refactor(query): do some internal refactor.

source/libs/executor/src/executorimpl.c

@@ -6352,6 +6352,9 @@ SOperatorInfo* createOperatorTree(SPhysiNode* pPhyNode, SExecTaskInfo* pTaskInfo
 
       int32_t     numOfCols = 0;
       tsdbReaderT pDataReader = doCreateDataReader(pTableScanNode, pHandle, pTableGroupInfo, (uint64_t)queryId, taskId);
+      if (pDataReader == NULL) {
+        return NULL;
+      }
 
       SArray* pColList =
           extractColMatchInfo(pScanPhyNode->pScanCols, pScanPhyNode->node.pOutputDataBlockDesc, &numOfCols);
@@ -6375,17 +6378,14 @@ SOperatorInfo* createOperatorTree(SPhysiNode* pPhyNode, SExecTaskInfo* pTaskInfo
     } else if (QUERY_NODE_PHYSICAL_PLAN_STREAM_SCAN == type) {
       SScanPhysiNode* pScanPhyNode = (SScanPhysiNode*)pPhyNode;  // simple child table.
 
-      int32_t code = doCreateTableGroup(pHandle->meta, pScanPhyNode->tableType, pScanPhyNode->uid, pTableGroupInfo,
-                                        queryId, taskId);
+      int32_t code = doCreateTableGroup(pHandle->meta, pScanPhyNode->tableType, pScanPhyNode->uid, pTableGroupInfo, queryId, taskId);
       SArray* tableIdList = extractTableIdList(pTableGroupInfo);
 
       SSDataBlock* pResBlock = createResDataBlock(pScanPhyNode->node.pOutputDataBlockDesc);
 
       int32_t numOfCols = 0;
-      SArray* pColList =
-          extractColMatchInfo(pScanPhyNode->pScanCols, pScanPhyNode->node.pOutputDataBlockDesc, &numOfCols);
-      SOperatorInfo* pOperator =
-          createStreamScanOperatorInfo(pHandle->reader, pResBlock, pColList, tableIdList, pTaskInfo);
+      SArray* pCols = extractColMatchInfo(pScanPhyNode->pScanCols, pScanPhyNode->node.pOutputDataBlockDesc, &numOfCols);
+      SOperatorInfo* pOperator = createStreamScanOperatorInfo(pHandle->reader, pResBlock, pCols, tableIdList, pTaskInfo);
       taosArrayDestroy(tableIdList);
       return pOperator;
     } else if (QUERY_NODE_PHYSICAL_PLAN_SYSTABLE_SCAN == type) {
@@ -6411,6 +6411,9 @@ SOperatorInfo* createOperatorTree(SPhysiNode* pPhyNode, SExecTaskInfo* pTaskInfo
   for (int32_t i = 0; i < size; ++i) {
     SPhysiNode* pChildNode = (SPhysiNode*)nodesListGetNode(pPhyNode->pChildren, i);
     ops[i] = createOperatorTree(pChildNode, pTaskInfo, pHandle, queryId, taskId, pTableGroupInfo);
+    if (ops[i] == NULL) {
+      return NULL;
+    }
   }
 
   SOperatorInfo* pOptr = NULL;