refactor: do some internal refactor.

source/libs/executor/inc/executorimpl.h

@@ -254,17 +254,18 @@ typedef struct SExchangeInfo {
   SArray*             pSourceDataInfo;
   tsem_t              ready;
   void*               pTransporter;
+
   // SArray<SSDataBlock*>, result block list, used to keep the multi-block that
   // passed by downstream operator
-  SArray*             pResultBlockList;
-  int32_t             rspBlockIndex;  // indicate the return block index in pResultBlockList
+  SArray*             pReadyBlocks;
+  SArray*             pRecycledBlocks;// build a pool for small data block to avoid to repeatly create and then destroy.
   SSDataBlock*        pDummyBlock;    // dummy block, not keep data
   bool                seqLoadData;    // sequential load data or not, false by default
   int32_t             current;
   SLoadRemoteDataInfo loadInfo;
   uint64_t            self;
   SLimitInfo          limitInfo;
-  int64_t             openedTs;         // start exec time stamp
+  int64_t             openedTs;       // start exec time stamp, todo: move to SLoadRemoteDataInfo
 } SExchangeInfo;
 
 typedef struct SScanInfo {

source/libs/executor/src/cachescanoperator.c

@@ -74,9 +74,8 @@ SOperatorInfo* createCacherowsScanOperator(SLastRowScanPhysiNode* pScanNode, SRe
 
     STableKeyInfo* pList = tableListGetInfo(pTableList, 0);
 
-    size_t   num = tableListGetSize(pTableList);
     uint64_t suid = tableListGetSuid(pTableList);
-    code = tsdbCacherowsReaderOpen(pInfo->readHandle.vnode, pInfo->retrieveType, pList, num,
+    code = tsdbCacherowsReaderOpen(pInfo->readHandle.vnode, pInfo->retrieveType, pList, totalTables,
                                    taosArrayGetSize(pInfo->matchInfo.pList), suid, &pInfo->pLastrowReader);
     if (code != TSDB_CODE_SUCCESS) {
       goto _error;

source/libs/executor/src/exchangeoperator.c

@@ -100,14 +100,23 @@ static void concurrentlyLoadRemoteDataImpl(SOperatorInfo* pOperator, SExchangeIn
       int32_t            index = 0;
       char*              pStart = pRetrieveRsp->data;
       while (index++ < pRetrieveRsp->numOfBlocks) {
-        SSDataBlock* pb = createOneDataBlock(pExchangeInfo->pDummyBlock, false);
+        SSDataBlock* pb = NULL;
+
+        void* p = taosArrayPop(pExchangeInfo->pRecycledBlocks);
+        if (p != NULL) {
+          pb = *(SSDataBlock**) p;
+          blockDataCleanup(pb);
+        } else {
+          pb = createOneDataBlock(pExchangeInfo->pDummyBlock, false);
+        }
+
         code = extractDataBlockFromFetchRsp(pb, pStart, NULL, &pStart);
         if (code != 0) {
           taosMemoryFreeClear(pDataInfo->pRsp);
           goto _error;
         }
 
-        taosArrayPush(pExchangeInfo->pResultBlockList, &pb);
+        taosArrayPush(pExchangeInfo->pReadyBlocks, &pb);
       }
 
       updateLoadRemoteInfo(pLoadInfo, pRetrieveRsp->numOfRows, pRetrieveRsp->compLen, pExchangeInfo->openedTs, pOperator);
@@ -170,23 +179,26 @@ static SSDataBlock* doLoadRemoteDataImpl(SOperatorInfo* pOperator) {
     return NULL;
   }
 
-  size_t size = taosArrayGetSize(pExchangeInfo->pResultBlockList);
-  if (size == 0 || pExchangeInfo->rspBlockIndex >= size) {
-    pExchangeInfo->rspBlockIndex = 0;
-    taosArrayClearEx(pExchangeInfo->pResultBlockList, freeBlock);
+  // we have buffered retrieved datablock, return it directly
+  SSDataBlock** p = taosArrayPop(pExchangeInfo->pReadyBlocks);
+  if (p != NULL) {
+    taosArrayPush(pExchangeInfo->pRecycledBlocks, p);
+    return *p;
+  } else {
     if (pExchangeInfo->seqLoadData) {
       seqLoadRemoteData(pOperator);
     } else {
       concurrentlyLoadRemoteDataImpl(pOperator, pExchangeInfo, pTaskInfo);
     }
 
-    if (taosArrayGetSize(pExchangeInfo->pResultBlockList) == 0) {
+    if (taosArrayGetSize(pExchangeInfo->pReadyBlocks) == 0) {
       return NULL;
+    } else {
+      p = taosArrayPop(pExchangeInfo->pReadyBlocks);
+      taosArrayPush(pExchangeInfo->pRecycledBlocks, p);
+      return *p;
     }
   }
-
-  // we have buffered retrieved datablock, return it directly
-  return taosArrayGetP(pExchangeInfo->pResultBlockList, pExchangeInfo->rspBlockIndex++);
 }
 
 static SSDataBlock* doLoadRemoteData(SOperatorInfo* pOperator) {
@@ -284,7 +296,8 @@ SOperatorInfo* createExchangeOperatorInfo(void* pTransporter, SExchangePhysiNode
 
   tsem_init(&pInfo->ready, 0, 0);
   pInfo->pDummyBlock = createResDataBlock(pExNode->node.pOutputDataBlockDesc);
-  pInfo->pResultBlockList = taosArrayInit(1, POINTER_BYTES);
+  pInfo->pReadyBlocks = taosArrayInit(64, POINTER_BYTES);
+  pInfo->pRecycledBlocks = taosArrayInit(64, POINTER_BYTES);
 
   pInfo->seqLoadData = false;
   pInfo->pTransporter = pTransporter;
@@ -326,11 +339,9 @@ void doDestroyExchangeOperatorInfo(void* param) {
   taosArrayDestroy(pExInfo->pSources);
   taosArrayDestroyEx(pExInfo->pSourceDataInfo, freeSourceDataInfo);
 
-  if (pExInfo->pResultBlockList != NULL) {
-    taosArrayDestroyEx(pExInfo->pResultBlockList, freeBlock);
-    pExInfo->pResultBlockList = NULL;
-  }
-
+  taosArrayDestroyEx(pExInfo->pReadyBlocks, freeBlock);
+  taosArrayDestroyEx(pExInfo->pRecycledBlocks, freeBlock);
+  
   blockDataDestroy(pExInfo->pDummyBlock);
 
   tsem_destroy(&pExInfo->ready);