MySQL 8.0 新特性之原子 DDL
MySQL 8.0 新增原子 DDL(Atomic DDL)特性,支持针对库和表相关的 DDL 操作,但前提对象必须是 InnoDB 存储引擎,同时也支持部分非表相关的 DDL 语句,如 CREATE|ALTER|DROP USER,GRANT,REVOKE
等。
新增 innodb_print_ddl_logs
参数,用于控制是否将 DDL 操作日志打印到数据库日志中,默认为 OFF
。
测试用例1:原子 DDL
MySQL 5.7
mysql> show tables;
+--------------------+
| Tables_in_sbtest57 |
+--------------------+
| t1 |
| t2 |
+--------------------+
3 rows in set (0.00 sec)
## 执行删除表操作,此时命令报错,因为表 t3 并不存在
mysql> drop table t2,t3;
ERROR 1051 (42S02): Unknown table 'sbtest57.t3'
## 上条 DDL 语句虽执行报错,但 t2 仍然被删除
mysql> show tables;
+--------------------+
| Tables_in_sbtest57 |
+--------------------+
| t1 |
+--------------------+
2 rows in set (0.00 sec)
MySQL 8.0
mysql> show tables;
+-------------------+
| Tables_in_sbtest8 |
+-------------------+
| t1 |
| t2 |
+-------------------+
4 rows in set (0.00 sec)
## 执行删除表操作,此时同样报错
mysql> drop table t2,t3;
ERROR 1051 (42S02): Unknown table 'sbtest8.t3'
## 查看表,t2 未被删除,符合原子 DDL 特性
mysql> show tables;
+-------------------+
| Tables_in_sbtest8 |
+-------------------+
| t1 |
| t2 |
+-------------------+
4 rows in set (0.00 sec)
测试用例2:innodb_print_ddl_logs 参数
## MySQL 8.0
## log_error_verbosity,用于控制错误日志中事件的详细程度,默认为 2,设置为 3 可打印更为详细的信息
mysql> set global log_error_verbosity=3;
mysql> set global innodb_print_ddl_logs=1;
mysql> drop table t1;
Query OK, 0 rows affected (0.01 sec)
## MySQL 错误日志
2024-03-06T14:09:47.311610+08:00 31 [Note] [MY-012475] [InnoDB] DDL log insert : [DDL record: DROP, id=68, thread_id=31, table_id=1077]
2024-03-06T14:09:47.311829+08:00 31 [Note] [MY-012473] [InnoDB] DDL log insert : [DDL record: DELETE SPACE, id=69, thread_id=31, space_id=15, old_file_path=./sbtest8/t1.ibd]
2024-03-06T14:09:47.316996+08:00 31 [Note] [MY-012485] [InnoDB] DDL log post ddl : begin for thread id : 31
2024-03-06T14:09:47.317073+08:00 31 [Note] [MY-012479] [InnoDB] DDL log replay : [DDL record: DELETE SPACE, id=69, thread_id=31, space_id=15, old_file_path=./sbtest8/t1.ibd]
2024-03-06T14:09:47.318231+08:00 31 [Note] [MY-012479] [InnoDB] DDL log replay : [DDL record: DROP, id=68, thread_id=31, table_id=1077]
2024-03-06T14:09:47.319411+08:00 31 [Note] [MY-012486] [InnoDB] DDL log post ddl : end for thread id : 31
注:更多关于原子 DDL 的信息,请查看 《MySQL 8.0 Reference Manual:15.1.1 Atomic Data Definition Statement Support》。