diff --git a/src/inc/taosdef.h b/src/inc/taosdef.h
index 7c552a0da0ba714de1b93fda35c74338b0aa9263..77e21554889e96ba634f3e5c5e8095c75eff7cdd 100644
--- a/src/inc/taosdef.h
+++ b/src/inc/taosdef.h
@@ -321,8 +321,8 @@ do { \
 #define TSDB_MAX_JOIN_TABLE_NUM         10
 #define TSDB_MAX_UNION_CLAUSE           5
 
-#define TSDB_MAX_BINARY_LEN            (TSDB_MAX_BYTES_PER_ROW-TSDB_KEYSIZE)
-#define TSDB_MAX_NCHAR_LEN             (TSDB_MAX_BYTES_PER_ROW-TSDB_KEYSIZE)
+#define TSDB_MAX_BINARY_LEN            (16384-TSDB_KEYSIZE) // TD-4666: TODO use TSDB_MAX_BYTES_PER_ROW later. 
+#define TSDB_MAX_NCHAR_LEN             (16384-TSDB_KEYSIZE) // TD-4666: TODO use TSDB_MAX_BYTES_PER_ROW later. 
 #define PRIMARYKEY_TIMESTAMP_COL_INDEX  0
 
 #define TSDB_MAX_RPC_THREADS            5