MySQL 如何获得当前会话的TRX_ID 事务ID

mysql>  show variables like '%commit%';
+--------------------------------+-------+
| Variable_name                  | Value |
+--------------------------------+-------+
| autocommit                     | OFF   |
| innodb_commit_concurrency      | 0     |
| innodb_flush_log_at_trx_commit | 1     |
+--------------------------------+-------+

mysql> SELECT TRX_ID FROM INFORMATION_SCHEMA.INNODB_TRX  WHERE TRX_MYSQL_THREAD_ID = CONNECTION_ID();