diff --git a/src/common/inc/tdataformat.h b/src/common/inc/tdataformat.h
index fb6bab0cf29d50f196a18eeff990b1fc62dac9ea..1637c4832b7e2ac9d4be52b7f94dd301ba4eb617 100644
--- a/src/common/inc/tdataformat.h
+++ b/src/common/inc/tdataformat.h
@@ -328,11 +328,10 @@ static FORCE_INLINE void dataColReset(SDataCol *pDataCol) { pDataCol->len = 0; }
 int tdAllocMemForCol(SDataCol *pCol, int maxPoints);
 
 void dataColInit(SDataCol *pDataCol, STColumn *pCol, int maxPoints);
-void dataColAppendVal(SDataCol *pCol, const void *value, int numOfRows, int maxPoints);
+int dataColAppendVal(SDataCol *pCol, const void *value, int numOfRows, int maxPoints);
 void dataColSetOffset(SDataCol *pCol, int nEle);
 
 bool isNEleNull(SDataCol *pCol, int nEle);
-void dataColSetNEleNull(SDataCol *pCol, int nEle, int maxPoints);
 
 // Get the data pointer from a column-wised data
 static FORCE_INLINE const void *tdGetColDataOfRow(SDataCol *pCol, int row) {
@@ -357,13 +356,11 @@ static FORCE_INLINE int32_t dataColGetNEleLen(SDataCol *pDataCol, int rows) {
 }
 
 typedef struct {
-  int maxRowSize;
-  int maxCols;    // max number of columns
-  int maxPoints;  // max number of points
-
-  int       numOfRows;
-  int       numOfCols;  // Total number of cols
-  int       sversion;   // TODO: set sversion
+  int      maxCols;    // max number of columns
+  int      maxPoints;  // max number of points
+  int      numOfRows;
+  int      numOfCols;  // Total number of cols
+  int      sversion;   // TODO: set sversion
   SDataCol *cols;
 } SDataCols;
 
@@ -407,7 +404,7 @@ static FORCE_INLINE TSKEY dataColsKeyLast(SDataCols *pCols) {
   }
 }
 
-SDataCols *tdNewDataCols(int maxRowSize, int maxCols, int maxRows);
+SDataCols *tdNewDataCols(int maxCols, int maxRows);
 void       tdResetDataCols(SDataCols *pCols);
 int        tdInitDataCols(SDataCols *pCols, STSchema *pSchema);
 SDataCols *tdDupDataCols(SDataCols *pCols, bool keepData);
diff --git a/src/common/src/tdataformat.c b/src/common/src/tdataformat.c
index 3f0ab7f93ead2bbba62e8c75035530614798bd28..c793d241f6f175268802830c6a96b35c689e69d1 100644
--- a/src/common/src/tdataformat.c
+++ b/src/common/src/tdataformat.c
@@ -19,10 +19,10 @@
 #include "wchar.h"
 #include "tarray.h"
 
+static void dataColSetNEleNull(SDataCol *pCol, int nEle);
 static void tdMergeTwoDataCols(SDataCols *target, SDataCols *src1, int *iter1, int limit1, SDataCols *src2, int *iter2,
                                int limit2, int tRows, bool forceSetNull);
 
-//TODO: change caller to use return val
 int tdAllocMemForCol(SDataCol *pCol, int maxPoints) {
   int spaceNeeded = pCol->bytes * maxPoints;
   if(IS_VAR_DATA_TYPE(pCol->type)) {
@@ -31,7 +31,7 @@ int tdAllocMemForCol(SDataCol *pCol, int maxPoints) {
   if(pCol->spaceSize < spaceNeeded) {
     void* ptr = realloc(pCol->pData, spaceNeeded);
     if(ptr == NULL) {
-      uDebug("malloc failure, size:%" PRId64 " failed, reason:%s", (int64_t)pCol->spaceSize,
+      uDebug("malloc failure, size:%" PRId64 " failed, reason:%s", (int64_t)spaceNeeded,
              strerror(errno));
       return -1;
     } else {
@@ -239,20 +239,19 @@ void dataColInit(SDataCol *pDataCol, STColumn *pCol, int maxPoints) {
   pDataCol->len = 0;
 }
 // value from timestamp should be TKEY here instead of TSKEY
-void dataColAppendVal(SDataCol *pCol, const void *value, int numOfRows, int maxPoints) {
+int dataColAppendVal(SDataCol *pCol, const void *value, int numOfRows, int maxPoints) {
   ASSERT(pCol != NULL && value != NULL);
 
   if (isAllRowsNull(pCol)) {
     if (isNull(value, pCol->type)) {
       // all null value yet, just return
-      return;
+      return 0;
     }
 
+    if(tdAllocMemForCol(pCol, maxPoints) < 0) return -1;
     if (numOfRows > 0) {
       // Find the first not null value, fill all previouse values as NULL
-      dataColSetNEleNull(pCol, numOfRows, maxPoints);
-    } else {
-      tdAllocMemForCol(pCol, maxPoints);
+      dataColSetNEleNull(pCol, numOfRows);
     }
   }
 
@@ -268,12 +267,21 @@ void dataColAppendVal(SDataCol *pCol, const void *value, int numOfRows, int maxP
     memcpy(POINTER_SHIFT(pCol->pData, pCol->len), value, pCol->bytes);
     pCol->len += pCol->bytes;
   }
+  return 0;
+}
+
+static FORCE_INLINE const void *tdGetColDataOfRowUnsafe(SDataCol *pCol, int row) {
+  if (IS_VAR_DATA_TYPE(pCol->type)) {
+    return POINTER_SHIFT(pCol->pData, pCol->dataOff[row]);
+  } else {
+    return POINTER_SHIFT(pCol->pData, TYPE_BYTES[pCol->type] * row);
+  }
 }
 
 bool isNEleNull(SDataCol *pCol, int nEle) {
   if(isAllRowsNull(pCol)) return true;
   for (int i = 0; i < nEle; i++) {
-    if (!isNull(tdGetColDataOfRow(pCol, i), pCol->type)) return false;
+    if (!isNull(tdGetColDataOfRowUnsafe(pCol, i), pCol->type)) return false;
   }
   return true;
 }
@@ -290,9 +298,7 @@ static FORCE_INLINE void dataColSetNullAt(SDataCol *pCol, int index) {
   }
 }
 
-void dataColSetNEleNull(SDataCol *pCol, int nEle, int maxPoints) {
-  tdAllocMemForCol(pCol, maxPoints);
-
+static void dataColSetNEleNull(SDataCol *pCol, int nEle) {
   if (IS_VAR_DATA_TYPE(pCol->type)) {
     pCol->len = 0;
     for (int i = 0; i < nEle; i++) {
@@ -318,7 +324,7 @@ void dataColSetOffset(SDataCol *pCol, int nEle) {
   }
 }
 
-SDataCols *tdNewDataCols(int maxRowSize, int maxCols, int maxRows) {
+SDataCols *tdNewDataCols(int maxCols, int maxRows) {
   SDataCols *pCols = (SDataCols *)calloc(1, sizeof(SDataCols));
   if (pCols == NULL) {
     uDebug("malloc failure, size:%" PRId64 " failed, reason:%s", (int64_t)sizeof(SDataCols), strerror(errno));
@@ -326,6 +332,9 @@ SDataCols *tdNewDataCols(int maxRowSize, int maxCols, int maxRows) {
   }
 
   pCols->maxPoints = maxRows;
+  pCols->maxCols = maxCols;
+  pCols->numOfRows = 0;
+  pCols->numOfCols = 0;
 
   if (maxCols > 0) {
     pCols->cols = (SDataCol *)calloc(maxCols, sizeof(SDataCol));
@@ -342,13 +351,8 @@ SDataCols *tdNewDataCols(int maxRowSize, int maxCols, int maxRows) {
       pCols->cols[i].pData = NULL;
       pCols->cols[i].dataOff = NULL;
     }
-
-    pCols->maxCols = maxCols;
   }
 
-  pCols->maxRowSize = maxRowSize;
-
-
   return pCols;
 }
 
@@ -357,8 +361,9 @@ int tdInitDataCols(SDataCols *pCols, STSchema *pSchema) {
   int oldMaxCols = pCols->maxCols;
   if (schemaNCols(pSchema) > oldMaxCols) {
     pCols->maxCols = schemaNCols(pSchema);
-    pCols->cols = (SDataCol *)realloc(pCols->cols, sizeof(SDataCol) * pCols->maxCols);
-    if (pCols->cols == NULL) return -1;
+    void* ptr = (SDataCol *)realloc(pCols->cols, sizeof(SDataCol) * pCols->maxCols);
+    if (ptr == NULL) return -1;
+    pCols->cols = ptr;
     for(i = oldMaxCols; i < pCols->maxCols; i++) {
       pCols->cols[i].pData = NULL;
       pCols->cols[i].dataOff = NULL;
@@ -366,10 +371,6 @@ int tdInitDataCols(SDataCols *pCols, STSchema *pSchema) {
     }
   }
 
-  if (schemaTLen(pSchema) > pCols->maxRowSize) {
-    pCols->maxRowSize = schemaTLen(pSchema);
-  }
-
   tdResetDataCols(pCols);
   pCols->numOfCols = schemaNCols(pSchema);
 
@@ -398,7 +399,7 @@ SDataCols *tdFreeDataCols(SDataCols *pCols) {
 }
 
 SDataCols *tdDupDataCols(SDataCols *pDataCols, bool keepData) {
-  SDataCols *pRet = tdNewDataCols(pDataCols->maxRowSize, pDataCols->maxCols, pDataCols->maxPoints);
+  SDataCols *pRet = tdNewDataCols(pDataCols->maxCols, pDataCols->maxPoints);
   if (pRet == NULL) return NULL;
 
   pRet->numOfCols = pDataCols->numOfCols;
@@ -413,7 +414,10 @@ SDataCols *tdDupDataCols(SDataCols *pDataCols, bool keepData) {
 
     if (keepData) {
       if (pDataCols->cols[i].len > 0) {
-        tdAllocMemForCol(&pRet->cols[i], pRet->maxPoints);
+        if(tdAllocMemForCol(&pRet->cols[i], pRet->maxPoints) < 0) {
+          tdFreeDataCols(pRet);
+          return NULL;
+        }
         pRet->cols[i].len = pDataCols->cols[i].len;
         memcpy(pRet->cols[i].pData, pDataCols->cols[i].pData, pDataCols->cols[i].len);
         if (IS_VAR_DATA_TYPE(pRet->cols[i].type)) {
@@ -584,9 +588,12 @@ static void tdMergeTwoDataCols(SDataCols *target, SDataCols *src1, int *iter1, i
       if ((key1 > key2) || (key1 == key2 && !TKEY_IS_DELETED(tkey2))) {
         for (int i = 0; i < src2->numOfCols; i++) {
           ASSERT(target->cols[i].type == src2->cols[i].type);
-          if (src2->cols[i].len > 0 && (forceSetNull || (!forceSetNull && !isNull(src2->cols[i].pData, src2->cols[i].type)))) {
+          if (src2->cols[i].len > 0 && !isNull(src2->cols[i].pData, src2->cols[i].type)) {
             dataColAppendVal(&(target->cols[i]), tdGetColDataOfRow(src2->cols + i, *iter2), target->numOfRows,
                              target->maxPoints);
+          } else if(!forceSetNull && key1 == key2 && src1->cols[i].len > 0) {
+            dataColAppendVal(&(target->cols[i]), tdGetColDataOfRow(src1->cols + i, *iter1), target->numOfRows,
+                             target->maxPoints);
           }
         }
         target->numOfRows++;
diff --git a/src/tsdb/src/tsdbCommit.c b/src/tsdb/src/tsdbCommit.c
index 6c98283189b8a3e83ff888bfb9530bb85127c27d..8f5f885d692f723bc1690a708571093bbe0a2717 100644
--- a/src/tsdb/src/tsdbCommit.c
+++ b/src/tsdb/src/tsdbCommit.c
@@ -722,7 +722,7 @@ static int tsdbInitCommitH(SCommitH *pCommith, STsdbRepo *pRepo) {
     return -1;
   }
 
-  pCommith->pDataCols = tdNewDataCols(0, 0, pCfg->maxRowsPerFileBlock);
+  pCommith->pDataCols = tdNewDataCols(0, pCfg->maxRowsPerFileBlock);
   if (pCommith->pDataCols == NULL) {
     terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
     tsdbDestroyCommitH(pCommith);
@@ -920,7 +920,6 @@ int tsdbWriteBlockImpl(STsdbRepo *pRepo, STable *pTable, SDFile *pDFile, SDataCo
     SDataCol * pDataCol = pDataCols->cols + ncol;
     SBlockCol *pBlockCol = pBlockData->cols + nColsNotAllNull;
 
-    // if (isNEleNull(pDataCol, rowsToWrite)) {  // all data to commit are NULL, just ignore it
     if (isAllRowsNull(pDataCol)) {  // all data to commit are NULL, just ignore it
       continue;
     }
@@ -1277,6 +1276,7 @@ static void tsdbLoadAndMergeFromCache(SDataCols *pDataCols, int *iter, SCommitIt
 
     if (key1 < key2) {
       for (int i = 0; i < pDataCols->numOfCols; i++) {
+        //TODO: dataColAppendVal may fail
         dataColAppendVal(pTarget->cols + i, tdGetColDataOfRow(pDataCols->cols + i, *iter), pTarget->numOfRows,
                          pTarget->maxPoints);
       }
@@ -1308,6 +1308,7 @@ static void tsdbLoadAndMergeFromCache(SDataCols *pDataCols, int *iter, SCommitIt
         ASSERT(!isRowDel);
 
         for (int i = 0; i < pDataCols->numOfCols; i++) {
+          //TODO: dataColAppendVal may fail
           dataColAppendVal(pTarget->cols + i, tdGetColDataOfRow(pDataCols->cols + i, *iter), pTarget->numOfRows,
                            pTarget->maxPoints);
         }
diff --git a/src/tsdb/src/tsdbCompact.c b/src/tsdb/src/tsdbCompact.c
index 62f9e41119ef7ed1b2f0151deeae6e6c4d4eb75e..5ccb9e90f2407561709d36a85ac3e992e5d5a8ba 100644
--- a/src/tsdb/src/tsdbCompact.c
+++ b/src/tsdb/src/tsdbCompact.c
@@ -296,7 +296,7 @@ static int tsdbCompactMeta(STsdbRepo *pRepo) {
       return -1;
     }
 
-    pComph->pDataCols = tdNewDataCols(0, 0, pCfg->maxRowsPerFileBlock);
+    pComph->pDataCols = tdNewDataCols(0, pCfg->maxRowsPerFileBlock);
     if (pComph->pDataCols == NULL) {
       terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
       tsdbDestroyCompactH(pComph);
diff --git a/src/tsdb/src/tsdbMemTable.c b/src/tsdb/src/tsdbMemTable.c
index 8bb2d1c44e17d7409c5e290adf3cf0e7d1e79528..e766d97a97a5905db87691426d282a219eef9d68 100644
--- a/src/tsdb/src/tsdbMemTable.c
+++ b/src/tsdb/src/tsdbMemTable.c
@@ -702,11 +702,12 @@ static int tsdbScanAndConvertSubmitMsg(STsdbRepo *pRepo, SSubmitMsg *pMsg) {
 }
 
 //row1 has higher priority
-static SMemRow tsdbInsertDupKeyMerge(SMemRow row1, SMemRow row2, STsdbRepo* pRepo, STSchema **ppSchema1, STSchema **ppSchema2, STable* pTable, int32_t* pAffectedRows, int64_t* pPoints, SMemRow* pLastRow) {
+static SMemRow tsdbInsertDupKeyMerge(SMemRow row1, SMemRow row2, STsdbRepo* pRepo,
+                                     STSchema **ppSchema1, STSchema **ppSchema2,
+                                     STable* pTable, int32_t* pPoints, SMemRow* pLastRow) {
   
   //for compatiblity, duplicate key inserted when update=0 should be also calculated as affected rows!
   if(row1 == NULL && row2 == NULL && pRepo->config.update == TD_ROW_DISCARD_UPDATE) {
-    (*pAffectedRows)++;
     (*pPoints)++;
     return NULL;
   }
@@ -715,7 +716,6 @@ static SMemRow tsdbInsertDupKeyMerge(SMemRow row1, SMemRow row2, STsdbRepo* pRep
     void* pMem = tsdbAllocBytes(pRepo, memRowTLen(row1));
     if(pMem == NULL) return NULL;
     memRowCpy(pMem, row1);
-    (*pAffectedRows)++;
     (*pPoints)++;
     *pLastRow = pMem;
     return pMem;
@@ -750,18 +750,16 @@ static SMemRow tsdbInsertDupKeyMerge(SMemRow row1, SMemRow row2, STsdbRepo* pRep
   if(pMem == NULL) return NULL;
   memRowCpy(pMem, tmp);
 
-  (*pAffectedRows)++;
   (*pPoints)++;
-
   *pLastRow = pMem;
   return pMem;
 }
 
 static void* tsdbInsertDupKeyMergePacked(void** args) {
-  return tsdbInsertDupKeyMerge(args[0], args[1], args[2], (STSchema**)&args[3], (STSchema**)&args[4], args[5], args[6], args[7], args[8]);
+  return tsdbInsertDupKeyMerge(args[0], args[1], args[2], (STSchema**)&args[3], (STSchema**)&args[4], args[5], args[6], args[7]);
 }
 
-static void tsdbSetupSkipListHookFns(SSkipList* pSkipList, STsdbRepo *pRepo, STable *pTable, int32_t* pAffectedRows, int64_t* pPoints, SMemRow* pLastRow) {
+static void tsdbSetupSkipListHookFns(SSkipList* pSkipList, STsdbRepo *pRepo, STable *pTable, int32_t* pPoints, SMemRow* pLastRow) {
 
   if(pSkipList->insertHandleFn == NULL) {
     tGenericSavedFunc *dupHandleSavedFunc = genericSavedFuncInit((GenericVaFunc)&tsdbInsertDupKeyMergePacked, 9);
@@ -769,17 +767,16 @@ static void tsdbSetupSkipListHookFns(SSkipList* pSkipList, STsdbRepo *pRepo, STa
     dupHandleSavedFunc->args[3] = NULL;
     dupHandleSavedFunc->args[4] = NULL;
     dupHandleSavedFunc->args[5] = pTable;
-    dupHandleSavedFunc->args[6] = pAffectedRows;
-    dupHandleSavedFunc->args[7] = pPoints;
-    dupHandleSavedFunc->args[8] = pLastRow;
     pSkipList->insertHandleFn = dupHandleSavedFunc;
   }
+  pSkipList->insertHandleFn->args[6] = pPoints;
+  pSkipList->insertHandleFn->args[7] = pLastRow;
 }
 
 static int tsdbInsertDataToTable(STsdbRepo* pRepo, SSubmitBlk* pBlock, int32_t *pAffectedRows) {
 
   STsdbMeta       *pMeta = pRepo->tsdbMeta;
-  int64_t          points = 0;
+  int32_t          points = 0;
   STable          *pTable = NULL;
   SSubmitBlkIter   blkIter = {0};
   SMemTable       *pMemTable = NULL;
@@ -830,9 +827,10 @@ static int tsdbInsertDataToTable(STsdbRepo* pRepo, SSubmitBlk* pBlock, int32_t *
 
   SMemRow lastRow = NULL;
   int64_t osize = SL_SIZE(pTableData->pData);
-  tsdbSetupSkipListHookFns(pTableData->pData, pRepo, pTable, pAffectedRows, &points, &lastRow);
+  tsdbSetupSkipListHookFns(pTableData->pData, pRepo, pTable, &points, &lastRow);
   tSkipListPutBatchByIter(pTableData->pData, &blkIter, (iter_next_fn_t)tsdbGetSubmitBlkNext);
   int64_t dsize = SL_SIZE(pTableData->pData) - osize;
+  (*pAffectedRows) += points;
 
 
   if(lastRow != NULL) {
diff --git a/src/tsdb/src/tsdbMeta.c b/src/tsdb/src/tsdbMeta.c
index 619b32b3d92cc27f93855e3c5ffe42d327bc4695..21150c66e21cf2488981bd9d475f333073e7aa22 100644
--- a/src/tsdb/src/tsdbMeta.c
+++ b/src/tsdb/src/tsdbMeta.c
@@ -17,7 +17,6 @@
 #define TSDB_SUPER_TABLE_SL_LEVEL 5
 #define DEFAULT_TAG_INDEX_COLUMN 0
 
-static int     tsdbCompareSchemaVersion(const void *key1, const void *key2);
 static char *  getTagIndexKey(const void *pData);
 static STable *tsdbNewTable();
 static STable *tsdbCreateTableFromCfg(STableCfg *pCfg, bool isSuper, STable *pSTable);
diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index c578555df274aa970c1f107463977c61c0a60d16..716f82d1545d5aa3adb257dc3ed8ea3047acb3ca 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -466,7 +466,7 @@ static STsdbQueryHandle* tsdbQueryTablesImpl(STsdbRepo* tsdb, STsdbQueryCond* pC
   STsdbMeta* pMeta = tsdbGetMeta(tsdb);
   assert(pMeta != NULL);
 
-  pQueryHandle->pDataCols = tdNewDataCols(pMeta->maxRowBytes, pMeta->maxCols, pQueryHandle->pTsdb->config.maxRowsPerFileBlock);
+  pQueryHandle->pDataCols = tdNewDataCols(pMeta->maxCols, pQueryHandle->pTsdb->config.maxRowsPerFileBlock);
   if (pQueryHandle->pDataCols == NULL) {
     tsdbError("%p failed to malloc buf for pDataCols, %"PRIu64, pQueryHandle, pQueryHandle->qId);
     terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
@@ -1446,7 +1446,7 @@ static int doBinarySearchKey(char* pValue, int num, TSKEY key, int order) {
   return midPos;
 }
 
-int32_t doCopyRowsFromFileBlock(STsdbQueryHandle* pQueryHandle, int32_t capacity, int32_t numOfRows, int32_t start, int32_t end) {
+static int32_t doCopyRowsFromFileBlock(STsdbQueryHandle* pQueryHandle, int32_t capacity, int32_t numOfRows, int32_t start, int32_t end) {
   char* pData = NULL;
   int32_t step = ASCENDING_TRAVERSE(pQueryHandle->order)? 1 : -1;
 
@@ -1481,7 +1481,7 @@ int32_t doCopyRowsFromFileBlock(STsdbQueryHandle* pQueryHandle, int32_t capacity
       pData = (char*)pColInfo->pData + (capacity - numOfRows - num) * pColInfo->info.bytes;
     }
 
-    if (pColInfo->info.colId == src->colId) {
+    if (!isAllRowsNull(src) && pColInfo->info.colId == src->colId) {
       if (pColInfo->info.type != TSDB_DATA_TYPE_BINARY && pColInfo->info.type != TSDB_DATA_TYPE_NCHAR) {
         memmove(pData, (char*)src->pData + bytes * start, bytes * num);
       } else {  // handle the var-string
diff --git a/src/tsdb/src/tsdbReadImpl.c b/src/tsdb/src/tsdbReadImpl.c
index 711c32535bb00bae55d7faafadc115a22c76a949..74d41cce194f9921ee0c521de9e329bad5eeb3f9 100644
--- a/src/tsdb/src/tsdbReadImpl.c
+++ b/src/tsdb/src/tsdbReadImpl.c
@@ -42,14 +42,14 @@ int tsdbInitReadH(SReadH *pReadh, STsdbRepo *pRepo) {
     return -1;
   }
 
-  pReadh->pDCols[0] = tdNewDataCols(0, 0, pCfg->maxRowsPerFileBlock);
+  pReadh->pDCols[0] = tdNewDataCols(0, pCfg->maxRowsPerFileBlock);
   if (pReadh->pDCols[0] == NULL) {
     terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
     tsdbDestroyReadH(pReadh);
     return -1;
   }
 
-  pReadh->pDCols[1] = tdNewDataCols(0, 0, pCfg->maxRowsPerFileBlock);
+  pReadh->pDCols[1] = tdNewDataCols(0, pCfg->maxRowsPerFileBlock);
   if (pReadh->pDCols[1] == NULL) {
     terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
     tsdbDestroyReadH(pReadh);
@@ -463,7 +463,7 @@ static int tsdbLoadBlockDataImpl(SReadH *pReadh, SBlock *pBlock, SDataCols *pDat
     SDataCol *pDataCol = &(pDataCols->cols[dcol]);
     if (dcol != 0 && ccol >= pBlockData->numOfCols) {
       // Set current column as NULL and forward
-      dataColSetNEleNull(pDataCol, pBlock->numOfRows, pDataCols->maxPoints);
+      dataColReset(pDataCol);
       dcol++;
       continue;
     }
@@ -503,7 +503,7 @@ static int tsdbLoadBlockDataImpl(SReadH *pReadh, SBlock *pBlock, SDataCols *pDat
       ccol++;
     } else {
       // Set current column as NULL and forward
-      dataColSetNEleNull(pDataCol, pBlock->numOfRows, pDataCols->maxPoints);
+      dataColReset(pDataCol);
       dcol++;
     }
   }
@@ -608,7 +608,7 @@ static int tsdbLoadBlockDataColsImpl(SReadH *pReadh, SBlock *pBlock, SDataCols *
       }
 
       if (pBlockCol == NULL) {
-        dataColSetNEleNull(pDataCol, pBlock->numOfRows, pDataCols->maxPoints);
+        dataColReset(pDataCol);
         continue;
       }