diff --git a/src/client/src/tscParseLineProtocol.c b/src/client/src/tscParseLineProtocol.c
index 9af7547b1cc091d9006b7425104765687bef65e7..c4fdead649e991e9ba820fc83709000ded2d2733 100644
--- a/src/client/src/tscParseLineProtocol.c
+++ b/src/client/src/tscParseLineProtocol.c
@@ -246,9 +246,9 @@ static int32_t buildDataPointSchemas(TAOS_SML_DATA_POINT* points, int numPoint,
         buildSmlChildTableName(point, info);
       }
       char tagNullName[TSDB_COL_NAME_LEN] = {0};
-      int16_t nameLen = strlen(tsSmlTagNullName);
+      size_t nameLen = strlen(tsSmlTagNullName);
       strncpy(tagNullName, tsSmlTagNullName, nameLen);
-      addEscapeCharToString(tagNullName, nameLen);
+      addEscapeCharToString(tagNullName, (int32_t)nameLen);
       size_t* pTagNullIdx = taosHashGet(pStableSchema->tagHash, tagNullName, nameLen + TS_ESCAPE_CHAR_SIZE);
       if (!pTagNullIdx) {
         SSchema tagNull = {0};