diff --git a/source/libs/executor/src/joinoperator.c b/source/libs/executor/src/joinoperator.c
index 07b8a4db114689516fbfc36cd9fb16d24a4dc0e1..68f6951c26fd0457700097af5c3704463ea6e0a5 100644
--- a/source/libs/executor/src/joinoperator.c
+++ b/source/libs/executor/src/joinoperator.c
@@ -55,12 +55,10 @@ typedef struct SJoinOperatorInfo {
   SNode*       pTagEqualConditions;
 
   SArray*      leftTagCols;
-  SArray*      leftTagKeys;
   char*        leftTagKeyBuf;
   int32_t      leftTagKeyLen;
 
   SArray*      rightTagCols;
-  SArray*      rightTagKeys;
   char*        rightTagKeyBuf;
   int32_t      rightTagKeyLen;
 
@@ -141,27 +139,11 @@ static void extractTagEqualCondCols(SJoinOperatorInfo* pInfo, SOperatorInfo** pD
   }
 }
 
-static int32_t initTagColsGroupkeys(SArray** pGroupColVals, int32_t* keyLen, char** keyBuf, const SArray* pGroupColList) {
-  *pGroupColVals = taosArrayInit(4, sizeof(SGroupKeys));
-  if ((*pGroupColVals) == NULL) {
-    return TSDB_CODE_OUT_OF_MEMORY;
-  }
-
+static int32_t initTagColskeyBuf(int32_t* keyLen, char** keyBuf, const SArray* pGroupColList) {
   int32_t numOfGroupCols = taosArrayGetSize(pGroupColList);
   for (int32_t i = 0; i < numOfGroupCols; ++i) {
     SColumn* pCol = (SColumn*)taosArrayGet(pGroupColList, i);
     (*keyLen) += pCol->bytes;  // actual data + null_flag
-
-    SGroupKeys key = {0};
-    key.bytes = pCol->bytes;
-    key.type = pCol->type;
-    key.isNull = false;
-    key.pData = taosMemoryCalloc(1, pCol->bytes);
-    if (key.pData == NULL) {
-      return TSDB_CODE_OUT_OF_MEMORY;
-    }
-
-    taosArrayPush((*pGroupColVals), &key);
   }
 
   int32_t nullFlagSize = sizeof(int8_t) * numOfGroupCols;
@@ -175,10 +157,11 @@ static int32_t initTagColsGroupkeys(SArray** pGroupColVals, int32_t* keyLen, cha
   return TSDB_CODE_SUCCESS;
 }
 
-static void fillGroupKeyValsFromTagCols(SArray* pCols, SArray* pGroupKeys, SSDataBlock* pBlock, int32_t rowIndex) {
+static int32_t fillKeyBufFromTagCols(SArray* pCols, SSDataBlock* pBlock, int32_t rowIndex, void* pKey) {
   SColumnDataAgg* pColAgg = NULL;
-
   size_t numOfGroupCols = taosArrayGetSize(pCols);
+  char* isNull = (char*)pKey;
+  char* pStart = (char*)pKey + sizeof(int8_t) * numOfGroupCols;
 
   for (int32_t i = 0; i < numOfGroupCols; ++i) {
     SColumn*         pCol = (SColumn*) taosArrayGet(pCols, i);
@@ -193,56 +176,24 @@ static void fillGroupKeyValsFromTagCols(SArray* pCols, SArray* pGroupKeys, SSDat
       pColAgg = pBlock->pBlockAgg[pCol->slotId];  // TODO is agg data matched?
     }
 
-    SGroupKeys* pkey = taosArrayGet(pGroupKeys, i);
     if (colDataIsNull(pColInfoData, pBlock->info.rows, rowIndex, pColAgg)) {
-      pkey->isNull = true;
+      isNull[i] = 1;
     } else {
-      pkey->isNull = false;
+      isNull[i] = 0;
       char* val = colDataGetData(pColInfoData, rowIndex);
-      if (pkey->type == TSDB_DATA_TYPE_JSON) {
-        if (tTagIsJson(val)) {
-          terrno = TSDB_CODE_QRY_JSON_IN_GROUP_ERROR;
-          return;
-        }
+      if (pCol->type == TSDB_DATA_TYPE_JSON) {
         int32_t dataLen = getJsonValueLen(val);
-        memcpy(pkey->pData, val, dataLen);
-      } else if (IS_VAR_DATA_TYPE(pkey->type)) {
-        memcpy(pkey->pData, val, varDataTLen(val));
-        ASSERT(varDataTLen(val) <= pkey->bytes);
+        memcpy(pStart, val, dataLen);
+        pStart += dataLen;
+      } else if (IS_VAR_DATA_TYPE(pCol->type)) {
+        varDataCopy(pStart, val);
+        pStart += varDataTLen(val);
       } else {
-        memcpy(pkey->pData, val, pkey->bytes);
+        memcpy(pStart, val, pCol->bytes);
+        pStart += pCol->bytes;
       }
     }
   }
-}
-
-static int32_t combineGroupKeysIntoBuf(void* pKey, const SArray* pGroupKeys) {
-  size_t numOfGroupCols = taosArrayGetSize(pGroupKeys);
-
-  char* isNull = (char*)pKey;
-  char* pStart = (char*)pKey + sizeof(int8_t) * numOfGroupCols;
-  for (int32_t i = 0; i < numOfGroupCols; ++i) {
-    SGroupKeys* pkey = taosArrayGet(pGroupKeys, i);
-    if (pkey->isNull) {
-      isNull[i] = 1;
-      continue;
-    }
-
-    isNull[i] = 0;
-    if (pkey->type == TSDB_DATA_TYPE_JSON) {
-      int32_t dataLen = getJsonValueLen(pkey->pData);
-      memcpy(pStart, (pkey->pData), dataLen);
-      pStart += dataLen;
-    } else if (IS_VAR_DATA_TYPE(pkey->type)) {
-      varDataCopy(pStart, pkey->pData);
-      pStart += varDataTLen(pkey->pData);
-      ASSERT(varDataTLen(pkey->pData) <= pkey->bytes);
-    } else {
-      memcpy(pStart, pkey->pData, pkey->bytes);
-      pStart += pkey->bytes;
-    }
-  }
-
   return (int32_t)(pStart - (char*)pKey);
 }
 
@@ -312,8 +263,8 @@ SOperatorInfo* createMergeJoinOperatorInfo(SOperatorInfo** pDownstream, int32_t
     pInfo->leftTagCols = taosArrayInit(4, sizeof(SColumn));
     pInfo->rightTagCols = taosArrayInit(4, sizeof(SColumn));
     extractTagEqualCondCols(pInfo, pDownstream, pInfo->pTagEqualConditions, pInfo->leftTagCols, pInfo->rightTagCols);
-    initTagColsGroupkeys(&pInfo->leftTagKeys, &pInfo->leftTagKeyLen, &pInfo->leftTagKeyBuf, pInfo->leftTagCols);
-    initTagColsGroupkeys(&pInfo->rightTagKeys, &pInfo->rightTagKeyLen, &pInfo->rightTagKeyBuf, pInfo->rightTagCols);
+    initTagColskeyBuf(&pInfo->leftTagKeyLen, &pInfo->leftTagKeyBuf, pInfo->leftTagCols);
+    initTagColskeyBuf(&pInfo->rightTagKeyLen, &pInfo->rightTagKeyBuf, pInfo->rightTagCols);
   }
   pOperator->fpSet = createOperatorFpSet(optrDummyOpenFn, doMergeJoin, NULL, destroyMergeJoinOperator, optrDefaultBufFn, NULL);
   code = appendDownstream(pOperator, pDownstream, numOfDownstream);
@@ -341,20 +292,13 @@ void setJoinColumnInfo(SColumnInfo* pColumn, const SColumnNode* pColumnNode) {
   pColumn->scale = pColumnNode->node.resType.scale;
 }
 
-static void freeGroupKeyData(void* param) {
-  SGroupKeys* pKey = (SGroupKeys*)param;
-  taosMemoryFree(pKey->pData);
-}
-
 void destroyMergeJoinOperator(void* param) {
   SJoinOperatorInfo* pJoinOperator = (SJoinOperatorInfo*)param;
   if (pJoinOperator->pTagEqualConditions != NULL) {
     taosMemoryFreeClear(pJoinOperator->rightTagKeyBuf);
-    taosArrayDestroyEx(pJoinOperator->rightTagKeys, freeGroupKeyData);
     taosArrayDestroy(pJoinOperator->rightTagCols);
 
     taosMemoryFreeClear(pJoinOperator->leftTagKeyBuf);
-    taosArrayDestroyEx(pJoinOperator->leftTagKeys, freeGroupKeyData);
     taosArrayDestroy(pJoinOperator->leftTagCols);
   }
   nodesDestroyNode(pJoinOperator->pCondAfterMerge);
@@ -482,8 +426,7 @@ static int32_t mergeJoinCreateBuildTable(SJoinOperatorInfo* pInfo, SArray* right
   SSHashObj* buildTable = tSimpleHashInit(buildTableCap,  hashFn);
   for (int32_t i = 0; i < taosArrayGetSize(rightRowLocations); ++i) {
     SRowLocation* rightRow = taosArrayGet(rightRowLocations, i);
-    fillGroupKeyValsFromTagCols(pInfo->rightTagCols, pInfo->rightTagKeys, rightRow->pDataBlock, rightRow->pos);
-    int32_t keyLen = combineGroupKeysIntoBuf(pInfo->rightTagKeyBuf, pInfo->rightTagKeys);
+    int32_t keyLen = fillKeyBufFromTagCols(pInfo->rightTagCols, rightRow->pDataBlock, rightRow->pos, pInfo->rightTagKeyBuf);
     SArray** ppRows = tSimpleHashGet(buildTable, pInfo->rightTagKeyBuf, keyLen);
     if (!ppRows) {
       SArray* rows = taosArrayInit(4, sizeof(SRowLocation));
@@ -511,8 +454,7 @@ static int32_t mergeJoinLeftRowsRightRows(SOperatorInfo* pOperator, SSDataBlock*
     SRowLocation* leftRow = taosArrayGet(leftRowLocations, i);
     SArray* pRightRows = NULL;
     if (rightTableHash != NULL) {
-      fillGroupKeyValsFromTagCols(pJoinInfo->leftTagCols, pJoinInfo->leftTagKeys, leftRow->pDataBlock, leftRow->pos);
-      int32_t  keyLen = combineGroupKeysIntoBuf(pJoinInfo->leftTagKeyBuf, pJoinInfo->leftTagKeys);
+      int32_t  keyLen = fillKeyBufFromTagCols(pJoinInfo->leftTagCols, leftRow->pDataBlock, leftRow->pos, pJoinInfo->leftTagKeyBuf);
       SArray** ppRightRows = tSimpleHashGet(rightTableHash, pJoinInfo->leftTagKeyBuf, keyLen);
       if (!ppRightRows) {
         continue;