diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index e0f8943a48..2d1800a92c 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -1985,7 +1985,7 @@ static void doMergeTwoLevelData(STsdbReadHandle* pTsdbReadHandle, STableCheckInf
     return;
   } else if (pCheckInfo->iter != NULL || pCheckInfo->iiter != NULL) {
     SSkipListNode* node = NULL;
-    TSKEY          lastRowKey = TSKEY_INITIAL_VAL;
+    TSKEY          lastKeyAppend = TSKEY_INITIAL_VAL;
 
     do {
       STSRow* row2 = NULL;
@@ -2019,8 +2019,8 @@ static void doMergeTwoLevelData(STsdbReadHandle* pTsdbReadHandle, STableCheckInf
         }
 
         numOfRows += mergeTwoRowFromMem(pTsdbReadHandle, pTsdbReadHandle->outputCapacity, &curRow, row1, row2, numOfCols,
-                           pCheckInfo->tableId, pSchema1, pSchema2, pCfg->update, &lastRowKey);
-        // numOfRows += 1;
+                           pCheckInfo->tableId, pSchema1, pSchema2, pCfg->update, &lastKeyAppend);
+
         if (cur->win.skey == TSKEY_INITIAL_VAL) {
           cur->win.skey = key;
         }
@@ -2028,7 +2028,6 @@ static void doMergeTwoLevelData(STsdbReadHandle* pTsdbReadHandle, STableCheckInf
         cur->win.ekey = key;
         cur->lastKey = key + step;
         cur->mixBlock = true;
-
         moveToNextRowInMem(pCheckInfo);
       } else if (key == tsArray[pos]) {  // data in buffer has the same timestamp of data in file block, ignore it
 #if 0
@@ -2064,7 +2063,11 @@ static void doMergeTwoLevelData(STsdbReadHandle* pTsdbReadHandle, STableCheckInf
         }
 #endif
         if (TD_SUPPORT_UPDATE(pCfg->update)) {
-          doCopyRowsFromFileBlock(pTsdbReadHandle, pTsdbReadHandle->outputCapacity, curRow, pos, pos);
+          if(lastKeyAppend != key) {
+            lastKeyAppend = key;
+            ++curRow;
+          }
+          numOfRows = doCopyRowsFromFileBlock(pTsdbReadHandle, pTsdbReadHandle->outputCapacity, curRow, pos, pos);
 
           if (rv1 != TD_ROW_SVER(row1)) {
             //            pSchema1 = tsdbGetTableSchemaByVersion(pTable, memRowVersion(row1));
@@ -2074,10 +2077,8 @@ static void doMergeTwoLevelData(STsdbReadHandle* pTsdbReadHandle, STableCheckInf
             //            pSchema2 = tsdbGetTableSchemaByVersion(pTable, memRowVersion(row2));
             rv2 = TD_ROW_SVER(row2);
           }
-
           numOfRows += mergeTwoRowFromMem(pTsdbReadHandle, pTsdbReadHandle->outputCapacity, &curRow, row1, row2, numOfCols,
-                             pCheckInfo->tableId, pSchema1, pSchema2, pCfg->update, &lastRowKey);
-          // ++numOfRows;
+                             pCheckInfo->tableId, pSchema1, pSchema2, pCfg->update, &lastKeyAppend);
           if (cur->win.skey == TSKEY_INITIAL_VAL) {
             cur->win.skey = key;
           }
@@ -2118,11 +2119,19 @@ static void doMergeTwoLevelData(STsdbReadHandle* pTsdbReadHandle, STableCheckInf
         int32_t qstart = 0, qend = 0;
         getQualifiedRowsPos(pTsdbReadHandle, pos, end, numOfRows, &qstart, &qend);
 
-        numOfRows = doCopyRowsFromFileBlock(pTsdbReadHandle, pTsdbReadHandle->outputCapacity, numOfRows, qstart, qend);
+        if ((lastKeyAppend != TSKEY_INITIAL_VAL) &&
+            (lastKeyAppend != (ASCENDING_TRAVERSE(pTsdbReadHandle->order) ? tsArray[qstart] : tsArray[qend]))) {
+          ++curRow;
+        }
+        numOfRows = doCopyRowsFromFileBlock(pTsdbReadHandle, pTsdbReadHandle->outputCapacity, curRow, qstart, qend);
         pos += (qend - qstart + 1) * step;
+        if (numOfRows > 0) {
+          curRow = numOfRows - 1;
+        }
 
         cur->win.ekey = ASCENDING_TRAVERSE(pTsdbReadHandle->order) ? tsArray[qend] : tsArray[qstart];
         cur->lastKey = cur->win.ekey + step;
+        lastKeyAppend = cur->win.ekey;
       }
     } while (numOfRows < pTsdbReadHandle->outputCapacity);