refactor(query): do some internal refactor.

source/dnode/vnode/src/tsdb/tsdbRead.c

@@ -84,8 +84,6 @@ typedef struct SBlockLoadSuppInfo {
 } SBlockLoadSuppInfo;
 
 typedef struct SLastBlockReader {
-  int32_t       currentBlockIndex;
-  SBlockData    lastBlockData;
   STimeWindow   window;
   SVersionRange verRange;
   int32_t       order;
@@ -345,11 +343,6 @@ static int32_t initFilesetIterator(SFilesetIter* pIter, SArray* aDFileSet,
     pLReader->order = pReader->order;
     pLReader->window = pReader->window;
     pLReader->verRange = pReader->verRange;
-
-    int32_t code = tBlockDataCreate(&pLReader->lastBlockData);
-    if (code != TSDB_CODE_SUCCESS) {
-      return code;
-    }
   }
 
   tsdbDebug("init fileset iterator, total files:%d %s", pIter->numOfFiles, pReader->idStr);
@@ -1269,15 +1262,13 @@ static int32_t doMergeBufAndFileRows(STsdbReader* pReader, STableBlockScanInfo*
   SFileBlockDumpInfo* pDumpInfo = &pReader->status.fBlockDumpInfo;
 
   int64_t tsLast = INT64_MIN;
-  if ((pLastBlockReader->lastBlockData.nRow > 0) && hasDataInLastBlock(pLastBlockReader)) {
+  if (hasDataInLastBlock(pLastBlockReader)) {
     tsLast = getCurrentKeyInLastBlock(pLastBlockReader);
   }
 
   TSDBKEY k = TSDBROW_KEY(pRow);
   TSDBROW fRow = tsdbRowFromBlockData(pBlockData, pDumpInfo->rowIndex);
 
-  SBlockData* pLastBlockData = &pLastBlockReader->lastBlockData;
-
   int64_t minKey = 0;
   if (pReader->order == TSDB_ORDER_ASC) {
     minKey = INT64_MAX;  // chosen the minimum value
@@ -1408,7 +1399,7 @@ static int32_t mergeFileBlockAndLastBlock(STsdbReader* pReader, SLastBlockReader
 
   if (pBlockData->nRow > 0) {
     // no last block available, only data block exists
-    if (pLastBlockReader->lastBlockData.nRow == 0 || (!hasDataInLastBlock(pLastBlockReader))) {
+    if (!hasDataInLastBlock(pLastBlockReader)) {
       return mergeRowsInFileBlocks(pBlockData, pBlockScanInfo, key, pReader);
     }
 
@@ -1458,8 +1449,7 @@ static int32_t doMergeMultiLevelRows(STsdbReader* pReader, STableBlockScanInfo*
   TSDBROW* piRow = getValidMemRow(&pBlockScanInfo->iiter, pDelList, pReader);
   ASSERT(pRow != NULL && piRow != NULL);
 
-  SBlockData* pLastBlockData = &pLastBlockReader->lastBlockData;
-  int64_t     tsLast = INT64_MIN;
+  int64_t tsLast = INT64_MIN;
   if (hasDataInLastBlock(pLastBlockReader)) {
     tsLast = getCurrentKeyInLastBlock(pLastBlockReader);
   }
@@ -1781,14 +1771,6 @@ static bool initLastBlockReader(SLastBlockReader* pLastBlockReader, uint64_t uid
   }
 
   pLastBlockReader->uid = uid;
-  if (*startPos == -1) {
-    if (ASCENDING_TRAVERSE(pLastBlockReader->order)) {
-      // do nothing
-    } else {
-      *startPos = pLastBlockReader->lastBlockData.nRow;
-    }
-  }
-
   /*int32_t code = */ tMergeTreeOpen(&pLastBlockReader->mergeTree, (pLastBlockReader->order == TSDB_ORDER_DESC),
                                      pFReader, uid, &pLastBlockReader->window, &pLastBlockReader->verRange);
   bool hasVal = tMergeTreeNext(&pLastBlockReader->mergeTree);
@@ -2535,7 +2517,7 @@ static int32_t buildBlockFromFiles(STsdbReader* pReader) {
         bool hasNext = blockIteratorNext(&pReader->status.blockIter);
         if (hasNext) {  // check for the next block in the block accessed order list
           initBlockDumpInfo(pReader, pBlockIter);
-        } else if (1/*taosArrayGetSize(pReader->status.fileIter.pLastBlockReader->pBlockL) > 0*/) {
+        } else if (hasDataInLastBlock(pReader->status.fileIter.pLastBlockReader)) {
           // data blocks in current file are exhausted, let's try the next file now
           tBlockDataReset(&pReader->status.fileBlockData);
           resetDataBlockIterator(pBlockIter, pReader->order);
@@ -3316,6 +3298,7 @@ void tsdbReaderClose(STsdbReader* pReader) {
       taosMemoryFreeClear(pSupInfo->buildBuf[i]);
     }
   }
+
   taosMemoryFree(pSupInfo->buildBuf);
   tBlockDataDestroy(&pReader->status.fileBlockData, true);
 
@@ -3333,7 +3316,6 @@ void tsdbReaderClose(STsdbReader* pReader) {
 
   SFilesetIter* pFilesetIter = &pReader->status.fileIter;
   if (pFilesetIter->pLastBlockReader != NULL) {
-    tBlockDataDestroy(&pFilesetIter->pLastBlockReader->lastBlockData, true);
     taosMemoryFree(pFilesetIter->pLastBlockReader);
   }