diff --git a/src/query/src/qAggMain.c b/src/query/src/qAggMain.c
index 2b69eb57a87a2ef8e419b83a4fefc5ce8b9ed2a3..9fbd60639a60f8b3a89de9140d6ef31449945091 100644
--- a/src/query/src/qAggMain.c
+++ b/src/query/src/qAggMain.c
@@ -3487,9 +3487,6 @@ static void diff_function(SQLFunctionCtx *pCtx) {
     int32_t forwardStep = (isFirstBlock) ? notNullElems - 1 : notNullElems;
     
     GET_RES_INFO(pCtx)->numOfRes += forwardStep;
-    
-    pCtx->pOutput += forwardStep * pCtx->outputBytes;
-    pCtx->ptsOutputBuf = (char*)pCtx->ptsOutputBuf + forwardStep * TSDB_KEYSIZE;
   }
 }
 
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index df753d6f18467bc0fb9226e3e19740535dd0dcd2..5904f606b56ba77af67170006a369e72ecdd490a 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -324,6 +324,13 @@ int64_t getNumOfResult_rv(SQueryRuntimeEnv *pRuntimeEnv, SQLFunctionCtx* pCtx, i
   return maxOutput;
 }
 
+static void setNumOfRes(SQLFunctionCtx* pCtx, int32_t numOfOutput) {
+  for (int32_t j = 0; j < numOfOutput; ++j) {
+    SResultRowCellInfo *pResInfo = GET_RES_INFO(&pCtx[j]);
+    pResInfo->numOfRes = 0;
+  }
+}
+
 bool isGroupbyColumn(SSqlGroupbyExpr *pGroupbyExpr) {
   if (pGroupbyExpr == NULL || pGroupbyExpr->numOfGroupCols == 0) {
     return false;
@@ -3559,16 +3566,20 @@ void setDefaultOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, SQLFunctionCtx* pCtx, SR
 }
 
 void updateOutputBuf(SArithOperatorInfo* pInfo, int32_t numOfInputRows) {
-  SSDataBlock* pDataBlock = pInfo->binfo.pRes;
-
-  if (pInfo->bufCapacity < pDataBlock->info.rows + numOfInputRows) {
-    int32_t newSize = pDataBlock->info.rows + numOfInputRows;
+  SOptrBasicInfo* pBInfo = &pInfo->binfo;
+  SSDataBlock* pDataBlock = pBInfo->pRes;
 
+  int32_t newSize = pDataBlock->info.rows + numOfInputRows;
+  if (pInfo->bufCapacity < newSize) {
     for(int32_t i = 0; i < pDataBlock->info.numOfCols; ++i) {
       SColumnInfoData *pColInfo = taosArrayGet(pDataBlock->pDataBlock, i);
       char* p = realloc(pColInfo->pData, newSize * pColInfo->info.bytes);
       if (p != NULL) {
         pColInfo->pData = p;
+
+        // it starts from the tail of the previously generated results.
+        pBInfo->pCtx[i].pOutput = pColInfo->pData;
+        pInfo->bufCapacity = newSize;
       } else {
         // longjmp
       }
@@ -3577,7 +3588,13 @@ void updateOutputBuf(SArithOperatorInfo* pInfo, int32_t numOfInputRows) {
 
   for (int32_t i = 0; i < pDataBlock->info.numOfCols; ++i) {
     SColumnInfoData *pColInfo = taosArrayGet(pDataBlock->pDataBlock, i);
-    pInfo->binfo.pCtx[i].pOutput = pColInfo->pData + pColInfo->info.bytes * pDataBlock->info.rows;
+    pBInfo->pCtx[i].pOutput = pColInfo->pData + pColInfo->info.bytes * pDataBlock->info.rows;
+
+    // re-estabilish output buffer pointer.
+    int32_t functionId = pBInfo->pCtx[i].functionId;
+    if (functionId == TSDB_FUNC_TOP || functionId == TSDB_FUNC_BOTTOM || functionId == TSDB_FUNC_DIFF) {
+      pBInfo->pCtx[i].ptsOutputBuf = pBInfo->pCtx[0].pOutput;
+    }
   }
 }
 
@@ -3697,8 +3714,6 @@ void prepareRepeatTableScan(SQueryRuntimeEnv* pRuntimeEnv) {
     }
   }
 }
-
-
 #endif
 
 void initCtxOutputBuf_rv(SQLFunctionCtx* pCtx, int32_t size) {
@@ -6383,12 +6398,14 @@ static SSDataBlock* doArithmeticOperation(void* param) {
     updateOutputBuf(pArithInfo, pBlock->info.rows);
     arithmeticApplyFunctions(pRuntimeEnv, pArithInfo->binfo.pCtx, pOperator->numOfOutput);
 
-    pArithInfo->binfo.pRes->info.rows += pBlock->info.rows;
+    pArithInfo->binfo.pRes->info.rows = getNumOfResult_rv(pRuntimeEnv, pArithInfo->binfo.pCtx, pOperator->numOfOutput);
     if (pArithInfo->binfo.pRes->info.rows >= 4096) {
       break;
     }
   }
 
+  setNumOfRes(pArithInfo->binfo.pCtx, pOperator->numOfOutput);
+
   if (pArithInfo->binfo.pRes->info.rows > 0) {
     return pArithInfo->binfo.pRes;
   } else {
@@ -6414,8 +6431,12 @@ static SSDataBlock* doLimit(void* param) {
   if (pInfo->total + pBlock->info.rows >= pInfo->limit) {
     pBlock->info.rows = (pInfo->limit - pInfo->total);
 
+    pInfo->total = pInfo->limit;
+
     setQueryStatus(pOperator->pRuntimeEnv->pQuery, QUERY_COMPLETED);
     pOperator->completed = true;
+  } else {
+    pInfo->total += pBlock->info.rows;
   }
 
   return pBlock;
@@ -6753,8 +6774,9 @@ SOperatorInfo* createStableAggOperatorInfo(SQueryRuntimeEnv* pRuntimeEnv, SOpera
 SOperatorInfo* createArithOperatorInfo(SQueryRuntimeEnv* pRuntimeEnv, SOperatorInfo* upstream, SExprInfo* pExpr, int32_t numOfOutput) {
   SArithOperatorInfo* pInfo = calloc(1, sizeof(SArithOperatorInfo));
 
-  pInfo->binfo.pRes = createOutputBuf(pExpr, numOfOutput);
-  pInfo->binfo.pCtx = createSQLFunctionCtx(pRuntimeEnv, pExpr, numOfOutput, &pInfo->binfo.rowCellInfoOffset);
+  pInfo->bufCapacity = 4096;
+  pInfo->binfo.pRes  = createOutputBuf(pExpr, numOfOutput);
+  pInfo->binfo.pCtx  = createSQLFunctionCtx(pRuntimeEnv, pExpr, numOfOutput, &pInfo->binfo.rowCellInfoOffset);
 
   initResultRowInfo(&pInfo->binfo.resultRowInfo, 8, TSDB_DATA_TYPE_INT);
   setDefaultOutputBuf(pRuntimeEnv, pInfo->binfo.pCtx, &pInfo->binfo.resultRowInfo, pInfo->binfo.pRes, pInfo->binfo.rowCellInfoOffset);