diff --git a/source/libs/parser/inc/parInsertUtil.h b/source/libs/parser/inc/parInsertUtil.h
index 61fbf1504bf132aff62ce4f0e9dc551914e67366..b74ba8d2993f5eca7859029abfe987bbcd6bc54d 100644
--- a/source/libs/parser/inc/parInsertUtil.h
+++ b/source/libs/parser/inc/parInsertUtil.h
@@ -155,6 +155,7 @@ typedef struct STableDataCxt {
   SSubmitTbData *pData;
   TSKEY          lastTs;
   bool           ordered;
+  bool           duplicateTs;
 } STableDataCxt;
 
 typedef struct SVgroupDataCxt {
diff --git a/source/libs/parser/src/parInsertUtil.c b/source/libs/parser/src/parInsertUtil.c
index b8158ea7ede7124da231514cf1daac23276119a3..b5309e16bf972f22152fd1dff6fb7c1231c5d9a2 100644
--- a/source/libs/parser/src/parInsertUtil.c
+++ b/source/libs/parser/src/parInsertUtil.c
@@ -982,15 +982,19 @@ int32_t insInitBoundColsInfo(int32_t numOfBound, SBoundColInfo* pInfo) {
 }
 
 void insCheckTableDataOrder(STableDataCxt* pTableCxt, TSKEY tsKey) {
-  // once the data block is disordered, we do NOT keep previous timestamp any more
+  // once the data block is disordered, we do NOT keep last timestamp any more
   if (!pTableCxt->ordered) {
     return;
   }
 
-  if (tsKey <= pTableCxt->lastTs) {
+  if (tsKey < pTableCxt->lastTs) {
     pTableCxt->ordered = false;
   }
 
+  if (tsKey == pTableCxt->lastTs) {
+    pTableCxt->duplicateTs = true;
+  }
+
   pTableCxt->lastTs = tsKey;
   return;
 }
@@ -1005,8 +1009,9 @@ static int32_t createTableDataCxt(STableMeta* pTableMeta, SVCreateTbReq** pCreat
 
   int32_t code = TSDB_CODE_SUCCESS;
 
-  pTableCxt->ordered = true;
   pTableCxt->lastTs = 0;
+  pTableCxt->ordered = true;
+  pTableCxt->duplicateTs = false;
 
   pTableCxt->pMeta = tableMetaDup(pTableMeta);
   if (NULL == pTableCxt->pMeta) {
@@ -1196,10 +1201,12 @@ int32_t insMergeTableDataCxt(SHashObj* pTableHash, SArray** pVgDataBlocks) {
   void* p = taosHashIterate(pTableHash, NULL);
   while (TSDB_CODE_SUCCESS == code && NULL != p) {
     STableDataCxt* pTableCxt = *(STableDataCxt**)p;
-    if (pTableCxt->ordered) {
+    if (!pTableCxt->ordered) {
       tRowSort(pTableCxt->pData->aRowP);
     }
-    code = tRowMerge(pTableCxt->pData->aRowP, pTableCxt->pSchema, 0);
+    if (!pTableCxt->ordered || pTableCxt->duplicateTs) {
+      code = tRowMerge(pTableCxt->pData->aRowP, pTableCxt->pSchema, 0);
+    }
     if (TSDB_CODE_SUCCESS == code) {
       SVgroupDataCxt* pVgCxt = NULL;
       int32_t         vgId = pTableCxt->pMeta->vgId;