diff --git a/source/common/src/tdatablock.c b/source/common/src/tdatablock.c
index 3558feaa66..b439f0437c 100644
--- a/source/common/src/tdatablock.c
+++ b/source/common/src/tdatablock.c
@@ -120,6 +120,7 @@ int32_t colDataSetVal(SColumnInfoData* pColumnInfoData, uint32_t rowIndex, const
     pColumnInfoData->varmeta.length += dataLen;
   } else {
     memcpy(pColumnInfoData->pData + pColumnInfoData->info.bytes * rowIndex, pData, pColumnInfoData->info.bytes);
+    colDataClearNull_f(pColumnInfoData->nullbitmap, rowIndex);
   }
 
   return 0;
@@ -1857,7 +1858,6 @@ static char* formatTimestamp(char* buf, int64_t val, int precision) {
   return buf;
 }
 
-#if 0
 void blockDebugShowDataBlock(SSDataBlock* pBlock, const char* flag) {
   SArray* dataBlocks = taosArrayInit(1, sizeof(SSDataBlock*));
   taosArrayPush(dataBlocks, &pBlock);
@@ -1950,11 +1950,10 @@ void blockDebugShowDataBlocks(const SArray* dataBlocks, const char* flag) {
   }
 }
 
-#endif
 
 // for debug
 char* dumpBlockData(SSDataBlock* pDataBlock, const char* flag, char** pDataBuf) {
-  int32_t size = 2048;
+  int32_t size = 2048*1024;
   *pDataBuf = taosMemoryCalloc(size, 1);
   char*   dumpBuf = *pDataBuf;
   char    pBuf[128] = {0};
@@ -1970,7 +1969,7 @@ char* dumpBlockData(SSDataBlock* pDataBlock, const char* flag, char** pDataBuf)
   if (len >= size - 1) return dumpBuf;
 
   for (int32_t j = 0; j < rows; j++) {
-    len += snprintf(dumpBuf + len, size - len, "%s |", flag);
+    len += snprintf(dumpBuf + len, size - len, "%s %d|", flag, j);
     if (len >= size - 1) return dumpBuf;
 
     for (int32_t k = 0; k < colNum; k++) {