diff --git a/source/libs/executor/src/tsort.c b/source/libs/executor/src/tsort.c
index 34f9dfc233..6b93f95099 100644
--- a/source/libs/executor/src/tsort.c
+++ b/source/libs/executor/src/tsort.c
@@ -837,6 +837,10 @@ static int32_t appendDataBlockToPageBuf(SSortHandle* pHandle, SSDataBlock* blk,
   int32_t pageId = -1;
   void*   pPage = getNewBufPage(pHandle->pBuf, &pageId);
   taosArrayPush(aPgId, &pageId);
+
+  int32_t size = blockDataGetSize(blk) + sizeof(int32_t) + taosArrayGetSize(blk->pDataBlock) * sizeof(int32_t);
+  ASSERT(size <= getBufPageSize(pHandle->pBuf));
+
   blockDataToBuf(pPage, blk);
 
   setBufPageDirty(pPage, true);
@@ -846,13 +850,39 @@ static int32_t appendDataBlockToPageBuf(SSortHandle* pHandle, SSDataBlock* blk,
   return 0;
 }
 
+static int32_t getPageBufIncForRow(SSDataBlock* blk, int32_t row, int32_t rowIdxInPage) {
+  int sz = 0;
+  int numCols = taosArrayGetSize(blk->pDataBlock);
+  if (!blk->info.hasVarCol) {
+    sz += numCols * ((rowIdxInPage & 0x7) == 0 ? 1: 0);
+    sz += blockDataGetRowSize(blk);
+  } else {
+    for (int32_t i = 0; i < numCols; ++i) {
+      SColumnInfoData* pColInfoData = TARRAY_GET_ELEM(blk->pDataBlock, i);
+      if (IS_VAR_DATA_TYPE(pColInfoData->info.type)) {
+        if (pColInfoData->varmeta.offset[row] != -1) {
+          char* p = colDataGetData(pColInfoData, row);
+          sz += varDataTLen(p);
+        }
+
+        sz += sizeof(pColInfoData->varmeta.offset[0]);
+      } else {
+        sz += pColInfoData->info.bytes;
+
+        if (((rowIdxInPage) & 0x07) == 0) {
+          sz += 1; // bitmap
+        }
+      }
+    }    
+  }
+  return sz;
+}
 
 static int32_t sortBlocksToExtSource(SSortHandle* pHandle, SArray* aBlk, SBlockOrderInfo* order, SArray* aExtSrc) {
-  int32_t rowCap = blockDataGetCapacityInRow(pHandle->pDataBlock, pHandle->pageSize,
-                                                blockDataGetSerialMetaSize(taosArrayGetSize(pHandle->pDataBlock->pDataBlock)));
+  int pgHeaderSz = sizeof(int32_t) + sizeof(int32_t) * taosArrayGetSize(pHandle->pDataBlock->pDataBlock);
+  int32_t rowCap = blockDataGetCapacityInRow(pHandle->pDataBlock, pHandle->pageSize, pgHeaderSz);
   blockDataEnsureCapacity(pHandle->pDataBlock, rowCap);
   blockDataCleanup(pHandle->pDataBlock);
-
   int32_t numBlks = taosArrayGetSize(aBlk);
 
   SBlkMergeSupport sup;
@@ -878,16 +908,25 @@ static int32_t sortBlocksToExtSource(SSortHandle* pHandle, SArray* aBlk, SBlockO
   tMergeTreeCreate(&pTree, taosArrayGetSize(aBlk), &sup, blockCompareTsFn);
   int32_t numEnded = 0;
   int32_t nRows = 0;
+
+  size_t blkPgSz = pgHeaderSz;
+
   while (nRows < totalRows) {
     int32_t minIdx = tMergeTreeGetChosenIndex(pTree);
     SSDataBlock* minBlk = taosArrayGetP(aBlk, minIdx);
     int32_t minRow = sup.aRowIdx[minIdx];
+    int32_t bufInc = getPageBufIncForRow(minBlk, minRow, pHandle->pDataBlock->info.rows);
 
-    appendOneRowToDataBlock(pHandle->pDataBlock, minBlk, &minRow);
-    ++nRows;
-    if (pHandle->pDataBlock->info.rows >= rowCap) {
-      appendDataBlockToPageBuf(pHandle, pHandle->pDataBlock, aPgId);
+    if (blkPgSz <= pHandle->pageSize && blkPgSz + bufInc > pHandle->pageSize) {
+        appendDataBlockToPageBuf(pHandle, pHandle->pDataBlock, aPgId);
+        blkPgSz = pgHeaderSz;
+        bufInc = getPageBufIncForRow(minBlk, minRow, 0);
     }
+    blockDataEnsureCapacity(pHandle->pDataBlock, pHandle->pDataBlock->info.rows + 1);
+    appendOneRowToDataBlock(pHandle->pDataBlock, minBlk, &minRow);
+    blkPgSz += bufInc;
+
+    ++nRows;
 
     if (sup.aRowIdx[minIdx] == minBlk->info.rows - 1) {
       sup.aRowIdx[minIdx] = -1;
@@ -1073,10 +1112,10 @@ static int32_t createInitialSources(SSortHandle* pHandle) {
   } else if (pHandle->type == SORT_TABLE_MERGE_SCAN) {
     code = createBlocksMergeSortInitialSources(pHandle);
   }
-  qInfo("%zu sources created", taosArrayGetSize(pHandle->pOrderedSource));
+  uInfo("%zu sources created", taosArrayGetSize(pHandle->pOrderedSource));
   for (int i = 0; i < taosArrayGetSize(pHandle->pOrderedSource); ++i) {
     SSortSource* pSrc = taosArrayGetP(pHandle->pOrderedSource, i);
-    qInfo("source %d, num of pages %zu", i,taosArrayGetSize(pSrc->pageIdList));
+    uInfo("source %d, num of pages %zu", i,taosArrayGetSize(pSrc->pageIdList));
   }
   return code;
 }