gtid_mode=on with log_bin=off

[aaron chan]

"GTIDs are stored in the mysql.gtid_executed table only when gtid_mode is ON or ON_PERMISSIVE. GTIDs are stored in this table without regard to whether binary logging is enabled.".

however,in 5.7.[17-19],when i disable binary logging,there's nothing in mysql.gtid_executed table,and @@global.gtid_executed is also null. is this a bug?or that's because my misunderstanding of the concept?

mysql> select @@global.gtid_mode,@@global.log_bin;
+--------------------+------------------+
| @@global.gtid_mode | @@global.log_bin |
+--------------------+------------------+
| ON | 0 |
+--------------------+------------------+
mysql> flush logs;
Query OK, 0 rows affected (0.00 sec)

mysql> select @@global.gtid_executed;
+------------------------+
| @@global.gtid_executed |
+------------------------+
| |
+------------------------+
1 row in set (0.00 sec)

mysql> select * from mysql.gtid_executed;
Empty set (0.00 sec)