Mycat 水平分表，垂直分表实践（2）
本文原文连接: http://blog.csdn.net/freewebsys/article/details/44399901 转载请注明出处！
1，迁移数据
举例说明，比如一个博客数据库数据表如下：
这里水平拆分，垂直拆分，只是做个简单的实验，真正的线上业务要根据情况，数据进行拆分。
--分类
CREATE TABLE category (
id INT NOT NULL AUTO_INCREMENT,
user_id INT NOT NULL,
name VARCHAR(200) NOT NULL,
PRIMARY KEY (id)
);
--标签
CREATE TABLE tag (
id INT NOT NULL AUTO_INCREMENT,
user_id INT NOT NULL,
name VARCHAR(100) NOT NULL,
PRIMARY KEY (id)
);
--文章
CREATE TABLE `article` (
`id` int(11) NOT NULL PRIMARY KEY ,
`user_id` int(11) NOT NULL,
`title` varchar(200) NOT NULL,
`abstract` text,
`content` text,
`publish_time` datetime NOT NULL,
`create_time` datetime NOT NULL,
`update_time` datetime NOT NULL,
`category_id` int(11) NOT NULL,
KEY `category_id` (`category_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
--标签
CREATE TABLE article_tags (
user_id INT NOT NULL,
article_id INT NOT NULL,
tag_id INT NOT NULL,
PRIMARY KEY (user_id,article_id,tag_id)
);
--用户信息
CREATE TABLE user_info (
id INT NOT NULL AUTO_INCREMENT,
email VARCHAR(200) NOT NULL,
name VARCHAR(200) NOT NULL,
password VARCHAR(100) NOT NULL,
create_time DATETIME NOT NULL,
update_time DATETIME NOT NULL,
last_login_time DATETIME NOT NULL,
PRIMARY KEY (id),
UNIQUE KEY (name)
);
--链接
CREATE TABLE link (
id INT NOT NULL AUTO_INCREMENT,
user_id INT NOT NULL,
name VARCHAR(100) NOT NULL,
url VARCHAR(300) NOT NULL,
PRIMARY KEY (id),
KEY (user_id)
);
将所有数据都迁移到mycat中，一共有4个数据库，blog01，blog02，blog_article01，blog_article02。
article，article_tags分别在blog_article01，blog_article02，按照uid进行水平拆分。
user_info表在blog01，link，category，tag在blog02数据库中。
CREATE DATABASE blog01 DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
CREATE DATABASE blog02 DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
CREATE DATABASE blog_article01 DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
CREATE DATABASE blog_article02 DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
#创建一共mycat数据库，存储mycat相关数据比如sequence。
CREATE DATABASE mycat DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
2，schema.xml,配置
<schema name="mycat" checkSQLschema="false" sqlMaxLimit="100">
<table name="MYCAT_SEQUENCE" primaryKey="name" type="global" dataNode="nodeUser" />
schema>
<schema name="blog_user" checkSQLschema="false" sqlMaxLimit="100">
<table name="user_info" primaryKey="id" type="global" dataNode="nodeUser" />
schema>
<schema name="blog_category" checkSQLschema="false" sqlMaxLimit="100">
<table name="category" primaryKey="id" type="global" dataNode="nodeCategory" />
<table name="tag" primaryKey="id" type="global" dataNode="nodeCategory" />
<table name="link" primaryKey="id" type="global" dataNode="nodeCategory" />
schema>
<schema name="blog_article" checkSQLschema="false" sqlMaxLimit="100">
<table name="article" primaryKey="user_id" dataNode="nodeArticle01,nodeArticle02" rule="mod-long" />
<table name="article_tags" primaryKey="id" type="global" dataNode="nodeArticle01,nodeArticle02" />
schema>
<dataNode name="nodeMycat" dataHost="dataHost01" database="mycat" />
<dataNode name="nodeUser" dataHost="dataHost01" database="blog01" />
<dataNode name="nodeCategory" dataHost="dataHost01" database="blog02" />
<dataNode name="nodeArticle01" dataHost="dataHost01" database="blog_article01" />
<dataNode name="nodeArticle02" dataHost="dataHost01" database="blog_article02" />
<dataHost name="dataHost01" maxCon="1000" minCon="10" balance="0"
writeType="0" dbType="mysql" dbDriver="native">
<heartbeat>select 1heartbeat>
<writeHost host="hostM1" url="127.0.0.1:3306" user="root" password="root"/>
dataHost>
mycat:schema>配置4个数据库连接，user_info做垂直拆分（配置type=global）。
blog_article，数据库进行水平拆分，拆分成两个数据库。
当设置成全局表的时候必须保证这个表在所有的数据库中，和配置的dataNode无关。
article规则配置：
<mycat:rule xmlns:mycat="http://org.opencloudb/">
<tableRule name="mod-long">
<rule>
<columns>user_idcolumns>
<algorithm>mod-longalgorithm>
rule>
tableRule>
<function name="mod-long"
class="org.opencloudb.route.function.PartitionByMod">
<property name="count">2property>
function>
mycat:rule>配置service.xml:
<mycat:server xmlns:mycat="http://org.opencloudb/">
<system>
<property name="defaultSqlParser">druidparserproperty>
system>
<user name="mycat">
<property name="password">mycatproperty>
<property name="schemas">mycat,blog_user,blog_category,blog_articleproperty>
user>
mycat:server>3，数据库sequence生成
牵扯到分库的时候就一定要由sequence生成，mysql的主键自增就不能使用了。
mycat的文档里面没有找到这部分的配置资料，但是找到了sequence的存储过程。
可以把这个存储过程存储到一个单独的数据库中，然后进行一次查询，再做入库。
存储过程地址：
https://github.com/MyCATApache/Mycat-doc/blob/master/%E5%85%A5%E9%97%A8%E6%8C%87%E5%8D%97/sequnce-sql.txt
DROP TABLE IF EXISTS MYCAT_SEQUENCE;
CREATE TABLE MYCAT_SEQUENCE ( name VARCHAR(50) NOT NULL, current_value INT NOT NULL, increment INT NOT NULL DEFAULT 100, PRIMARY KEY (name) ) ENGINE=InnoDB;
DROP FUNCTION IF EXISTS `mycat_seq_currval`;
DELIMITER ;;
CREATE DEFINER=`root`@`%` FUNCTION `mycat_seq_currval`(seq_name VARCHAR(50)) RETURNS varchar(64) CHARSET latin1
DETERMINISTIC
BEGIN
DECLARE retval VARCHAR(64);
SET retval="-999999999,null";
SELECT concat(CAST(current_value AS CHAR),",",CAST(increment AS CHAR) ) INTO retval FROM MYCAT_SEQUENCE WHERE name = seq_name;
RETURN retval ;
END
;;
DELIMITER ;
DROP FUNCTION IF EXISTS `mycat_seq_nextval`;
DELIMITER ;;
CREATE DEFINER=`root`@`%` FUNCTION `mycat_seq_nextval`(seq_name VARCHAR(50)) RETURNS varchar(64) CHARSET latin1
DETERMINISTIC
BEGIN
UPDATE MYCAT_SEQUENCE
SET current_value = current_value + increment WHERE name = seq_name;
RETURN mycat_seq_currval(seq_name);
END
;;
DELIMITER ;
DROP FUNCTION IF EXISTS `mycat_seq_setval`;
DELIMITER ;;
CREATE DEFINER=`root`@`%` FUNCTION `mycat_seq_setval`(seq_name VARCHAR(50), value INTEGER) RETURNS varchar(64) CHARSET latin1
DETERMINISTIC
BEGIN
UPDATE MYCAT_SEQUENCE
SET current_value = value
WHERE name = seq_name;
RETURN mycat_seq_currval(seq_name);
END
;;
DELIMITER ;
--同时增加权限，否则不能执行。
mysql> grant all privileges on *.* to root@"%" identified by ".";
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)4，测试mycat数据库
–mycat数据库的ip是192.168.1.16，端口是8066。
mysql -umycat -pmycat -P8066 -h 192.168.1.16
mysql> show databases;
+---------------+
| DATABASE |
+---------------+
| blog_article |
| blog_category |
| blog_user |
| mycat |
+---------------+
4 rows in set (0.00 sec)
mysql> use blog_user;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+---------------------+
| Tables in blog_user |
+---------------------+
| user_info |
+---------------------+
1 row in set (0.00 sec)
mysql> insert into user_info(email,`name`,password,create_time,update_time,last_login_time) values('[email protected]','zhangsan',password('123456'),now(),now(),now());
Query OK, 1 row affected (0.01 sec)
mysql> select * from user_info;
+----+------------------+----------+-------------------------------------------+---------------------+---------------------+---------------------+
| id | email | name | password | create_time | update_time | last_login_time |
+----+------------------+----------+-------------------------------------------+---------------------+---------------------+---------------------+
| 1 | [email protected] | zhangsan | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | 2015-03-26 02:47:38 | 2015-03-26 02:47:38 | 2015-03-26 02:47:38 |
+----+------------------+----------+-------------------------------------------+---------------------+---------------------+---------------------+
1 row in set (0.11 sec)
mysql> update user_info set name = 'lisi' where id = 1;
Query OK, 1 row affected (0.08 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> delete from user_info where name = 'lisi';
Query OK, 1 row affected (0.00 sec)
mysql> use blog_category;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+-------------------------+
| Tables in blog_category |
+-------------------------+
| category |
| link |
| tag |
+-------------------------+
3 rows in set (0.00 sec)
mysql> insert into tag(id,user_id,name) values(1,1,'java');
Query OK, 1 row affected (0.11 sec)
mysql> select * from tag;
+----+---------+------+
| id | user_id | name |
+----+---------+------+
| 1 | 1 | java |
+----+---------+------+
1 row in set (0.11 sec)
mysql> update tag set name = 'j2ee' where id = 1;
Query OK, 1 row affected (0.08 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> insert into tag(user_id,name) values(2,'mysql');
Query OK, 1 row affected (0.00 sec)
mysql> select * from tag;
+----+---------+-------+
| id | user_id | name |
+----+---------+-------+
| 1 | 1 | j2ee |
| 2 | 2 | mysql |
+----+---------+-------+
2 rows in set (0.00 sec)
mysql> delete from tag where id = 1;
Query OK, 1 row affected (0.00 sec)
mysql> use blog_article;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
mysql> insert into article(id,user_id,title,publish_time,create_time,update_time,category_id) \
-> values (1,1,'test1',now(),now(),now(),1),(2,1,'test2',now(),now(),now(),2),\
-> (3,1,'test3',now(),now(),now(),3),(4,2,'test4',now(),now(),now(),3);
Query OK, 4 rows affected (0.00 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> select * from article;
+----+---------+-------+----------+---------+---------------------+---------------------+---------------------+-------------+
| id | user_id | title | abstract | content | publish_time | create_time | update_time | category_id |
+----+---------+-------+----------+---------+---------------------+---------------------+---------------------+-------------+
| 4 | 2 | test4 | NULL | NULL | 2015-03-26 03:30:55 | 2015-03-26 03:30:55 | 2015-03-26 03:30:55 | 3 |
| 1 | 1 | test1 | NULL | NULL | 2015-03-26 03:30:55 | 2015-03-26 03:30:55 | 2015-03-26 03:30:55 | 1 |
| 2 | 1 | test2 | NULL | NULL | 2015-03-26 03:30:55 | 2015-03-26 03:30:55 | 2015-03-26 03:30:55 | 2 |
| 3 | 1 | test3 | NULL | NULL | 2015-03-26 03:30:55 | 2015-03-26 03:30:55 | 2015-03-26 03:30:55 | 3 |
+----+---------+-------+----------+---------+---------------------+---------------------+---------------------+-------------+
4 rows in set (0.00 sec)
mysql> update article set title = 'new title' where user_id = 1 and id =2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
测试sequence生成：
mysql> INSERT INTO MYCAT_SEQUENCE VALUES ('article_seq', 1, 1);
1 row in set (0.06 sec)
mysql> SELECT MYCAT_SEQ_CURRVAL('article_seq');
+----------------------------------+
| MYCAT_SEQ_CURRVAL('article_seq') |
+----------------------------------+
| 1,1 |
+----------------------------------+
1 row in set (0.01 sec)
mysql> SELECT MYCAT_SEQ_SETVAL('article_seq', 2);
+------------------------------------+
| MYCAT_SEQ_SETVAL('article_seq', 2) |
+------------------------------------+
| 2,1 |
+------------------------------------+
1 row in set (0.01 sec)
mysql> SELECT MYCAT_SEQ_CURRVAL('article_seq');
+----------------------------------+
| MYCAT_SEQ_CURRVAL('article_seq') |
+----------------------------------+
| 2,1 |
+----------------------------------+
1 row in set (0.01 sec)
mysql> SELECT MYCAT_SEQ_NEXTVAL('article_seq');
+----------------------------------+
| MYCAT_SEQ_NEXTVAL('article_seq') |
+----------------------------------+
| 3,1 |
+----------------------------------+
1 row in set (0.01 sec)
mysql> SELECT MYCAT_SEQ_NEXTVAL('article_seq');
+----------------------------------+
| MYCAT_SEQ_NEXTVAL('article_seq') |
+----------------------------------+
| 4,1 |
+----------------------------------+
1 row in set (0.02 sec)总结
mycat提供了数据库垂直拆分和水平拆分的方案，对于数据迁移可以按照id，user_id进行拆分。
也可以将数据分库存储，不拆分，但必须放到不同的库中（和水平拆分的分开）。
同时，如果进行拆分，则需要修改主键生成方式，目前看到mycat中提供一个sequence的存储过程，可以直接使用。