标签:usr into card 应该 模拟 online one connect 情况
1.创建一个和源表一样表结构的新表
2.空表执行表结构修改
3.在源表创建三个触发器分别对应insert、update、delete操作
4.copy数据到新表
5.将源表改名,并将新表改成源表名
6.删除源表
7.删除trigger
1.源表不能有触发器存在
不是不能有任何触发器,只是不能有针对insert、update、delete的触发器存在,因为一个表上不能有两个相同类型的触发器
2.源表必须要有主键
3.源表有外键,必须使用--alter-foreign-keys-method 指定特定的值
1.如果是add column并且定义了not null,那么必须指定default值,否则会失败
The new table `test`.`_t1_new` does not have a PRIMARY KEY or a unique index which is required for the DELETE trigger.
Please check you have at least one UNIQUE and NOT NULLABLE index.
Cannot connect to MySQL: DBI connect(‘test;host=10.0.1.51;mysql_read_default_group=client‘,‘root‘,...) failed: Access denied for user ‘root‘@‘10.0.1.51‘ (using password: YES) at /usr/bin/pt-online-schema-change line 2345.
The table `db_name`.`table_name` has triggers. This tool needs to create its own triggers, so the table cannot already have triggers.
连接实例信息,缩写-h xxx -u xxx -p xxx,密码可以使用参数--ask-pass 手动输入
指定要ddl的数据库名和表名
创建和修改新表,但不会创建触发器、复制数据、和替换原表。并不真正执行,可以看到生成的执行语句,了解其执行步骤与细节,和--print配合最佳
修改表,则指定该参数。真正执行alter。–dry-run与–execute必须指定一个,二者相互排斥
----[no]check-alter
解析并检查alter指定的命令:
在以前的版本,使用CHANGE COLUMN命令会导致数据丢失,现在的版本虽然改进,但是在执行前,还应该使用 --dry-run 和 --print 查看一下详细的操作情况.
db01 [test]>create database yufenchi charset utf8mb4;
db01 [test]>use yufenchi
db01 [yufenchi]>create table t1(id int primary key,name varchar(10),age tinyint);
b01 [yufenchi]>insert into t1 values(1,‘zs‘,18),(2,‘lisi‘,19),(3,‘wangwu‘,20);
db01 [yufenchi]>select * from t1;
+----+--------+------+
| id | name | age |
+----+--------+------+
| 1 | zs | 18 |
| 2 | lisi | 19 |
| 3 | wangwu | 20 |
+----+--------+------+
[root@db01 ~]# pt-online-schema-change --host=10.0.1.51 -uroot -p123 --alter "add column qq int(20) default 0" D=yufenchi,t=t1 --execute --no-check-alter
登录数据库并检查
db01 [yufenchi]>select * from t1;
+----+--------+------+------+
| id | name | age | qq |
+----+--------+------+------+
| 1 | zs | 18 | 0 |
| 2 | lisi | 19 | 0 |
| 3 | wangwu | 20 | 0 |
+----+--------+------+------+
[root@db01 ~]# pt-online-schema-change --host=10.0.1.51 -uroot -p123 --alter "add column weixin int(20) not null default 0" D=yufenchi,t=t1 --execute --print --no-check-alter
db01 [yufenchi]>select * from t1;
+----+--------+------+------+--------+
| id | name | age | qq | weixin |
+----+--------+------+------+--------+
| 1 | zs | 18 | 0 | 0 |
| 2 | lisi | 19 | 0 | 0 |
| 3 | wangwu | 20 | 0 | 0 |
+----+--------+------+------+--------+
[root@db01 ~]# pt-online-schema-change --host=10.0.1.51 -uroot --ask-pass --alter "modify name varchar(20) default 0" D=yufenchi,t=t1 --execute --print --no-check-alter
db01 [yufenchi]>show create table t1;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| t1 | CREATE TABLE `t1` (
`id` int(11) NOT NULL,
`name` varchar(20) DEFAULT ‘0‘,
`age` tinyint(4) DEFAULT NULL,
`qq` int(20) DEFAULT ‘0‘,
`weixin` int(20) NOT NULL DEFAULT ‘0‘,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 |
[root@db01 ~]# pt-online-schema-change --host=10.0.1.51 -uroot --ask-pass --alter "change name sname varchar(20) default 0" D=yufenchi,t=t1 --execute --no-check-alter
db01 [yufenchi]>desc t1;
+--------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| id | int(11) | NO | PRI | NULL | |
| sname | varchar(20) | YES | | 0 | |
| age | tinyint(4) | YES | | NULL | |
| qq | int(20) | YES | | 0 | |
| weixin | int(20) | NO | | 0 | |
+--------+-------------+------+-----+---------+-------+
[root@db01 ~]# pt-online-schema-change --host=10.0.1.51 -uroot -p123 --alter "add index idx_sna(sname)" D=yufenchi,t=t1 --execute --no-check-alter
db01 [yufenchi]>show index from t1;
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| t1 | 0 | PRIMARY | 1 | id | A | 3 | NULL | NULL | | BTREE | | |
| t1 | 1 | idx_sna | 1 | sname | A | 3 | NULL | NULL | YES | BTREE | | |
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--
标签:usr into card 应该 模拟 online one connect 情况
原文地址:https://www.cnblogs.com/yufenchi/p/12961750.html