diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index 73454e2a63..48b7502e8f 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -28,6 +28,11 @@ typedef struct {
   bool         hasVal;
 } SIterInfo;
 
+typedef struct {
+  int32_t numOfBlocks;
+  int32_t numOfLastBlocks;
+} SBlockNumber;
+
 typedef struct STableBlockScanInfo {
   uint64_t  uid;
   TSKEY     lastKey;
@@ -71,10 +76,11 @@ typedef struct SBlockLoadSuppInfo {
 } SBlockLoadSuppInfo;
 
 typedef struct SFilesetIter {
-  int32_t numOfFiles;  // number of total files
-  int32_t index;       // current accessed index in the list
-  SArray* pFileList;   // data file list
+  int32_t numOfFiles;    // number of total files
+  int32_t index;         // current accessed index in the list
+  SArray* pFileList;     // data file list
   int32_t order;
+  SArray* pLastBlockList;// last block array list
 } SFilesetIter;
 
 typedef struct SFileDataBlockInfo {
@@ -84,12 +90,14 @@ typedef struct SFileDataBlockInfo {
 } SFileDataBlockInfo;
 
 typedef struct SDataBlockIter {
-  int32_t   numOfBlocks;
+  SBlockNumber  numOfBlocks;
   int32_t   index;
-  SArray*   blockList;  // SArray<SFileDataBlockInfo>
+  SArray*   blockList;      // SArray<SFileDataBlockInfo>
+  SArray*   pLastBlockList; // last block list
   int32_t   order;
-  SBlock    block;  // current SBlock data
+  SBlock    block;          // current SBlock data
   SHashObj* pTableMap;
+  SArray*   pBlockL;        // ptr to SBlockL in fileIterator
 } SDataBlockIter;
 
 typedef struct SFileBlockDumpInfo {
@@ -132,6 +140,7 @@ struct STsdbReader {
   STSchema*          pSchema;
   SDataFReader*      pFileReader;
   SVersionRange      verRange;
+  SArray*            pLastBlock;  // last block info
 
   int32_t      step;
   STsdbReader* innerReader[2];
@@ -299,6 +308,13 @@ static int32_t initFilesetIterator(SFilesetIter* pIter, SArray* aDFileSet, int32
   pIter->pFileList = aDFileSet;
   pIter->numOfFiles = numOfFileset;
 
+  pIter->pLastBlockList = taosArrayInit(4, sizeof(SBlockL));
+  if (pIter->pLastBlockList == NULL) {
+    int32_t code = TSDB_CODE_OUT_OF_MEMORY;
+    tsdbError("failed to prepare the last block iterator, code:%d %s", tstrerror(code), idstr);
+    return code;
+  }
+
   tsdbDebug("init fileset iterator, total files:%d %s", pIter->numOfFiles, idstr);
   return TSDB_CODE_SUCCESS;
 }
@@ -359,7 +375,7 @@ _err:
 static void resetDataBlockIterator(SDataBlockIter* pIter, int32_t order, SHashObj* pTableMap) {
   pIter->order = order;
   pIter->index = -1;
-  pIter->numOfBlocks = -1;
+  pIter->numOfBlocks = (SBlockNumber){-1, -1};
   if (pIter->blockList == NULL) {
     pIter->blockList = taosArrayInit(4, sizeof(SFileDataBlockInfo));
   } else {
@@ -592,10 +608,10 @@ _end:
   return code;
 }
 
-static int32_t doLoadFileBlock(STsdbReader* pReader, SArray* pIndexList, uint32_t* numOfValidTables,
-                               int32_t* numOfBlocks) {
+static int32_t doLoadFileBlock(STsdbReader* pReader, SArray* pIndexList, SArray* pLastBlockIndex,
+                               SBlockNumber * pBlockNum, SArray* pQualifiedLastBlock) {
+  int32_t numOfQTable= 0;
   size_t numOfTables = taosArrayGetSize(pIndexList);
-  *numOfValidTables = 0;
 
   int64_t st = taosGetTimestampUs();
   size_t  size = 0;
@@ -640,19 +656,44 @@ static int32_t doLoadFileBlock(STsdbReader* pReader, SArray* pIndexList, uint32_
         return TSDB_CODE_OUT_OF_MEMORY;
       }
 
-      (*numOfBlocks) += 1;
+      pBlockNum->numOfBlocks += 1;
     }
 
     if (pScanInfo->pBlockList != NULL && taosArrayGetSize(pScanInfo->pBlockList) > 0) {
-      (*numOfValidTables) += 1;
+      numOfQTable += 1;
     }
   }
 
-  double el = (taosGetTimestampUs() - st) / 1000.0;
-  tsdbDebug("load block of %d tables completed, blocks:%d in %d tables, size:%.2f Kb, elapsed time:%.2f ms %s",
-            numOfTables, *numOfBlocks, *numOfValidTables, size / 1000.0, el, pReader->idStr);
+  size_t numOfLast = taosArrayGetSize(pLastBlockIndex);
+  for(int32_t i = 0; i < numOfLast; ++i) {
+    SBlockL* pLastBlock = taosArrayGet(pLastBlockIndex, i);
+    if (pLastBlock->suid != pReader->suid) {
+      continue;
+    }
 
-  pReader->cost.numOfBlocks += (*numOfBlocks);
+    {
+      // 1. time range check, todo add later
+//      if (pLastBlock->.minKey.ts > pReader->window.ekey || block.maxKey.ts < pReader->window.skey) {
+//        continue;
+//      }
+
+      // 2. version range check
+      if (pLastBlock->minVer > pReader->verRange.maxVer || pLastBlock->maxVer < pReader->verRange.minVer) {
+        continue;
+      }
+
+      pBlockNum->numOfLastBlocks += 1;
+      taosArrayPush(pQualifiedLastBlock, &i);
+    }
+  }
+
+  int32_t total = pBlockNum->numOfLastBlocks + pBlockNum->numOfBlocks;
+
+  double el = (taosGetTimestampUs() - st) / 1000.0;
+  tsdbDebug("load block of %d tables completed, blocks:%d in %d tables, lastBlock:%d, size:%.2f Kb, elapsed time:%.2f ms %s",
+            numOfTables, total, numOfQTable, pBlockNum->numOfLastBlocks, size / 1000.0, el, pReader->idStr);
+
+  pReader->cost.numOfBlocks += total;
   pReader->cost.headFileLoadTime += el;
 
   return TSDB_CODE_SUCCESS;
@@ -682,8 +723,12 @@ static void doCopyColVal(SColumnInfoData* pColInfoData, int32_t rowIndex, int32_
 }
 
 static SFileDataBlockInfo* getCurrentBlockInfo(SDataBlockIter* pBlockIter) {
-  SFileDataBlockInfo* pFBlockInfo = taosArrayGet(pBlockIter->blockList, pBlockIter->index);
-  return pFBlockInfo;
+  if (pBlockIter->index >= pBlockIter->numOfBlocks.numOfBlocks) {
+    return NULL;
+  } else {
+    SFileDataBlockInfo* pFBlockInfo = taosArrayGet(pBlockIter->blockList, pBlockIter->index);
+    return pFBlockInfo;
+  }
 }
 
 static SBlock* getCurrentBlock(SDataBlockIter* pBlockIter) { return &pBlockIter->block; }
@@ -771,41 +816,45 @@ static int32_t copyBlockDataToSDataBlock(STsdbReader* pReader, STableBlockScanIn
   return TSDB_CODE_SUCCESS;
 }
 
-static int32_t doLoadFileBlockData(STsdbReader* pReader, SDataBlockIter* pBlockIter,
-                                   STableBlockScanInfo* pBlockScanInfo, SBlockData* pBlockData) {
+static int32_t doLoadFileBlockData(STsdbReader* pReader, SDataBlockIter* pBlockIter, SBlockData* pBlockData) {
   int64_t st = taosGetTimestampUs();
+  double elapsedTime = 0;
+  int32_t code = 0;
 
   SFileDataBlockInfo* pFBlock = getCurrentBlockInfo(pBlockIter);
-  SBlock*             pBlock = getCurrentBlock(pBlockIter);
-
-  SSDataBlock* pResBlock = pReader->pResBlock;
-  int32_t      numOfCols = blockDataGetNumOfCols(pResBlock);
-
-  SBlockLoadSuppInfo* pSupInfo = &pReader->suppInfo;
   SFileBlockDumpInfo* pDumpInfo = &pReader->status.fBlockDumpInfo;
 
-  SBlockIdx blockIdx = {.suid = pReader->suid, .uid = pBlockScanInfo->uid};
-  int32_t   code = tsdbReadDataBlock(pReader->pFileReader, pBlock, pBlockData /*, pSupInfo->colIds, numOfCols*/);
-  if (code != TSDB_CODE_SUCCESS) {
-    goto _error;
+  if (pFBlock != NULL) {
+    SBlock* pBlock = getCurrentBlock(pBlockIter);
+    code = tsdbReadDataBlock(pReader->pFileReader, pBlock, pBlockData);
+    if (code != TSDB_CODE_SUCCESS) {
+      goto _error;
+    }
+
+    elapsedTime = (taosGetTimestampUs() - st) / 1000.0;
+
+    tsdbDebug("%p load file block into buffer, global index:%d, table index:%d, brange:%" PRId64 "-%" PRId64
+                  ", rows:%d, minVer:%" PRId64 ", maxVer:%" PRId64 ", elapsed time:%.2f ms, %s",
+              pReader, pBlockIter->index, pFBlock->tbBlockIdx, pBlock->minKey.ts, pBlock->maxKey.ts, pBlock->nRow,
+              pBlock->minVer, pBlock->maxVer, elapsedTime, pReader->idStr);
+  } else {
+    int32_t pos = pBlockIter->index - pBlockIter->numOfBlocks.numOfBlocks;
+    int32_t* index = taosArrayGet(pBlockIter->pLastBlockList, pos);
+
+    SBlockL* pBlockL = taosArrayGet(pReader->status.fileIter.pLastBlockList, *index);
+    code = tsdbReadLastBlock(pReader->pFileReader, pBlockL, pBlockData);
   }
 
-  double elapsedTime = (taosGetTimestampUs() - st) / 1000.0;
   pReader->cost.blockLoadTime += elapsedTime;
-
   pDumpInfo->allDumped = false;
-  tsdbDebug("%p load file block into buffer, global index:%d, table index:%d, brange:%" PRId64 "-%" PRId64
-            ", rows:%d, minVer:%" PRId64 ", maxVer:%" PRId64 ", elapsed time:%.2f ms, %s",
-            pReader, pBlockIter->index, pFBlock->tbBlockIdx, pBlock->minKey.ts, pBlock->maxKey.ts, pBlock->nRow,
-            pBlock->minVer, pBlock->maxVer, elapsedTime, pReader->idStr);
 
   return TSDB_CODE_SUCCESS;
 
 _error:
-  tsdbError("%p error occurs in loading file block, global index:%d, table index:%d, brange:%" PRId64 "-%" PRId64
-            ", rows:%d, %s",
-            pReader, pBlockIter->index, pFBlock->tbBlockIdx, pBlock->minKey.ts, pBlock->maxKey.ts, pBlock->nRow,
-            pReader->idStr);
+//  tsdbError("%p error occurs in loading file block, global index:%d, table index:%d, brange:%" PRId64 "-%" PRId64
+//            ", rows:%d, %s",
+//            pReader, pBlockIter->index, pFBlock->tbBlockIdx, pBlock->minKey.ts, pBlock->maxKey.ts, pBlock->nRow,
+//            pReader->idStr);
   return code;
 }
 
@@ -861,10 +910,11 @@ static int32_t fileDataBlockOrderCompar(const void* pLeft, const void* pRight, v
 
 static int32_t doSetCurrentBlock(SDataBlockIter* pBlockIter) {
   SFileDataBlockInfo*  pFBlock = getCurrentBlockInfo(pBlockIter);
-  STableBlockScanInfo* pScanInfo = taosHashGet(pBlockIter->pTableMap, &pFBlock->uid, sizeof(pFBlock->uid));
-
-  int32_t* mapDataIndex = taosArrayGet(pScanInfo->pBlockList, pFBlock->tbBlockIdx);
-  tMapDataGetItemByIdx(&pScanInfo->mapData, *mapDataIndex, &pBlockIter->block, tGetBlock);
+  if (pFBlock != NULL) {
+    STableBlockScanInfo* pScanInfo = taosHashGet(pBlockIter->pTableMap, &pFBlock->uid, sizeof(pFBlock->uid));
+    int32_t* mapDataIndex = taosArrayGet(pScanInfo->pBlockList, pFBlock->tbBlockIdx);
+    tMapDataGetItemByIdx(&pScanInfo->mapData, *mapDataIndex, &pBlockIter->block, tGetBlock);
+  }
 
 #if 0
   qDebug("check file block, table uid:%"PRIu64" index:%d offset:%"PRId64", ", pScanInfo->uid, *mapDataIndex, pBlockIter->block.aSubBlock[0].offset);
@@ -873,12 +923,17 @@ static int32_t doSetCurrentBlock(SDataBlockIter* pBlockIter) {
   return TSDB_CODE_SUCCESS;
 }
 
-static int32_t initBlockIterator(STsdbReader* pReader, SDataBlockIter* pBlockIter, int32_t numOfBlocks) {
+static int32_t initBlockIterator(STsdbReader* pReader, SDataBlockIter* pBlockIter, SBlockNumber* pBlockNum, SArray* pQLastBlock) {
   bool asc = ASCENDING_TRAVERSE(pReader->order);
 
-  pBlockIter->numOfBlocks = numOfBlocks;
+  pBlockIter->numOfBlocks = *pBlockNum;
   taosArrayClear(pBlockIter->blockList);
 
+  if (pBlockNum->numOfLastBlocks > 0) {
+    taosArrayDestroy(pBlockIter->pLastBlockList);
+    pBlockIter->pLastBlockList = pQLastBlock;
+  }
+
   // access data blocks according to the offset of each block in asc/desc order.
   int32_t numOfTables = (int32_t)taosHashGetSize(pReader->status.pTableMap);
 
@@ -930,20 +985,21 @@ static int32_t initBlockIterator(STsdbReader* pReader, SDataBlockIter* pBlockIte
     sup.numOfTables += 1;
   }
 
-  ASSERT(numOfBlocks == cnt);
+  ASSERT(pBlockNum->numOfBlocks == cnt);
+  int32_t total = pBlockNum->numOfLastBlocks + pBlockNum->numOfBlocks;
 
   // since there is only one table qualified, blocks are not sorted
-  if (sup.numOfTables == 1) {
-    for (int32_t i = 0; i < numOfBlocks; ++i) {
+  if (sup.numOfTables == 1 || pBlockNum->numOfBlocks == 0) {
+    for (int32_t i = 0; i < pBlockNum->numOfBlocks; ++i) {
       SFileDataBlockInfo blockInfo = {.uid = sup.pDataBlockInfo[0][i].uid, .tbBlockIdx = i};
       taosArrayPush(pBlockIter->blockList, &blockInfo);
     }
 
     int64_t et = taosGetTimestampUs();
     tsdbDebug("%p create blocks info struct completed for one table, %d blocks not sorted, elapsed time:%.2f ms %s",
-              pReader, cnt, (et - st) / 1000.0, pReader->idStr);
+              pReader, total, (et - st) / 1000.0, pReader->idStr);
 
-    pBlockIter->index = asc ? 0 : (numOfBlocks - 1);
+    pBlockIter->index = asc ? 0 : (total - 1);
     cleanupBlockOrderSupporter(&sup);
     doSetCurrentBlock(pBlockIter);
     return TSDB_CODE_SUCCESS;
@@ -952,7 +1008,7 @@ static int32_t initBlockIterator(STsdbReader* pReader, SDataBlockIter* pBlockIte
   tsdbDebug("%p create data blocks info struct completed, %d blocks in %d tables %s", pReader, cnt, sup.numOfTables,
             pReader->idStr);
 
-  assert(cnt <= numOfBlocks && sup.numOfTables <= numOfTables);
+  ASSERT(cnt <= pBlockNum->numOfBlocks && sup.numOfTables <= numOfTables);
 
   SMultiwayMergeTreeInfo* pTree = NULL;
   uint8_t                 ret = tMergeTreeCreate(&pTree, sup.numOfTables, &sup, fileDataBlockOrderCompar);
@@ -979,12 +1035,12 @@ static int32_t initBlockIterator(STsdbReader* pReader, SDataBlockIter* pBlockIte
   }
 
   int64_t et = taosGetTimestampUs();
-  tsdbDebug("%p %d data blocks access order completed, elapsed time:%.2f ms %s", pReader, cnt, (et - st) / 1000.0,
+  tsdbDebug("%p %d data blocks access order completed, elapsed time:%.2f ms %s", pReader, total, (et - st) / 1000.0,
             pReader->idStr);
   cleanupBlockOrderSupporter(&sup);
   taosMemoryFree(pTree);
 
-  pBlockIter->index = asc ? 0 : (numOfBlocks - 1);
+  pBlockIter->index = asc ? 0 : (total - 1);
   doSetCurrentBlock(pBlockIter);
 
   return TSDB_CODE_SUCCESS;
@@ -994,7 +1050,7 @@ static bool blockIteratorNext(SDataBlockIter* pBlockIter) {
   bool asc = ASCENDING_TRAVERSE(pBlockIter->order);
 
   int32_t step = asc ? 1 : -1;
-  if ((pBlockIter->index >= pBlockIter->numOfBlocks - 1 && asc) || (pBlockIter->index <= 0 && (!asc))) {
+  if ((pBlockIter->index >= pBlockIter->numOfBlocks.numOfBlocks - 1 && asc) || (pBlockIter->index <= 0 && (!asc))) {
     return false;
   }
 
@@ -1041,7 +1097,7 @@ static int32_t findFileBlockInfoIndex(SDataBlockIter* pBlockIter, SFileDataBlock
   int32_t step = ASCENDING_TRAVERSE(pBlockIter->order) ? 1 : -1;
   int32_t index = pBlockIter->index;
 
-  while (index < pBlockIter->numOfBlocks && index >= 0) {
+  while (index < pBlockIter->numOfBlocks.numOfBlocks && index >= 0) {
     SFileDataBlockInfo* pFBlock = taosArrayGet(pBlockIter->blockList, index);
     if (pFBlock->uid == pFBlockInfo->uid && pFBlock->tbBlockIdx == pFBlockInfo->tbBlockIdx) {
       return index;
@@ -1055,7 +1111,7 @@ static int32_t findFileBlockInfoIndex(SDataBlockIter* pBlockIter, SFileDataBlock
 }
 
 static int32_t setFileBlockActiveInBlockIter(SDataBlockIter* pBlockIter, int32_t index, int32_t step) {
-  if (index < 0 || index >= pBlockIter->numOfBlocks) {
+  if (index < 0 || index >= pBlockIter->numOfBlocks.numOfBlocks) {
     return -1;
   }
 
@@ -1473,9 +1529,12 @@ static int32_t buildComposedDataBlockImpl(STsdbReader* pReader, STableBlockScanI
   }
 }
 
-static int32_t buildComposedDataBlock(STsdbReader* pReader, STableBlockScanInfo* pBlockScanInfo) {
+static int32_t buildComposedDataBlock(STsdbReader* pReader) {
   SSDataBlock* pResBlock = pReader->pResBlock;
 
+  SFileDataBlockInfo*  pBlockInfo = getCurrentBlockInfo(&pReader->status.blockIter);
+  STableBlockScanInfo* pBlockScanInfo = taosHashGet(pReader->status.pTableMap, &pBlockInfo->uid, sizeof(pBlockInfo->uid));
+
   SFileBlockDumpInfo* pDumpInfo = &pReader->status.fBlockDumpInfo;
   SBlockData*         pBlockData = &pReader->status.fileBlockData;
   int32_t             step = ASCENDING_TRAVERSE(pReader->order) ? 1 : -1;
@@ -1696,7 +1755,7 @@ static TSDBKEY getCurrentKeyInBuf(SDataBlockIter* pBlockIter, STsdbReader* pRead
   return key;
 }
 
-static int32_t moveToNextFile(STsdbReader* pReader, int32_t* numOfBlocks) {
+static int32_t moveToNextFile(STsdbReader* pReader, SBlockNumber* pBlockNum, SArray* pQLastBlock) {
   SReaderStatus* pStatus = &pReader->status;
 
   size_t  numOfTables = taosHashGetSize(pReader->status.pTableMap);
@@ -1715,18 +1774,25 @@ static int32_t moveToNextFile(STsdbReader* pReader, int32_t* numOfBlocks) {
       return code;
     }
 
-    if (taosArrayGetSize(pIndexList) > 0) {
-      uint32_t numOfValidTable = 0;
-      code = doLoadFileBlock(pReader, pIndexList, &numOfValidTable, numOfBlocks);
+    code = tsdbReadBlockL(pReader->pFileReader, pStatus->fileIter.pLastBlockList);
+    if (code != TSDB_CODE_SUCCESS) {
+      taosArrayDestroy(pIndexList);
+      return code;
+    }
+
+    if (taosArrayGetSize(pIndexList) > 0 || taosArrayGetSize(pStatus->fileIter.pLastBlockList) > 0) {
+      code = doLoadFileBlock(pReader, pIndexList, pStatus->fileIter.pLastBlockList, pBlockNum, pQLastBlock);
       if (code != TSDB_CODE_SUCCESS) {
         taosArrayDestroy(pIndexList);
         return code;
       }
 
-      if (numOfValidTable > 0) {
+      if (pBlockNum->numOfBlocks + pBlockNum->numOfLastBlocks > 0) {
+        ASSERT(taosArrayGetSize(pQLastBlock) == pBlockNum->numOfLastBlocks);
         break;
       }
     }
+
     // no blocks in current file, try next files
   }
 
@@ -1741,21 +1807,27 @@ static int32_t doBuildDataBlock(STsdbReader* pReader) {
   SDataBlockIter* pBlockIter = &pStatus->blockIter;
 
   SFileDataBlockInfo*  pFBlock = getCurrentBlockInfo(pBlockIter);
-  STableBlockScanInfo* pScanInfo = taosHashGet(pStatus->pTableMap, &pFBlock->uid, sizeof(pFBlock->uid));
+  STableBlockScanInfo* pScanInfo = NULL;
+  SBlock* pBlock = NULL;
+  TSDBKEY key = {0};
 
-  SBlock* pBlock = getCurrentBlock(pBlockIter);
+  if (pFBlock != NULL) {
+    pScanInfo = taosHashGet(pStatus->pTableMap, &pFBlock->uid, sizeof(pFBlock->uid));
+    pBlock = getCurrentBlock(pBlockIter);
+    key = getCurrentKeyInBuf(pBlockIter, pReader);
+  }
 
-  TSDBKEY key = getCurrentKeyInBuf(pBlockIter, pReader);
-  if (fileBlockShouldLoad(pReader, pFBlock, pBlock, pScanInfo, key)) {
+  if (pFBlock == NULL || fileBlockShouldLoad(pReader, pFBlock, pBlock, pScanInfo, key)) {
     tBlockDataReset(&pStatus->fileBlockData);
     tBlockDataClear(&pStatus->fileBlockData);
-    code = doLoadFileBlockData(pReader, pBlockIter, pScanInfo, &pStatus->fileBlockData);
+
+    code = doLoadFileBlockData(pReader, pBlockIter, &pStatus->fileBlockData);
     if (code != TSDB_CODE_SUCCESS) {
       return code;
     }
 
     // build composed data block
-    code = buildComposedDataBlock(pReader, pScanInfo);
+    code = buildComposedDataBlock(pReader);
   } else if (bufferDataInFileBlockGap(pReader->order, key, pBlock)) {
     // data in memory that are earlier than current file block
     // todo rows in buffer should be less than the file block in asc, greater than file block in desc
@@ -1819,20 +1891,23 @@ static void initBlockDumpInfo(STsdbReader* pReader, SDataBlockIter* pBlockIter)
 }
 
 static int32_t initForFirstBlockInFile(STsdbReader* pReader, SDataBlockIter* pBlockIter) {
-  int32_t numOfBlocks = 0;
-  int32_t code = moveToNextFile(pReader, &numOfBlocks);
+  SBlockNumber num = {0};
+  SArray* pQLastBlock = taosArrayInit(4, sizeof(int32_t));
+
+  int32_t code = moveToNextFile(pReader, &num, pQLastBlock);
   if (code != TSDB_CODE_SUCCESS) {
     return code;
   }
 
   // all data files are consumed, try data in buffer
-  if (numOfBlocks == 0) {
+  if (num.numOfBlocks + num.numOfLastBlocks == 0) {
+    taosArrayDestroy(pQLastBlock);
     pReader->status.loadFromFile = false;
     return code;
   }
 
   // initialize the block iterator for a new fileset
-  code = initBlockIterator(pReader, pBlockIter, numOfBlocks);
+  code = initBlockIterator(pReader, pBlockIter, &num, pQLastBlock);
 
   // set the correct start position according to the query time window
   initBlockDumpInfo(pReader, pBlockIter);
@@ -1851,13 +1926,10 @@ static int32_t buildBlockFromFiles(STsdbReader* pReader) {
   SDataBlockIter* pBlockIter = &pReader->status.blockIter;
 
   while (1) {
-    SFileDataBlockInfo*  pFBlock = getCurrentBlockInfo(&pReader->status.blockIter);
-    STableBlockScanInfo* pScanInfo = taosHashGet(pReader->status.pTableMap, &pFBlock->uid, sizeof(pFBlock->uid));
-
     SFileBlockDumpInfo* pDumpInfo = &pReader->status.fBlockDumpInfo;
 
     if (fileBlockPartiallyRead(pDumpInfo, asc)) {  // file data block is partially loaded
-      code = buildComposedDataBlock(pReader, pScanInfo);
+      code = buildComposedDataBlock(pReader);
     } else {
       // current block are exhausted, try the next file block
       if (pDumpInfo->allDumped) {
@@ -2209,7 +2281,7 @@ static int32_t checkForNeighborFileBlock(STsdbReader* pReader, STableBlockScanIn
     // 3. load the neighbor block, and set it to be the currently accessed file data block
     tBlockDataReset(&pStatus->fileBlockData);
     tBlockDataClear(&pStatus->fileBlockData);
-    int32_t code = doLoadFileBlockData(pReader, pBlockIter, pScanInfo, &pStatus->fileBlockData);
+    int32_t code = doLoadFileBlockData(pReader, pBlockIter, &pStatus->fileBlockData);
     if (code != TSDB_CODE_SUCCESS) {
       return code;
     }
@@ -2569,6 +2641,7 @@ int32_t tsdbReaderOpen(SVnode* pVnode, SQueryTableDataCond* pCond, SArray* pTabl
       pCond->order = TSDB_ORDER_ASC;
     }
 
+    // here we only need one more row, so the capacity is set to be ONE.
     code = tsdbReaderCreate(pVnode, pCond, &pReader->innerReader[0], 1, idstr);
     if (code != TSDB_CODE_SUCCESS) {
       goto _err;
@@ -2872,7 +2945,7 @@ static SArray* doRetrieveDataBlock(STsdbReader* pReader) {
 
   tBlockDataReset(&pStatus->fileBlockData);
   tBlockDataClear(&pStatus->fileBlockData);
-  int32_t code = doLoadFileBlockData(pReader, &pStatus->blockIter, pBlockScanInfo, &pStatus->fileBlockData);
+  int32_t code = doLoadFileBlockData(pReader, &pStatus->blockIter, &pStatus->fileBlockData);
   if (code != TSDB_CODE_SUCCESS) {
     tBlockDataDestroy(&pStatus->fileBlockData, 1);
 
@@ -2968,12 +3041,12 @@ int32_t tsdbGetFileBlocksDistInfo(STsdbReader* pReader, STableBlockDistInfo* pTa
   SDataBlockIter* pBlockIter = &pStatus->blockIter;
   pTableBlockInfo->numOfFiles += pStatus->fileIter.numOfFiles;
 
-  if (pBlockIter->numOfBlocks > 0) {
-    pTableBlockInfo->numOfBlocks += pBlockIter->numOfBlocks;
+  if (pBlockIter->numOfBlocks.numOfBlocks > 0) {
+    pTableBlockInfo->numOfBlocks += pBlockIter->numOfBlocks.numOfBlocks;
   }
 
   pTableBlockInfo->numOfTables = numOfTables;
-  bool hasNext = (pBlockIter->numOfBlocks > 0);
+  bool hasNext = (pBlockIter->numOfBlocks.numOfBlocks > 0);
 
   while (true) {
     if (hasNext) {
@@ -3004,8 +3077,8 @@ int32_t tsdbGetFileBlocksDistInfo(STsdbReader* pReader, STableBlockDistInfo* pTa
         break;
       }
 
-      pTableBlockInfo->numOfBlocks += pBlockIter->numOfBlocks;
-      hasNext = (pBlockIter->numOfBlocks > 0);
+      pTableBlockInfo->numOfBlocks += pBlockIter->numOfBlocks.numOfBlocks;
+      hasNext = (pBlockIter->numOfBlocks.numOfBlocks > 0);
     }
 
     //    tsdbDebug("%p %d blocks found in file for %d table(s), fid:%d, %s", pReader, numOfBlocks, numOfTables,