diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index 95b4afe6d8d1b84735c08b2c5f907c85db5d92ef..07d8a2e6a7aac383aa89c346173546341125771b 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -3329,7 +3329,7 @@ int32_t tsdbReaderOpen(SVnode* pVnode, SQueryTableDataCond* pCond, SArray* pTabl
 
   if (pCond->type == TIMEWINDOW_RANGE_EXTERNAL) {
     // update the SQueryTableDataCond to create inner reader
-    int32_t     order = pCond->order;
+    int32_t order = pCond->order;
     if (order == TSDB_ORDER_ASC) {
       pCond->twindows.ekey = window.skey;
       pCond->twindows.skey = INT64_MIN;
@@ -3353,6 +3353,8 @@ int32_t tsdbReaderOpen(SVnode* pVnode, SQueryTableDataCond* pCond, SArray* pTabl
       pCond->twindows.skey = INT64_MIN;
       pCond->twindows.ekey = window.ekey;
     }
+    pCond->order = order;
+
     code = tsdbReaderCreate(pVnode, pCond, &pReader->innerReader[1], 1, idstr);
     if (code != TSDB_CODE_SUCCESS) {
       goto _err;
@@ -3373,8 +3375,10 @@ int32_t tsdbReaderOpen(SVnode* pVnode, SQueryTableDataCond* pCond, SArray* pTabl
     }
   }
 
+  STsdbReader* p = pReader->innerReader[0] != NULL? pReader->innerReader[0]:pReader;
+
   int32_t numOfTables = taosArrayGetSize(pTableList);
-  pReader->status.pTableMap = createDataBlockScanInfo(pReader, pTableList->pData, numOfTables);
+  pReader->status.pTableMap = createDataBlockScanInfo(p, pTableList->pData, numOfTables);
   if (pReader->status.pTableMap == NULL) {
     tsdbReaderClose(pReader);
     *ppReader = NULL;
@@ -3541,8 +3545,9 @@ bool tsdbNextDataBlock(STsdbReader* pReader) {
   if (pReader->innerReader[0] != NULL && pReader->step == 0) {
     bool ret = doTsdbNextDataBlock(pReader->innerReader[0]);
     resetDataBlockScanInfo(pReader->innerReader[0]->status.pTableMap, pReader->innerReader[0]->window.ekey);
+    pReader->step = EXTERNAL_ROWS_PREV;
+
     if (ret) {
-      pReader->step = EXTERNAL_ROWS_PREV;
       return ret;
     }
   }
@@ -3559,8 +3564,8 @@ bool tsdbNextDataBlock(STsdbReader* pReader) {
   if (pReader->innerReader[1] != NULL && pReader->step == EXTERNAL_ROWS_MAIN) {
     resetDataBlockScanInfo(pReader->innerReader[1]->status.pTableMap, pReader->window.ekey);
     bool ret1 = doTsdbNextDataBlock(pReader->innerReader[1]);
+    pReader->step = EXTERNAL_ROWS_NEXT;
     if (ret1) {
-      pReader->step = EXTERNAL_ROWS_NEXT;
       return ret1;
     }
   }
diff --git a/source/libs/executor/src/timewindowoperator.c b/source/libs/executor/src/timewindowoperator.c
index 0c6cc51efdf2bdbf52ef5de52efc696a2930793c..8ddaca5b706a43b16b67144b0fda601b65434338 100644
--- a/source/libs/executor/src/timewindowoperator.c
+++ b/source/libs/executor/src/timewindowoperator.c
@@ -1994,7 +1994,7 @@ static void doKeepLinearInfo(STimeSliceOperatorInfo* pSliceInfo, const SSDataBlo
     }
   }
 
-  pSliceInfo->fillLastPoint = isLastRow ? true : false;
+  pSliceInfo->fillLastPoint = isLastRow;
 }
 
 static void genInterpolationResult(STimeSliceOperatorInfo* pSliceInfo, SExprSupp* pExprSup, SSDataBlock* pResBlock) {
@@ -2342,6 +2342,9 @@ static SSDataBlock* doTimeslice(SOperatorInfo* pOperator) {
                 break;
               }
             }
+          } else {
+            // store ts value as start, and calculate interp value when processing next block
+            doKeepLinearInfo(pSliceInfo, pBlock, i, true);
           }
         } else {  // non-linear interpolation
           if (i < pBlock->info.rows - 1) {
@@ -2420,6 +2423,9 @@ static SSDataBlock* doTimeslice(SOperatorInfo* pOperator) {
                   break;
                 }
               }
+            } else {  // it is the last row of current block
+              // store ts value as start, and calculate interp value when processing next block
+              doKeepLinearInfo(pSliceInfo, pBlock, i, true);
             }
           } else {  // non-linear interpolation
             pSliceInfo->current =