfo->rows);
+      doBlockwiseApplyFunctions(pRuntimeEnv, &nextWin, startPos, forwardStep, tsCols, pDataBlockInfo->rows);
     }
 
-    pWindowResInfo->curIndex = index;
   } else {
     /*
      * the sqlfunctionCtx parameters should be set done before all functions are invoked,
@@ -1297,6 +1259,7 @@ static void blockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *
     }
   }
 
+  _end:
   if (pRuntimeEnv->timeWindowInterpo) {
     saveDataBlockLastRow(pRuntimeEnv, pDataBlockInfo, pDataBlock);
   }
@@ -1317,8 +1280,6 @@ static int32_t setGroupResultOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, char *pDat
     return -1;
   }
 
-  int32_t GROUPRESULTID = 1;
-
   SDiskbasedResultBuf *pResultBuf = pRuntimeEnv->pResultBuf;
 
   // not assign result buffer yet, add new result buffer, TODO remove it
@@ -1334,11 +1295,8 @@ static int32_t setGroupResultOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, char *pDat
     longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_APP_ERROR);
   }
 
-  uint64_t uid = groupIndex;
-  SResultRow *pResultRow = doPrepareResultRowFromKey(pRuntimeEnv, &pRuntimeEnv->windowResInfo, d, len, true, uid);
-  if (pResultRow == NULL) {
-    return -1;
-  }
+  SResultRow *pResultRow = doPrepareResultRowFromKey(pRuntimeEnv, &pRuntimeEnv->windowResInfo, d, len, true, groupIndex);
+  assert (pResultRow != NULL);
 
   int64_t v = -1;
   GET_TYPED_DATA(v, int64_t, type, pData);
@@ -1355,7 +1313,7 @@ static int32_t setGroupResultOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, char *pDat
   }
 
   if (pResultRow->pageId == -1) {
-    int32_t ret = addNewWindowResultBuf(pResultRow, pResultBuf, GROUPRESULTID, pRuntimeEnv->numOfRowsPerPage);
+    int32_t ret = addNewWindowResultBuf(pResultRow, pResultBuf, groupIndex, pRuntimeEnv->numOfRowsPerPage);
     if (ret != 0) {
       return -1;
     }
@@ -1490,7 +1448,7 @@ void doRowwiseTimeWindowInterpolation(SQueryRuntimeEnv* pRuntimeEnv, SArray* pDa
     double v1 = 0, v2 = 0, v = 0;
 
     if (prevRowIndex == -1) {
-      GET_TYPED_DATA(v1, double, pColInfo->info.type, (char *)pRuntimeEnv->prevRow[k]);
+      GET_TYPED_DATA(v1, double, pColInfo->info.type, (char *)pRuntimeEnv->prevRow[index]);
     } else {
       GET_TYPED_DATA(v1, double, pColInfo->info.type, (char *)pColInfo->pData + prevRowIndex * pColInfo->info.bytes);
     }
@@ -1557,6 +1515,8 @@ static void rowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *pS
   SQuery *pQuery = pRuntimeEnv->pQuery;
   STableQueryInfo* item = pQuery->current;
 
+  int64_t groupId = item->groupIndex;
+
   SColumnInfoData* pColumnInfoData = (SColumnInfoData *)taosArrayGet(pDataBlock, 0);
 
   TSKEY  *tsCols = (pColumnInfoData->info.type == TSDB_DATA_TYPE_TIMESTAMP)? (TSKEY*) pColumnInfoData->pData:NULL;
@@ -1627,15 +1587,10 @@ static void rowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *pS
 
       STimeWindow win = getActiveTimeWindow(pWindowResInfo, ts, pQuery);
 
-      bool hasTimeWindow  = false;
       SResultRow* pResult = NULL;
-      int32_t ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, pDataBlockInfo, &win, masterScan, &hasTimeWindow, &pResult);
-      if (ret != TSDB_CODE_SUCCESS) {  // null data, too many state code
-        continue;
-      }
-
-      if (!hasTimeWindow) {
-        continue;
+      int32_t ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, &win, masterScan, &pResult, groupId);
+      if (ret != TSDB_CODE_SUCCESS || pResult == NULL) {  // null data, too many state code
+        goto _end;
       }
 
       // window start key interpolation
@@ -1646,18 +1601,15 @@ static void rowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *pS
           for (int32_t k = prevWindowIndex; k < curIndex; ++k) {
             SResultRow *pRes = pWindowResInfo->pResult[k];
 
-            ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, pDataBlockInfo, &pRes->win, masterScan, &hasTimeWindow, &pResult);
+            ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, &pRes->win, masterScan, &pResult, groupId);
             assert(ret == TSDB_CODE_SUCCESS && !resultRowInterpolated(pResult, RESULT_ROW_END_INTERP));
 
             setTimeWindowEKeyInterp(pRuntimeEnv, pDataBlock, prevTs, prevRowIndex, ts, offset, pResult, &pRes->win);
-
-            bool closed = getResultRowStatus(pWindowResInfo, curTimeWindowIndex(pWindowResInfo));
-            doRowwiseApplyFunctions(pRuntimeEnv, closed, &pRes->win, offset);
+            doRowwiseApplyFunctions(pRuntimeEnv, &pRes->win, offset);
           }
 
           // restore current time window
-          ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, pDataBlockInfo, &win, masterScan, &hasTimeWindow,
-                                        &pResult);
+          ret = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, &win, masterScan, &pResult, groupId);
           if (ret != TSDB_CODE_SUCCESS) {  // null data, too many state code
             continue;
           }
@@ -1666,8 +1618,7 @@ static void rowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *pS
         setTimeWindowSKeyInterp(pRuntimeEnv, pDataBlock, prevTs, prevRowIndex, ts, offset, pResult, &win);
       }
 
-      bool closed = getResultRowStatus(pWindowResInfo, curTimeWindowIndex(pWindowResInfo));
-      doRowwiseApplyFunctions(pRuntimeEnv, closed, &win, offset);
+      doRowwiseApplyFunctions(pRuntimeEnv, &win, offset);
 
       STimeWindow nextWin = win;
       int32_t     index = pWindowResInfo->curIndex;
@@ -1684,16 +1635,13 @@ static void rowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *pS
         }
 
         // null data, failed to allocate more memory buffer
-        hasTimeWindow = false;
-        if (setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, pDataBlockInfo, &nextWin, masterScan, &hasTimeWindow, &pResult) != TSDB_CODE_SUCCESS) {
+        int32_t code = setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, &nextWin, masterScan, &pResult, groupId);
+        if (code != TSDB_CODE_SUCCESS || pResult == NULL) {
           break;
         }
 
-        if (hasTimeWindow) {
-          setTimeWindowSKeyInterp(pRuntimeEnv, pDataBlock, prevTs, prevRowIndex, ts, offset, pResult, &nextWin);
-          closed = getResultRowStatus(pWindowResInfo, curTimeWindowIndex(pWindowResInfo));
-          doRowwiseApplyFunctions(pRuntimeEnv, closed, &nextWin, offset);
-        }
+        setTimeWindowSKeyInterp(pRuntimeEnv, pDataBlock, prevTs, prevRowIndex, ts, offset, pResult, &nextWin);
+        doRowwiseApplyFunctions(pRuntimeEnv, &nextWin, offset);
       }
 
       pWindowResInfo->curIndex = index;
@@ -1728,6 +1676,7 @@ static void rowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *pS
     }
   }
 
+  _end:
   assert(offset >= 0);
   if (tsCols != NULL) {
     item->lastKey = tsCols[offset] + step;
@@ -1755,28 +1704,26 @@ static int32_t tableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBl
                                           SDataStatis *pStatis, __block_search_fn_t searchFn, SArray *pDataBlock) {
   SQuery *pQuery = pRuntimeEnv->pQuery;
 
-  STableQueryInfo* pTableQInfo = pQuery->current;
-  SResultRowInfo*  pWindowResInfo = &pRuntimeEnv->windowResInfo;
+  STableQueryInfo* pTableQueryInfo = pQuery->current;
+  SResultRowInfo*  pResultRowInfo = &pRuntimeEnv->windowResInfo;
 
   if (pQuery->numOfFilterCols > 0 || pRuntimeEnv->pTsBuf != NULL || pRuntimeEnv->groupbyNormalCol) {
-    rowwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pWindowResInfo, pDataBlock);
+    rowwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pResultRowInfo, pDataBlock);
   } else {
-    blockwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pWindowResInfo, searchFn, pDataBlock);
+    blockwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pResultRowInfo, searchFn, pDataBlock);
   }
 
   // update the lastkey of current table
   TSKEY lastKey = QUERY_IS_ASC_QUERY(pQuery) ? pDataBlockInfo->window.ekey : pDataBlockInfo->window.skey;
-  pTableQInfo->lastKey = lastKey + GET_FORWARD_DIRECTION_FACTOR(pQuery->order.order);
+  pTableQueryInfo->lastKey = lastKey + GET_FORWARD_DIRECTION_FACTOR(pQuery->order.order);
 
   // interval query with limit applied
   int32_t numOfRes = 0;
-  if (QUERY_IS_INTERVAL_QUERY(pQuery)) {
-    numOfRes = doCheckQueryCompleted(pRuntimeEnv, lastKey, pWindowResInfo);
-  } else if (pRuntimeEnv->groupbyNormalCol) {
-    closeAllResultRows(pWindowResInfo);
-    numOfRes = pWindowResInfo->size;
+  if (QUERY_IS_INTERVAL_QUERY(pQuery) || pRuntimeEnv->groupbyNormalCol) {
+    numOfRes = pResultRowInfo->size;
+    updateResultRowIndex(pResultRowInfo, pTableQueryInfo, QUERY_IS_ASC_QUERY(pQuery));
   } else { // projection query
-    numOfRes = (int32_t)getNumOfResult(pRuntimeEnv);
+    numOfRes = (int32_t) getNumOfResult(pRuntimeEnv);
 
     // update the number of output result
     if (numOfRes > 0 && pQuery->checkBuffer == 1) {
@@ -1791,8 +1738,8 @@ static int32_t tableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBl
         setQueryStatus(pQuery, QUERY_COMPLETED);
       }
 
-      if (((pTableQInfo->lastKey > pTableQInfo->win.ekey) && QUERY_IS_ASC_QUERY(pQuery)) ||
-          ((pTableQInfo->lastKey < pTableQInfo->win.ekey) && (!QUERY_IS_ASC_QUERY(pQuery)))) {
+      if (((pTableQueryInfo->lastKey > pTableQueryInfo->win.ekey) && QUERY_IS_ASC_QUERY(pQuery)) ||
+          ((pTableQueryInfo->lastKey < pTableQueryInfo->win.ekey) && (!QUERY_IS_ASC_QUERY(pQuery)))) {
         setQueryStatus(pQuery, QUERY_COMPLETED);
       }
     }
@@ -2610,6 +2557,8 @@ int32_t loadDataBlockOnDemand(SQueryRuntimeEnv *pRuntimeEnv, SResultRowInfo * pW
   *status = BLK_DATA_NO_NEEDED;
 
   SQuery *pQuery = pRuntimeEnv->pQuery;
+  int64_t groupId = pQuery->current->groupIndex;
+
   SQueryCostInfo* pCost = &pRuntimeEnv->summary;
 
   if (pQuery->numOfFilterCols > 0 || pRuntimeEnv->pTsBuf > 0) {
@@ -2626,15 +2575,13 @@ int32_t loadDataBlockOnDemand(SQueryRuntimeEnv *pRuntimeEnv, SResultRowInfo * pW
       // the pCtx[i] result is belonged to previous time window since the outputBuf has not been set yet,
       // the filter result may be incorrect. So in case of interval query, we need to set the correct time output buffer
       if (QUERY_IS_INTERVAL_QUERY(pQuery)) {
-        bool hasTimeWindow = false;
         SResultRow* pResult = NULL;
 
         bool masterScan = IS_MASTER_SCAN(pRuntimeEnv);
 
         TSKEY k = QUERY_IS_ASC_QUERY(pQuery)? pBlockInfo->window.skey:pBlockInfo->window.ekey;
         STimeWindow win = getActiveTimeWindow(pWindowResInfo, k, pQuery);
-        if (setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, pBlockInfo, &win, masterScan, &hasTimeWindow, &pResult) !=
-            TSDB_CODE_SUCCESS) {
+        if (setWindowOutputBufByKey(pRuntimeEnv, pWindowResInfo, &win, masterScan, &pResult, groupId) != TSDB_CODE_SUCCESS) {
           // todo handle error in set result for timewindow
         }
       }
@@ -2832,13 +2779,9 @@ static void doSetInitialTimewindow(SQueryRuntimeEnv* pRuntimeEnv, SDataBlockInfo
 
     if (QUERY_IS_ASC_QUERY(pQuery)) {
       getAlignQueryTimeWindow(pQuery, pBlockInfo->window.skey, pBlockInfo->window.skey, pQuery->window.ekey, &w);
-      pWindowResInfo->startTime = w.skey;
       pWindowResInfo->prevSKey = w.skey;
-    } else {
-      // the start position of the first time window in the endpoint that spreads beyond the queried last timestamp
+    } else { // the start position of the first time window in the endpoint that spreads beyond the queried last timestamp
       getAlignQueryTimeWindow(pQuery, pBlockInfo->window.ekey, pQuery->window.ekey, pBlockInfo->window.ekey, &w);
-
-      pWindowResInfo->startTime = pQuery->window.skey;
       pWindowResInfo->prevSKey = w.skey;
     }
   }
@@ -2908,13 +2851,9 @@ static int64_t doScanAllDataBlocks(SQueryRuntimeEnv *pRuntimeEnv) {
     setQueryStatus(pQuery, QUERY_COMPLETED);
   }
 
-  if (QUERY_IS_INTERVAL_QUERY(pQuery) && (IS_MASTER_SCAN(pRuntimeEnv)|| pRuntimeEnv->scanFlag == REPEAT_SCAN)) {
-    if (Q_STATUS_EQUAL(pQuery->status, QUERY_COMPLETED)) {
-      closeAllResultRows(&pRuntimeEnv->windowResInfo);
-      pRuntimeEnv->windowResInfo.curIndex = pRuntimeEnv->windowResInfo.size - 1;  // point to the last time window
-    } else {
-      assert(Q_STATUS_EQUAL(pQuery->status, QUERY_RESBUF_FULL));
-    }
+  if (QUERY_IS_INTERVAL_QUERY(pQuery)) {
+    closeAllResultRows(&pRuntimeEnv->windowResInfo);
+    pRuntimeEnv->windowResInfo.curIndex = pRuntimeEnv->windowResInfo.size - 1;  // point to the last time window
   }
 
   return 0;
@@ -3019,7 +2958,7 @@ void setTagVal(SQueryRuntimeEnv *pRuntimeEnv, void *pTable, void *tsdb) {
   }
 }
 
-static void doMerge(SQueryRuntimeEnv *pRuntimeEnv, int64_t timestamp, SResultRow *pWindowRes, bool mergeFlag) {
+static UNUSED_FUNC void doMerge(SQueryRuntimeEnv *pRuntimeEnv, int64_t timestamp, SResultRow *pWindowRes, bool mergeFlag) {
   SQuery *        pQuery = pRuntimeEnv->pQuery;
   SQLFunctionCtx *pCtx = pRuntimeEnv->pCtx;
 
@@ -3168,19 +3107,18 @@ void UNUSED_FUNC displayInterResult(tFilePage **pdata, SQueryRuntimeEnv* pRuntim
 
 typedef struct SCompSupporter {
   STableQueryInfo **pTableQueryInfo;
-  int32_t *         position;
-  SQInfo *          pQInfo;
+  int32_t          *rowIndex;
+  int32_t           order;
 } SCompSupporter;
 
 int32_t tableResultComparFn(const void *pLeft, const void *pRight, void *param) {
-  int32_t left = *(int32_t *)pLeft;
+  int32_t left  = *(int32_t *)pLeft;
   int32_t right = *(int32_t *)pRight;
 
   SCompSupporter *  supporter = (SCompSupporter *)param;
-  SQueryRuntimeEnv *pRuntimeEnv = &supporter->pQInfo->runtimeEnv;
 
-  int32_t leftPos = supporter->position[left];
-  int32_t rightPos = supporter->position[right];
+  int32_t leftPos  = supporter->rowIndex[left];
+  int32_t rightPos = supporter->rowIndex[right];
 
   /* left source is exhausted */
   if (leftPos == -1) {
@@ -3192,53 +3130,55 @@ int32_t tableResultComparFn(const void *pLeft, const void *pRight, void *param)
     return -1;
   }
 
-  SResultRowInfo *pWindowResInfo1 = &supporter->pTableQueryInfo[left]->windowResInfo;
-  SResultRow * pWindowRes1 = getResultRow(pWindowResInfo1, leftPos);
-  tFilePage *page1 = getResBufPage(pRuntimeEnv->pResultBuf, pWindowRes1->pageId);
+  STableQueryInfo** pList = supporter->pTableQueryInfo;
 
-  char *b1 = getPosInResultPage(pRuntimeEnv, PRIMARYKEY_TIMESTAMP_COL_INDEX, pWindowRes1, page1);
-  TSKEY leftTimestamp = GET_INT64_VAL(b1);
+  SResultRowInfo *pWindowResInfo1 = &(pList[left]->windowResInfo);
+  SResultRow * pWindowRes1 = getResultRow(pWindowResInfo1, leftPos);
+  TSKEY leftTimestamp = pWindowRes1->win.skey;
 
-  SResultRowInfo *pWindowResInfo2 = &supporter->pTableQueryInfo[right]->windowResInfo;
+  SResultRowInfo *pWindowResInfo2 = &(pList[right]->windowResInfo);
   SResultRow * pWindowRes2 = getResultRow(pWindowResInfo2, rightPos);
-  tFilePage *page2 = getResBufPage(pRuntimeEnv->pResultBuf, pWindowRes2->pageId);
-
-  char *b2 = getPosInResultPage(pRuntimeEnv, PRIMARYKEY_TIMESTAMP_COL_INDEX, pWindowRes2, page2);
-  TSKEY rightTimestamp = GET_INT64_VAL(b2);
+  TSKEY rightTimestamp = pWindowRes2->win.skey;
 
   if (leftTimestamp == rightTimestamp) {
     return 0;
   }
 
-  return leftTimestamp > rightTimestamp ? 1 : -1;
+  if (supporter->order == TSDB_ORDER_ASC) {
+    return (leftTimestamp > rightTimestamp)? 1:-1;
+  } else {
+    return (leftTimestamp < rightTimestamp)? 1:-1;
+  }
 }
 
-int32_t mergeIntoGroupResult(SQInfo *pQInfo) {
+int32_t mergeGroupResult(SQInfo *pQInfo) {
   int64_t st = taosGetTimestampUs();
-  int32_t ret = TSDB_CODE_SUCCESS;
 
-  int32_t numOfGroups = (int32_t)(GET_NUM_OF_TABLEGROUP(pQInfo));
+  SGroupResInfo* pGroupResInfo = &pQInfo->groupResInfo;
 
+  int32_t numOfGroups = (int32_t)(GET_NUM_OF_TABLEGROUP(pQInfo));
   while (pQInfo->groupIndex < numOfGroups) {
     SArray *group = GET_TABLEGROUP(pQInfo, pQInfo->groupIndex);
-    ret = mergeIntoGroupResultImpl(pQInfo, group);
-    if (ret < 0) {  // not enough disk space to save the data into disk
+
+    int32_t ret = mergeIntoGroupResultImpl(pGroupResInfo, group, pQInfo);
+    if (ret < 0) {
       return -1;
     }
 
-    pQInfo->groupIndex += 1;
-
     // this group generates at least one result, return results
-    if (ret > 0) {
+    pQInfo->groupIndex += 1;
+    if (taosArrayGetSize(pGroupResInfo->pRows) > 0) {
       break;
     }
 
-    assert(pQInfo->groupResInfo.numOfDataPages == 0);
     qDebug("QInfo:%p no result in group %d, continue", pQInfo, pQInfo->groupIndex - 1);
+    taosArrayClear(pGroupResInfo->pRows);
+
+    pGroupResInfo->index = 0;
+    pGroupResInfo->rowId = 0;
   }
 
-  SGroupResInfo* info = &pQInfo->groupResInfo;
-  if (pQInfo->groupIndex == numOfGroups && info->pageId == info->numOfDataPages) {
+  if (pQInfo->groupIndex == numOfGroups && taosArrayGetSize(pGroupResInfo->pRows) == 0) {
     SET_STABLE_QUERY_OVER(pQInfo);
   }
 
@@ -3250,89 +3190,28 @@ int32_t mergeIntoGroupResult(SQInfo *pQInfo) {
   return TSDB_CODE_SUCCESS;
 }
 
+static int32_t doCopyToSData(SQInfo *pQInfo, SResultRow **pRows, int32_t numOfRows, int32_t* index, int32_t orderType);
+
 void copyResToQueryResultBuf(SQInfo *pQInfo, SQuery *pQuery) {
   SGroupResInfo* pGroupResInfo = &pQInfo->groupResInfo;
 
-  // all results have been return to client, try next group
-  if (pGroupResInfo->pageId == pGroupResInfo->numOfDataPages) {
-    pGroupResInfo->numOfDataPages = 0;
-    pGroupResInfo->pageId = 0;
-    pGroupResInfo->rowId = 0;
-
+  // all results in current group have been returned to client, try next group
+  if (pGroupResInfo->index >= taosArrayGetSize(pGroupResInfo->pRows)) {
     // current results of group has been sent to client, try next group
-    if (mergeIntoGroupResult(pQInfo) != TSDB_CODE_SUCCESS) {
+    if (mergeGroupResult(pQInfo) != TSDB_CODE_SUCCESS) {
       return;  // failed to save data in the disk
     }
 
     // check if all results has been sent to client
     int32_t numOfGroup = (int32_t)(GET_NUM_OF_TABLEGROUP(pQInfo));
-    if (pGroupResInfo->numOfDataPages == 0 && pQInfo->groupIndex == numOfGroup) {
+    if (taosArrayGetSize(pGroupResInfo->pRows) == 0 && pQInfo->groupIndex == numOfGroup) {
       SET_STABLE_QUERY_OVER(pQInfo);
       return;
     }
   }
 
-  SQueryRuntimeEnv *   pRuntimeEnv = &pQInfo->runtimeEnv;
-  SDiskbasedResultBuf *pResultBuf = pRuntimeEnv->pResultBuf;
-
-  int32_t id = pQInfo->groupResInfo.groupId;
-  SIDList list = getDataBufPagesIdList(pResultBuf, id);
-
-  int32_t offset = 0;
-  int32_t numOfCopiedRows = 0;
-
-  size_t size = taosArrayGetSize(list);
-  assert(size == pGroupResInfo->numOfDataPages);
-
-  bool done = false;
-
-  //TODO add API for release none-dirty pages
-//  SPageInfo* prev = NULL;
-
-  for (int32_t j = pGroupResInfo->pageId; j < size; ++j) {
-    SPageInfo* pi = *(SPageInfo**) taosArrayGet(list, j);
-    tFilePage* pData = getResBufPage(pResultBuf, pi->pageId);
-
-    // release previous buffer pages
-//    if (prev == NULL) {
-//      prev = pi;
-//    } else {
-//      if (prev->pageId != pi->pageId) {
-//        releaseResBufPageInfo(pResultBuf, prev);
-//        prev = pi;
-//      }
-//    }
-
-    assert(pData->num > 0 && pData->num <= pRuntimeEnv->numOfRowsPerPage && pGroupResInfo->rowId < pData->num);
-    int32_t numOfRes = (int32_t)(pData->num - pGroupResInfo->rowId);
-
-    if (numOfRes > pQuery->rec.capacity - offset) {
-      numOfCopiedRows = (int32_t)(pQuery->rec.capacity - offset);
-      pGroupResInfo->rowId += numOfCopiedRows;
-      done = true;
-    } else {
-      numOfCopiedRows = (int32_t)pData->num;
-
-      pGroupResInfo->pageId += 1;
-      pGroupResInfo->rowId = 0;
-    }
-
-    for (int32_t i = 0; i < pQuery->numOfOutput; ++i) {
-      int32_t bytes = pRuntimeEnv->pCtx[i].outputBytes;
-      char *  pDest = pQuery->sdata[i]->data;
-
-      memcpy(pDest + offset * bytes, pData->data + pRuntimeEnv->offset[i] * pRuntimeEnv->numOfRowsPerPage,
-          (size_t)bytes * numOfCopiedRows);
-    }
-
-    offset += numOfCopiedRows;
-    if (done) {
-      break;
-    }
-  }
-
-  assert(pQuery->rec.rows == 0);
-  pQuery->rec.rows += offset;
+  int32_t size = (int32_t) taosArrayGetSize(pGroupResInfo->pRows);
+  pQuery->rec.rows = doCopyToSData(pQInfo, pGroupResInfo->pRows->pData, (int32_t) size, &pGroupResInfo->index, TSDB_ORDER_ASC);
 }
 
 int64_t getNumOfResultWindowRes(SQueryRuntimeEnv* pRuntimeEnv, SResultRow *pResultRow) {
@@ -3360,155 +3239,99 @@ int64_t getNumOfResultWindowRes(SQueryRuntimeEnv* pRuntimeEnv, SResultRow *pResu
   return 0;
 }
 
-int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *pGroup) {
+int32_t mergeIntoGroupResultImpl(SGroupResInfo* pGroupResInfo, SArray *pTableList, SQInfo* pQInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
-  SQuery *          pQuery = pRuntimeEnv->pQuery;
+  bool ascQuery = QUERY_IS_ASC_QUERY(pRuntimeEnv->pQuery);
+
+  int32_t code = TSDB_CODE_SUCCESS;
 
-  size_t size = taosArrayGetSize(pGroup);
-  tFilePage **buffer = pQuery->sdata;
+  int32_t *posList = NULL;
+  SLoserTreeInfo *pTree = NULL;
+  STableQueryInfo **pTableQueryInfoList = NULL;
 
-  int32_t *posList = calloc(size, sizeof(int32_t));
-  STableQueryInfo **pTableList = malloc(POINTER_BYTES * size);
+  size_t size = taosArrayGetSize(pTableList);
+  if (pGroupResInfo->pRows == NULL) {
+    pGroupResInfo->pRows = taosArrayInit(100, POINTER_BYTES);
+  }
 
-  if (pTableList == NULL || posList == NULL) {
-    tfree(posList);
-    tfree(pTableList);
+  posList = calloc(size, sizeof(int32_t));
+  pTableQueryInfoList = malloc(POINTER_BYTES * size);
 
+  if (pTableQueryInfoList == NULL || posList == NULL) {
     qError("QInfo:%p failed alloc memory", pQInfo);
-    longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_OUT_OF_MEMORY);
+    code = TSDB_CODE_QRY_OUT_OF_MEMORY;
+    goto _end;
   }
 
-  // todo opt for the case of one table per group
   int32_t numOfTables = 0;
-  SIDList pageList = NULL;
-  int32_t tid = -1;
-
   for (int32_t i = 0; i < size; ++i) {
-    STableQueryInfo *item = taosArrayGetP(pGroup, i);
-
-    SIDList list = getDataBufPagesIdList(pRuntimeEnv->pResultBuf, TSDB_TABLEID(item->pTable)->tid);
-    if (taosArrayGetSize(list) > 0 && item->windowResInfo.size > 0) {
-      pTableList[numOfTables++] = item;
-      tid = TSDB_TABLEID(item->pTable)->tid;
-      pageList = list;
+    STableQueryInfo *item = taosArrayGetP(pTableList, i);
+    if (item->windowResInfo.size > 0) {
+      pTableQueryInfoList[numOfTables++] = item;
     }
   }
 
   // there is no data in current group
+  // no need to merge results since only one table in each group
   if (numOfTables == 0) {
-    tfree(posList);
-    tfree(pTableList);
-    return 0;
-  } else if (numOfTables == 1) { // no need to merge results since only one table in each group
-    tfree(posList);
-    tfree(pTableList);
-
-    SGroupResInfo* pGroupResInfo = &pQInfo->groupResInfo;
-
-    pGroupResInfo->numOfDataPages = (int32_t)taosArrayGetSize(pageList);
-    pGroupResInfo->groupId = tid;
-    pGroupResInfo->pageId = 0;
-    pGroupResInfo->rowId = 0;
-
-    return pGroupResInfo->numOfDataPages;
+    goto _end;
   }
 
-  SCompSupporter cs = {pTableList, posList, pQInfo};
-
-  SLoserTreeInfo *pTree = NULL;
-  tLoserTreeCreate(&pTree, numOfTables, &cs, tableResultComparFn);
+  SCompSupporter cs = {pTableQueryInfoList, posList, pRuntimeEnv->pQuery->order.order};
 
-  SResultRow* pRow = getNewResultRow(pRuntimeEnv->pool);
-  resetMergeResultBuf(pRuntimeEnv, pRuntimeEnv->pCtx, pRow);
-
-  pQInfo->groupResInfo.groupId = getMergeResultGroupId(pQInfo->groupIndex);
+  int32_t ret = tLoserTreeCreate(&pTree, numOfTables, &cs, tableResultComparFn);
+  if (ret != TSDB_CODE_SUCCESS) {
+    code = TSDB_CODE_QRY_OUT_OF_MEMORY;
+    goto _end;
+  }
 
-  // todo add windowRes iterator
-  int64_t lastTimestamp = -1;
+  int64_t lastTimestamp = ascQuery? INT64_MIN:INT64_MAX;
   int64_t startt = taosGetTimestampMs();
 
   while (1) {
     if (isQueryKilled(pQInfo)) {
       qDebug("QInfo:%p it is already killed, abort", pQInfo);
-
-      tfree(pTableList);
-      tfree(posList);
-      tfree(pTree);
-      longjmp(pRuntimeEnv->env, TSDB_CODE_TSC_QUERY_CANCELLED);
+      code = TSDB_CODE_TSC_QUERY_CANCELLED;
+      goto _end;
     }
 
-    int32_t pos = pTree->pNode[0].index;
-
-    SResultRowInfo *pWindowResInfo = &pTableList[pos]->windowResInfo;
-    SResultRow  *pWindowRes = getResultRow(pWindowResInfo, cs.position[pos]);
-    tFilePage *page = getResBufPage(pRuntimeEnv->pResultBuf, pWindowRes->pageId);
+    int32_t tableIndex = pTree->pNode[0].index;
 
-    char *b = getPosInResultPage(pRuntimeEnv, PRIMARYKEY_TIMESTAMP_COL_INDEX, pWindowRes, page);
-    TSKEY ts = GET_INT64_VAL(b);
+    SResultRowInfo *pWindowResInfo = &pTableQueryInfoList[tableIndex]->windowResInfo;
+    SResultRow  *pWindowRes = getResultRow(pWindowResInfo, cs.rowIndex[tableIndex]);
 
-    assert(ts == pWindowRes->win.skey);
     int64_t num = getNumOfResultWindowRes(pRuntimeEnv, pWindowRes);
     if (num <= 0) {
-      cs.position[pos] += 1;
+      cs.rowIndex[tableIndex] += 1;
 
-      if (cs.position[pos] >= pWindowResInfo->size) {
-        cs.position[pos] = -1;
-
-        // all input sources are exhausted
-        if (--numOfTables == 0) {
+      if (cs.rowIndex[tableIndex] >= pWindowResInfo->size) {
+        cs.rowIndex[tableIndex] = -1;
+        if (--numOfTables == 0) { // all input sources are exhausted
           break;
         }
       }
     } else {
-      if (ts == lastTimestamp) {  // merge with the last one
-        doMerge(pRuntimeEnv, ts, pWindowRes, true);
-      } else {  // copy data to disk buffer
-        if (buffer[0]->num == pQuery->rec.capacity) {
-          if (flushFromResultBuf(pRuntimeEnv, &pQInfo->groupResInfo) != TSDB_CODE_SUCCESS) {
-            return -1;
-          }
-
-          resetMergeResultBuf(pRuntimeEnv, pRuntimeEnv->pCtx, pRow);
-        }
+      assert((pWindowRes->win.skey >= lastTimestamp && ascQuery) || (pWindowRes->win.skey <= lastTimestamp && !ascQuery));
 
-        doMerge(pRuntimeEnv, ts, pWindowRes, false);
-        buffer[0]->num += 1;
+      if (pWindowRes->win.skey != lastTimestamp) {
+        taosArrayPush(pGroupResInfo->pRows, &pWindowRes);
+        pWindowRes->numOfRows = num;
       }
 
-      lastTimestamp = ts;
+      lastTimestamp = pWindowRes->win.skey;
 
-      // move to the next element of current entry
-      int32_t currentPageId = pWindowRes->pageId;
-
-      cs.position[pos] += 1;
-      if (cs.position[pos] >= pWindowResInfo->size) {
-        cs.position[pos] = -1;
+      // move to the next row of current entry
+      if ((++cs.rowIndex[tableIndex]) >= pWindowResInfo->size) {
+        cs.rowIndex[tableIndex] = -1;
 
         // all input sources are exhausted
-        if (--numOfTables == 0) {
+        if ((--numOfTables) == 0) {
           break;
         }
-      } else {
-        // current page is not needed anymore
-        SResultRow  *pNextWindowRes = getResultRow(pWindowResInfo, cs.position[pos]);
-        if (pNextWindowRes->pageId != currentPageId) {
-          releaseResBufPage(pRuntimeEnv->pResultBuf, page);
-        }
       }
     }
 
-    tLoserTreeAdjust(pTree, pos + pTree->numOfEntries);
-  }
-
-  if (buffer[0]->num != 0) {  // there are data in buffer
-    if (flushFromResultBuf(pRuntimeEnv, &pQInfo->groupResInfo) != TSDB_CODE_SUCCESS) {
-      qError("QInfo:%p failed to flush data into temp file, abort query", pQInfo);
-
-      tfree(pTree);
-      tfree(pTableList);
-      tfree(posList);
-      return -1;
-    }
+    tLoserTreeAdjust(pTree, tableIndex + pTree->numOfEntries);
   }
 
   int64_t endt = taosGetTimestampMs();
@@ -3519,65 +3342,16 @@ int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *pGroup) {
 
   qDebug("QInfo:%p result merge completed for group:%d, elapsed time:%" PRId64 " ms", pQInfo, pQInfo->groupIndex, endt - startt);
 
-  tfree(pTableList);
+  _end:
+  tfree(pTableQueryInfoList);
   tfree(posList);
   tfree(pTree);
 
-//  tfree(pResultInfo);
-//  tfree(buf);
-
-  return pQInfo->groupResInfo.numOfDataPages;
-}
-
-int32_t flushFromResultBuf(SQueryRuntimeEnv* pRuntimeEnv, SGroupResInfo* pGroupResInfo) {
-  SQuery *pQuery = pRuntimeEnv->pQuery;
-
-  SDiskbasedResultBuf *pResultBuf = pRuntimeEnv->pResultBuf;
-
-  // the base value for group result, since the maximum number of table for each vnode will not exceed 100,000.
-  int32_t pageId = -1;
-  int32_t capacity = pResultBuf->numOfRowsPerPage;
-
-  int32_t remain = (int32_t) pQuery->sdata[0]->num;
-  int32_t offset = 0;
-
-  while (remain > 0) {
-    int32_t rows = (remain > capacity)? capacity:remain;
-    assert(rows > 0);
-
-    // get the output buffer page
-    tFilePage *buf = getNewDataBuf(pResultBuf, pGroupResInfo->groupId, &pageId);
-    buf->num = rows;
-
-    // pagewisely copy to dest buffer
-    for (int32_t i = 0; i < pQuery->numOfOutput; ++i) {
-      int32_t bytes = pRuntimeEnv->pCtx[i].outputBytes;
-
-      char* output = buf->data + pRuntimeEnv->offset[i] * pRuntimeEnv->numOfRowsPerPage;
-      char* src = ((char *) pQuery->sdata[i]->data) + offset * bytes;
-      memcpy(output, src, (size_t)(buf->num * bytes));
-    }
-
-    offset += rows;
-    remain -= rows;
-
-    pGroupResInfo->numOfDataPages += 1;
+  if (code != TSDB_CODE_SUCCESS) {
+    longjmp(pRuntimeEnv->env, code);
   }
 
-  return TSDB_CODE_SUCCESS;
-}
-
-void resetMergeResultBuf(SQueryRuntimeEnv* pRuntimeEnv, SQLFunctionCtx *pCtx, SResultRow *pRow) {
-  SQuery* pQuery = pRuntimeEnv->pQuery;
-
-  for (int32_t k = 0; k < pQuery->numOfOutput; ++k) {
-    pCtx[k].aOutputBuf = pQuery->sdata[k]->data - pCtx[k].outputBytes;
-    pCtx[k].size = 1;
-    pCtx[k].startOffset = 0;
-    pCtx[k].resultInfo = getResultCell(pRuntimeEnv, pRow, k);
-
-    pQuery->sdata[k]->num = 0;
-  }
+  return code;
 }
 
 static void updateTableQueryInfoForReverseScan(SQuery *pQuery, STableQueryInfo *pTableQueryInfo) {
@@ -3698,7 +3472,7 @@ void resetDefaultResInfoOutputBuf(SQueryRuntimeEnv *pRuntimeEnv) {
   SQuery *pQuery = pRuntimeEnv->pQuery;
 
   int32_t tid = 0;
-  int64_t uid = getResultInfoUId(pRuntimeEnv);
+  int64_t uid = 0;
   SResultRow* pRow = doPrepareResultRowFromKey(pRuntimeEnv, &pRuntimeEnv->windowResInfo, (char *)&tid, sizeof(tid), true, uid);
 
   for (int32_t i = 0; i < pQuery->numOfOutput; ++i) {
@@ -3830,12 +3604,8 @@ bool needScanDataBlocksAgain(SQueryRuntimeEnv *pRuntimeEnv) {
 
     for (int32_t i = 0; i < pWindowResInfo->size; ++i) {
       SResultRow *pResult = getResultRow(pWindowResInfo, i);
-      if (!pResult->closed) {
-        continue;
-      }
 
       setResultOutputBuf(pRuntimeEnv, pResult);
-
       for (int32_t j = 0; j < pQuery->numOfOutput; ++j) {
         int16_t functId = pQuery->pExpr1[j].base.functionId;
         if (functId == TSDB_FUNC_TS) {
@@ -4119,9 +3889,9 @@ void destroyTableQueryInfoImpl(STableQueryInfo *pTableQueryInfo) {
  * @param pDataBlockInfo
  */
 void setExecutionContext(SQInfo *pQInfo, int32_t groupIndex, TSKEY nextKey) {
-  SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
+  SQueryRuntimeEnv *pRuntimeEnv     = &pQInfo->runtimeEnv;
   STableQueryInfo  *pTableQueryInfo = pRuntimeEnv->pQuery->current;
-  SResultRowInfo   *pWindowResInfo = &pRuntimeEnv->windowResInfo;
+  SResultRowInfo   *pWindowResInfo  = &pRuntimeEnv->windowResInfo;
 
   // lastKey needs to be updated
   pTableQueryInfo->lastKey = nextKey;
@@ -4134,12 +3904,10 @@ void setExecutionContext(SQInfo *pQInfo, int32_t groupIndex, TSKEY nextKey) {
     return;
   }
 
-  uint64_t uid = getResultInfoUId(pRuntimeEnv);
+  int64_t uid = 0;
   SResultRow *pResultRow = doPrepareResultRowFromKey(pRuntimeEnv, pWindowResInfo, (char *)&groupIndex,
       sizeof(groupIndex), true, uid);
-  if (pResultRow == NULL) {
-    return;
-  }
+  assert (pResultRow != NULL);
 
   /*
    * not assign result buffer yet, add new result buffer
@@ -4285,7 +4053,7 @@ void setIntervalQueryRange(SQInfo *pQInfo, TSKEY key) {
     /**
      * In handling the both ascending and descending order super table query, we need to find the first qualified
      * timestamp of this table, and then set the first qualified start timestamp.
-     * In ascending query, key is the first qualified timestamp. However, in the descending order query, additional
+     * In ascending query, the key is the first qualified timestamp. However, in the descending order query, additional
      * operations involve.
      */
     STimeWindow     w = TSWINDOW_INITIALIZER;
@@ -4294,7 +4062,6 @@ void setIntervalQueryRange(SQInfo *pQInfo, TSKEY key) {
     TSKEY sk = MIN(win.skey, win.ekey);
     TSKEY ek = MAX(win.skey, win.ekey);
     getAlignQueryTimeWindow(pQuery, win.skey, sk, ek, &w);
-    pWindowResInfo->startTime = pTableQueryInfo->win.skey;  // windowSKey may be 0 in case of 1970 timestamp
 
     if (pWindowResInfo->prevSKey == TSKEY_INITIAL_VAL) {
       if (!QUERY_IS_ASC_QUERY(pQuery)) {
@@ -4333,36 +4100,33 @@ bool needPrimaryTimestampCol(SQuery *pQuery, SDataBlockInfo *pDataBlockInfo) {
   return loadPrimaryTS;
 }
 
-static int32_t doCopyToSData(SQInfo *pQInfo, SResultRowInfo *pResultInfo, int32_t orderType) {
+static int32_t doCopyToSData(SQInfo *pQInfo, SResultRow **pRows, int32_t numOfRows, int32_t *index, int32_t orderType) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
   SQuery *          pQuery = pRuntimeEnv->pQuery;
 
   int32_t numOfResult = 0;
-  int32_t startIdx = 0;
+  int32_t start = 0;
   int32_t step = -1;
 
   qDebug("QInfo:%p start to copy data from windowResInfo to query buf", pQInfo);
-  int32_t totalSet = numOfClosedResultRows(pResultInfo);
-  SResultRow** result = pResultInfo->pResult;
-
   if (orderType == TSDB_ORDER_ASC) {
-    startIdx = pQInfo->groupIndex;
+    start = (*index);
     step = 1;
   } else {  // desc order copy all data
-    startIdx = totalSet - pQInfo->groupIndex - 1;
+    start = numOfRows - (*index) - 1;
     step = -1;
   }
 
   SGroupResInfo* pGroupResInfo = &pQInfo->groupResInfo;
 
-  for (int32_t i = startIdx; (i < totalSet) && (i >= 0); i += step) {
-    if (result[i]->numOfRows == 0) {
-      pQInfo->groupIndex += 1;
+  for (int32_t i = start; (i < numOfRows) && (i >= 0); i += step) {
+    if (pRows[i]->numOfRows == 0) {
+      (*index) += 1;
       pGroupResInfo->rowId = 0;
       continue;
     }
 
-    int32_t numOfRowsToCopy = result[i]->numOfRows - pGroupResInfo->rowId;
+    int32_t numOfRowsToCopy = pRows[i]->numOfRows - pGroupResInfo->rowId;
     int32_t oldOffset = pGroupResInfo->rowId;
 
     /*
@@ -4374,16 +4138,16 @@ static int32_t doCopyToSData(SQInfo *pQInfo, SResultRowInfo *pResultInfo, int32_
       pGroupResInfo->rowId += numOfRowsToCopy;
     } else {
       pGroupResInfo->rowId = 0;
-      pQInfo->groupIndex += 1;
+      (*index) += 1;
     }
 
-    tFilePage *page = getResBufPage(pRuntimeEnv->pResultBuf, result[i]->pageId);
+    tFilePage *page = getResBufPage(pRuntimeEnv->pResultBuf, pRows[i]->pageId);
 
     for (int32_t j = 0; j < pQuery->numOfOutput; ++j) {
       int32_t size = pRuntimeEnv->pCtx[j].outputBytes;
 
       char *out = pQuery->sdata[j]->data + numOfResult * size;
-      char *in = getPosInResultPage(pRuntimeEnv, j, result[i], page);
+      char *in  = getPosInResultPage(pRuntimeEnv, j, pRows[i], page);
       memcpy(out, in + oldOffset * size, size * numOfRowsToCopy);
     }
 
@@ -4414,10 +4178,9 @@ void copyFromWindowResToSData(SQInfo *pQInfo, SResultRowInfo *pResultInfo) {
   SQuery *pQuery = pQInfo->runtimeEnv.pQuery;
 
   int32_t orderType = (pQuery->pGroupbyExpr != NULL) ? pQuery->pGroupbyExpr->orderType : TSDB_ORDER_ASC;
-  int32_t numOfResult = doCopyToSData(pQInfo, pResultInfo, orderType);
+  int32_t numOfResult = doCopyToSData(pQInfo, pResultInfo->pResult, pResultInfo->size, &pQInfo->groupIndex, orderType);
 
   pQuery->rec.rows += numOfResult;
-
   assert(pQuery->rec.rows <= pQuery->rec.capacity);
 }
 
@@ -4449,25 +4212,17 @@ static void stableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBloc
   SQuery *         pQuery = pRuntimeEnv->pQuery;
   STableQueryInfo* pTableQueryInfo = pQuery->current;
 
-  SResultRowInfo * pWindowResInfo = &pTableQueryInfo->windowResInfo;
+  SResultRowInfo * pResultRowInfo = &pTableQueryInfo->windowResInfo;
   pQuery->pos = QUERY_IS_ASC_QUERY(pQuery)? 0 : pDataBlockInfo->rows - 1;
 
   if (pQuery->numOfFilterCols > 0 || pRuntimeEnv->pTsBuf != NULL || pRuntimeEnv->groupbyNormalCol) {
-    rowwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pWindowResInfo, pDataBlock);
+    rowwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pResultRowInfo, pDataBlock);
   } else {
-    blockwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pWindowResInfo, searchFn, pDataBlock);
+    blockwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pResultRowInfo, searchFn, pDataBlock);
   }
 
   if (QUERY_IS_INTERVAL_QUERY(pQuery)) {
-    bool ascQuery = QUERY_IS_ASC_QUERY(pQuery);
-
-    // TODO refactor
-    if ((pTableQueryInfo->lastKey >= pTableQueryInfo->win.ekey && ascQuery) || (pTableQueryInfo->lastKey <= pTableQueryInfo->win.ekey && (!ascQuery))) {
-      closeAllResultRows(pWindowResInfo);
-      pWindowResInfo->curIndex = pWindowResInfo->size - 1;
-    } else {
-      updateResultRowCurrentIndex(pWindowResInfo, pTableQueryInfo->lastKey, ascQuery);
-    }
+    updateResultRowIndex(pResultRowInfo, pTableQueryInfo, QUERY_IS_ASC_QUERY(pQuery));
   }
 }
 
@@ -4801,13 +4556,10 @@ static bool skipTimeInterval(SQueryRuntimeEnv *pRuntimeEnv, TSKEY* start) {
     if (QUERY_IS_ASC_QUERY(pQuery)) {
       if (pWindowResInfo->prevSKey == TSKEY_INITIAL_VAL) {
         getAlignQueryTimeWindow(pQuery, blockInfo.window.skey, blockInfo.window.skey, pQuery->window.ekey, &w);
-        pWindowResInfo->startTime = w.skey;
         pWindowResInfo->prevSKey = w.skey;
       }
     } else {
       getAlignQueryTimeWindow(pQuery, blockInfo.window.ekey, pQuery->window.ekey, blockInfo.window.ekey, &w);
-
-      pWindowResInfo->startTime = pQuery->window.skey;
       pWindowResInfo->prevSKey = w.skey;
     }
 
@@ -5758,6 +5510,7 @@ static void doRestoreContext(SQInfo *pQInfo) {
   SQuery *          pQuery = pRuntimeEnv->pQuery;
 
   SWAP(pQuery->window.skey, pQuery->window.ekey, TSKEY);
+  SWITCH_ORDER(pQuery->order.order);
 
   if (pRuntimeEnv->pTsBuf != NULL) {
     SWITCH_ORDER(pRuntimeEnv->pTsBuf->cur.order);
@@ -5797,9 +5550,6 @@ static void multiTableQueryProcess(SQInfo *pQInfo) {
      */
     if (QUERY_IS_INTERVAL_QUERY(pQuery)) {
       copyResToQueryResultBuf(pQInfo, pQuery);
-#ifdef _DEBUG_VIEW
-      displayInterResult(pQuery->sdata, pRuntimeEnv, pQuery->sdata[0]->num);
-#endif
     } else {
       copyFromWindowResToSData(pQInfo, &pRuntimeEnv->windowResInfo);
     }
@@ -5844,7 +5594,7 @@ static void multiTableQueryProcess(SQInfo *pQInfo) {
   }
 
   if (QUERY_IS_INTERVAL_QUERY(pQuery) || isSumAvgRateQuery(pQuery)) {
-    if (mergeIntoGroupResult(pQInfo) == TSDB_CODE_SUCCESS) {
+    if (mergeGroupResult(pQInfo) == TSDB_CODE_SUCCESS) {
       copyResToQueryResultBuf(pQInfo, pQuery);
 
 #ifdef _DEBUG_VIEW
@@ -6016,33 +5766,6 @@ static void tableMultiOutputProcess(SQInfo *pQInfo, STableQueryInfo* pTableInfo)
   }
 }
 
-static void tableIntervalProcessImpl(SQueryRuntimeEnv *pRuntimeEnv, TSKEY start) {
-  SQuery *pQuery = pRuntimeEnv->pQuery;
-
-  while (1) {
-    scanOneTableDataBlocks(pRuntimeEnv, start);
-
-    assert(!Q_STATUS_EQUAL(pQuery->status, QUERY_NOT_COMPLETED));
-    finalizeQueryResult(pRuntimeEnv);
-
-    // here we can ignore the records in case of no interpolation
-    // todo handle offset, in case of top/bottom interval query
-    if ((pQuery->numOfFilterCols > 0 || pRuntimeEnv->pTsBuf != NULL) && pQuery->limit.offset > 0 &&
-        pQuery->fillType == TSDB_FILL_NONE) {
-      // maxOutput <= 0, means current query does not generate any results
-      int32_t numOfClosed = numOfClosedResultRows(&pRuntimeEnv->windowResInfo);
-
-      int32_t c = (int32_t)(MIN(numOfClosed, pQuery->limit.offset));
-      popFrontResultRow(pRuntimeEnv, &pRuntimeEnv->windowResInfo, c);
-      pQuery->limit.offset -= c;
-    }
-
-    if (Q_STATUS_EQUAL(pQuery->status, QUERY_COMPLETED | QUERY_RESBUF_FULL)) {
-      break;
-    }
-  }
-}
-
 // handle time interval query on table
 static void tableIntervalProcess(SQInfo *pQInfo, STableQueryInfo* pTableInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &(pQInfo->runtimeEnv);
@@ -6050,7 +5773,6 @@ static void tableIntervalProcess(SQInfo *pQInfo, STableQueryInfo* pTableInfo) {
   SQuery *pQuery = pRuntimeEnv->pQuery;
   pQuery->current = pTableInfo;
 
-  int32_t numOfFilled = 0;
   TSKEY newStartKey = TSKEY_INITIAL_VAL;
 
   // skip blocks without load the actual data block from file if no filter condition present
@@ -6062,59 +5784,39 @@ static void tableIntervalProcess(SQInfo *pQInfo, STableQueryInfo* pTableInfo) {
     }
   }
 
-  while (1) {
-    tableIntervalProcessImpl(pRuntimeEnv, newStartKey);
+  scanOneTableDataBlocks(pRuntimeEnv, newStartKey);
+  assert(!Q_STATUS_EQUAL(pQuery->status, QUERY_NOT_COMPLETED));
 
-    if (QUERY_IS_INTERVAL_QUERY(pQuery)) {
-      pQInfo->groupIndex = 0;  // always start from 0
-      pQuery->rec.rows = 0;
-      copyFromWindowResToSData(pQInfo, &pRuntimeEnv->windowResInfo);
+  finalizeQueryResult(pRuntimeEnv);
 
-      popFrontResultRow(pRuntimeEnv, &pRuntimeEnv->windowResInfo, pQInfo->groupIndex);
-    }
+  // skip offset result rows
+  pQuery->rec.rows = 0;
 
-    // no result generated, abort
-    if (pQuery->rec.rows == 0 || pRuntimeEnv->groupbyNormalCol) {
-      break;
+  if (pQuery->fillType == TSDB_FILL_NONE) {
+    // all data scanned, the group by normal column can return
+    int32_t numOfClosed = numOfClosedResultRows(&pRuntimeEnv->windowResInfo);
+    if (pQuery->limit.offset > numOfClosed) {
+      return;
     }
 
-    doSecondaryArithmeticProcess(pQuery);
-    
-    // the offset is handled at prepare stage if no interpolation involved
-    if (pQuery->fillType == TSDB_FILL_NONE) {
-      limitResults(pRuntimeEnv);
-      break;
-    } else {
-      taosFillSetStartInfo(pRuntimeEnv->pFillInfo, (int32_t)pQuery->rec.rows, pQuery->window.ekey);
-      taosFillCopyInputDataFromFilePage(pRuntimeEnv->pFillInfo, (const tFilePage**) pQuery->sdata);
-      numOfFilled = 0;
+    pQInfo->groupIndex = pQuery->limit.offset;
 
-      pQuery->rec.rows = doFillGapsInResults(pRuntimeEnv, (tFilePage **)pQuery->sdata, &numOfFilled);
-      if (pQuery->rec.rows > 0 || Q_STATUS_EQUAL(pQuery->status, QUERY_COMPLETED)) {
-        limitResults(pRuntimeEnv);
-        break;
-      }
+    copyFromWindowResToSData(pQInfo, &pRuntimeEnv->windowResInfo);
+    doSecondaryArithmeticProcess(pQuery);
 
-      // no result generated yet, continue retrieve data
-      pQuery->rec.rows = 0;
-    }
-  }
+    limitResults(pRuntimeEnv);
+  } else {
 
-  // all data scanned, the group by normal column can return
-  if (pRuntimeEnv->groupbyNormalCol) {  // todo refactor with merge interval time result
-    // maxOutput <= 0, means current query does not generate any results
-    int32_t numOfClosed = numOfClosedResultRows(&pRuntimeEnv->windowResInfo);
+    copyFromWindowResToSData(pQInfo, &pRuntimeEnv->windowResInfo);
+    doSecondaryArithmeticProcess(pQuery);
 
-    if ((pQuery->limit.offset > 0 && pQuery->limit.offset < numOfClosed) || pQuery->limit.offset == 0) {
-      // skip offset result rows
-      popFrontResultRow(pRuntimeEnv, &pRuntimeEnv->windowResInfo, (int32_t) pQuery->limit.offset);
+    taosFillSetStartInfo(pRuntimeEnv->pFillInfo, (int32_t)pQuery->rec.rows, pQuery->window.ekey);
+    taosFillCopyInputDataFromFilePage(pRuntimeEnv->pFillInfo, (const tFilePage **)pQuery->sdata);
 
-      pQuery->rec.rows   = 0;
-      pQInfo->groupIndex = 0;
-      copyFromWindowResToSData(pQInfo, &pRuntimeEnv->windowResInfo);
-      popFrontResultRow(pRuntimeEnv, &pRuntimeEnv->windowResInfo, pQInfo->groupIndex);
+    int32_t numOfFilled = 0;
+    pQuery->rec.rows = doFillGapsInResults(pRuntimeEnv, (tFilePage **)pQuery->sdata, &numOfFilled);
 
-      doSecondaryArithmeticProcess(pQuery);
+    if (pQuery->rec.rows > 0 || Q_STATUS_EQUAL(pQuery->status, QUERY_COMPLETED)) {
       limitResults(pRuntimeEnv);
     }
   }
@@ -6125,7 +5827,6 @@ static void tableQueryImpl(SQInfo *pQInfo) {
   SQuery *          pQuery = pRuntimeEnv->pQuery;
 
   if (queryHasRemainResForTableQuery(pRuntimeEnv)) {
-
     if (pQuery->fillType != TSDB_FILL_NONE) {
       /*
        * There are remain results that are not returned due to result interpolation
@@ -6142,23 +5843,23 @@ static void tableQueryImpl(SQInfo *pQInfo) {
       return;
     } else {
       pQuery->rec.rows = 0;
-      pQInfo->groupIndex = 0;  // always start from 0
+      assert(pRuntimeEnv->windowResInfo.size > 0);
 
-      if (pRuntimeEnv->windowResInfo.size > 0) {
+      if (pQInfo->groupIndex < pRuntimeEnv->windowResInfo.size) {
         copyFromWindowResToSData(pQInfo, &pRuntimeEnv->windowResInfo);
-        popFrontResultRow(pRuntimeEnv, &pRuntimeEnv->windowResInfo, pQInfo->groupIndex);
-
-        if (pQuery->rec.rows > 0) {
-          qDebug("QInfo:%p %"PRId64" rows returned from group results, total:%"PRId64"", pQInfo, pQuery->rec.rows, pQuery->rec.total);
+      }
 
-          // there are not data remains
-          if (pRuntimeEnv->windowResInfo.size <= 0) {
-            qDebug("QInfo:%p query over, %"PRId64" rows are returned", pQInfo, pQuery->rec.total);
-          }
+      if (pQuery->rec.rows > 0) {
+        qDebug("QInfo:%p %" PRId64 " rows returned from group results, total:%" PRId64 "", pQInfo, pQuery->rec.rows,
+               pQuery->rec.total);
+      }
 
-          return;
-        }
+      // there are not data remains
+      if (pQuery->rec.rows <= 0 || pRuntimeEnv->windowResInfo.size <= pQInfo->groupIndex) {
+        qDebug("QInfo:%p query over, %" PRId64 " rows are returned", pQInfo, pQuery->rec.total);
       }
+
+      return;
     }
   }
 
@@ -7276,6 +6977,8 @@ static void freeQInfo(SQInfo *pQInfo) {
   tsdbDestroyTableGroup(&pQInfo->tableGroupInfo);
   taosHashCleanup(pQInfo->arrTableIdInfo);
 
+  taosArrayDestroy(pQInfo->groupResInfo.pRows);
+
   pQInfo->signature = 0;
 
   qDebug("QInfo:%p QInfo is freed", pQInfo);
@@ -7695,7 +7398,7 @@ int32_t qDumpRetrieveResult(qinfo_t qinfo, SRetrieveTableRsp **pRsp, int32_t *co
     (*pRsp)->completed = 1;  // notify no more result to client
   } else {
     *continueExec = true;
-    qDebug("QInfo:%p has more results waits for client retrieve", pQInfo);
+    qDebug("QInfo:%p has more results to retrieve", pQInfo);
   }
 
   return pQInfo->code;
@@ -8060,6 +7763,4 @@ void** qReleaseQInfo(void* pMgmt, void* pQInfo, bool freeHandle) {
 
   taosCacheRelease(pQueryMgmt->qinfoPool, pQInfo, freeHandle);
   return 0;
-}
-
-
+}
\ No newline at end of file
diff --git a/src/query/src/qHistogram.c b/src/query/src/qHistogram.c
index 35e5906d1f797c2f53f3906bf93c6797ac766c3e..bd979f1244953f747513fbc5b2f820eb34e85213 100644
--- a/src/query/src/qHistogram.c
+++ b/src/query/src/qHistogram.c
@@ -120,6 +120,7 @@
 //}
 
 static int32_t histogramCreateBin(SHistogramInfo* pHisto, int32_t index, double val);
+static int32_t histoBinarySearch(SHistBin* pEntry, int32_t len, double val);
 
 SHistogramInfo* tHistogramCreate(int32_t numOfEntries) {
   /* need one redundant slot */
@@ -158,8 +159,8 @@ int32_t tHistogramAdd(SHistogramInfo** pHisto, double val) {
   }
 
 #if defined(USE_ARRAYLIST)
-  int32_t idx = vnodeHistobinarySearch((*pHisto)->elems, (*pHisto)->numOfEntries, val);
-  assert(idx >= 0 && idx <= (*pHisto)->maxEntries);
+  int32_t idx = histoBinarySearch((*pHisto)->elems, (*pHisto)->numOfEntries, val);
+  assert(idx >= 0 && idx <= (*pHisto)->maxEntries && (*pHisto)->elems != NULL);
 
   if ((*pHisto)->elems[idx].val == val && idx >= 0) {
     (*pHisto)->elems[idx].num += 1;
@@ -356,7 +357,7 @@ int32_t tHistogramAdd(SHistogramInfo** pHisto, double val) {
   return 0;
 }
 
-int32_t vnodeHistobinarySearch(SHistBin* pEntry, int32_t len, double val) {
+int32_t histoBinarySearch(SHistBin* pEntry, int32_t len, double val) {
   int32_t end = len - 1;
   int32_t start = 0;
 
@@ -466,7 +467,7 @@ void tHistogramPrint(SHistogramInfo* pHisto) {
  */
 int64_t tHistogramSum(SHistogramInfo* pHisto, double v) {
 #if defined(USE_ARRAYLIST)
-  int32_t slotIdx = vnodeHistobinarySearch(pHisto->elems, pHisto->numOfEntries, v);
+  int32_t slotIdx = histoBinarySearch(pHisto->elems, pHisto->numOfEntries, v);
   if (pHisto->elems[slotIdx].val != v) {
     slotIdx -= 1;
 
diff --git a/src/query/src/qUtil.c b/src/query/src/qUtil.c
index 65ac60e91fc9901e8bf96cca9b799b767b7e4d4a..d09993ae4e6c0bc6f101275aa7a03cb5c40f5e26 100644
--- a/src/query/src/qUtil.c
+++ b/src/query/src/qUtil.c
@@ -96,8 +96,6 @@ void resetResultRowInfo(SQueryRuntimeEnv *pRuntimeEnv, SResultRowInfo *pResultRo
   
   pResultRowInfo->curIndex = -1;
   pResultRowInfo->size = 0;
-  
-  pResultRowInfo->startTime = TSKEY_INITIAL_VAL;
   pResultRowInfo->prevSKey = TSKEY_INITIAL_VAL;
 }
 
@@ -110,7 +108,7 @@ void popFrontResultRow(SQueryRuntimeEnv *pRuntimeEnv, SResultRowInfo *pResultRow
   assert(num >= 0 && num <= numOfClosed);
 
   int16_t type = pResultRowInfo->type;
-  int64_t uid = getResultInfoUId(pRuntimeEnv);
+  int64_t uid  = 0;
 
   char    *key  = NULL;
   int16_t  bytes = -1;
@@ -181,11 +179,12 @@ void closeAllResultRows(SResultRowInfo *pResultRowInfo) {
   assert(pResultRowInfo->size >= 0 && pResultRowInfo->capacity >= pResultRowInfo->size);
   
   for (int32_t i = 0; i < pResultRowInfo->size; ++i) {
-    if (pResultRowInfo->pResult[i]->closed) {
+    SResultRow* pRow = pResultRowInfo->pResult[i];
+    if (pRow->closed) {
       continue;
     }
     
-    pResultRowInfo->pResult[i]->closed = true;
+    pRow->closed = true;
   }
 }
 
@@ -383,18 +382,4 @@ void* destroyResultRowPool(SResultRowPool* p) {
 
   tfree(p);
   return NULL;
-}
-
-uint64_t getResultInfoUId(SQueryRuntimeEnv* pRuntimeEnv) {
-  if (!pRuntimeEnv->stableQuery) {
-    return 0;  // for simple table query, the uid is always set to be 0;
-  }
-
-  SQuery* pQuery = pRuntimeEnv->pQuery;
-  if (pQuery->interval.interval == 0 || isPointInterpoQuery(pQuery) || pRuntimeEnv->groupbyNormalCol) {
-    return 0;
-  }
-
-  STableId* id = TSDB_TABLEID(pRuntimeEnv->pQuery->current->pTable);
-  return id->uid;
 }
\ No newline at end of file