diff --git a/source/libs/executor/src/tsort.c b/source/libs/executor/src/tsort.c
index 906fe0626b..6f690b8911 100644
--- a/source/libs/executor/src/tsort.c
+++ b/source/libs/executor/src/tsort.c
@@ -1479,11 +1479,12 @@ static int32_t getPageBufIncForRow(SSDataBlock* pSrcBlock, int32_t srcRowIndex,
   return size;
 }
 
-static int32_t getPageBufIncForRowIdSort(SSDataBlock* pDstBlock, int32_t srcRowIndex, int32_t dstRowIndex, SColumnInfoData* pPkCol) {
+static int32_t getPageBufIncForRowIdSort(SSDataBlock* pDstBlock, int32_t srcRowIndex, int32_t dstRowIndex,
+                                         SColumnInfoData* pPkCol) {
   int32_t size = 0;
   int32_t numOfCols = blockDataGetNumOfCols(pDstBlock);
 
-  if (pPkCol == NULL) {
+  if (pPkCol == NULL) { // no var column
     ASSERT((numOfCols == 4) && (!pDstBlock->info.hasVarCol));
 
     size += numOfCols * ((dstRowIndex & 0x7) == 0 ? 1: 0);
@@ -1492,8 +1493,12 @@ static int32_t getPageBufIncForRowIdSort(SSDataBlock* pDstBlock, int32_t srcRowI
     ASSERT(numOfCols == 5);
 
     size += (numOfCols - 1) * (((dstRowIndex & 0x7) == 0)? 1:0);
-    size += (8 + 4 + 4 + 4);  // todo refactor later
+    for(int32_t i = 0; i < numOfCols - 1; ++i) {
+      SColumnInfoData* pColInfo = TARRAY_GET_ELEM(pDstBlock->pDataBlock, i);
+      size += pColInfo->info.bytes;
+    }
 
+    // handle the pk column, the last column, may be the var char column
     if (IS_VAR_DATA_TYPE(pPkCol->info.type)) {
       if ((pPkCol->varmeta.offset[srcRowIndex] != -1) && (pPkCol->pData)) {
         char* p = colDataGetData(pPkCol, srcRowIndex);
@@ -1512,6 +1517,27 @@ static int32_t getPageBufIncForRowIdSort(SSDataBlock* pDstBlock, int32_t srcRowI
   return size;
 }
 
+static int32_t getBufIncForNewRow(SSortHandle* pHandle, int32_t dstRowIndex, SSDataBlock* pSrcBlock,
+                                  int32_t srcRowIndex) {
+  int32_t inc = 0;
+
+  if (pHandle->bSortByRowId) {
+    SColumnInfoData* pPkCol = NULL;
+
+    // there may be varchar column exists, so we need to get the pk info, and then calculate the row length
+    if (pHandle->bSortPk) {
+      SBlockOrderInfo* extRowsPkOrder = taosArrayGet(pHandle->aExtRowsOrders, 1);
+      pPkCol = taosArrayGet(pSrcBlock->pDataBlock, extRowsPkOrder->slotId);
+    }
+
+    inc = getPageBufIncForRowIdSort(pHandle->pDataBlock, srcRowIndex, dstRowIndex, pPkCol);
+  } else {
+    inc = getPageBufIncForRow(pSrcBlock, srcRowIndex, dstRowIndex);
+  }
+
+  return inc;
+}
+
 static int32_t sortBlocksToExtSource(SSortHandle* pHandle, SArray* aBlk, SArray* aExtSrc) {
   int32_t code = TSDB_CODE_SUCCESS;
   int32_t pgHeaderSz = sizeof(int32_t) + sizeof(int32_t) * taosArrayGetSize(pHandle->pDataBlock->pDataBlock);
@@ -1574,19 +1600,7 @@ static int32_t sortBlocksToExtSource(SSortHandle* pHandle, SArray* aBlk, SArray*
     SSDataBlock* minBlk = taosArrayGetP(aBlk, minIdx);
     int32_t      minRow = sup.aRowIdx[minIdx];
 
-    int32_t bufInc = 0;
-    if (pHandle->bSortByRowId) {
-      if (!pHandle->bSortPk) {
-        bufInc = getPageBufIncForRowIdSort(pHandle->pDataBlock, minRow, pHandle->pDataBlock->info.rows, NULL);
-      } else { // there may be varchar column exists, so we need to get the pk info, and then calculate the row length
-        SBlockOrderInfo* extRowsPkOrder = taosArrayGet(pHandle->aExtRowsOrders, 1);
-        SColumnInfoData* pPkCol = taosArrayGet(minBlk->pDataBlock, extRowsPkOrder->slotId);
-        bufInc = getPageBufIncForRowIdSort(pHandle->pDataBlock, minRow, pHandle->pDataBlock->info.rows, pPkCol);
-      }
-    } else {
-      bufInc = getPageBufIncForRow(minBlk, minRow, pHandle->pDataBlock->info.rows);
-    }
-
+    int32_t bufInc = getBufIncForNewRow(pHandle, pHandle->pDataBlock->info.rows, minBlk, minRow);
     if (blkPgSz <= pHandle->pageSize && blkPgSz + bufInc > pHandle->pageSize) {
       SColumnInfoData* tsCol = taosArrayGet(pHandle->pDataBlock->pDataBlock, pHandleBlockTsOrder->slotId);
       lastPageBufTs = ((int64_t*)tsCol->pData)[pHandle->pDataBlock->info.rows - 1];
@@ -1604,8 +1618,7 @@ static int32_t sortBlocksToExtSource(SSortHandle* pHandle, SArray* aBlk, SArray*
       blockDataCleanup(pHandle->pDataBlock);
       blkPgSz = pgHeaderSz;
 
-      SSDataBlock* incBlock = (pHandle->bSortByRowId) ? pHandle->pDataBlock : minBlk;
-      bufInc = getPageBufIncForRow(incBlock, minRow, 0);
+      bufInc = getBufIncForNewRow(pHandle, 0, minBlk, minRow);
 
       if ((pHandle->mergeLimit != -1) && (nMergedRows >= pHandle->mergeLimit)) {
         mergeLimitReached = true;
@@ -1613,6 +1626,7 @@ static int32_t sortBlocksToExtSource(SSortHandle* pHandle, SArray* aBlk, SArray*
             (lastPageBufTs > pHandle->currMergeLimitTs && pHandleBlockTsOrder->order == TSDB_ORDER_DESC)) {
           pHandle->currMergeLimitTs = lastPageBufTs;
         }
+
         break;
       }
     }