diff --git a/src/client/src/tscParseInsert.c b/src/client/src/tscParseInsert.c
index 5d3f41acd3dd3aeab02823d85a2d7bf4a9a930ce..0081dac11bbe53295d538cafe2d16fdc11ed9bb0 100644
--- a/src/client/src/tscParseInsert.c
+++ b/src/client/src/tscParseInsert.c
@@ -685,8 +685,8 @@ static int32_t tsParseOneColumnKV(SSchema *pSchema, SStrToken *pToken, char *pay
       if (pToken->type == TK_NULL) {
         payloadColSetId(payload, pSchema->colId);
         payloadColSetType(payload, pSchema->type);
-        memcpy(POINTER_SHIFT(payloadStart,tOffset), tdGetNullVal(TSDB_DATA_TYPE_NCHAR), VARSTR_HEADER_SIZE + INT_BYTES);
-        *sizeAppend = (TDRowLenT)(VARSTR_HEADER_SIZE + INT_BYTES);
+        memcpy(POINTER_SHIFT(payloadStart,tOffset), tdGetNullVal(TSDB_DATA_TYPE_NCHAR), VARSTR_HEADER_SIZE + TSDB_NCHAR_SIZE);
+        *sizeAppend = (TDRowLenT)(VARSTR_HEADER_SIZE + TSDB_NCHAR_SIZE);
       } else {
         // if the converted output len is over than pColumnModel->bytes, return error: 'Argument list too long'
         int32_t output = 0;
diff --git a/src/inc/taosdef.h b/src/inc/taosdef.h
index acebdaa30a9055f894d791101ab3f1ebeeda8c2e..7c6b3bbed91dd5a8cca8d6670a848ada7d55a42f 100644
--- a/src/inc/taosdef.h
+++ b/src/inc/taosdef.h
@@ -199,9 +199,9 @@ do { \
    *  In some scenarios uint16_t (0~65535) is used to store the row len.
    *  - Firstly, we use 65531(65535 - 4), as the SDataRow and SKVRow including 4 bits header.
    *  - Secondly, if all cols are VarType except primary key, we need 4 bits to store the offset, thus
-   *    the final value is 65531-8-4095*4 = 49143.
+   *    the final value is 65531-(4096-1)*4 = 49151.
    */
-#define TSDB_MAX_BYTES_PER_ROW    49143
+#define TSDB_MAX_BYTES_PER_ROW    49151
 #define TSDB_MAX_TAGS_LEN         16384
 #define TSDB_MAX_TAGS             128
 #define TSDB_MAX_TAG_CONDITIONS   1024