diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index bf72f209d6add6e85269fecc2a8ab0bb814d8241..8cd6a12322130bb2dce3c8253db8ba54ea0e57cf 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -4501,8 +4501,10 @@ static int64_t scanMultiTableDataBlocks(SQInfo *pQInfo) {
     summary->totalRows += blockInfo.rows;
     stableApplyFunctionsOnBlock(pRuntimeEnv, &blockInfo, pStatis, pDataBlock, binarySearchForKey);
   
-    qDebug("QInfo:%p check data block, uid:%"PRId64", tid:%d, brange:%" PRId64 "-%" PRId64 ", numOfRows:%d, lastKey:%" PRId64,
-           pQInfo, blockInfo.uid, blockInfo.tid, blockInfo.window.skey, blockInfo.window.ekey, blockInfo.rows, pQuery->current->lastKey);
+    qDebug("QInfo:%p check data block completed, uid:%"PRId64", tid:%d, brange:%" PRId64 "-%" PRId64 ", numOfRows:%d, "
+           "lastKey:%" PRId64,
+           pQInfo, blockInfo.uid, blockInfo.tid, blockInfo.window.skey, blockInfo.window.ekey, blockInfo.rows,
+           pQuery->current->lastKey);
   }
 
   if (terrno != TSDB_CODE_SUCCESS) {
diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index b189c7a40692d73eee4f97d05e456970043963ab..6d0966e52a0f4b667e5811d60455a8b8b9bb2802 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -409,7 +409,7 @@ static bool initTableMemIterator(STsdbQueryHandle* pHandle, STableCheckInfo* pCh
 
     SDataRow row = *(SDataRow *)SL_GET_NODE_DATA(node);
     TSKEY key = dataRowKey(row);  // first timestamp in buffer
-    tsdbDebug("%p uid:%" PRId64 ", tid:%d check data in mem from skey:%" PRId64 ", order:%d, ts range in buf:%" PRId64
+    tsdbDebug("%p uid:%" PRId64 ", tid:%d check data in imem from skey:%" PRId64 ", order:%d, ts range in buf:%" PRId64
               "-%" PRId64 ", lastKey:%" PRId64 ", %p",
               pHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, key, order, pIMem->keyFirst, pIMem->keyLast,
               pCheckInfo->lastKey, pHandle->qinfo);
@@ -744,6 +744,8 @@ static int32_t handleDataMergeIfNeeded(STsdbQueryHandle* pQueryHandle, SCompBloc
   SDataRow row = getSDataRowInTableMem(pCheckInfo, pQueryHandle->order);
 
   TSKEY key = (row != NULL)? dataRowKey(row):TSKEY_INITIAL_VAL;
+  tsdbDebug("%p key in mem:%"PRId64", %p", pQueryHandle, key, pQueryHandle->qinfo);
+
   cur->pos = ASCENDING_TRAVERSE(pQueryHandle->order)? 0:(binfo.rows-1);
 
   if ((ASCENDING_TRAVERSE(pQueryHandle->order) && (key != TSKEY_INITIAL_VAL && key <= binfo.window.ekey)) ||
@@ -755,7 +757,8 @@ static int32_t handleDataMergeIfNeeded(STsdbQueryHandle* pQueryHandle, SCompBloc
       // do not load file block into buffer
       int32_t step = ASCENDING_TRAVERSE(pQueryHandle->order) ? 1 : -1;
 
-      cur->rows = tsdbReadRowsFromCache(pCheckInfo, binfo.window.skey - step, pQueryHandle->outputCapacity, &cur->win, pQueryHandle);
+      TSKEY maxKey = ASCENDING_TRAVERSE(pQueryHandle->order)? (binfo.window.skey - step):(binfo.window.ekey - step);
+      cur->rows = tsdbReadRowsFromCache(pCheckInfo, maxKey, pQueryHandle->outputCapacity, &cur->win, pQueryHandle);
       pQueryHandle->realNumOfRows = cur->rows;
 
       // update the last key value
@@ -1170,6 +1173,11 @@ static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo*
     cur->mixBlock = true;
   }
 
+  tsdbDebug("%p uid:%" PRIu64",tid:%d start merge data block, file block range:%"PRIu64"-%"PRIu64" rows:%d, start:%d,"
+            "end:%d, %p",
+            pQueryHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, blockInfo.window.skey, blockInfo.window.ekey,
+            blockInfo.rows, cur->pos, endPos, pQueryHandle->qinfo);
+
   // compared with the data from in-memory buffer, to generate the correct timestamp array list
   int32_t numOfRows = 0;
   int32_t pos = cur->pos;
@@ -1199,6 +1207,10 @@ static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo*
     moveDataToFront(pQueryHandle, numOfRows, numOfCols);
     updateInfoAfterMerge(pQueryHandle, pCheckInfo, numOfRows, pos);
     doCheckGeneratedBlockRange(pQueryHandle);
+
+    tsdbDebug("%p uid:%" PRIu64",tid:%d data block created, mixblock:%d, brange:%"PRIu64"-%"PRIu64" rows:%d, %p",
+              pQueryHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, cur->mixBlock, cur->win.skey,
+              cur->win.ekey, cur->rows, pQueryHandle->qinfo);
     return;
   } else if (pCheckInfo->iter != NULL || pCheckInfo->iiter != NULL) {
     SSkipListNode* node = NULL;
@@ -1279,6 +1291,7 @@ static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo*
 
         cur->win.ekey = ASCENDING_TRAVERSE(pQueryHandle->order)? tsArray[end]:tsArray[start];
         cur->lastKey  = cur->win.ekey + step;
+        cur->mixBlock = true;
       }
     }
   }
@@ -1295,7 +1308,8 @@ static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo*
   updateInfoAfterMerge(pQueryHandle, pCheckInfo, numOfRows, pos);
   doCheckGeneratedBlockRange(pQueryHandle);
 
-  tsdbDebug("%p uid:%" PRIu64",tid:%d data block created, brange:%"PRIu64"-%"PRIu64" rows:%d, %p", pQueryHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, cur->win.skey,
+  tsdbDebug("%p uid:%" PRIu64",tid:%d data block created, mixblock:%d, brange:%"PRIu64"-%"PRIu64" rows:%d, %p",
+      pQueryHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, cur->mixBlock, cur->win.skey,
       cur->win.ekey, cur->rows, pQueryHandle->qinfo);
 }