diff --git a/include/common/tdataformat.h b/include/common/tdataformat.h
index e308666524ed114a7e9dfff9eb3bd25b9bcf52e2..5eeb76ec7941c3b3efedc3edc9ffb33947502a9e 100644
--- a/include/common/tdataformat.h
+++ b/include/common/tdataformat.h
@@ -89,12 +89,12 @@ void    tRowGet(SRow *pRow, STSchema *pTSchema, int32_t iCol, SColVal *pColVal);
 void    tRowDestroy(SRow *pRow);
 void    tRowSort(SArray *aRowP);
 int32_t tRowMerge(SArray *aRowP, STSchema *pTSchema, int8_t flag);
+int32_t tRowAppendToColData(SRow *pRow, STSchema *pTSchema, SColData *aColData, int32_t nColData);
 
 // SRowIter ================================
 int32_t  tRowIterOpen(SRow *pRow, STSchema *pTSchema, SRowIter **ppIter);
 void     tRowIterClose(SRowIter **ppIter);
 SColVal *tRowIterNext(SRowIter *pIter);
-int32_t  tRowAppendToColData(SRow *pRow, STSchema *pTSchema, SColData *aColData, int32_t nColData);
 
 // STag ================================
 int32_t tTagNew(SArray *pArray, int32_t version, int8_t isJson, STag **ppTag);
diff --git a/source/dnode/vnode/src/inc/tsdb.h b/source/dnode/vnode/src/inc/tsdb.h
index 4f96ba2042f99d3f0e467e2986c8c670887b598c..99adb6bf6a8faf45203b52e5f8034559e69903a8 100644
--- a/source/dnode/vnode/src/inc/tsdb.h
+++ b/source/dnode/vnode/src/inc/tsdb.h
@@ -117,7 +117,8 @@ static FORCE_INLINE int64_t tsdbLogicToFileSize(int64_t lSize, int32_t szPage) {
 void    tsdbRowGetColVal(TSDBROW *pRow, STSchema *pTSchema, int32_t iCol, SColVal *pColVal);
 int32_t tsdbRowCmprFn(const void *p1, const void *p2);
 // STSDBRowIter
-void     tsdbRowIterInit(STSDBRowIter *pIter, TSDBROW *pRow, STSchema *pTSchema);
+int32_t  tsdbRowIterOpen(STSDBRowIter *pIter, TSDBROW *pRow, STSchema *pTSchema);
+void     tsdbRowClose(STSDBRowIter *pIter);
 SColVal *tsdbRowIterNext(STSDBRowIter *pIter);
 // SRowMerger
 int32_t tsdbRowMergerInit2(SRowMerger *pMerger, STSchema *pResTSchema, TSDBROW *pRow, STSchema *pTSchema);
@@ -571,10 +572,14 @@ struct SDFileSet {
 };
 
 struct STSDBRowIter {
-  TSDBROW  *pRow;
-  STSchema *pTSchema;
-  SColVal   colVal;
-  int32_t   i;
+  TSDBROW *pRow;
+  union {
+    SRowIter *pIter;
+    struct {
+      int32_t iColData;
+      SColVal cv;
+    };
+  };
 };
 struct SRowMerger {
   STSchema *pTSchema;
diff --git a/source/dnode/vnode/src/tsdb/tsdbDiskData.c b/source/dnode/vnode/src/tsdb/tsdbDiskData.c
index b46a00363817666cdff7bc7756ff204483787c36..ae9af11f5ae8226c1fceefb57b4d83167800772a 100644
--- a/source/dnode/vnode/src/tsdb/tsdbDiskData.c
+++ b/source/dnode/vnode/src/tsdb/tsdbDiskData.c
@@ -596,7 +596,7 @@ int32_t tDiskDataAddRow(SDiskDataBuilder *pBuilder, TSDBROW *pRow, STSchema *pTS
   if (pBuilder->bi.maxKey < kRow.ts) pBuilder->bi.maxKey = kRow.ts;
 
   STSDBRowIter iter = {0};
-  tsdbRowIterInit(&iter, pRow, pTSchema);
+  tsdbRowIterOpen(&iter, pRow, pTSchema);
 
   SColVal *pColVal = tsdbRowIterNext(&iter);
   for (int32_t iBuilder = 0; iBuilder < pBuilder->nBuilder; iBuilder++) {
diff --git a/source/dnode/vnode/src/tsdb/tsdbUtil.c b/source/dnode/vnode/src/tsdb/tsdbUtil.c
index 2a5ae83b9b36c756751bd56101e0ea5cfbaf3d0a..36ee85df6b89e2a4e989d8b32200f81ae7381d64 100644
--- a/source/dnode/vnode/src/tsdb/tsdbUtil.c
+++ b/source/dnode/vnode/src/tsdb/tsdbUtil.c
@@ -594,42 +594,50 @@ int32_t tsdbRowCmprFn(const void *p1, const void *p2) {
 }
 
 // STSDBRowIter ======================================================
-void tsdbRowIterInit(STSDBRowIter *pIter, TSDBROW *pRow, STSchema *pTSchema) {
+int32_t tsdbRowIterOpen(STSDBRowIter *pIter, TSDBROW *pRow, STSchema *pTSchema) {
+  int32_t code = 0;
+
   pIter->pRow = pRow;
   if (pRow->type == TSDBROW_ROW_FMT) {
-    ASSERT(pTSchema);
-    pIter->pTSchema = pTSchema;
-    pIter->i = 1;
+    code = tRowIterOpen(pRow->pTSRow, pTSchema, &pIter->pIter);
+    if (code) goto _exit;
   } else if (pRow->type == TSDBROW_COL_FMT) {
-    pIter->pTSchema = NULL;
-    pIter->i = 0;
+    pIter->iColData = 0;
   } else {
     ASSERT(0);
   }
+
+_exit:
+  return code;
 }
 
-SColVal *tsdbRowIterNext(STSDBRowIter *pIter) {
+void tsdbRowClose(STSDBRowIter *pIter) {
   if (pIter->pRow->type == TSDBROW_ROW_FMT) {
-    if (pIter->i < pIter->pTSchema->numOfCols) {
-      tRowGet(pIter->pRow->pTSRow, pIter->pTSchema, pIter->i, &pIter->colVal);
-      pIter->i++;
+    tRowIterClose(&pIter->pIter);
+  }
+}
 
-      return &pIter->colVal;
-    }
+SColVal *tsdbRowIterNext(STSDBRowIter *pIter) {
+  if (pIter->pRow->type == TSDBROW_ROW_FMT) {
+    return tRowIterNext(pIter->pIter);
   } else if (pIter->pRow->type == TSDBROW_COL_FMT) {
-    if (pIter->i < pIter->pRow->pBlockData->nColData) {
-      SColData *pColData = tBlockDataGetColDataByIdx(pIter->pRow->pBlockData, pIter->i);
-
-      tColDataGetValue(pColData, pIter->pRow->iRow, &pIter->colVal);
-      pIter->i++;
+    if (pIter->iColData == 0) {
+      pIter->cv = COL_VAL_VALUE(PRIMARYKEY_TIMESTAMP_COL_ID, TSDB_DATA_TYPE_TIMESTAMP,
+                                (SValue){.val = pIter->pRow->pBlockData->aTSKEY[pIter->pRow->iRow]});
+      ++pIter->iColData;
+      return &pIter->cv;
+    }
 
-      return &pIter->colVal;
+    if (pIter->iColData < pIter->pRow->pBlockData->nColData) {
+      tColDataGetValue(&pIter->pRow->pBlockData->aColData[pIter->iColData], pIter->pRow->iRow, &pIter->cv);
+      ++pIter->iColData;
+      return &pIter->cv;
+    } else {
+      return NULL;
     }
   } else {
     ASSERT(0);
   }
-
-  return NULL;
 }
 
 // SRowMerger ======================================================