diff --git a/source/libs/executor/src/tsort.c b/source/libs/executor/src/tsort.c
index 4e5cc37d99..2a2d8cf2fc 100644
--- a/source/libs/executor/src/tsort.c
+++ b/source/libs/executor/src/tsort.c
@@ -32,6 +32,34 @@ struct STupleHandle {
   int32_t      rowIndex;
 };
 
+typedef struct SSortMemPageEntry {
+  int32_t pageId;
+  bool  active;
+
+  void* data;
+
+  struct SSortMemPageEntry* next;
+  struct SSortMemPageEntry* prev;
+
+} SSortMemPageEntry;
+
+typedef struct SSortMemFile {
+  int32_t pageSize;
+  int32_t cacheSize;
+  char* writeBuf;
+  
+  int32_t currPageId;
+  int32_t currPageOffset;
+  bool bDirty;
+
+  int32_t totalMemPages;
+  SSortMemPageEntry* memPages;
+  int32_t numMemPages;
+  SSHashObj* mActivePages;
+
+  TdFilePtr pBufFile;
+} SSortMemFile;
+
 struct SSortHandle {
   int32_t        type;
   int32_t        pageSize;
@@ -78,6 +106,7 @@ struct SSortHandle {
 
   bool           bSortByRowId;
   SDiskbasedBuf* pExtRowsBuf;
+  SSortMemFile* pExtRowsMemFile;
   int32_t        extRowBytes;
   int32_t        extRowsPageSize;
   int32_t        extRowsMemSize;
@@ -1025,6 +1054,41 @@ static int32_t saveBlockRowToExtRowsBuf(SSortHandle* pHandle, SSDataBlock* pBloc
   return 0;
 }
 
+// pageId * pageSize == pageStartOffset in file. write in pages
+// when pass the page boundaries, the page is move to the front(old). 
+// find hash from pageid to page entry. if the page can not be found, 
+//   1) nuse inactive pages, 2) then new pages if not exceeding mem limit, 3) then active pages
+// new pages is added or moved to the back.
+
+static int32_t createSortMemFile(SSortHandle* pHandle) {
+  if (pHandle->pExtRowsMemFile != NULL) {
+    return TSDB_CODE_SUCCESS;
+  }
+  SSortMemFile* pMemFile = taosMemoryCalloc(1, sizeof(SSortMemFile));
+  pMemFile->pBufFile =
+      taosOpenFile(pBuf->path, TD_FILE_CREATE | TD_FILE_WRITE | TD_FILE_READ | TD_FILE_TRUNC | TD_FILE_AUTO_DEL);  
+  return TSDB_CODE_SUCCESS;
+} 
+
+static int32_t saveBlockRowToExtRowsMemFile(SSortHandle* pHandle, SSDataBlock* pBlock, int32_t rowIdx, int32_t* pPageId, int32_t* pOffset, int32_t* pLength) {
+  SDiskbasedBuf* pResultBuf = pHandle->pExtRowsBuf;
+  int32_t rowBytes = pHandle->extRowBytes;
+  int32_t pageId = -1;
+  SFilePage* pFilePage = NULL;
+  int32_t code = getPageFromExtSrcRowsBuf(pResultBuf, rowBytes, &pageId, &pFilePage);
+  if (code != TSDB_CODE_SUCCESS) {
+    return code;
+  }
+
+  *pPageId = pageId;
+  *pOffset = pFilePage->num;
+  *pLength = blockRowToBuf(pBlock, rowIdx, (char*)pFilePage + (*pOffset));
+
+  pFilePage->num += (*pLength);
+  setBufPageDirty(pFilePage, true);
+  releaseBufPage(pResultBuf, pFilePage);
+  return 0;
+}
 
 static void appendToRowIndexDataBlock(SSortHandle* pHandle, SSDataBlock* pSource, int32_t* rowIndex) {
   int32_t pageId = -1;