diff --git a/source/libs/executor/src/scanoperator.c b/source/libs/executor/src/scanoperator.c
index 0c90c654f430d1c74097f577e37018b8bee94c8e..ab8991bd05477e56751fc5aac6787fa5875dd3d5 100644
--- a/source/libs/executor/src/scanoperator.c
+++ b/source/libs/executor/src/scanoperator.c
@@ -2840,7 +2840,7 @@ int32_t startGroupTableMergeScan(SOperatorInfo* pOperator) {
   int32_t tableStartIdx = pInfo->tableStartIndex;
   int32_t tableEndIdx = pInfo->tableEndIndex;
 
-  pInfo->sortBufSize = 2048 * pInfo->bufPageSize;
+  pInfo->sortBufSize = 1024 * pInfo->bufPageSize;
   int32_t numOfBufPage = pInfo->sortBufSize / pInfo->bufPageSize;
   pInfo->pSortHandle = tsortCreateSortHandle(pInfo->pSortInfo, SORT_TABLE_MERGE_SCAN, pInfo->bufPageSize, numOfBufPage,
                                              pInfo->pSortInputBlock, pTaskInfo->id.str, 0, 0, 0);
diff --git a/source/libs/executor/src/tsort.c b/source/libs/executor/src/tsort.c
index f274e9717b860696cad30e138c06e7a1b201c2c8..34f9dfc23373dc707484e22e84edec37b60e7027 100644
--- a/source/libs/executor/src/tsort.c
+++ b/source/libs/executor/src/tsort.c
@@ -475,11 +475,11 @@ static int32_t adjustMergeTreeForNextTuple(SSortSource* pSource, SMultiwayMergeT
     if (pHandle->type == SORT_SINGLESOURCE_SORT) {
       pSource->pageIndex++;
       if (pSource->pageIndex >= taosArrayGetSize(pSource->pageIdList)) {
+        qInfo("adjust merge tree. %d source completed %d", *numOfCompleted, pSource->pageIndex);
         (*numOfCompleted) += 1;
         pSource->src.rowIndex = -1;
         pSource->pageIndex = -1;
         pSource->src.pBlock = blockDataDestroy(pSource->src.pBlock);
-        uInfo("adjust merge tree. %d source completed", *numOfCompleted);
       } else {
         int32_t* pPgId = taosArrayGet(pSource->pageIdList, pSource->pageIndex);
 
@@ -495,8 +495,6 @@ static int32_t adjustMergeTreeForNextTuple(SSortSource* pSource, SMultiwayMergeT
         }
 
         releaseBufPage(pHandle->pBuf, pPage);
-        if (pSource->pageIndex % 256 == 0)
-          uInfo("got block from page %d from ext mem source %p", pSource->pageIndex, pSource);
       }
     } else {
       int64_t st = taosGetTimestampUs();      
@@ -506,7 +504,7 @@ static int32_t adjustMergeTreeForNextTuple(SSortSource* pSource, SMultiwayMergeT
       if (pSource->src.pBlock == NULL) {
         (*numOfCompleted) += 1;
         pSource->src.rowIndex = -1;
-        uInfo("adjust merge tree. %d source completed", *numOfCompleted);
+        qInfo("adjust merge tree. %d source completed", *numOfCompleted);
       }
     }
   }
@@ -688,7 +686,7 @@ static int32_t doInternalMergeSort(SSortHandle* pHandle) {
 
     // Only *numOfInputSources* can be loaded into buffer to perform the external sort.
     for (int32_t i = 0; i < sortGroup; ++i) {
-      uInfo("internal merge sort pass %d group %d. num input sources %d ", t, i, numOfInputSources);
+      qInfo("internal merge sort pass %d group %d. num input sources %d ", t, i, numOfInputSources);
       pHandle->sourceId += 1;
 
       int32_t end = (i + 1) * numOfInputSources - 1;
@@ -884,11 +882,13 @@ static int32_t sortBlocksToExtSource(SSortHandle* pHandle, SArray* aBlk, SBlockO
     int32_t minIdx = tMergeTreeGetChosenIndex(pTree);
     SSDataBlock* minBlk = taosArrayGetP(aBlk, minIdx);
     int32_t minRow = sup.aRowIdx[minIdx];
+
     appendOneRowToDataBlock(pHandle->pDataBlock, minBlk, &minRow);
     ++nRows;
     if (pHandle->pDataBlock->info.rows >= rowCap) {
       appendDataBlockToPageBuf(pHandle, pHandle->pDataBlock, aPgId);
-    } 
+    }
+
     if (sup.aRowIdx[minIdx] == minBlk->info.rows - 1) {
       sup.aRowIdx[minIdx] = -1;
       ++numEnded;
@@ -911,39 +911,101 @@ static int32_t sortBlocksToExtSource(SSortHandle* pHandle, SArray* aBlk, SBlockO
   return 0;
 }
 
-static int32_t createInitialSources(SSortHandle* pHandle) {
-  size_t sortBufSize = pHandle->numOfPages * pHandle->pageSize;
-  int32_t code = 0;
+static int32_t createBlocksMergeSortInitialSources(SSortHandle* pHandle) {
+  SBlockOrderInfo* pOrder = taosArrayGet(pHandle->pSortInfo, 0);
+  size_t           nSrc = taosArrayGetSize(pHandle->pOrderedSource);
+  SArray*          aExtSrc = taosArrayInit(nSrc, POINTER_BYTES);
 
-  if (pHandle->type == SORT_SINGLESOURCE_SORT) {
-    SSortSource** pSource = taosArrayGet(pHandle->pOrderedSource, 0);
-    SSortSource*  source = *pSource;
-    *pSource = NULL;
+  size_t maxBufSize = pHandle->numOfPages * pHandle->pageSize;
+  createPageBuf(pHandle);
 
-    tsortClearOrderdSource(pHandle->pOrderedSource, NULL, NULL);
+  SSortSource* pSrc = taosArrayGetP(pHandle->pOrderedSource, 0);
+  int32_t      szSort = 0;
 
-    while (1) {
-      SSDataBlock* pBlock = pHandle->fetchfp(source->param);
-      if (pBlock == NULL) {
-        break;
-      }
+  SArray* aBlkSort = taosArrayInit(8, POINTER_BYTES);
+  while (1) {
+    SSDataBlock* pBlk = pHandle->fetchfp(pSrc->param);
 
-      if (pHandle->pDataBlock == NULL) {
-        uint32_t numOfCols = taosArrayGetSize(pBlock->pDataBlock);
-        pHandle->pageSize = getProperSortPageSize(blockDataGetRowSize(pBlock), numOfCols);
+    if (pBlk != NULL) {
+      szSort += blockDataGetSize(pBlk);
+      SSDataBlock* blk = createOneDataBlock(pBlk, true);
+      taosArrayPush(aBlkSort, &blk);
+    }
+    if ((pBlk != NULL && szSort > maxBufSize) || (pBlk == NULL && szSort > 0)) {
+      int64_t p = taosGetTimestampUs();
+      sortBlocksToExtSource(pHandle, aBlkSort, pOrder, aExtSrc);
+      int64_t el = taosGetTimestampUs() - p;
+      pHandle->sortElapsed += el;
 
-        // todo, number of pages are set according to the total available sort buffer
-        pHandle->numOfPages = 1024;
-        sortBufSize = pHandle->numOfPages * pHandle->pageSize;
-        pHandle->pDataBlock = createOneDataBlock(pBlock, false);
+      for (int i = 0; i < taosArrayGetSize(aBlkSort); ++i) {
+        blockDataDestroy(taosArrayGetP(aBlkSort, i));
       }
+      taosArrayClear(aBlkSort);
+      szSort = 0;
+    }
+    if (pBlk == NULL) {
+      break;
+    };
+  }
+
+  taosArrayDestroy(aBlkSort);
+  tsortClearOrderdSource(pHandle->pOrderedSource, NULL, NULL);
+  taosArrayAddAll(pHandle->pOrderedSource, aExtSrc);
+  taosArrayDestroy(aExtSrc);
+
+  pHandle->type = SORT_SINGLESOURCE_SORT;
+  return 0;
+}
 
-      if (pHandle->beforeFp != NULL) {
-        pHandle->beforeFp(pBlock, pHandle->param);
+static int32_t createBlocksQuickSortInitialSources(SSortHandle* pHandle) {
+  int32_t code = 0;
+  size_t  sortBufSize = pHandle->numOfPages * pHandle->pageSize;
+
+  SSortSource** pSource = taosArrayGet(pHandle->pOrderedSource, 0);
+  SSortSource*  source = *pSource;
+  *pSource = NULL;
+
+  tsortClearOrderdSource(pHandle->pOrderedSource, NULL, NULL);
+
+  while (1) {
+    SSDataBlock* pBlock = pHandle->fetchfp(source->param);
+    if (pBlock == NULL) {
+      break;
+    }
+
+    if (pHandle->pDataBlock == NULL) {
+      uint32_t numOfCols = taosArrayGetSize(pBlock->pDataBlock);
+      pHandle->pageSize = getProperSortPageSize(blockDataGetRowSize(pBlock), numOfCols);
+
+      // todo, number of pages are set according to the total available sort buffer
+      pHandle->numOfPages = 1024;
+      sortBufSize = pHandle->numOfPages * pHandle->pageSize;
+      pHandle->pDataBlock = createOneDataBlock(pBlock, false);
+    }
+
+    if (pHandle->beforeFp != NULL) {
+      pHandle->beforeFp(pBlock, pHandle->param);
+    }
+
+    code = blockDataMerge(pHandle->pDataBlock, pBlock);
+    if (code != TSDB_CODE_SUCCESS) {
+      if (source->param && !source->onlyRef) {
+        taosMemoryFree(source->param);
       }
+      if (!source->onlyRef && source->src.pBlock) {
+        blockDataDestroy(source->src.pBlock);
+        source->src.pBlock = NULL;
+      }
+      taosMemoryFree(source);
+      return code;
+    }
 
-      code = blockDataMerge(pHandle->pDataBlock, pBlock);
-      if (code != TSDB_CODE_SUCCESS) {
+    size_t size = blockDataGetSize(pHandle->pDataBlock);
+    if (size > sortBufSize) {
+      // Perform the in-memory sort and then flush data in the buffer into disk.
+      int64_t p = taosGetTimestampUs();
+      code = blockDataSort(pHandle->pDataBlock, pHandle->pSortInfo);
+      if (code != 0) {
         if (source->param && !source->onlyRef) {
           taosMemoryFree(source->param);
         }
@@ -951,122 +1013,71 @@ static int32_t createInitialSources(SSortHandle* pHandle) {
           blockDataDestroy(source->src.pBlock);
           source->src.pBlock = NULL;
         }
+
         taosMemoryFree(source);
         return code;
       }
 
-      size_t size = blockDataGetSize(pHandle->pDataBlock);
-      if (size > sortBufSize) {
-        // Perform the in-memory sort and then flush data in the buffer into disk.
-        int64_t p = taosGetTimestampUs();
-        code = blockDataSort(pHandle->pDataBlock, pHandle->pSortInfo);
-        if (code != 0) {
-          if (source->param && !source->onlyRef) {
-            taosMemoryFree(source->param);
-          }
-          if (!source->onlyRef && source->src.pBlock) {
-            blockDataDestroy(source->src.pBlock);
-            source->src.pBlock = NULL;
-          }
-
-          taosMemoryFree(source);
-          return code;
-        }
-
-        int64_t el = taosGetTimestampUs() - p;
-        pHandle->sortElapsed += el;
-        if (pHandle->maxRows > 0) blockDataKeepFirstNRows(pHandle->pDataBlock, pHandle->maxRows);
-        code = doAddToBuf(pHandle->pDataBlock, pHandle);
-        if (code != TSDB_CODE_SUCCESS) {
-          return code;
-        }
+      int64_t el = taosGetTimestampUs() - p;
+      pHandle->sortElapsed += el;
+      if (pHandle->maxRows > 0) blockDataKeepFirstNRows(pHandle->pDataBlock, pHandle->maxRows);
+      code = doAddToBuf(pHandle->pDataBlock, pHandle);
+      if (code != TSDB_CODE_SUCCESS) {
+        return code;
       }
     }
+  }
 
-    if (source->param && !source->onlyRef) {
-      taosMemoryFree(source->param);
-    }
+  if (source->param && !source->onlyRef) {
+    taosMemoryFree(source->param);
+  }
 
-    taosMemoryFree(source);
+  taosMemoryFree(source);
 
-    if (pHandle->pDataBlock != NULL && pHandle->pDataBlock->info.rows > 0) {
-      size_t size = blockDataGetSize(pHandle->pDataBlock);
+  if (pHandle->pDataBlock != NULL && pHandle->pDataBlock->info.rows > 0) {
+    size_t size = blockDataGetSize(pHandle->pDataBlock);
 
-      // Perform the in-memory sort and then flush data in the buffer into disk.
-      int64_t p = taosGetTimestampUs();
+    // Perform the in-memory sort and then flush data in the buffer into disk.
+    int64_t p = taosGetTimestampUs();
 
-      code = blockDataSort(pHandle->pDataBlock, pHandle->pSortInfo);
-      if (code != 0) {
-        return code;
-      }
+    code = blockDataSort(pHandle->pDataBlock, pHandle->pSortInfo);
+    if (code != 0) {
+      return code;
+    }
 
-      if (pHandle->maxRows > 0) blockDataKeepFirstNRows(pHandle->pDataBlock, pHandle->maxRows);
-      int64_t el = taosGetTimestampUs() - p;
-      pHandle->sortElapsed += el;
+    if (pHandle->maxRows > 0) blockDataKeepFirstNRows(pHandle->pDataBlock, pHandle->maxRows);
+    int64_t el = taosGetTimestampUs() - p;
+    pHandle->sortElapsed += el;
 
-      // All sorted data can fit in memory, external memory sort is not needed. Return to directly
-      if (size <= sortBufSize && pHandle->pBuf == NULL) {
-        pHandle->cmpParam.numOfSources = 1;
-        pHandle->inMemSort = true;
+    // All sorted data can fit in memory, external memory sort is not needed. Return to directly
+    if (size <= sortBufSize && pHandle->pBuf == NULL) {
+      pHandle->cmpParam.numOfSources = 1;
+      pHandle->inMemSort = true;
 
-        pHandle->loops = 1;
-        pHandle->tupleHandle.rowIndex = -1;
-        pHandle->tupleHandle.pBlock = pHandle->pDataBlock;
-        return 0;
-      } else {
-        code = doAddToBuf(pHandle->pDataBlock, pHandle);
-      }
+      pHandle->loops = 1;
+      pHandle->tupleHandle.rowIndex = -1;
+      pHandle->tupleHandle.pBlock = pHandle->pDataBlock;
+      return 0;
+    } else {
+      code = doAddToBuf(pHandle->pDataBlock, pHandle);
     }
-  } else if (pHandle->type == SORT_TABLE_MERGE_SCAN) {
-    SBlockOrderInfo* pOrder = taosArrayGet(pHandle->pSortInfo, 0);
-    size_t nSrc = taosArrayGetSize(pHandle->pOrderedSource);
-    SArray* aExtSrc = taosArrayInit(nSrc, POINTER_BYTES);
-
-    size_t maxBufSize = pHandle->numOfPages * pHandle->pageSize;
-    createPageBuf(pHandle);
-
-    SSortSource* pSrc = taosArrayGetP(pHandle->pOrderedSource, 0);
-    int32_t szSort = 0;
-
-    SArray* aBlkSort = taosArrayInit(8, POINTER_BYTES);
-    while (1) {
-      SSDataBlock* pBlk = pHandle->fetchfp(pSrc->param);
-      if (pBlk == NULL) {
-        break;
-      };
-      
-      szSort += blockDataGetSize(pBlk);
-      SSDataBlock* blk = createOneDataBlock(pBlk, true);
-      taosArrayPush(aBlkSort, &blk);
-
-      if (szSort > maxBufSize) {
-        sortBlocksToExtSource(pHandle, aBlkSort, pOrder, aExtSrc);
-        uInfo("initial source %zu created for %zu blocks", taosArrayGetSize(aExtSrc), taosArrayGetSize(aBlkSort));
+  }
+  return code;
+}
 
-        for (int i = 0; i < taosArrayGetSize(aBlkSort); ++i) {
-          blockDataDestroy(taosArrayGetP(aBlkSort, i));
-        }
-        taosArrayClear(aBlkSort);
-        szSort = 0;
-      }
-    }
-    if (szSort > 0) {
-      sortBlocksToExtSource(pHandle, aBlkSort, pOrder, aExtSrc);
-      for (int i = 0; i < taosArrayGetSize(aBlkSort); ++i) {
-        blockDataDestroy(taosArrayGetP(aBlkSort, i));
-      }
-      taosArrayClear(aBlkSort);
-      szSort = 0;
-    }
-    taosArrayDestroy(aBlkSort);
-    tsortClearOrderdSource(pHandle->pOrderedSource, NULL, NULL);
-    taosArrayAddAll(pHandle->pOrderedSource, aExtSrc);
-    taosArrayDestroy(aExtSrc);
+static int32_t createInitialSources(SSortHandle* pHandle) {
+  int32_t code = 0;
 
-    pHandle->type = SORT_SINGLESOURCE_SORT;
-    uInfo("create initial sources for table merge scan ended");
+  if (pHandle->type == SORT_SINGLESOURCE_SORT) {
+    code = createBlocksQuickSortInitialSources(pHandle);
+  } else if (pHandle->type == SORT_TABLE_MERGE_SCAN) {
+    code = createBlocksMergeSortInitialSources(pHandle);
+  }
+  qInfo("%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));
   }
-
   return code;
 }