diff --git a/src/inc/tsqlfunction.h b/src/inc/tsqlfunction.h
index 8783285fbbda3086550067ee74cc586871de51f2..b42358967213ae182574cd6a4c806fc090431af4 100644
--- a/src/inc/tsqlfunction.h
+++ b/src/inc/tsqlfunction.h
@@ -169,9 +169,9 @@ typedef struct SExtTagsInfo {
 
 // sql function runtime context
 typedef struct SQLFunctionCtx {
-  int32_t startOffset;
-  int32_t size;      // number of rows
-  int32_t order;     // asc|desc
+  int32_t  startOffset;
+  int32_t  size;      // number of rows
+  uint32_t order;     // asc|desc
   uint32_t scanFlag;  // TODO merge with currentStage
 
   int16_t inputType;
diff --git a/src/system/detail/src/vnodeQueryImpl.c b/src/system/detail/src/vnodeQueryImpl.c
index 09c3e14dfbe877d347604f553e8ed0c78c936556..aebd5b28c6a20e83be0dc2f967542c28cb71ff64 100644
--- a/src/system/detail/src/vnodeQueryImpl.c
+++ b/src/system/detail/src/vnodeQueryImpl.c
@@ -1861,7 +1861,7 @@ static int32_t blockwiseApplyAllFunctions(SQueryRuntimeEnv *pRuntimeEnv, int32_t
   }
 
   int32_t step = GET_FORWARD_DIRECTION_FACTOR(pQuery->order.order);
-  if (isIntervalQuery(pQuery) && pQuery->slidingTime > 0) {
+  if (isIntervalQuery(pQuery)) {
     int32_t offset = GET_COL_DATA_POS(pQuery, 0, step);
     TSKEY   ts = primaryKeyCol[offset];
 
@@ -2423,7 +2423,7 @@ static int32_t rowwiseApplyAllFunctions(SQueryRuntimeEnv *pRuntimeEnv, int32_t *
    * because the results of group by normal column is put into intermediate buffer.
    */
   int32_t num = 0;
-  if (!groupbyStateValue && !(isIntervalQuery(pQuery) && pQuery->slidingTime > 0)) {
+  if (!groupbyStateValue && !isIntervalQuery(pQuery)) {
     num = getNumOfResult(pRuntimeEnv) - prevNumOfRes;
   }
 
@@ -4588,7 +4588,7 @@ int32_t vnodeQueryTablePrepare(SQInfo *pQInfo, SMeterObj *pMeterObj, STableQuery
   vnodeRecordAllFiles(pQInfo, pMeterObj->vnode);
 
   pRuntimeEnv->numOfRowsPerPage = getNumOfRowsInResultPage(pQuery, false);
-  if (isGroupbyNormalCol(pQuery->pGroupbyExpr) || (isIntervalQuery(pQuery) && pQuery->slidingTime > 0)) {
+  if (isGroupbyNormalCol(pQuery->pGroupbyExpr) || isIntervalQuery(pQuery)) {
     int32_t rows = getInitialPageNum(pSupporter);
 
     code = createDiskbasedResultBuffer(&pRuntimeEnv->pResultBuf, rows, pQuery->rowSize);
@@ -4731,9 +4731,9 @@ void vnodeQueryFreeQInfoEx(SQInfo *pQInfo) {
   }
 
   if (pSupporter->pSidSet != NULL || isGroupbyNormalCol(pQInfo->query.pGroupbyExpr) ||
-      (isIntervalQuery(pQuery) && pQuery->slidingTime > 0)) {
+      isIntervalQuery(pQuery)) {
     int32_t size = 0;
-    if (isGroupbyNormalCol(pQInfo->query.pGroupbyExpr) || (isIntervalQuery(pQuery) && pQuery->slidingTime > 0)) {
+    if (isGroupbyNormalCol(pQInfo->query.pGroupbyExpr) || isIntervalQuery(pQuery)) {
       size = 10000;
     } else if (pSupporter->pSidSet != NULL) {
       size = pSupporter->pSidSet->numOfSubSet;
@@ -5889,7 +5889,11 @@ void disableFunctForTableSuppleScan(SQueryRuntimeEnv *pRuntimeEnv, int32_t order
 void disableFunctForSuppleScan(STableQuerySupportObj *pSupporter, int32_t order) {
   SQueryRuntimeEnv *pRuntimeEnv = &pSupporter->runtimeEnv;
   SQuery *          pQuery = pRuntimeEnv->pQuery;
-
+  
+  for (int32_t i = 0; i < pQuery->numOfOutputCols; ++i) {
+    pRuntimeEnv->pCtx[i].order = (pRuntimeEnv->pCtx[i].order) ^ 1u;
+  }
+  
   if (isIntervalQuery(pQuery)) {
     for (int32_t i = 0; i < pSupporter->numOfMeters; ++i) {
       SMeterQueryInfo *pMeterQueryInfo = pSupporter->pMeterDataInfo[i].pMeterQInfo;
@@ -5898,10 +5902,6 @@ void disableFunctForSuppleScan(STableQuerySupportObj *pSupporter, int32_t order)
       doDisableFunctsForSupplementaryScan(pQuery, pWindowResInfo, order);
     }
   } else {
-    for (int32_t i = 0; i < pQuery->numOfOutputCols; ++i) {
-      pRuntimeEnv->pCtx[i].order = (pRuntimeEnv->pCtx[i].order) ^ 1u;
-    }
-
     SWindowResInfo *pWindowResInfo = &pRuntimeEnv->windowResInfo;
     doDisableFunctsForSupplementaryScan(pQuery, pWindowResInfo, order);
   }
@@ -6193,7 +6193,7 @@ bool needScanDataBlocksAgain(SQueryRuntimeEnv *pRuntimeEnv) {
   SQuery *pQuery = pRuntimeEnv->pQuery;
   bool    toContinue = false;
 
-  if (isGroupbyNormalCol(pQuery->pGroupbyExpr) || (isIntervalQuery(pQuery) && pQuery->slidingTime > 0)) {
+  if (isGroupbyNormalCol(pQuery->pGroupbyExpr) || isIntervalQuery(pQuery)) {
     // for each group result, call the finalize function for each column
     SWindowResInfo *pWindowResInfo = &pRuntimeEnv->windowResInfo;
 
@@ -6530,7 +6530,7 @@ void changeMeterQueryInfoForSuppleQuery(SQuery *pQuery, SMeterQueryInfo *pMeterQ
   SWAP(pMeterQueryInfo->skey, pMeterQueryInfo->ekey, TSKEY);
   pMeterQueryInfo->lastKey = pMeterQueryInfo->skey;
 
-  pMeterQueryInfo->cur.order = pMeterQueryInfo->cur.order ^ 1;
+  pMeterQueryInfo->cur.order = pMeterQueryInfo->cur.order ^ 1u;
   pMeterQueryInfo->cur.vnodeIndex = -1;
 }
 
@@ -7115,7 +7115,7 @@ int32_t LoadDatablockOnDemand(SCompBlock *pBlock, SField **pFields, uint8_t *blk
                                           pQuery->pSelectExpr[i].pBase.colInfo.colId, *blkStatus);
       }
 
-      if (pRuntimeEnv->pTSBuf > 0 || (isIntervalQuery(pQuery) && pQuery->slidingTime > 0)) {
+      if (pRuntimeEnv->pTSBuf > 0 || isIntervalQuery(pQuery)) {
         req |= BLK_DATA_ALL_NEEDED;
       }
     }
diff --git a/src/system/detail/src/vnodeQueryProcess.c b/src/system/detail/src/vnodeQueryProcess.c
index 4caf79f6c9068a7ee1688c22fba0d8d8a9c4aff0..ae51365918b142e392dcffa27a6b071543f3d02e 100644
--- a/src/system/detail/src/vnodeQueryProcess.c
+++ b/src/system/detail/src/vnodeQueryProcess.c
@@ -872,7 +872,7 @@ static void doMultiMeterSupplementaryScan(SQInfo *pQInfo) {
   disableFunctForSuppleScan(pSupporter, pQuery->order.order);
 
   if (pRuntimeEnv->pTSBuf != NULL) {
-    pRuntimeEnv->pTSBuf->cur.order = pRuntimeEnv->pTSBuf->cur.order ^ 1;
+    pRuntimeEnv->pTSBuf->cur.order = pRuntimeEnv->pTSBuf->cur.order ^ 1u;
   }
 
   SWAP(pSupporter->rawSKey, pSupporter->rawEKey, TSKEY);
@@ -945,7 +945,7 @@ static void vnodeMultiMeterQueryProcessor(SQInfo *pQInfo) {
   doOrderedScan(pQInfo);
   int64_t et = taosGetTimestampMs();
   dTrace("QInfo:%p main scan completed, elapsed time: %lldms, supplementary scan start, order:%d", pQInfo, et - st,
-         pQuery->order.order ^ 1);
+         pQuery->order.order ^ 1u);
 
   if (pQuery->intervalTime > 0) {
     for (int32_t i = 0; i < pSupporter->numOfMeters; ++i) {
diff --git a/src/util/src/tinterpolation.c b/src/util/src/tinterpolation.c
index 279dd07265d124ae6f31cf4851851ea2baf2d74a..cb7c8854ce914d22680db5429871857ac445f1fe 100644
--- a/src/util/src/tinterpolation.c
+++ b/src/util/src/tinterpolation.c
@@ -91,7 +91,7 @@ void taosInterpoSetStartInfo(SInterpolationInfo* pInterpoInfo, int32_t numOfRawD
     return;
   }
 
-  pInterpoInfo->rowIdx = 0;  // INTERPOL_IS_ASC_INTERPOL(pInterpoInfo) ? 0 : numOfRawDataInRows - 1;
+  pInterpoInfo->rowIdx = 0;
   pInterpoInfo->numOfRawDataInRows = numOfRawDataInRows;
 }
 
@@ -295,6 +295,20 @@ static void doInterpoResultImpl(SInterpolationInfo* pInterpoInfo, int16_t interp
   (*num) += 1;
 }
 
+static void initBeforeAfterDataBuf(SColumnModel* pModel, char** nextValues) {
+  if (*nextValues != NULL) {
+    return;
+  }
+  
+  *nextValues = calloc(1, pModel->rowSize);
+  for (int i = 1; i < pModel->numOfCols; i++) {
+    int16_t  offset = getColumnModelOffset(pModel, i);
+    SSchema* pSchema = getColumnModelSchema(pModel, i);
+    
+    setNull(*nextValues + offset, pSchema->type, pSchema->bytes);
+  }
+}
+
 int32_t taosDoInterpoResult(SInterpolationInfo* pInterpoInfo, int16_t interpoType, tFilePage** data,
                             int32_t numOfRawDataInRows, int32_t outputRows, int64_t nInterval,
                             const int64_t* pPrimaryKeyArray, SColumnModel* pModel, char** srcData, int64_t* defaultVal,
@@ -329,16 +343,8 @@ int32_t taosDoInterpoResult(SInterpolationInfo* pInterpoInfo, int16_t interpoTyp
       if ((pInterpoInfo->startTimestamp < currentTimestamp && INTERPOL_IS_ASC_INTERPOL(pInterpoInfo)) ||
           (pInterpoInfo->startTimestamp > currentTimestamp && !INTERPOL_IS_ASC_INTERPOL(pInterpoInfo))) {
         /* set the next value for interpolation */
-        if (*nextValues == NULL) {
-          *nextValues = calloc(1, pModel->rowSize);
-          for (int i = 1; i < pModel->numOfCols; i++) {
-            int16_t  offset = getColumnModelOffset(pModel, i);
-            SSchema* pSchema = getColumnModelSchema(pModel, i);
-
-            setNull(*nextValues + offset, pSchema->type, pSchema->bytes);
-          }
-        }
-
+        initBeforeAfterDataBuf(pModel, nextValues);
+        
         int32_t offset = pInterpoInfo->rowIdx;
         for (int32_t tlen = 0, i = 0; i < pModel->numOfCols - numOfTags; ++i) {
           SSchema* pSchema = getColumnModelSchema(pModel, i);
@@ -365,17 +371,10 @@ int32_t taosDoInterpoResult(SInterpolationInfo* pInterpoInfo, int16_t interpoTyp
           return outputRows;
         }
       } else {
-        //      if (pInterpoInfo->startTimestamp == currentTimestamp) {
-        if (*prevValues == NULL) {
-          *prevValues = calloc(1, pModel->rowSize);
-          for (int i = 1; i < pModel->numOfCols; i++) {
-            int16_t  offset = getColumnModelOffset(pModel, i);
-            SSchema* pSchema = getColumnModelSchema(pModel, i);
-
-            setNull(*prevValues + offset, pSchema->type, pSchema->bytes);
-          }
-        }
-
+        assert(pInterpoInfo->startTimestamp == currentTimestamp);
+        
+        initBeforeAfterDataBuf(pModel, prevValues);
+        
         // assign rows to dst buffer
         int32_t i = 0;
         for (int32_t tlen = 0; i < pModel->numOfCols - numOfTags; ++i) {
@@ -383,19 +382,19 @@ int32_t taosDoInterpoResult(SInterpolationInfo* pInterpoInfo, int16_t interpoTyp
           SSchema* pSchema = getColumnModelSchema(pModel, i);
 
           char* val1 = getPos(data[i]->data, pSchema->bytes, num);
-
+          char* src = srcData[i] + pInterpoInfo->rowIdx * pSchema->bytes;
+          
           if (i == 0 ||
-              (functionIDs[i] != TSDB_FUNC_COUNT &&
-               !isNull(srcData[i] + pInterpoInfo->rowIdx * pSchema->bytes, pSchema->type)) ||
-              (functionIDs[i] == TSDB_FUNC_COUNT &&
-               *(int64_t*)(srcData[i] + pInterpoInfo->rowIdx * pSchema->bytes) != 0)) {
-            assignVal(val1, srcData[i] + pInterpoInfo->rowIdx * pSchema->bytes, pSchema->bytes, pSchema->type);
-            memcpy(*prevValues + tlen, srcData[i] + pInterpoInfo->rowIdx * pSchema->bytes, pSchema->bytes);
-          } else {  // i > 0 and isNULL, do interpolation
+              (functionIDs[i] != TSDB_FUNC_COUNT && !isNull(src, pSchema->type)) ||
+              (functionIDs[i] == TSDB_FUNC_COUNT && *(int64_t*)(src) != 0)) {
+            assignVal(val1, src, pSchema->bytes, pSchema->type);
+            memcpy(*prevValues + tlen, src, pSchema->bytes);
+          } else {  // i > 0 and data is null , do interpolation
             if (interpoType == TSDB_INTERPO_PREV) {
               assignVal(val1, *prevValues + offset, pSchema->bytes, pSchema->type);
             } else if (interpoType == TSDB_INTERPO_LINEAR) {
-              // TODO:
+              assignVal(val1, src, pSchema->bytes, pSchema->type);
+              memcpy(*prevValues + tlen, src, pSchema->bytes);
             } else {
               assignVal(val1, (char*)&defaultVal[i], pSchema->bytes, pSchema->type);
             }