Mycat 水平分表，垂直分表实践（2）

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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

<?xml version="1.0"?><!DOCTYPE mycat:schema SYSTEM "schema.dtd">        <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 1</heartbeat>                <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：

<!DOCTYPE mycat:rule SYSTEM "rule.dtd"><mycat:rule xmlns:mycat="http://org.opencloudb/">    <!--article 分区配置，按照id进行模2.-->    <tableRule name="mod-long">        <rule>            <columns>user_id</columns>            <algorithm>mod-long</algorithm>        </rule>    </tableRule>    <function name="mod-long"     class="org.opencloudb.route.function.PartitionByMod">        <property name="count">2</property>    </function></mycat:rule>

配置service.xml:

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE mycat:server SYSTEM "server.dtd"><mycat:server xmlns:mycat="http://org.opencloudb/">        <system>            <property name="defaultSqlParser">druidparser</property>        </system>        <user name="mycat">                <property name="password">mycat</property>                <property name="schemas">mycat,blog_user,blog_category,blog_article</property>        </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    DETERMINISTICBEGIN          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    DETERMINISTICBEGIN           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    DETERMINISTICBEGIN           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 namesYou can turn off this feature to get a quicker startup with -ADatabase changedmysql> 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('[e-mail]','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 | [e-mail] | 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: 0mysql> 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 namesYou can turn off this feature to get a quicker startup with -ADatabase changedmysql> 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: 0mysql> 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 namesYou can turn off this feature to get a quicker startup with -Amysql> 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: 0mysql> 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。