Merge pull request #19559 from taosdata/fix/liaohj

fix(query): use the recycled blocks to reduce the cached buffer.

source/libs/executor/src/exchangeoperator.c

@@ -584,7 +584,13 @@ int32_t doExtractResultBlocks(SExchangeInfo* pExchangeInfo, SSourceDataInfo* pDa
   int32_t index = 0;
   int32_t code = 0;
   while (index++ < pRetrieveRsp->numOfBlocks) {
-    SSDataBlock* pb = createOneDataBlock(pExchangeInfo->pDummyBlock, false);
+    SSDataBlock* pb = NULL;
+    if (taosArrayGetSize(pExchangeInfo->pRecycledBlocks) > 0) {
+      pb = *(SSDataBlock**)taosArrayPop(pExchangeInfo->pRecycledBlocks);
+      blockDataCleanup(pb);
+    } else {
+      pb = createOneDataBlock(pExchangeInfo->pDummyBlock, false);
+    }
 
     code = extractDataBlockFromFetchRsp(pb, pStart, NULL, &pStart);
     if (code != 0) {