Online DDL：
一.FIC之前的添加删除二级索引：
- 1.首先创建临时表，定义目标新表的选项和索引
- 2.逐行拷贝数据到临时表
- 3.插入行时更新索引信息
- 4.数据全部被拷贝到新表后，删除旧表，rename新表
为保证数据一致性，旧表复制数据到新表的全程只允许读，不允许改
二.5.1 5.5FIC新特性 fast index creation
- 1.创建二级索引给表加上共享S锁
- 2.创建过程不需要重建表
- 3.删除二级索引只需要更新内部视图，并标记索引的空间可用，去除数据库元数据的关于该索引的定义
依然只能读，不允许改，但加快了修改索引的速度
因为聚簇索引的特性，主键索引修改依然需要通过旧方式copy table过程
三.5.6之后
- 1.之前FIC只对二级索引创建删除有效，5.6之后将此特性扩展到添加列、删除列，修改列类型、列重命名、设置默认值
Online DDL选项
索引的copy与inplace创建
一.ALGORITHM=COPY
- 1.新建带索引(主键索引)的临时表
- 2.将原表锁定，禁止DML操作，只允许select查询
- 3.将原表数据拷贝到临时表
- 4.禁止读写，进行rename，升级字典锁
- 5.完成创建索引操作
需要记录undo和redo，效率不如inplace，短期占用buffer pool，影响性能
二.ALGORITHM=INPLACE
- 1.创建索引(二级索引，主键+普通字段)数据字典
- 2.加表共享锁S，禁止DML，允许select查询
- 3.读取聚簇索引，构造新的索引项，排序并插入新索引
- 5.等待打开当前表的所有只读事务提交
- 6.创建索引结束
避免重建表带来的IO和CPU消耗，保证DDL期间的性能和并发
三.ALGORITHM=DEFAULT
- 1.
alter table后面什么都不加的时候，默认是这个方式 - 2.如果
old_alter_table为OFF，默认就是inplace方式 - 3.inplace不支持则进行copy
四.lock选项
控制是否锁表，根据不同的DDL操作类型表现不同，mysql原则是尽量不锁表，但是修改主键这样的昂贵操作不得不锁表
- 1.
LOCK=NONE，允许DDL期间并发读写涉及的表，显式指定时，当不支持对该表的继续写入，则alter语句失败，是ALGORITHM=COPY的默认lock级别 - 2.
LOCK=SHARED，DDL期间表上的写操作会被阻塞，但是不影响select - 3.
LOCK=DEFAULT，让mysql自己判断lock模式，原则是尽量不锁表 - 4.
LOCK=EXCLUSIVE，DDL期间该表不可用，堵塞任何读写请求，使用场景：- 最短时间内完成
- 短时间表不可用能刚接受
注意：
- 1.任何模式下，online DDL开始之前都需要一个短时间的排它锁X来准备环境
- 2.当alter命令发出后，会首先等待该表上的其他操作完成
- 3.alter命令之后的其他请求会出现等待MDL锁
- 4.alter完成之前，其他DDL也会被阻塞一小段时间？
ddl实现细节
Prepare阶段
- 1.创建frm文件
- 2.持有exclusive-mdl锁，禁止读写，速度非常快
- 3.根据alter类型，确定执行方式，检查存储引擎是否支持inplace，不支持则使用copy---copy,online-rebuild：重新组织表,online-norebuild：改数据字典即可
- 4.更新数据字典的内存对象
- 5.分配row_log对象记录增量，记录DDL期间数据修改的日志，如果日志量超过参数
innodb_online_alter_log_max_size的上限，则DDL失败 - 6.生成临时ibd文件（rebuild类型)
ddl执行阶段
- 1.降级exclusvie-mdl锁，允许读写
- 2.扫描原表的聚簇索引每条记录
- 3.遍历新表的聚簇索引和二级索引，逐一处理
- 4.根据记录构造对应的索引项
- 5.将构造索引项插入sort_buffer块进行排序
- 6.将sort_buffer块中的排序结果插入新的索引
- 7.处理ddl执行过程中产生的增量-row-log，rebuild类型需要
commit阶段
- 1.升级到exclusive-mdl索引，禁止读写
- 2.应用最后row_log中产生的日志
- 3.更新innodb的数据字典
- 4.提交事务-刷数据的redo日志
- 5.修改统计信息
- 6.rename临时ibd文件，frm文件
- 7.变更完成
DDL SQL组合使用
1.全部变更写到一条sql里面
alter table t1 add index idx1(c1),add unique index idx2(c2),change c4_old_name c4_new_name integer unsigned;
copy方式下，效率最高，只需要拷贝1次
2.每个变更一条sql
alter table t1 add index idx1(c1);
alter table t1 add unique index idx2(c2);
alter table t1 change c4_old_name c4_new_name integer unsigned not null;
测试
1.显式开启一个查询事务，默认DDL并不好？理论与实际不一样
- session1
mysql session 1 >use db1;
Database changed
mysql session 1 >begin;
Query OK, 0 rows affected (0.00 sec)
mysql session 1 >select * from t1;
+------+------+
| id | name |
+------+------+
| 1 | yzw |
+------+------+
1 row in set (0.00 sec)
mysql session 1 >
开始一个事务，执行简单查询
- session2
mysql session 2 >use db1
Database changed
mysql session 2 >alter table t1 add index idx_id(id);
Query OK, 0 rows affected (9 min 47.09 sec)
Records: 0 Duplicates: 0 Warnings: 0
被阻塞9分47.09秒
- session3
mysql session 3 >use db1;
Database changed
mysql session 3 >select * from t1;
+------+------+
| id | name |
+------+------+
| 1 | yzw |
+------+------+
1 row in set (9 min 37.60 sec)
被阻塞9分37.60秒
- session4
mysql session 4 >mysql session 4 >show processlist;
+----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+-------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+-------------------------------------+
| 47 | repl | 172.16.3.154:42173 | NULL | Binlog Dump GTID | 432908 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 48 | repl | 172.16.3.153:57245 | NULL | Binlog Dump GTID | 432806 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 53 | mha | 172.16.3.152:43681 | NULL | Sleep | 0 | | NULL |
| 67 | root | localhost | db1 | Query | 23 | Waiting for table metadata lock | alter table t1 add index idx_id(id) |
| 68 | root | localhost | db1 | Query | 14 | Waiting for table metadata lock | select * from t1 |
| 69 | root | localhost | NULL | Query | 0 | starting | show processlist |
| 70 | root | localhost | db1 | Sleep | 36 | | NULL |
+----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+-------------------------------------+
7 rows in set (0.00 sec)
session2的alter和session3的select被阻塞
都在等待MDL锁 alter
2.第二个加了算法，时间更长，dml并发更好？理论与实际不一样
- session1
mysql session 1 >begin;
Query OK, 0 rows affected (0.00 sec)
mysql session 1 >select * from t1;
+------+------+
| id | name |
+------+------+
| 1 | yzw |
+------+------+
1 row in set (0.00 sec)
开启一个事务
- session2
mysql session 2 >use db1
Database changed
mysql session 2 >alter table t1 add index idx_id(id), algorithm=inplace,lock=none;
Query OK, 0 rows affected (9 min 34.48 sec)
Records: 0 Duplicates: 0 Warnings: 0
显示指定inplace方式增加索引
- session3
mysql session 3 >use db1;
Database changed
mysql session 3 >select * from t1;
+------+------+
| id | name |
+------+------+
| 1 | yzw |
+------+------+
1 row in set (9 min 22.13 sec)
查询被阻塞
- session4
mysql session 4 >show processlist;
+----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+------------------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+------------------------------------------------------------------+
| 47 | repl | 172.16.3.154:42173 | NULL | Binlog Dump GTID | 500684 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 48 | repl | 172.16.3.153:57245 | NULL | Binlog Dump GTID | 500582 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 53 | mha | 172.16.3.152:43681 | NULL | Sleep | 1 | | NULL |
| 71 | root | localhost | db1 | Sleep | 45 | | NULL |
| 72 | root | localhost | db1 | Query | 20 | Waiting for table metadata lock | alter table t1 add index idx_id(id), algorithm=inplace,lock=none |
| 73 | root | localhost | db1 | Query | 7 | Waiting for table metadata lock | select * from t1 |
| 74 | root | localhost | NULL | Query | 0 | starting | show processlist |
+----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+------------------------------------------------------------------+
7 rows in set (0.00 sec)
等待MDL锁
3.原有copy方式DDL
1.构造测试数据
sysbench --test=insert.lua --oltp-table-size=5000000 --mysql-table-engine=innodb --mysql-user=root --mysql-password=123456 --mysql-port=3306 --mysql-host=localhost --mysql-db=test --max-requests=0 --time=60 --oltp-tables-count=2 --report-interval=10 --threads=2 prepare
2.使用原有copy方式进行ddl
mysql session 1 >select version();
+------------+
| version() |
+------------+
| 5.7.16-log |
+------------+
1 row in set (0.00 sec)
mysql session 1 >show create table sbtest1
-> ;
+---------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+---------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| sbtest1 | CREATE TABLE `sbtest1` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`k` int(10) unsigned NOT NULL DEFAULT ‘0‘,
`c` char(120) NOT NULL DEFAULT ‘‘,
`pad` char(60) NOT NULL DEFAULT ‘‘,
PRIMARY KEY (`id`),
KEY `k_1` (`k`)
) ENGINE=InnoDB AUTO_INCREMENT=5000001 DEFAULT CHARSET=utf8 MAX_ROWS=1000000 |
+---------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql session 1 >show variables like ‘%old_alter_table%‘;
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| old_alter_table | OFF |
+-----------------+-------+
1 row in set (0.01 sec)
mysql session 1 >set global old_alter_table=on;
Query OK, 0 rows affected (0.00 sec)
mysql session 1 >show variables like ‘old_alter_table‘;
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| old_alter_table | OFF |
+-----------------+-------+
1 row in set (0.00 sec)
mysql session 1 >set old_alter_table=1;
Query OK, 0 rows affected (0.00 sec)
mysql session 1 >show variables like ‘old_alter_table‘;
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| old_alter_table | ON |
+-----------------+-------+
1 row in set (0.00 sec)
mysql session 1 >show index from sbtest1;
+---------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+---------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| sbtest1 | 0 | PRIMARY | 1 | id | A | 4804854 | NULL | NULL | | BTREE | | |
| sbtest1 | 1 | k_1 | 1 | k | A | 883154 | NULL | NULL | | BTREE | | |
+---------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
2 rows in set (0.00 sec)
2.删除增加索引
会触发copy操作，并在数据目录产生临时frm和ibd文件
其他DML会被阻塞，请求MDL锁
- session1
mysql session 1 >alter table sbtest1 drop index k_1;
Query OK, 5000000 rows affected (55.42 sec)
Records: 5000000 Duplicates: 0 Warnings: 0
mysql session 1 >alter table sbtest1 add index k_1(k);
Query OK, 5000000 rows affected (1 min 20.26 sec)
Records: 5000000 Duplicates: 0 Warnings: 0
- session2
mysql session 2 >update sbtest1 set k=2496416 where id=1;
Query OK, 1 row affected (14.39 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql session 2 >update sbtest1 set k=2496417 where id=1;
Query OK, 1 row affected (1 min 12.48 sec)
Rows matched: 1 Changed: 1 Warnings: 0
- session3
+-----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+-----------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+-----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+-----------------------------------------+
| 47 | repl | 172.16.3.154:42173 | NULL | Binlog Dump GTID | 507514 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 48 | repl | 172.16.3.153:57245 | NULL | Binlog Dump GTID | 507412 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 53 | mha | 172.16.3.152:43681 | NULL | Sleep | 0 | | NULL |
| 716 | root | localhost | test | Query | 46 | copy to tmp table | alter table sbtest1 drop index k_1 |
| 834 | root | localhost | test | Query | 5 | Waiting for table metadata lock | update sbtest1 set k=2496416 where id=1 |
| 835 | root | localhost | NULL | Sleep | 35 | | NULL |
| 836 | root | localhost | db1 | Query | 0 | starting | show processlist |
+-----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+-----------------------------------------+
mysql session 3 >mysql session 3 >show processlist;
+-----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+-----------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+-----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+-----------------------------------------+
| 47 | repl | 172.16.3.154:42173 | NULL | Binlog Dump GTID | 507617 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 48 | repl | 172.16.3.153:57245 | NULL | Binlog Dump GTID | 507515 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 53 | mha | 172.16.3.152:43681 | NULL | Sleep | 1 | | NULL |
| 716 | root | localhost | test | Query | 27 | copy to tmp table | alter table sbtest1 add index k_1(k) |
| 834 | root | localhost | test | Query | 20 | Waiting for table metadata lock | update sbtest1 set k=2496417 where id=1 |
| 835 | root | localhost | NULL | Sleep | 138 | | NULL |
| 836 | root | localhost | db1 | Query | 0 | starting | show processlist |
+-----+------+--------------------+------+------------------+--------+---------------------------------------------------------------+-----------------------------------------+
7 rows in set (0.00 sec)
- session4
[root@master test]# pwd
/mysqlData/data/test
[root@master test]# ls -ltr
total 2564148
-rw-r-----. 1 mysql mysql 61 Mar 13 10:45 db.opt
-rw-r-----. 1 mysql mysql 8632 Mar 13 11:25 sbtest2.frm
-rw-r-----. 1 mysql mysql 1224736768 Mar 13 11:26 sbtest2.ibd
-rw-r-----. 1 mysql mysql 8632 Mar 13 11:33 sbtest1.frm
-rw-r-----. 1 mysql mysql 1149239296 Mar 13 11:34 sbtest1.ibd
-rw-r-----. 1 mysql mysql 8632 Mar 13 11:35 #sql-663e_2cc.frm
-rw-r-----. 1 mysql mysql 251658240 Mar 13 11:35 #sql-663e_2cc.ibd
4.新特性online DDL
1.改成online DDL方式
并不影响DML
- session1
mysql session 1 >set old_alter_table=0;
Query OK, 0 rows affected (0.00 sec)
mysql session 1 >show variables like ‘%old_alter_table%‘;
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| old_alter_table | OFF |
+-----------------+-------+
1 row in set (0.01 sec)
mysql session 1 >alter table sbtest1 drop index k_1;
Query OK, 0 rows affected (0.07 sec)
Records: 0 Duplicates: 0 Warnings: 0
# 索引瞬间被删掉了
mysql session 1 >alter table sbtest1 add index k_1(k);
Query OK, 0 rows affected (9.45 sec)
Records: 0 Duplicates: 0 Warnings: 0
- session2
mysql session 2 >update sbtest1 set k=2496417 where id=1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
# 添加二级索引的时候，也不会阻塞DML
- session3
mysql session 3 >show processlist;
+------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+--------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+--------------------------------------+
| 47 | repl | 172.16.3.154:42173 | NULL | Binlog Dump GTID | 508423 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 48 | repl | 172.16.3.153:57245 | NULL | Binlog Dump GTID | 508321 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 53 | mha | 172.16.3.152:43681 | NULL | Sleep | 1 | | NULL |
| 716 | root | localhost | test | Query | 1 | altering table | alter table sbtest1 add index k_1(k) |
| 1328 | root | localhost | test | Sleep | 0 | | NULL |
| 1329 | root | localhost | db1 | Query | 0 | starting | show processlist |
+------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+--------------------------------------+
6 rows in set (0.00 sec)
5.大事务之前的online DDL
alter之前有大事务执行，ddl会被阻塞，且后面的所有其他所有请求都会被阻塞
操作DDL之前最好还是先检查一下是否有大事务在进行中
- session1
mysql session 1 >select * from sbtest1 where c=‘long select before alter‘;
Empty set (2.49 sec)
- session2
mysql session 2 >alter table sbtest1 add index k_1(k);
Query OK, 0 rows affected (11.46 sec)
Records: 0 Duplicates: 0 Warnings: 0
- session3
mysql session 3 >select * from sbtest1 where c=‘long select after alter execution but not complete‘;
Empty set (3.69 sec)
- session4
mysql session 4 >show processlist;
+------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+------------------------------------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+------------------------------------------------------------------------------------+
| 47 | repl | 172.16.3.154:42173 | NULL | Binlog Dump GTID | 508885 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 48 | repl | 172.16.3.153:57245 | NULL | Binlog Dump GTID | 508783 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 53 | mha | 172.16.3.152:43681 | NULL | Sleep | 1 | | NULL |
| 1328 | root | localhost | test | Query | 1 | Waiting for table metadata lock | alter table sbtest1 add index k_1(k) |
| 1329 | root | localhost | test | Query | 1 | Waiting for table metadata lock | select * from sbtest1 where c=‘long select after alter execution but not complete‘ |
| 1480 | root | localhost | test | Query | 2 | Sending data | select * from sbtest1 where c=‘long select before alter‘ |
| 1619 | root | localhost | NULL | Query | 0 | starting | show processlist |
+------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+------------------------------------------------------------------------------------+
7 rows in set (0.00 sec)
6.添加删除列，不加inplace算法
允许ddl期间进行并发DML操作，并产生临时文件
- session1，添加删除列
mysql session 1 >ALTER TABLE `sbtest2` -> ADD COLUMN `f_new_col1` int(11) NULL DEFAULT 0, -> ADD COLUMN `f_new_col2` varchar(32) NULL DEFAULT ‘‘ AFTER `f_new_col1`;
Query OK, 0 rows affected (51.50 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql session 1 >alter table sbtest2 drop column f_new_col1, -> drop column f_new_col2;
Query OK, 0 rows affected (48.64 sec)
Records: 0 Duplicates: 0 Warnings: 0
- session2，进行update
mysql session 2 >update sbtest2 set c="update when add colomun ddl start" where c=‘33333‘;
Query OK, 0 rows affected (25.67 sec)
Rows matched: 0 Changed: 0 Warnings: 0
mysql session 2 >update sbtest2 set c="update when add colomun ddl start" where c=‘33333‘;
Query OK, 0 rows affected (6.15 sec)
Rows matched: 0 Changed: 0 Warnings: 0
- session3，查询
mysql session 3 >select * from sbtest2 where c=‘select when add colomun ddl start‘;
Empty set (23.74 sec)
mysql session 3 >select * from sbtest2 where c=‘select when add colomun ddl start‘;
Empty set (2.24 sec)
- session4
mysql session 4 >show processlist;
+-------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+------------------------------------------------------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+-------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+------------------------------------------------------------------------------------------------------+
| 47 | repl | 172.16.3.154:42173 | NULL | Binlog Dump GTID | 523165 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 48 | repl | 172.16.3.153:57245 | NULL | Binlog Dump GTID | 523063 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 53 | mha | 172.16.3.152:43681 | NULL | Sleep | 0 | | NULL |
| 11000 | root | localhost | NULL | Query | 0 | starting | show processlist |
| 11021 | root | localhost | test | Query | 9 | altering table | ALTER TABLE `sbtest2`
ADD COLUMN `f_new_col1` int(11) NULL DEFAULT 0,
ADD COLUMN `f_new_col2` varc |
| 11110 | root | localhost | test | Query | 6 | updating | update sbtest2 set c="update when add colomun ddl start" where c=‘33333‘ |
| 11113 | root | localhost | test | Query | 5 | Sending data | select * from sbtest2 where c=‘select when add colomun ddl start‘ |
+-------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+------------------------------------------------------------------------------------------------------+
7 rows in set (0.00 sec)
mysql session 4 >show processlist;
+-------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+--------------------------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+-------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+--------------------------------------------------------------------------+
| 47 | repl | 172.16.3.154:42173 | NULL | Binlog Dump GTID | 523338 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 48 | repl | 172.16.3.153:57245 | NULL | Binlog Dump GTID | 523236 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 53 | mha | 172.16.3.152:43681 | NULL | Sleep | 1 | | NULL |
| 11000 | root | localhost | NULL | Query | 0 | starting | show processlist |
| 11021 | root | localhost | test | Query | 22 | altering table | alter table sbtest2 drop column f_new_col1,
drop column f_new_col2 |
| 11110 | root | localhost | test | Query | 6 | updating | update sbtest2 set c="update when add colomun ddl start" where c=‘33333‘ |
| 11113 | root | localhost | test | Query | 2 | Sending data | select * from sbtest2 where c=‘select when add colomun ddl start‘ |
+-------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+--------------------------------------------------------------------------+
7 rows in set (0.00 sec)
- session5，产生临时文件
[root@master test]# ls -ltr
total 4010036
-rw-r-----. 1 mysql mysql 61 Mar 13 10:45 db.opt
-rw-r-----. 1 mysql mysql 8632 Mar 13 11:56 sbtest1.frm
-rw-r-----. 1 mysql mysql 1275068416 Mar 13 11:57 sbtest1.ibd
-rw-r-----. 1 mysql mysql 8716 Mar 13 15:54 sbtest2.frm
-rw-r-----. 1 mysql mysql 1442840576 Mar 13 15:55 sbtest2.ibd
-rw-r-----. 1 mysql mysql 8632 Mar 13 15:57 #sql-663e_2b0d.frm
-rw-r-----. 1 mysql mysql 1388314624 Mar 13 15:58 #sql-ib87-1396920660.ibd
- 删除的时候产生的临时文件比ibd更大
[root@master test]# ls -ltrh
total 3.9G
-rw-r-----. 1 mysql mysql 61 Mar 13 10:45 db.opt
-rw-r-----. 1 mysql mysql 8.5K Mar 13 11:56 sbtest1.frm
-rw-r-----. 1 mysql mysql 1.2G Mar 13 11:57 sbtest1.ibd
-rw-r-----. 1 mysql mysql 8.5K Mar 13 16:10 sbtest2.frm
-rw-r-----. 1 mysql mysql 1.3G Mar 13 16:11 sbtest2.ibd
-rw-r-----. 1 mysql mysql 8.6K Mar 13 16:12 #sql-663e_2b0d.frm
-rw-r-----. 1 mysql mysql 1.4G Mar 13 16:13 #sql-ib90-1396920666.ibd
7.修改列，加inplace算法(5.7)
- 1).创建
f_new_col2的时候长度是32
mysql session 1 >ALTER TABLE `sbtest2` -> ADD COLUMN `f_new_col1` int(11) NULL DEFAULT 0, -> ADD COLUMN `f_new_col2` varchar(32) NULL DEFAULT ‘‘ AFTER `f_new_col1`;
Query OK, 0 rows affected (1 min 4.21 sec)
Records: 0 Duplicates: 0 Warnings: 0
- 2).更改
f_new_col2长度为50
mysql session 1 >ALTER TABLE sbtest2 -> CHANGE f_new_col2 f_new_col2 varchar(50) NULL DEFAULT ‘‘, algorithm=inplace ;
Query OK, 0 rows affected (0.09 sec)
Records: 0 Duplicates: 0 Warnings: 0
- 3).可以发现长度已经被更改
mysql session 1 >show create table sbtest2;
+---------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+---------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| sbtest2 | CREATE TABLE `sbtest2` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`k` int(10) unsigned NOT NULL DEFAULT ‘0‘,
`c` char(120) NOT NULL DEFAULT ‘‘,
`pad` char(60) NOT NULL DEFAULT ‘‘,
`f_new_col1` int(11) DEFAULT ‘0‘,
`f_new_col2` varchar(50) DEFAULT ‘‘,
PRIMARY KEY (`id`),
KEY `k_2` (`k`)
) ENGINE=InnoDB AUTO_INCREMENT=5000001 DEFAULT CHARSET=utf8 MAX_ROWS=1000000 |
+---------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
- 4).再更改更长长度时不支持
inplace，但是改成长度是50又支持，50改短或长都不支持？
mysql session 1 >ALTER TABLE sbtest2 -> CHANGE f_new_col2 f_new_col2 varchar(150) NULL DEFAULT ‘‘, algorithm=inplace ;
ERROR 1846 (0A000): ALGORITHM=INPLACE is not supported. Reason: Cannot change column type INPLACE. Try ALGORITHM=COPY.
mysql session 1 >ALTER TABLE sbtest2 -> CHANGE f_new_col2 f_new_col2 varchar(32) NULL DEFAULT ‘‘, algorithm=inplace ;
ERROR 1846 (0A000): ALGORITHM=INPLACE is not supported. Reason: Cannot change column type INPLACE. Try ALGORITHM=COPY.
mysql session 1 >ALTER TABLE sbtest2 -> CHANGE f_new_col2 f_new_col2 varchar(50) NULL DEFAULT ‘‘, algorithm=inplace ;
Query OK, 0 rows affected (0.01 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql session 1 >ALTER TABLE sbtest2 -> CHANGE f_new_col2 f_new_col2 varchar(32) NULL DEFAULT ‘‘, algorithm=inplace ;
ERROR 1846 (0A000): ALGORITHM=INPLACE is not supported. Reason: Cannot change column type INPLACE. Try ALGORITHM=COPY.
mysql session 1 >ALTER TABLE sbtest2 -> CHANGE f_new_col2 f_new_col2 varchar(88) NULL DEFAULT ‘‘, algorithm=inplace ;
ERROR 1846 (0A000): ALGORITHM=INPLACE is not supported. Reason: Cannot change column type INPLACE. Try ALGORITHM=COPY.
修改列类型应该要rebuild整张表
8.继续上面的修改列长度(5.7)
ddl堵塞DML，但是不阻塞select
- 1).session1
mysql session 1 >ALTER TABLE sbtest2 -> CHANGE f_new_col2 f_new_col2 varchar(200) NULL DEFAULT ‘‘;
Query OK, 5000000 rows affected (1 min 28.96 sec)
Records: 5000000 Duplicates: 0 Warnings: 0
- 2).session2
mysql session 2 >update sbtest2 set c="update when add colomun ddl start" where c=‘33333‘;
Query OK, 0 rows affected (1 min 34.01 sec)
Rows matched: 0 Changed: 0 Warnings: 0
- 3).session3
mysql session 3 >select * from sbtest2 where c=‘select when add colomun ddl start‘;
Empty set (2.82 sec)
- 4).session4
mysql session 4 >show processlist;
+-------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+--------------------------------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+-------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+--------------------------------------------------------------------------------+
| 47 | repl | 172.16.3.154:42173 | NULL | Binlog Dump GTID | 524786 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 48 | repl | 172.16.3.153:57245 | NULL | Binlog Dump GTID | 524684 | Master has sent all binlog to slave; waiting for more updates | NULL |
| 53 | mha | 172.16.3.152:43681 | NULL | Sleep | 1 | | NULL |
| 11000 | root | localhost | NULL | Query | 0 | starting | show processlist |
| 11021 | root | localhost | test | Query | 3 | copy to tmp table | ALTER TABLE sbtest2
CHANGE f_new_col2 f_new_col2 varchar(200) NULL DEFAULT ‘‘ |
| 12186 | root | localhost | test | Query | 2 | Waiting for table metadata lock | update sbtest2 set c="update when add colomun ddl start" where c=‘33333‘ |
| 12189 | root | localhost | test | Query | 1 | Sending data | select * from sbtest2 where c=‘select when add colomun ddl start‘ |
+-------+------+--------------------+------+------------------+--------+---------------------------------------------------------------+--------------------------------------------------------------------------------+
7 rows in set (0.01 sec)
- 5).session5，copy肯定是产生临时文件
[root@master test]# ls -ltrh
total 3.2G
-rw-r-----. 1 mysql mysql 61 Mar 13 10:45 db.opt
-rw-r-----. 1 mysql mysql 8.5K Mar 13 11:56 sbtest1.frm
-rw-r-----. 1 mysql mysql 1.2G Mar 13 11:57 sbtest1.ibd
-rw-r-----. 1 mysql mysql 1.4G Mar 13 16:13 sbtest2.ibd
-rw-r-----. 1 mysql mysql 8.6K Mar 13 16:15 sbtest2.frm
-rw-r-----. 1 mysql mysql 8.6K Mar 13 16:21 #sql-663e_2b0d.frm
-rw-r-----. 1 mysql mysql 648M Mar 13 16:22 #sql-663e_2b0d.ibd
https://www.cnblogs.com/zengkefu/p/5674945.html
https://dev.mysql.com/doc/refman/5.6/en/upgrading-from-previous-series.html
OAK DDL
5.6之前使用第三方工具进行ddl
1.oak_online_alter_table前提条件
- 1.单列唯一索引，联合索引和联合主键索引不可以，触发mysqlbug
- 2.没有外键foreign key
- 3.没有定义触发器，有的话也一棍打死
2.oak ddl流程
- 1.确认表符合oak_online_alter_table的执行条件
- 2.如果有触发器，备份触发器，删除触发器
- 3.预估oak命令执行时间，表有1亿，1秒执行3000条，大概执行12个小时，计划时间执行
- 4.进行新旧表数据校验，如果DDL改变了表字段类型，可能导致表数据变化
- 5.表切换rename
- 6.删除原表触发器
- 7.删除表
3.check list功能
./run_bat IP onlineddl_check port dbname tabname
4.检查外键和触发器SQL
- 1.information_schema.key_column_usage
- 2.
select * from information_schema.key_column_usage where table_schema=dbname and table_name=tabname and referenced_table_name is not null - 3.
select * from information_schema.key_column_usage where referenced_table_schema=dbname and referenced_table_name=tabname;
5.安装openark-kit工具包
wget -O /etc/yum.repos.d/oak.repo http://download.opensuse.org/repositories/home:LenzGr/CentOS_7/home:LenzGr.repo
install openark-kit
6.操作过程
- 1).构造测试数据
sysbench --test=insert.lua --oltp-table-size=500000 --mysql-table-engine=innodb --mysql-user=root --mysql-password=123456 --mysql-port=3306 --mysql-host=localhost --mysql-db=test --max-requests=0 --time=60 --oltp-tables-count=2 --report-interval=10 --threads=2 prepare
- 2).检查是否有触发器
select trigger_schema,trigger_name,event_object_schema,event_object_table from information_schema.triggers where event_object_schema=‘test‘;
- 3).执行online DDL
oak-online-alter-table -u root --ask-pass -S /usr/local/mysql/mysql.sock -d test -t sbtest1 -g new_sbtest1 -a "add last_update_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,add key last_update_time(last_update_time)" --sleep=300 --skip-delete-pass
执行ddl的时候，依然可以进行ddl操作
root@master 22:34: [test]> insert into sbtest1 values(10000000,10000,‘AAAAA‘,‘BBBBB‘);
Query OK, 1 row affected (0.01 sec)
- 4).执行校验
select sum(crc32(concat(ifnull(id,‘NULL‘),ifnull(k,‘NULL‘)))) as sum from sbtest1 union all \
select sum(crc32(concat(ifnull(id,‘NULL‘),ifnull(k,‘NULL‘)))) as sum from new_sbtest1;
# select count(*) from sbtest1 union all select count(*) from new_sbtest1;
root@master 22:34: [test]> select count(*) from sbtest1 union all select count(*) from new_sbtest1;
+----------+
| count(*) |
+----------+
| 500001 |
| 291001 |
+----------+
2 rows in set (0.19 sec)
#
desc sbtest1;
desc new_sbtest1;
- 5).因为在原表增加了触发器，即使ddl完成之后，新的DML依然会插入到新表
root@master 22:34: [test]> select trigger_schema,trigger_name,event_object_schema,event_object_table from information_schema.triggers where event_object_schema=‘test‘;
+----------------+----------------+---------------------+--------------------+
| trigger_schema | trigger_name | event_object_schema | event_object_table |
+----------------+----------------+---------------------+--------------------+
| test | sbtest1_AI_oak | test | sbtest1 |
| test | sbtest1_AU_oak | test | sbtest1 |
| test | sbtest1_AD_oak | test | sbtest1 |
+----------------+----------------+---------------------+--------------------+
3 rows in set (0.00 sec)
root@master 22:38: [test]> select count(*) from sbtest1 union all select count(*) from new_sbtest1;
+----------+
| count(*) |
+----------+
| 500001 |
| 500001 |
+----------+
2 rows in set (0.16 sec)
root@master 22:38: [test]> insert into sbtest1 values(10000001,10000,‘AAAAA‘,‘BBBBB‘);
Query OK, 1 row affected (0.00 sec)
root@master 22:39: [test]> select count(*) from sbtest1 union all select count(*) from new_sbtest1;
+----------+
| count(*) |
+----------+
| 500002 |
| 500002 |
+----------+
2 rows in set (0.16 sec)
- 6).表切换，更改数据字典
use test;
set names utf8;
rename table sbtest1 to old_sbtest1,new_sbtest1 to sbtest1;
- 7).删除触发器和原表
drop trigger sbtest1_AI_oak;
drop trigger sbtest1_AU_oak;
drop trigger sbtest1_AD_oak;
drop table old_sbtest1;
root@master 22:40: [test]> show tables;
+----------------+
| Tables_in_test |
+----------------+
| old_sbtest1 |
| sbtest1 |
| sbtest2 |
+----------------+
3 rows in set (0.00 sec)
root@master 22:41: [test]> select trigger_schema,trigger_name,event_object_schema,event_object_table from information_schema.triggers where event_object_schema=‘test‘;
+----------------+----------------+---------------------+--------------------+
| trigger_schema | trigger_name | event_object_schema | event_object_table |
+----------------+----------------+---------------------+--------------------+
| test | sbtest1_AI_oak | test | old_sbtest1 |
| test | sbtest1_AU_oak | test | old_sbtest1 |
| test | sbtest1_AD_oak | test | old_sbtest1 |
+----------------+----------------+---------------------+--------------------+
3 rows in set (0.01 sec)
root@master 22:41: [test]> drop trigger sbtest1_AI_oak;
Query OK, 0 rows affected (0.00 sec)
root@master 22:41: [test]> drop trigger sbtest1_AU_oak;
Query OK, 0 rows affected (0.01 sec)
root@master 22:41: [test]> drop trigger sbtest1_AD_oak;
Query OK, 0 rows affected (0.01 sec)
root@master 22:41: [test]> drop table old_sbtest1;
Query OK, 0 rows affected (0.23 sec)
root@master 22:41: [test]> show tables;
+----------------+
| Tables_in_test |
+----------------+
| sbtest1 |
| sbtest2 |
+----------------+
2 rows in set (0.00 sec)
7.用oak做Online DDL,如果rename那一步操作错了？在从库上rename了怎么恢复？（包含旧表删除和trigger删除）.
- 1)第一种情况加索引的Online DDL
- 2)第二种情况加字段的Online DDL
发现rename错表了？
再做一次drop ddl
不是从主库进行ddl，选择从库ddl，从库rename错了，想恢复？
http://www.cnblogs.com/xuanzhi201111/p/4549250.html
http://www.cnblogs.com/xinysu/p/6732646.html#_lab2_4_3
