diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index 60f59e46f798ee2cca55fe96ce030e5d59253b23..506d185d1cfb5cbcfef9ad2e7d5ba8a9eba0367d 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -798,7 +798,15 @@ static int32_t handleDataMergeIfNeeded(STsdbQueryHandle* pQueryHandle, SCompBloc
       cur->rows = binfo.rows;
       cur->win  = binfo.window;
       cur->mixBlock = false;
-      cur->lastKey = ASCENDING_TRAVERSE(pQueryHandle->order)? (binfo.window.ekey + 1): (binfo.window.skey -1);
+      cur->blockCompleted = true;
+
+      if (ASCENDING_TRAVERSE(pQueryHandle->order)) {
+        cur->lastKey = binfo.window.ekey + 1;
+        cur->pos = binfo.rows;
+      } else {
+        cur->lastKey = binfo.window.skey - 1;
+        cur->pos = -1;
+      }
     } else { // partially copy to dest buffer
       int32_t endPos = ASCENDING_TRAVERSE(pQueryHandle->order)? (binfo.rows - 1): 0;
       copyAllRemainRowsFromFileBlock(pQueryHandle, pCheckInfo, &binfo, endPos);
@@ -1195,7 +1203,6 @@ static void copyAllRemainRowsFromFileBlock(STsdbQueryHandle* pQueryHandle, STabl
             cur->win.ekey, cur->rows, pQueryHandle->qinfo);
 }
 
-
 // only return the qualified data to client in terms of query time window, data rows in the same block but do not
 // be included in the query time window will be discarded
 static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo* pCheckInfo, SCompBlock* pBlock) {