MySQL分布式架构——MyCAT

目录

• 一、MyCAT准备环境
• 二、MyCAT基础环境准备
  • 2.1 删除历史环境
  • 2.2 创建相应目录、初始化数据
  • 2.3 准备MySQL的配置文件
  • 2.4 准备MySQL的启动脚本
  • 2.5 修改权限，启动多实例
  • 2.6 配置主从关系
    • ① shard1
    • ② shard2
    • ③ 确认主从关系
• 三、安装MyCAT
  • 3.1 安装MyCAT
  • 3.2 MyCAT配置文件介绍
• 四、MyCAT实现读写分离
• 五、MyCAT配置读写分离及高可用
• 六、配置文件重要属性介绍
  • 6.1 balance属性
  • 6.2 writeType属性
  • 6.3 switchType属性
  • 6.4 datahost其他配置
• 七、MyCAT实现垂直拆分
• 八、MyCAT实现水平拆分
  • 8.1 范围分片
  • 8.2 取模分片
  • 8.3 枚举分片
• 九、MyCAT全局表

一、MyCAT准备环境

两台虚拟机 db01 db02
每台创建四个mysql实例：3307 3308 3309 3310

节点主从规划
箭头指向谁是主库
    192.168.1.1:3307    <----->  192.168.1.2:3307
    192.168.1.1:3309    ------>  192.168.1.1:3307
    192.168.1.2:3309    ------>  192.168.1.2:3307
 
    192.168.1.2:3308  <----->    192.168.1.1:3308
    192.168.1.2:3310  ----->     192.168.1.2:3308
    192.168.1.1:3310  ----->     192.168.1.1:3308
 
分片规划
shard1：
    Master：192.168.1.1:3307
    slave1：192.168.1.1:3309
    Standby Master：192.168.1.2:3307
    slave2：192.168.1.2:3309
shard2：
    Master：192.168.1.2:3308
    slave1：192.168.1.2:3310
    Standby Master：192.168.1.1:3308
    slave2：192.168.1.1:3310

二、MyCAT基础环境准备

2.1 删除历史环境

两台db数据库都需进行以下操作！

pkill mysqld
rm -rf /data/330*
mv /etc/my.cnf /etc/my.cnf.bak

2.2 创建相应目录、初始化数据

两台db数据库都需进行以下操作！

mkdir /data/33{07..10}/data -p
mysqld --initialize-insecure  --user=mysql --datadir=/data/3307/data --basedir=/app/database/mysql
mysqld --initialize-insecure  --user=mysql --datadir=/data/3308/data --basedir=/app/database/mysql
mysqld --initialize-insecure  --user=mysql --datadir=/data/3309/data --basedir=/app/database/mysql
mysqld --initialize-insecure  --user=mysql --datadir=/data/3310/data --basedir=/app/database/mysql

2.3 准备MySQL的配置文件

=====================db01=====================
cat >/data/3307/my.cnf<<EOF
[mysqld]
basedir=/app/database/mysql
datadir=/data/3307/data
socket=/data/3307/mysql.sock
port=3307
log-error=/data/3307/mysql.log
log_bin=/data/3307/mysql-bin
binlog_format=row
skip-name-resolve
server-id=7
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
EOF
 
cat >/data/3308/my.cnf<<EOF
[mysqld]
basedir=/app/database/mysql
datadir=/data/3308/data
port=3308
socket=/data/3308/mysql.sock
log-error=/data/3308/mysql.log
log_bin=/data/3308/mysql-bin
binlog_format=row
skip-name-resolve
server-id=8
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
EOF
 
cat >/data/3309/my.cnf<<EOF
[mysqld]
basedir=/app/database/mysql
datadir=/data/3309/data
socket=/data/3309/mysql.sock
port=3309
log-error=/data/3309/mysql.log
log_bin=/data/3309/mysql-bin
binlog_format=row
skip-name-resolve
server-id=9
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
EOF
 
cat >/data/3310/my.cnf<<EOF
[mysqld]
basedir=/app/database/mysql
datadir=/data/3310/data
socket=/data/3310/mysql.sock
port=3310
log-error=/data/3310/mysql.log
log_bin=/data/3310/mysql-bin
binlog_format=row
skip-name-resolve
server-id=10
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
EOF
 
=====================db02=====================
cat >/data/3307/my.cnf<<EOF
[mysqld]
basedir=/app/database/mysql
datadir=/data/3307/data
socket=/data/3307/mysql.sock
port=3307
log-error=/data/3307/mysql.log
log_bin=/data/3307/mysql-bin
binlog_format=row
skip-name-resolve
server-id=17
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
EOF
 
cat >/data/3308/my.cnf<<EOF
[mysqld]
basedir=/app/database/mysql
datadir=/data/3308/data
port=3308
socket=/data/3308/mysql.sock
log-error=/data/3308/mysql.log
log_bin=/data/3308/mysql-bin
binlog_format=row
skip-name-resolve
server-id=18
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
EOF
 
cat >/data/3309/my.cnf<<EOF
[mysqld]
basedir=/app/database/mysql
datadir=/data/3309/data
socket=/data/3309/mysql.sock
port=3309
log-error=/data/3309/mysql.log
log_bin=/data/3309/mysql-bin
binlog_format=row
skip-name-resolve
server-id=19
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
EOF
 
cat >/data/3310/my.cnf<<EOF
[mysqld]
basedir=/app/database/mysql
datadir=/data/3310/data
socket=/data/3310/mysql.sock
port=3310
log-error=/data/3310/mysql.log
log_bin=/data/3310/mysql-bin
binlog_format=row
skip-name-resolve
server-id=20
gtid-mode=on
enforce-gtid-consistency=true
log-slave-updates=1
EOF

2.4 准备MySQL的启动脚本

=====================db01=====================
cat >/etc/systemd/system/mysqld3307.service<<EOF
[Unit]
Description=MySQL Server
Documentation=man:mysqld(8)
Documentation=http://dev.mysql.com/doc/refman/en/using-systemd.html
After=network.target
After=syslog.target
[Install]
WantedBy=multi-user.target
[Service]
User=mysql
Group=mysql
ExecStart=/app/database/mysql/bin/mysqld --defaults-file=/data/3307/my.cnf
LimitNOFILE = 5000
EOF
 
cat >/etc/systemd/system/mysqld3308.service<<EOF
[Unit]
Description=MySQL Server
Documentation=man:mysqld(8)
Documentation=http://dev.mysql.com/doc/refman/en/using-systemd.html
After=network.target
After=syslog.target
[Install]
WantedBy=multi-user.target
[Service]
User=mysql
Group=mysql
ExecStart=/app/database/mysql/bin/mysqld --defaults-file=/data/3308/my.cnf
LimitNOFILE = 5000
EOF
 
cat >/etc/systemd/system/mysqld3309.service<<EOF
[Unit]
Description=MySQL Server
Documentation=man:mysqld(8)
Documentation=http://dev.mysql.com/doc/refman/en/using-systemd.html
After=network.target
After=syslog.target
[Install]
WantedBy=multi-user.target
[Service]
User=mysql
Group=mysql
ExecStart=/app/database/mysql/bin/mysqld --defaults-file=/data/3309/my.cnf
LimitNOFILE = 5000
EOF
cat >/etc/systemd/system/mysqld3310.service<<EOF
[Unit]
Description=MySQL Server
Documentation=man:mysqld(8)
Documentation=http://dev.mysql.com/doc/refman/en/using-systemd.html
After=network.target
After=syslog.target
[Install]
WantedBy=multi-user.target
[Service]
User=mysql
Group=mysql
ExecStart=/app/database/mysql/bin/mysqld --defaults-file=/data/3310/my.cnf
LimitNOFILE = 5000
EOF
 
=====================db02=====================
cat >/etc/systemd/system/mysqld3307.service<<EOF
[Unit]
Description=MySQL Server
Documentation=man:mysqld(8)
Documentation=http://dev.mysql.com/doc/refman/en/using-systemd.html
After=network.target
After=syslog.target
[Install]
WantedBy=multi-user.target
[Service]
User=mysql
Group=mysql
ExecStart=/app/database/mysql/bin/mysqld --defaults-file=/data/3307/my.cnf
LimitNOFILE = 5000
EOF
 
cat >/etc/systemd/system/mysqld3308.service<<EOF
[Unit]
Description=MySQL Server
Documentation=man:mysqld(8)
Documentation=http://dev.mysql.com/doc/refman/en/using-systemd.html
After=network.target
After=syslog.target
[Install]
WantedBy=multi-user.target
[Service]
User=mysql
Group=mysql
ExecStart=/app/database/mysql/bin/mysqld --defaults-file=/data/3308/my.cnf
LimitNOFILE = 5000
EOF
 
cat >/etc/systemd/system/mysqld3309.service<<EOF
[Unit]
Description=MySQL Server
Documentation=man:mysqld(8)
Documentation=http://dev.mysql.com/doc/refman/en/using-systemd.html
After=network.target
After=syslog.target
[Install]
WantedBy=multi-user.target
[Service]
User=mysql
Group=mysql
ExecStart=/app/database/mysql/bin/mysqld --defaults-file=/data/3309/my.cnf
LimitNOFILE = 5000
EOF
 
cat >/etc/systemd/system/mysqld3310.service<<EOF
[Unit]
Description=MySQL Server
Documentation=man:mysqld(8)
Documentation=http://dev.mysql.com/doc/refman/en/using-systemd.html
After=network.target
After=syslog.target
[Install]
WantedBy=multi-user.target
[Service]
User=mysql
Group=mysql
ExecStart=/app/database/mysql/bin/mysqld --defaults-file=/data/3310/my.cnf
LimitNOFILE = 5000
EOF

2.5 修改权限，启动多实例

两台db服务器都需进行以下操作：

chown -R mysql.mysql /data/*
systemctl daemon-reload
systemctl start mysqld3307
systemctl start mysqld3308
systemctl start mysqld3309
systemctl start mysqld3310

确认两台db服务器MySQL实例对应的端口已经启动！

2.6 配置主从关系

① shard1

192.168.1.1:3307 <-----> 192.168.1.2:3307

db02

mysql  -S /data/3307/mysql.sock -e "grant replication slave on *.* to repl@'192.168.1.%' identified by '123';"
mysql  -S /data/3307/mysql.sock -e "grant all  on *.* to root@'192.168.1.%' identified by '123'  with grant option;"

db01

mysql  -S /data/3307/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='192.168.1.2', MASTER_PORT=3307, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3307/mysql.sock -e "start slave;"
mysql  -S /data/3307/mysql.sock -e "show slave status\G"

db02

mysql  -S /data/3307/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='192.168.1.1', MASTER_PORT=3307, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3307/mysql.sock -e "start slave;"
mysql  -S /data/3307/mysql.sock -e "show slave status\G"

192.168.1.1:3309 ------> 192.168.1.1:3307

db01

mysql  -S /data/3309/mysql.sock  -e "CHANGE MASTER TO MASTER_HOST='192.168.1.1', MASTER_PORT=3307, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3309/mysql.sock  -e "start slave;"
mysql  -S /data/3309/mysql.sock  -e "show slave status\G"

192.168.1.2:3309 ------> 192.168.1.2:3307

db02

mysql  -S /data/3309/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='192.168.1.2', MASTER_PORT=3307, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3309/mysql.sock -e "start slave;"
mysql  -S /data/3309/mysql.sock -e "show slave status\G"

② shard2

192.168.1.2:3308 <-----> 192.168.1.1:3308

db01

mysql  -S /data/3308/mysql.sock -e "grant replication slave on *.* to repl@'192.168.1.%' identified by '123';"
mysql  -S /data/3308/mysql.sock -e "grant all  on *.* to root@'192.168.1.%' identified by '123'  with grant option;"

db02

mysql  -S /data/3308/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='192.168.1.1', MASTER_PORT=3308, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3308/mysql.sock -e "start slave;"
mysql  -S /data/3308/mysql.sock -e "show slave status\G"

db01

mysql  -S /data/3308/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='192.168.1.2', MASTER_PORT=3308, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3308/mysql.sock -e "start slave;"
mysql  -S /data/3308/mysql.sock -e "show slave status\G"

192.168.1.2:3310 -----> 192.168.1.2:3308

db02

mysql  -S /data/3310/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='192.168.1.2', MASTER_PORT=3308, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3310/mysql.sock -e "start slave;"
mysql  -S /data/3310/mysql.sock -e "show slave status\G"

192.168.1.1:3310 -----> 192.168.1.1:3308

db01

mysql  -S /data/3310/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='192.168.1.1', MASTER_PORT=3308, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3310/mysql.sock -e "start slave;"
mysql  -S /data/3310/mysql.sock -e "show slave status\G"

③ 确认主从关系

mysql -S /data/3307/mysql.sock -e "show slave status\G"|grep Yes
mysql -S /data/3308/mysql.sock -e "show slave status\G"|grep Yes
mysql -S /data/3309/mysql.sock -e "show slave status\G"|grep Yes
mysql -S /data/3310/mysql.sock -e "show slave status\G"|grep Yes

保证两条db服务器可以看到8个Yes输出！

注：如果中间出现错误，在每个节点进行执行以下命令：

mysql -S /data/3307/mysql.sock -e "stop slave; reset slave all;"
mysql -S /data/3308/mysql.sock -e "stop slave; reset slave all;"
mysql -S /data/3309/mysql.sock -e "stop slave; reset slave all;"
mysql -S /data/3310/mysql.sock -e "stop slave; reset slave all;"

重新部署主从关系！

以上都没有标注命令提示符，主要是为了测试加快速度，而且，已经指定在规定的节点上执行操作！

三、安装MyCAT

本次选择使用一台单独的服务器安装配置MyCAT！

3.1 安装MyCAT

[root@mycat ~]# wget http://dl.mycat.io/1.6.5/Mycat-server-1.6.5-release-20180122220033-linux.tar.gz
[root@mycat ~]# yum -y install java mysql
[root@mycat ~]# tar zxf Mycat-server-1.6.5-release-20180122220033-linux.tar.gz
[root@mycat ~]# echo -e "export PATH=/root/mycat/bin:$PATH" >> /etc/profile
[root@mycat ~]# source /etc/profile
[root@mycat ~]# mycat start
[root@mycat ~]# mysql -uroot -p123456 -h 127.0.0.1 -P8066
MySQL [(none)]>
#可以正常访问即可！

3.2 MyCAT配置文件介绍

logs目录:
wrapper.log       ---->mycat启动日志
mycat.log         ---->mycat详细工作日志
conf目录:
schema.xml      
主配置文件（读写分离、高可用、分布式策略定制、节点控制）
server.xml
mycat软件本身相关的配置
rule.xml 
分片规则配置文件,记录分片规则列表、使用方法等

四、MyCAT实现读写分离

[root@mycat ~]# cd mycat/conf/
[root@mycat conf]# mv schema.xml schema.xml.bak
[root@mycat conf]# vim schema.xml
<?xml version="1.0"?>  
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">  
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="dn1"> 
</schema>  
    <dataNode name="dn1" dataHost="localhost1" database= "test" />  
    <dataHost name="localhost1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1"> 
        <heartbeat>select user()</heartbeat>  
    <writeHost host="db1" url="192.168.1.1:3307" user="root" password="123"> 
            <readHost host="db2" url="192.168.1.1:3309" user="root" password="123" /> 
    </writeHost> 
    </dataHost>  
</mycat:schema>

配置文件简单介绍

逻辑库：schema
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="dn1"> 
 
 
数据节点（逻辑）：datanode
    <dataNode name="dn1" dataHost="localhost1" database= "test" />
#DN配置垂直和水平拆分
 
数据主机（逻辑）：datahost（w和r）
 <dataHost name="localhost1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1"> 
        <heartbeat>select user()</heartbeat>  
    <writeHost host="db1" url="192.168.1.1:3307" user="root" password="123"> 
            <readHost host="db2" url="192.168.1.1:3309" user="root" password="123" /> 
    </writeHost> 
    </dataHost>  
#DH主要配置高可用和读写分离	

测试读写分离

[root@mycat conf]# mycat restart
[root@mycat conf]# mysql -uroot -p123456 -h 127.0.0.1 -P8066
MySQL [(none)]> select @@server_id;
+-------------+
| @@server_id |
+-------------+
|           9 |
+-------------+
MySQL [(none)]> begin ; select @@server_id; commit;
+-------------+
| @@server_id |
+-------------+
|           7 |
+-------------+

如果出现错误，MyCAT使用用户连接数据进行测试：

[root@mycat ~]# mysql -uroot -p123 -h 192.168.1.1 -P 3307
[root@mycat ~]# mysql -uroot -p123 -h 192.168.1.1 -P 3309

五、MyCAT配置读写分离及高可用

[root@mycat conf]# mv schema.xml schema.xml.rw
[root@mycat conf]# vim schema.xml
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="sh1">
</schema>
    <dataNode name="sh1" dataHost="lzj" database= "test" />
    <dataHost name="lzj" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="192.168.1.1:3307" user="root" password="123">
            <readHost host="db2" url="192.168.1.1:3309" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="192.168.1.2:3307" user="root" password="123">
            <readHost host="db4" url="192.168.1.2:3309" user="root" password="123" />
    </writeHost>
    </dataHost>
</mycat:schema>

配置文件介绍

<writeHost host="db1" url="192.168.1.1:3307" user="root" password="123">
            <readHost host="db2" url="192.168.1.1:3309" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="192.168.1.2:3307" user="root" password="123">
            <readHost host="db4" url="192.168.1.2:3309" user="root" password="123" />
    </writeHost>
#真正的 writehost：负责写操作的writehost；standby  writeHost ：和readhost一样，只提供读服务（上述配置文件是一写三读）
#当写节点宕机后，后面跟的readhost也不提供服务，这时候standby的writehost就提供写服务，后面跟的readhost提供读服务（一写一读）
#故障修复之后，原本的写库也就变成了读库，依然是一写三读的架构

测试

[root@mycat conf]# mycat restart
[root@mycat conf]# mysql -uroot -p123456 -h 127.0.0.1 -P8066
MySQL [(none)]> select @@server_id;
+-------------+
| @@server_id |
+-------------+
|          19 |
+-------------+
1 row in set (0.01 sec)
 
MySQL [(none)]> select @@server_id;
+-------------+
| @@server_id |
+-------------+
|           9 |
+-------------+
1 row in set (0.00 sec)
 
MySQL [(none)]> select @@server_id;
+-------------+
| @@server_id |
+-------------+
|          17 |
+-------------+
 
MySQL [(none)]> begin ; select @@server_id; commit;
Query OK, 0 rows affected (0.00 sec)
 
+-------------+
| @@server_id |
+-------------+
|           7 |
+-------------+

此时将配置文件中第一个写节点宕机，模拟故障，进行测试：

[root@db01 ~]# systemctl stop mysqld3307
 
MySQL [(none)]> begin ; select @@server_id; commit;
+-------------+
| @@server_id |
+-------------+
|          17 |
+-------------+
MySQL [(none)]> select @@server_id;
+-------------+
| @@server_id |
+-------------+
|          19 |
+-------------+

将故障节点恢复再次进行测试：

[root@db01 ~]# systemctl start mysqld3307
 
MySQL [(none)]> select @@server_id;
+-------------+
| @@server_id |
+-------------+
|           7 |
+-------------+
MySQL [(none)]> select @@server_id;
+-------------+
| @@server_id |
+-------------+
|          19 |
+-------------+
MySQL [(none)]> select @@server_id;
+-------------+
| @@server_id |
+-------------+
|           9 |
+-------------+
MySQL [(none)]> begin ; select @@server_id; commit;
+-------------+
| @@server_id |
+-------------+
|          17 |
+-------------+

六、配置文件重要属性介绍

6.1 balance属性

负载均衡类型，目前的取值有3种:
1. balance="0", 不开启读写分离机制，所有读写操作都发送到当前可用的writeHost上。 
2. balance="1"，全部的readHost与standby writeHost参与select语句的负载均衡，简单的说：  当双主双从模式(M1->S1，M2->S2，并且M1与 M2互为主备)，正常情况下，M2,S1,S2都参与select语句的负载均衡。 
3. balance="2"，所有读操作都随机的在writeHost、readhost上分发。

6.2 writeType属性

负载均衡类型，目前的取值有2种：
1. writeType="0", 所有写操作发送到配置的第一个writeHost， 第一个挂了切到还生存的第二个writeHost，重新启动后已切换后的为主，切换记录在配置文件中:dnindex.properties； 
2. writeType=“1”，所有写操作都随机的发送到配置的writeHost，但不推荐使用；

6.3 switchType属性

取值范围有3种：
-1 表示不自动切换 
1 默认值，自动切换 
2 基于MySQL主从同步的状态决定是否切换 ，心跳语句为 show slave status 
#双主双从建议使用手动切换

6.4 datahost其他配置

<dataHost name="localhost1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1"> 
 
maxCon="1000"：最大的并发连接数
minCon="10" ：mycat在启动之后，会在后端节点上自动开启的连接线程
tempReadHostAvailable="1"
这个一主一从时（1个writehost，1个readhost时），可以开启这个参数，如果2个writehost，2个readhost时，如果开启，故障库发生故障时，就变成了一写两读
<heartbeat>select user()</heartbeat>  监测心跳

七、MyCAT实现垂直拆分

垂直拆分说白了就是将库中的表进行拆分！

[root@mycat conf]# mv schema.xml schema.xml.ha
[root@mycat conf]# vim schema.xml
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="sh1">
        <table name="user" dataNode="sh1"/>
        <table name="order_t" dataNode="sh2"/>
</schema>
    <dataNode name="sh1" dataHost="lzj1" database= "taobao" />
    <dataNode name="sh2" dataHost="lzj2" database= "taobao" />
    <dataHost name="lzj1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="192.168.1.1:3307" user="root" password="123">
            <readHost host="db2" url="192.168.1.1:3309" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="192.168.1.2:3307" user="root" password="123">
            <readHost host="db4" url="192.168.1.2:3309" user="root" password="123" />
    </writeHost>
    </dataHost>
    <dataHost name="lzj2" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="192.168.1.1:3308" user="root" password="123">
            <readHost host="db2" url="192.168.1.1:3310" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="192.168.1.2:3308" user="root" password="123">
            <readHost host="db4" url="192.168.1.2:3310" user="root" password="123" />
    </writeHost>
    </dataHost>
</mycat:schema>

创建测试库和表

mysql -S /data/3307/mysql.sock -e "create database taobao charset utf8;"
mysql -S /data/3308/mysql.sock -e "create database taobao charset utf8;"
mysql -S /data/3307/mysql.sock -e "use taobao;create table user(id int,name varchar(20))";
mysql -S /data/3308/mysql.sock -e "use taobao;create table order_t(id int,name varchar(20))"

生产中需要在配置文件中添加以下内容：

<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="sh3">
dataNode选项表示：如果不是访问的以下两个表，所有的表都走sh3
        <table name="user" dataNode="sh1"/>
        <table name="order_t" dataNode="sh2"/>
		
    <dataNode name="sh3" dataHost="lzj3" database= "taobao" />

测试

[root@mycat conf]# mycat restart
[root@mycat conf]# mysql -u root -p123456 -h 127.0.0.1 -P8066
MySQL [(none)]> use TESTDB;
MySQL [TESTDB]> show tables;
+------------------+
| Tables_in_taobao |
+------------------+
| order_t          |
| user             |
+------------------+
[root@mycat conf]# mysql -uroot -p123 -h 192.168.1.1 -P 3307 -e 'show tables from taobao;'
+------------------+
| Tables_in_taobao |
+------------------+
| user             |
+------------------+
[root@mycat conf]# mysql -uroot -p123 -h 192.168.1.1 -P 3308 -e 'show tables from taobao;'
+------------------+
| Tables_in_taobao |
+------------------+
| order_t          |
+------------------+

八、MyCAT实现水平拆分

8.1 范围分片

[root@mycat conf]# cp schema.xml schema.xml.1
[root@mycat conf]# vim schema.xml
更改为以下内容
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="sh1"> 
        <table name="t3" dataNode="sh1,sh2" rule="auto-sharding-long" />
</schema>  
    <dataNode name="sh1" dataHost="oldguo1" database= "taobao" /> 
    <dataNode name="sh2" dataHost="oldguo2" database= "taobao" />  

如图：

查看rule文件定义的auto-sharding-long：

[root@mycat conf]# vim rule.xml

如果生产中没有id列，可自行更改rule定义的条件！
这个rule文件无需修改，主要就是查看规则是如何定义的！

编辑规则中定义的autopartition-long.txt文件：

[root@mycat conf]# vim autopartition-long.txt
0-10=0
11-20=1
#这个文件默认有一些规则，直接将其删除，编写自己所需要的即可！

创建测试表：

mysql -S /data/3307/mysql.sock -e "use taobao;create table t3 (id int not null primary key auto_increment,name varchar(20) not null);"
 
mysql -S /data/3308/mysql.sock  -e "use taobao;create table t3 (id int not null primary key auto_increment,name varchar(20) not null);"

测试：

[root@mycat conf]# mycat restart
[root@mycat conf]# mysql -u root -p123456 -h 127.0.0.1 -P8066
MySQL [(none)]> use TESTDB
MySQL [TESTDB]> insert into t3(id,name) values(1,'a');
MySQL [TESTDB]> insert into t3(id,name) values(2,'b');
MySQL [TESTDB]> insert into t3(id,name) values(3,'c');
MySQL [TESTDB]> insert into t3(id,name) values(4,'d');
MySQL [TESTDB]> insert into t3(id,name) values(11,'aa');
MySQL [TESTDB]> insert into t3(id,name) values(12,'bb');
MySQL [TESTDB]> insert into t3(id,name) values(13,'cc');
MySQL [TESTDB]> insert into t3(id,name) values(14,'dd');
MySQL [TESTDB]> select * from t3;
+----+------+
| id | name |
+----+------+
|  1 | a    |
|  2 | b    |
|  3 | c    |
|  4 | d    |
| 11 | aa   |
| 12 | bb   |
| 13 | cc   |
| 14 | dd   |
+----+------+
[root@mycat conf]# mysql -uroot -p123 -h 192.168.1.1 -P 3307 -e 'select * from taobao.t3;'
+----+------+
| id | name |
+----+------+
|  1 | a    |
|  2 | b    |
|  3 | c    |
|  4 | d    |
+----+------+
[root@mycat conf]# mysql -uroot -p123 -h 192.168.1.1 -P 3308 -e 'select * from taobao.t3;'
+----+------+
| id | name |
+----+------+
| 11 | aa   |
| 12 | bb   |
| 13 | cc   |
| 14 | dd   |
+----+------+

8.2 取模分片

取余分片方式：分片键（一个列）与节点数量进行取余，得到余数，将数据写入对应节点！

[root@mycat conf]# vim schema.xml
<table name="t4" dataNode="sh1,sh2" rule="mod-long" />

查看rule文件定义的mod-long：

创建测试表：

mysql -S /data/3307/mysql.sock -e "use taobao;create table t4 (id int not null primary key auto_increment,name varchar(20) not null);"
mysql -S /data/3308/mysql.sock -e "use taobao;create table t4 (id int not null primary key auto_increment,name varchar(20) not null);"

测试：

[root@mycat conf]# mycat restart
[root@mycat conf]# mysql -u root -p123456 -h 127.0.0.1 -P8066
MySQL [(none)]> use TESTDB
MySQL [TESTDB]> insert into t4(id,name) values(1,'a');
MySQL [TESTDB]> insert into t4(id,name) values(2,'b');
MySQL [TESTDB]> insert into t4(id,name) values(3,'c');
MySQL [TESTDB]> insert into t4(id,name) values(4,'d');
MySQL [TESTDB]> select * from t4;
+----+------+
| id | name |
+----+------+
|  2 | b    |
|  4 | d    |
|  1 | a    |
|  3 | c    |
+----+------+
[root@mycat conf]# mysql -uroot -p123 -h 192.168.1.1 -P 3307 -e 'select * from taobao.t4;'
+----+------+
| id | name |
+----+------+
|  2 | b    |
|  4 | d    |
+----+------+
[root@mycat conf]# mysql -uroot -p123 -h 192.168.1.1 -P 3308 -e 'select * from taobao.t4;'
+----+------+
| id | name |
+----+------+
|  1 | a    |
|  3 | c    |
+----+------+

8.3 枚举分片

[root@mycat conf]# vim schema.xml
<table name="t5" dataNode="sh1,sh2" rule="sharding-by-intfile" />

查看rule文件定义的sharding-by-intfile：

[root@mycat conf]# vim rule.xml
<tableRule name="sharding-by-intfile"> 
<rule> <columns>name</columns> 
<algorithm>hash-int</algorithm> 
</rule> 
</tableRule> 
 
<function name="hash-int" class="org.opencloudb.route.function.PartitionByFileMap"> 
<property name="mapFile">partition-hash-int.txt</property> 
  <property name="type">1</property>
</function> 

编辑partition-hash-int.txt文件：

[root@mycat conf]# vim partition-hash-int.txt
bj=0
sh=1
DEFAULT_NODE=1
#bj存在在0号分片，sh存放在1号分片，剩余都存放在1号分片

创建测试表：

mysql -S /data/3307/mysql.sock -e "use taobao;create table t5 (id int not null primary key auto_increment,name varchar(20) not null);"
 
mysql -S /data/3308/mysql.sock -e "use taobao;create table t5 (id int not null primary key auto_increment,name varchar(20) not null);"

测试：

[root@mycat conf]# mycat restart
[root@mycat conf]# mysql -u root -p123456 -h 127.0.0.1 -P8066
MySQL [(none)]> use TESTDB
MySQL [TESTDB]> insert into t5(id,name) values(1,'bj');
MySQL [TESTDB]> insert into t5(id,name) values(2,'sh');
MySQL [TESTDB]> insert into t5(id,name) values(3,'bj');
MySQL [TESTDB]> insert into t5(id,name) values(4,'sh');
MySQL [TESTDB]> insert into t5(id,name) values(5,'tj');
MySQL [TESTDB]> select * from t5;
+----+------+
| id | name |
+----+------+
|  1 | bj   |
|  3 | bj   |
|  2 | sh   |
|  4 | sh   |
|  5 | tj   |
+----+------+
 
[root@mycat conf]# mysql -uroot -p123 -h 192.168.1.1 -P 3307 -e 'select * from taobao.t5;'
+----+------+
| id | name |
+----+------+
|  1 | bj   |
|  3 | bj   |
+----+------+
 
[root@mycat conf]# mysql -uroot -p123 -h 192.168.1.1 -P 3308 -e 'select * from taobao.t5;'
+----+------+
| id | name |
+----+------+
|  2 | sh   |
|  4 | sh   |
|  5 | tj   |
+----+------+

MyCAT还有很多的分片策略，可参考rule文件自行测试，也可以查看MyCAT官方文档！

九、MyCAT全局表

使用场景：
如果你的业务中有些数据类似于数据字典，比如配置文件的配置，
常用业务的配置或者数据量不大很少变动的表，这些表往往不是特别大，而且大部分的业务场景都会用到，那么这种表适合于Mycat全局表，无须对数据进行切分，要在所有的分片上保存一份数据即可，Mycat 在Join操作中，业务表与全局表进行Join聚合会优先选择相同分片内的全局表join，避免跨库Join，在进行数据插入操作时，mycat将把数据分发到全局表对应的所有分片执行，在进行数据读取时候将会随机获取一个节点读取数据。

[root@mycat conf]# vim schema.xml
<table name="t_area" primaryKey="id"  type="global" dataNode="sh1,sh2" /> 

创建测试数据：

mysql -S /data/3307/mysql.sock -e 'use taobao;create table t_area (id int not null primary key auto_increment,name varchar(20) not null);'
 
mysql -S /data/3308/mysql.sock -e 'use taobao;create table t_area  (id int not null primary key auto_increment,name varchar(20) not null);'

测试：

[root@mycat conf]# mycat restart
[root@mycat conf]# mysql -u root -p123456 -h 127.0.0.1 -P8066
MySQL [(none)]> use TESTDB
MySQL [TESTDB]> insert into t_area(id,name) values(1,'a');
MySQL [TESTDB]> insert into t_area(id,name) values(2,'b');
MySQL [TESTDB]> insert into t_area(id,name) values(3,'c');
MySQL [TESTDB]> insert into t_area(id,name) values(4,'d');
MySQL [TESTDB]> select * from t_area;
+----+------+
| id | name |
+----+------+
|  1 | a    |
|  2 | b    |
|  3 | c    |
|  4 | d    |
+----+------+
 
[root@mycat conf]# mysql -uroot -p123 -h 192.168.1.1 -P 3307 -e 'select * from taobao.t_area;'
+----+------+
| id | name |
+----+------+
|  1 | a    |
|  2 | b    |
|  3 | c    |
|  4 | d    |
+----+------+
[root@mycat conf]# mysql -uroot -p123 -h 192.168.1.1 -P 3308 -e 'select * from taobao.t_area;'
+----+------+
| id | name |
+----+------+
|  1 | a    |
|  2 | b    |
|  3 | c    |
|  4 | d    |
+----+------+

如果需要更改MyCAT默认的逻辑库，账号密码等信息，可修改server.xml这个文件！