diff --git a/source/common/src/tdatablock.c b/source/common/src/tdatablock.c
index 5a2aaed74e5e101d97b82388f199607fa646967e..6a4ddacf60be025a205c1fb1229d5f3f5859cca3 100644
--- a/source/common/src/tdatablock.c
+++ b/source/common/src/tdatablock.c
@@ -1226,6 +1226,7 @@ SSDataBlock* createOneDataBlock(const SSDataBlock* pDataBlock, bool copyData) {
     SColumnInfoData  colInfo = {0};
     SColumnInfoData* p = taosArrayGet(pDataBlock->pDataBlock, i);
     colInfo.info = p->info;
+    colInfo.hasNull = true;
     taosArrayPush(pBlock->pDataBlock, &colInfo);
   }
 
diff --git a/source/libs/executor/inc/tsort.h b/source/libs/executor/inc/tsort.h
index fd3581e2bfa86d9761eae6448ad249f178c96f15..e731c55a7df6b5a21fb383f041516abadf9d7cdd 100644
--- a/source/libs/executor/inc/tsort.h
+++ b/source/libs/executor/inc/tsort.h
@@ -151,6 +151,13 @@ SSDataBlock* tsortGetSortedDataBlock(const SSortHandle* pSortHandle);
  */
 SSortExecInfo tsortGetSortExecInfo(SSortHandle* pHandle);
 
+/**
+ * get proper sort buffer pages according to the row size
+ * @param rowSize
+ * @return
+ */
+int32_t getProperSortPageSize(size_t rowSize);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/libs/executor/src/sortoperator.c b/source/libs/executor/src/sortoperator.c
index 1008a5263cac638f35e5f8f80f368f16d30e1164..98a1aacbb651d95c5e3d808576b8581e0631b50f 100644
--- a/source/libs/executor/src/sortoperator.c
+++ b/source/libs/executor/src/sortoperator.c
@@ -420,24 +420,29 @@ SOperatorInfo* createMultiwaySortMergeOperatorInfo(SOperatorInfo** downStreams,
     goto _error;
   }
 
-  pInfo->binfo.pRes = pResBlock;
 
   initResultSizeInfo(pOperator, 1024);
 
-  pInfo->pSortInfo = pSortInfo;
+  pInfo->binfo.pRes    = pResBlock;
+  pInfo->pSortInfo     = pSortInfo;
   pInfo->pColMatchInfo = pColMatchColInfo;
-  pInfo->pInputBlock = pInputBlock;
-  pOperator->name = "MultiwaySortMerge";
+  pInfo->pInputBlock   = pInputBlock;
+  pOperator->name      = "MultiwaySortMerge";
   pOperator->operatorType = QUERY_NODE_PHYSICAL_PLAN_MERGE;
-  pOperator->blocking = false;
-  pOperator->status = OP_NOT_OPENED;
-  pOperator->info = pInfo;
-
-  pInfo->bufPageSize = rowSize < 1024 ? 1024 : rowSize * 2;
-  pInfo->sortBufSize = pInfo->bufPageSize * 16;
-  pInfo->hasGroupId = false;
+  pOperator->blocking  = false;
+  pOperator->status    = OP_NOT_OPENED;
+  pOperator->info      = pInfo;
+  pInfo->hasGroupId    = false;
   pInfo->prefetchedTuple = NULL;
   pOperator->pTaskInfo = pTaskInfo;
+
+  pInfo->bufPageSize   = getProperSortPageSize(rowSize);
+
+  uint32_t numOfSources = taosArrayGetSize(pSortInfo);
+  numOfSources = MAX(2, numOfSources);
+
+  pInfo->sortBufSize    = numOfSources * pInfo->bufPageSize;
+
   pOperator->fpSet =
       createOperatorFpSet(doOpenMultiwaySortMergeOperator, doMultiwaySortMerge, NULL, NULL,
                           destroyMultiwaySortMergeOperatorInfo, NULL, NULL, getMultiwaySortMergeExplainExecInfo);
diff --git a/source/libs/executor/src/tsort.c b/source/libs/executor/src/tsort.c
index 1473bd81bb23d1384fe60356573d6a69cb4e9f70..daaba74d7cb3f32b473f81e23904cc13b0fa20c4 100644
--- a/source/libs/executor/src/tsort.c
+++ b/source/libs/executor/src/tsort.c
@@ -532,6 +532,19 @@ static int32_t doInternalMergeSort(SSortHandle* pHandle) {
   return 0;
 }
 
+int32_t getProperSortPageSize(size_t rowSize) {
+  uint32_t defaultPageSize = 4096;
+
+  uint32_t pgSize = 0;
+  if (rowSize * 4 > defaultPageSize) {
+    pgSize = rowSize * 4;
+  } else {
+    pgSize = defaultPageSize;
+  }
+
+  return pgSize;
+}
+
 static int32_t createInitialSources(SSortHandle* pHandle) {
   size_t sortBufSize = pHandle->numOfPages * pHandle->pageSize;
 
@@ -557,14 +570,9 @@ static int32_t createInitialSources(SSortHandle* pHandle) {
 
       if (!hasGroupId) {
         // calculate the buffer pages according to the total available buffers.
-        int32_t rowSize = blockDataGetRowSize(pBlock);
-        if (rowSize * 4 > 4096) {
-          pHandle->pageSize = rowSize * 4;
-        } else {
-          pHandle->pageSize = 4096;
-        }
-        
-        // todo!!
+        pHandle->pageSize = getProperSortPageSize(blockDataGetRowSize(pBlock));
+
+        // todo, number of pages are set according to the total available sort buffer
         pHandle->numOfPages = 1024;
         sortBufSize = pHandle->numOfPages * pHandle->pageSize;
 
@@ -577,7 +585,7 @@ static int32_t createInitialSources(SSortHandle* pHandle) {
         if (pHandle->beforeFp != NULL) {
           pHandle->beforeFp(pBlock, pHandle->param);
         }
-        // todo relocate the columns
+
         int32_t code = blockDataMerge(pHandle->pDataBlock, pBlock);
         if (code != 0) {
           return code;