diff --git a/source/dnode/vnode/src/tsdb/tsdbRead2.c b/source/dnode/vnode/src/tsdb/tsdbRead2.c
index e96406567a8aaff2ed8c22ce1e66ada3f39f7633..5e6226d4787640adaa29b5f80a4c11d978fff4d0 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead2.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead2.c
@@ -1729,40 +1729,44 @@ static int32_t mergeFileBlockAndLastBlock(STsdbReader* pReader, SLastBlockReader
 
     // row in last file block
     TSDBROW fRow = tsdbRowFromBlockData(pBlockData, pDumpInfo->rowIndex);
-    int64_t ts = getCurrentKeyInLastBlock(pLastBlockReader);
-
+    int64_t tsLast = getCurrentKeyInLastBlock(pLastBlockReader);
     if (ASCENDING_TRAVERSE(pReader->info.order)) {
-      if (key < ts) {  // imem, mem are all empty, file blocks (data blocks and last block) exist
+      if (key < tsLast) {
         return mergeRowsInFileBlocks(pBlockData, pBlockScanInfo, key, pReader);
-      } else if (key == ts) {
-        SRow*   pTSRow = NULL;
-        int32_t code = tsdbRowMergerAdd(pMerger, &fRow, pReader->info.pSchema);
-        if (code != TSDB_CODE_SUCCESS) {
-          return code;
-        }
-
-        doMergeRowsInFileBlocks(pBlockData, pBlockScanInfo, pReader);
-
-        TSDBROW* pRow1 = tMergeTreeGetRow(&pLastBlockReader->mergeTree);
-        tsdbRowMergerAdd(pMerger, pRow1, NULL);
+      } else if (key > tsLast) {
+        return doMergeFileBlockAndLastBlock(pLastBlockReader, pReader, pBlockScanInfo, NULL, false);
+      }
+    } else {
+      if (key > tsLast) {
+        return mergeRowsInFileBlocks(pBlockData, pBlockScanInfo, key, pReader);
+      } else if (key < tsLast) {
+        return doMergeFileBlockAndLastBlock(pLastBlockReader, pReader, pBlockScanInfo, NULL, false);
+      }
+    }
+    if (key == tsLast) {
+      SRow*   pTSRow = NULL;
+      int32_t code = tsdbRowMergerAdd(pMerger, &fRow, pReader->info.pSchema);
+      if (code != TSDB_CODE_SUCCESS) {
+        return code;
+      }
 
-        doMergeRowsInLastBlock(pLastBlockReader, pBlockScanInfo, ts, pMerger, &pReader->info.verRange, pReader->idStr);
+      doMergeRowsInFileBlocks(pBlockData, pBlockScanInfo, pReader);
 
-        code = tsdbRowMergerGetRow(pMerger, &pTSRow);
-        if (code != TSDB_CODE_SUCCESS) {
-          return code;
-        }
+      TSDBROW* pRow1 = tMergeTreeGetRow(&pLastBlockReader->mergeTree);
+      tsdbRowMergerAdd(pMerger, pRow1, NULL);
 
-        code = doAppendRowFromTSRow(pReader->resBlockInfo.pResBlock, pReader, pTSRow, pBlockScanInfo);
+      doMergeRowsInLastBlock(pLastBlockReader, pBlockScanInfo, tsLast, pMerger, &pReader->info.verRange, pReader->idStr);
 
-        taosMemoryFree(pTSRow);
-        tsdbRowMergerClear(pMerger);
+      code = tsdbRowMergerGetRow(pMerger, &pTSRow);
+      if (code != TSDB_CODE_SUCCESS) {
         return code;
-      } else {  // key > ts
-        return doMergeFileBlockAndLastBlock(pLastBlockReader, pReader, pBlockScanInfo, NULL, false);
       }
-    } else {  // desc order
-      return doMergeFileBlockAndLastBlock(pLastBlockReader, pReader, pBlockScanInfo, pBlockData, true);
+
+      code = doAppendRowFromTSRow(pReader->resBlockInfo.pResBlock, pReader, pTSRow, pBlockScanInfo);
+
+      taosMemoryFree(pTSRow);
+      tsdbRowMergerClear(pMerger);
+      return code;
     }
   } else {  // only last block exists
     return doMergeFileBlockAndLastBlock(pLastBlockReader, pReader, pBlockScanInfo, NULL, false);
@@ -2190,7 +2194,8 @@ static int32_t buildComposedDataBlockImpl(STsdbReader* pReader, STableBlockScanI
   SFileBlockDumpInfo* pDumpInfo = &pReader->status.fBlockDumpInfo;
 
   TSDBROW *pRow = NULL, *piRow = NULL;
-  int64_t key = (pBlockData->nRow > 0 && (!pDumpInfo->allDumped)) ? pBlockData->aTSKEY[pDumpInfo->rowIndex] : INT64_MIN;
+  int64_t key = (pBlockData->nRow > 0 && (!pDumpInfo->allDumped)) ? pBlockData->aTSKEY[pDumpInfo->rowIndex] :
+                                                                   (ASCENDING_TRAVERSE(pReader->info.order) ? INT64_MAX : INT64_MIN);
   if (pBlockScanInfo->iter.hasVal) {
     pRow = getValidMemRow(&pBlockScanInfo->iter, pBlockScanInfo->delSkyline, pReader);
   }
@@ -2667,16 +2672,32 @@ static int32_t doBuildDataBlock(STsdbReader* pReader) {
         (ASCENDING_TRAVERSE(pReader->info.order)) ? pBlockInfo->record.firstKey : pBlockInfo->record.lastKey;
     code = buildDataBlockFromBuf(pReader, pScanInfo, endKey);
   } else {
-    if (hasDataInLastBlock(pLastBlockReader) && !ASCENDING_TRAVERSE(pReader->info.order)) {
-      // only return the rows in last block
-      int64_t tsLast = getCurrentKeyInLastBlock(pLastBlockReader);
-      ASSERT(tsLast >= pBlockInfo->record.lastKey);
+    bool bHasDataInLastBlock = hasDataInLastBlock(pLastBlockReader);
+    int64_t tsLast = bHasDataInLastBlock ? getCurrentKeyInLastBlock(pLastBlockReader) : INT64_MIN;
+    if (!bHasDataInLastBlock || ((ASCENDING_TRAVERSE(pReader->info.order) && pBlockInfo->record.lastKey < tsLast) ||
+                                 (!ASCENDING_TRAVERSE(pReader->info.order) && pBlockInfo->record.firstKey > tsLast))) {
+      // whole block is required, return it directly
+      SDataBlockInfo* pInfo = &pReader->resBlockInfo.pResBlock->info;
+      pInfo->rows = pBlockInfo->record.numRow;
+      pInfo->id.uid = pScanInfo->uid;
+      pInfo->dataLoad = 0;
+      pInfo->window = (STimeWindow){.skey = pBlockInfo->record.firstKey, .ekey = pBlockInfo->record.lastKey};
+      setComposedBlockFlag(pReader, false);
+      setBlockAllDumped(&pStatus->fBlockDumpInfo, pBlockInfo->record.lastKey, pReader->info.order);
 
+      // update the last key for the corresponding table
+      pScanInfo->lastKey = ASCENDING_TRAVERSE(pReader->info.order) ? pInfo->window.ekey : pInfo->window.skey;
+      tsdbDebug("%p uid:%" PRIu64
+                " clean file block retrieved from file, global index:%d, "
+                "table index:%d, rows:%d, brange:%" PRId64 "-%" PRId64 ", %s",
+                pReader, pScanInfo->uid, pBlockIter->index, pBlockInfo->tbBlockIdx, pBlockInfo->record.numRow,
+                pBlockInfo->record.firstKey, pBlockInfo->record.lastKey, pReader->idStr);
+    } else {
       SBlockData* pBData = &pReader->status.fileBlockData;
       tBlockDataReset(pBData);
 
       SSDataBlock* pResBlock = pReader->resBlockInfo.pResBlock;
-      tsdbDebug("load data in last block firstly, due to desc scan data, %s", pReader->idStr);
+      tsdbDebug("load data in last block firstly %s", pReader->idStr);
 
       int64_t st = taosGetTimestampUs();
 
@@ -2707,23 +2728,8 @@ static int32_t doBuildDataBlock(STsdbReader* pReader) {
                   pReader, pResBlock->info.id.uid, pResBlock->info.window.skey, pResBlock->info.window.ekey,
                   pResBlock->info.rows, el, pReader->idStr);
       }
-    } else {  // whole block is required, return it directly
-      SDataBlockInfo* pInfo = &pReader->resBlockInfo.pResBlock->info;
-      pInfo->rows = pBlockInfo->record.numRow;
-      pInfo->id.uid = pScanInfo->uid;
-      pInfo->dataLoad = 0;
-      pInfo->window = (STimeWindow){.skey = pBlockInfo->record.firstKey, .ekey = pBlockInfo->record.lastKey};
-      setComposedBlockFlag(pReader, false);
-      setBlockAllDumped(&pStatus->fBlockDumpInfo, pBlockInfo->record.lastKey, pReader->info.order);
-
-      // update the last key for the corresponding table
-      pScanInfo->lastKey = ASCENDING_TRAVERSE(pReader->info.order) ? pInfo->window.ekey : pInfo->window.skey;
-      tsdbDebug("%p uid:%" PRIu64
-                " clean file block retrieved from file, global index:%d, "
-                "table index:%d, rows:%d, brange:%" PRId64 "-%" PRId64 ", %s",
-                pReader, pScanInfo->uid, pBlockIter->index, pBlockInfo->tbBlockIdx, pBlockInfo->record.numRow,
-                pBlockInfo->record.firstKey, pBlockInfo->record.lastKey, pReader->idStr);
     }
+
   }
 
   return (pReader->code != TSDB_CODE_SUCCESS) ? pReader->code : code;