diff --git a/source/dnode/vnode/inc/vnode.h b/source/dnode/vnode/inc/vnode.h
index 2d053d04ae..eae398880b 100644
--- a/source/dnode/vnode/inc/vnode.h
+++ b/source/dnode/vnode/inc/vnode.h
@@ -178,7 +178,7 @@ typedef struct STsdbReader STsdbReader;
 
 int32_t tsdbSetTableList(STsdbReader *pReader, const void *pTableList, int32_t num);
 int32_t tsdbReaderOpen(SVnode *pVnode, SQueryTableDataCond *pCond, void *pTableList, int32_t numOfTables,
-                       SSDataBlock *pResBlock, STsdbReader **ppReader, const char *idstr);
+                       SSDataBlock *pResBlock, STsdbReader **ppReader, const char *idstr, bool countOnly);
 
 void         tsdbReaderSetId(STsdbReader* pReader, const char* idstr);
 void         tsdbReaderClose(STsdbReader *pReader);
diff --git a/source/dnode/vnode/src/inc/tsdb.h b/source/dnode/vnode/src/inc/tsdb.h
index 452b1f6c0b..0c4ada2cb1 100644
--- a/source/dnode/vnode/src/inc/tsdb.h
+++ b/source/dnode/vnode/src/inc/tsdb.h
@@ -224,6 +224,8 @@ int32_t tsdbTbDataIterCreate(STbData *pTbData, TSDBKEY *pFrom, int8_t backward,
 void   *tsdbTbDataIterDestroy(STbDataIter *pIter);
 void    tsdbTbDataIterOpen(STbData *pTbData, TSDBKEY *pFrom, int8_t backward, STbDataIter *pIter);
 bool    tsdbTbDataIterNext(STbDataIter *pIter);
+void    tsdbMemTableCountRows(SMemTable *pMemTable, SHashObj*        pTableMap, int64_t *rowsNum);
+
 // STbData
 int32_t tsdbGetNRowsInTbData(STbData *pTbData);
 // tsdbFile.c ==============================================================================================
diff --git a/source/dnode/vnode/src/tsdb/tsdbMemTable.c b/source/dnode/vnode/src/tsdb/tsdbMemTable.c
index d34af9acae..46d0509c38 100644
--- a/source/dnode/vnode/src/tsdb/tsdbMemTable.c
+++ b/source/dnode/vnode/src/tsdb/tsdbMemTable.c
@@ -282,6 +282,34 @@ bool tsdbTbDataIterNext(STbDataIter *pIter) {
   return true;
 }
 
+int64_t tsdbCountTbDataRows(STbData *pTbData) {
+  SMemSkipListNode *pNode = NULL;
+  int64_t rowsNum = 0;
+  
+  while (true) {
+    pNode = SL_GET_NODE_FORWARD(pTbData->sl.pHead, 0);
+    if (pNode == pTbData->sl.pTail) {
+      return rowsNum;
+    }
+
+    rowsNum++;
+  }
+}
+
+void tsdbMemTableCountRows(SMemTable *pMemTable, SHashObj*        pTableMap, int64_t *rowsNum) {
+  taosRLockLatch(&pMemTable->latch);
+  for (int32_t i = 0; i < pMemTable->nBucket; ++i) {
+    STbData *pTbData = pMemTable->aBucket[i];
+    
+    void* p = taosHashGet(pTableMap, &pTbData->uid, sizeof(pTbData->uid));
+    if (p == NULL) {
+      continue;
+    }
+    rowsNum += tsdbCountTbDataRows(pTbData);
+  }
+  taosRUnLockLatch(&pMemTable->latch);
+}
+
 static int32_t tsdbMemTableRehash(SMemTable *pMemTable) {
   int32_t code = 0;
 
@@ -787,4 +815,4 @@ SArray *tsdbMemTableGetTbDataArray(SMemTable *pMemTable) {
 
 _exit:
   return aTbDataP;
-}
\ No newline at end of file
+}
diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index c6444b5ded..8b6f318434 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -3113,7 +3113,7 @@ static int32_t doSumBlockRows(STsdbReader* pReader, SDataFReader* pFileReader) {
     }
 
     STableBlockScanInfo** p = taosHashGet(pReader->status.pTableMap, &pBlockIdx->uid, sizeof(pBlockIdx->uid));
-    if (p == NULL || *p == NULL) {
+    if (p == NULL) {
       continue;
     }
 
@@ -3189,6 +3189,10 @@ static int32_t readRowsCountFromStt(STsdbReader* pReader) {
           taosArrayClear(pBlockLoadInfo->aSttBlk);
           continue;
         }
+        for (int32_t i = 0; i < size; ++i) {
+          SSttBlk *p = taosArrayGet(pBlockLoadInfo->aSttBlk, i);
+          pReader->rowsNum += p->nRow;
+        }
       } else {
         for (int32_t i = 0; i < size; ++i) {
           SSttBlk *p = taosArrayGet(pBlockLoadInfo->aSttBlk, i);
@@ -3210,6 +3214,22 @@ static int32_t readRowsCountFromStt(STsdbReader* pReader) {
   return code;
 }
 
+static int32_t readRowsCountFromMem(STsdbReader* pReader) {
+  int32_t   code = TSDB_CODE_SUCCESS;
+  int64_t   memNum = 0, imemNum = 0;
+  if (pReader->pReadSnap->pMem != NULL) {
+    tsdbMemTableCountRows(pReader->pReadSnap->pMem, pReader->status.pTableMap, &memNum);
+  }
+
+  if (pReader->pReadSnap->pIMem != NULL) {
+    tsdbMemTableCountRows(pReader->pReadSnap->pIMem, pReader->status.pTableMap, &imemNum);
+  }
+
+  pReader->rowsNum += memNum + imemNum;
+
+  return code;
+}
+
 
 static int32_t buildBlockFromBufferSequentially(STsdbReader* pReader) {
   SReaderStatus* pStatus = &pReader->status;
@@ -4170,7 +4190,7 @@ static int32_t doOpenReaderImpl(STsdbReader* pReader) {
 
 // ====================================== EXPOSED APIs ======================================
 int32_t tsdbReaderOpen(SVnode* pVnode, SQueryTableDataCond* pCond, void* pTableList, int32_t numOfTables,
-                       SSDataBlock* pResBlock, STsdbReader** ppReader, const char* idstr) {
+                       SSDataBlock* pResBlock, STsdbReader** ppReader, const char* idstr, bool countOnly) {
   STimeWindow window = pCond->twindows;
   if (pCond->type == TIMEWINDOW_RANGE_EXTERNAL) {
     pCond->twindows.skey += 1;
@@ -4262,9 +4282,10 @@ int32_t tsdbReaderOpen(SVnode* pVnode, SQueryTableDataCond* pCond, void* pTableL
 
   pReader->suspended = true;
 
+  if (countOnly) {
+    pReader->readMode = READ_MODE_COUNT_ONLY;
+  }
   
-  pReader->readMode = READ_MODE_COUNT_ONLY;
-
   tsdbDebug("%p total numOfTable:%d in this query %s", pReader, numOfTables, pReader->idStr);
   return code;
 
@@ -4588,6 +4609,11 @@ static bool tsdbReadRowsCountOnly(STsdbReader* pReader) {
     }
   }
 
+  code = readRowsCountFromMem(pReader);
+  if (code != TSDB_CODE_SUCCESS) {
+    return false;
+  }
+
   pBlock->info.rows = pReader->rowsNum;
   pBlock->info.id.uid = 0;
   pBlock->info.dataLoad = 0;
diff --git a/source/libs/executor/inc/executorimpl.h b/source/libs/executor/inc/executorimpl.h
index 3f519568c4..fd29df1acc 100644
--- a/source/libs/executor/inc/executorimpl.h
+++ b/source/libs/executor/inc/executorimpl.h
@@ -339,6 +339,7 @@ typedef struct STableScanInfo {
   int8_t          scanMode;
   int8_t          assignBlockUid;
   bool            hasGroupByTag;
+  bool            countOnly;
 } STableScanInfo;
 
 typedef struct STableMergeScanInfo {
diff --git a/source/libs/executor/src/executor.c b/source/libs/executor/src/executor.c
index db58bd6f68..a1b27114b3 100644
--- a/source/libs/executor/src/executor.c
+++ b/source/libs/executor/src/executor.c
@@ -1140,7 +1140,7 @@ int32_t qStreamPrepareScan(qTaskInfo_t tinfo, STqOffsetVal* pOffset, int8_t subT
         int32_t        num = tableListGetSize(pTaskInfo->pTableInfoList);
 
         if (tsdbReaderOpen(pTableScanInfo->base.readHandle.vnode, &pTableScanInfo->base.cond, pList, num,
-                           pTableScanInfo->pResBlock, &pTableScanInfo->base.dataReader, NULL) < 0 ||
+                           pTableScanInfo->pResBlock, &pTableScanInfo->base.dataReader, NULL, false) < 0 ||
             pTableScanInfo->base.dataReader == NULL) {
           qError("tsdbReaderOpen failed. uid:%" PRIi64, pOffset->uid);
           return -1;
@@ -1192,7 +1192,7 @@ int32_t qStreamPrepareScan(qTaskInfo_t tinfo, STqOffsetVal* pOffset, int8_t subT
     STableKeyInfo* pList = tableListGetInfo(pTaskInfo->pTableInfoList, 0);
     int32_t        size = tableListGetSize(pTaskInfo->pTableInfoList);
 
-    tsdbReaderOpen(pInfo->vnode, &pTaskInfo->streamInfo.tableCond, pList, size, NULL, &pInfo->dataReader, NULL);
+    tsdbReaderOpen(pInfo->vnode, &pTaskInfo->streamInfo.tableCond, pList, size, NULL, &pInfo->dataReader, NULL, false);
 
     cleanupQueryTableDataCond(&pTaskInfo->streamInfo.tableCond);
     strcpy(pTaskInfo->streamInfo.tbName, mtInfo.tbName);
diff --git a/source/libs/executor/src/scanoperator.c b/source/libs/executor/src/scanoperator.c
index 2af13f083d..854a2c1aaf 100644
--- a/source/libs/executor/src/scanoperator.c
+++ b/source/libs/executor/src/scanoperator.c
@@ -31,6 +31,9 @@
 #include "thash.h"
 #include "ttypes.h"
 
+int32_t scanDebug = 0;
+
+
 #define MULTI_READER_MAX_TABLE_NUM 5000
 #define SET_REVERSE_SCAN_FLAG(_info) ((_info)->scanFlag = REVERSE_SCAN)
 #define SWITCH_ORDER(n)              (((n) = ((n) == TSDB_ORDER_ASC) ? TSDB_ORDER_DESC : TSDB_ORDER_ASC))
@@ -785,7 +788,7 @@ static SSDataBlock* doTableScan(SOperatorInfo* pOperator) {
       ASSERT(pInfo->base.dataReader == NULL);
 
       int32_t code = tsdbReaderOpen(pInfo->base.readHandle.vnode, &pInfo->base.cond, pList, num, pInfo->pResBlock,
-                                    (STsdbReader**)&pInfo->base.dataReader, GET_TASKID(pTaskInfo));
+                                    (STsdbReader**)&pInfo->base.dataReader, GET_TASKID(pTaskInfo), pInfo->countOnly);
       if (code != TSDB_CODE_SUCCESS) {
         T_LONG_JMP(pTaskInfo->env, code);
       }
@@ -916,6 +919,10 @@ SOperatorInfo* createTableScanOperatorInfo(STableScanPhysiNode* pTableScanNode,
     goto _error;
   }
 
+  if (scanDebug) {
+    pInfo->countOnly = true;
+  }
+
   taosLRUCacheSetStrictCapacity(pInfo->base.metaCache.pTableMetaEntryCache, false);
   pOperator->fpSet = createOperatorFpSet(optrDummyOpenFn, doTableScan, NULL, destroyTableScanOperatorInfo,
                                          optrDefaultBufFn, getTableScannerExecInfo);
@@ -1007,7 +1014,7 @@ static SSDataBlock* readPreVersionData(SOperatorInfo* pTableScanOp, uint64_t tbU
   SSDataBlock* pBlock = pTableScanInfo->pResBlock;
   STsdbReader* pReader = NULL;
   int32_t      code = tsdbReaderOpen(pTableScanInfo->base.readHandle.vnode, &cond, &tblInfo, 1, pBlock,
-                                     (STsdbReader**)&pReader, GET_TASKID(pTaskInfo));
+                                     (STsdbReader**)&pReader, GET_TASKID(pTaskInfo), false);
   if (code != TSDB_CODE_SUCCESS) {
     terrno = code;
     T_LONG_JMP(pTaskInfo->env, code);
@@ -2601,7 +2608,7 @@ static SSDataBlock* getTableDataBlockImpl(void* param) {
   SReadHandle* pHandle = &pInfo->base.readHandle;
 
   if (NULL == source->dataReader || !source->multiReader) {
-    code = tsdbReaderOpen(pHandle->vnode, pQueryCond, p, 1, pBlock, &source->dataReader, GET_TASKID(pTaskInfo));
+    code = tsdbReaderOpen(pHandle->vnode, pQueryCond, p, 1, pBlock, &source->dataReader, GET_TASKID(pTaskInfo), false);
     if (code != 0) {
       T_LONG_JMP(pTaskInfo->env, code);
     }
diff --git a/source/libs/executor/src/sysscanoperator.c b/source/libs/executor/src/sysscanoperator.c
index f24d3523c8..d05c692f19 100644
--- a/source/libs/executor/src/sysscanoperator.c
+++ b/source/libs/executor/src/sysscanoperator.c
@@ -2267,7 +2267,7 @@ SOperatorInfo* createDataBlockInfoScanOperator(SReadHandle* readHandle, SBlockDi
     size_t          num = tableListGetSize(pTableListInfo);
     void*           pList = tableListGetInfo(pTableListInfo, 0);
 
-    code = tsdbReaderOpen(readHandle->vnode, &cond, pList, num, pInfo->pResBlock, &pInfo->pHandle, pTaskInfo->id.str);
+    code = tsdbReaderOpen(readHandle->vnode, &cond, pList, num, pInfo->pResBlock, &pInfo->pHandle, pTaskInfo->id.str, false);
     cleanupQueryTableDataCond(&cond);
     if (code != 0) {
       goto _error;