数据库中间件Mycat的安装使用

2021-07-18 04:00:05

1、介绍
2、环境架构准备
3、安装MyCat软件
4、配置文件介绍
- 4.1 schema.xml 配置文件
- 4.2 schema.xml 部分参数说明
5、垂直分片应用
6、水平分片应用
7、Mycat日常管理

作者：AshesCat

1、介绍

MyCat是一个开源的分布式数据库中间件，是一个实现了MySQL协议的服务器

前端：用户可以把它看作是一个数据库代理，用MySQL客户端工具和命令行访问

后端：可以用MySQL原生协议与多个MySQL服务器通信，也可以用JDBC协议与大多数主流数据库服务器通信，其核心功能是分表分库，即将一个大表水平分割为N个小表，存储在后端MySQL服务器里或者其他数据库里

简单来说：数据库是对底层存储文件的抽象，而Mycat是对数据库的抽象

2、环境架构准备

两台虚拟机db04、db05
每台创建四个mysql实例：3307 3308 3309 3310

2.1 安装文件准备

cd /opt
wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.30-linux-glibc2.12-x86_64.tar.gz
tar xf mysql-5.7.30-linux-glibc2.12-x86_64.tar.gz
ln -s /opt/mysql-5.7.30-linux-glibc2.12-x86_64  /data/app/mysql
useradd -M -s /sbin/nologin mysql
chown -R mysql.mysql /data/*

2.2 创建相关目录并初始化数据

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

2.3 准备配置文件和启动脚本

2.3.1 db04

配置文件

cat >/data/3307/my.cnf<<EOF
[mysqld]
basedir=/data/app/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=/data/app/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=/data/app/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=/data/app/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

启动脚本

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=/data/app/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=/data/app/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=/data/app/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=/data/app/mysql/bin/mysqld --defaults-file=/data/3310/my.cnf
LimitNOFILE = 5000
EOF

2.3.2 db05

配置文件

cat >/data/3307/my.cnf<<EOF
[mysqld]
basedir=/data/app/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=/data/app/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=/data/app/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=/data/app/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

启动脚本

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=/data/app/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=/data/app/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=/data/app/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=/data/app/mysql/bin/mysqld --defaults-file=/data/3310/my.cnf
LimitNOFILE = 5000
EOF

2.4 启动多实例

启动多实例

systemctl start mysqld3307
systemctl start mysqld3308
systemctl start mysqld3309
systemctl start mysqld3310

测试服务状态

[root@db4 opt]# mysql -S /data/3307/mysql.sock -e "show variables like ‘server_id‘"
ke ‘server_id‘"+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 7     |
+---------------+-------+
[root@db4 opt]# mysql -S /data/3308/mysql.sock -e "show variables like ‘server_id‘"
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 8     |
+---------------+-------+
[root@db4 opt]# mysql -S /data/3309/mysql.sock -e "show variables like ‘server_id‘"
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 9     |
+---------------+-------+
[root@db4 opt]# mysql -S /data/3310/mysql.sock -e "show variables like ‘server_id‘"
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 10    |
+---------------+-------+

[root@db5 ~]# mysql -S /data/3307/mysql.sock -e "show variables like ‘server_id‘"
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 17    |
+---------------+-------+
[root@db5 ~]# mysql -S /data/3308/mysql.sock -e "show variables like ‘server_id‘"
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 18    |
+---------------+-------+
[root@db5 ~]# mysql -S /data/3309/mysql.sock -e "show variables like ‘server_id‘"
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 19    |
+---------------+-------+
[root@db5 ~]# mysql -S /data/3310/mysql.sock -e "show variables like ‘server_id‘"
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 20    |
+---------------+-------+

2.5 搭建主从环境

按照架构图进行搭建主从环境

2.5.1 stard1

192.168.10.54:3307 <---> 192.168.10.55:3307 双主搭建

# db05
mysql  -S /data/3307/mysql.sock -e "grant replication slave on *.* to repl@‘192.168.10.%‘ identified by ‘123‘;"
mysql  -S /data/3307/mysql.sock -e "grant all  on *.* to root@‘192.168.10.%‘ identified by ‘123‘  with grant option;"
# db04 
mysql  -S /data/3307/mysql.sock -e "CHANGE MASTER TO MASTER_HOST=‘192.168.10.55‘, 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"
# db05
mysql  -S /data/3307/mysql.sock -e "CHANGE MASTER TO MASTER_HOST=‘192.168.10.54‘, 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"

192.168.10.54:3309 ---> 192.168.10.54:3307 主从搭建

# db04
mysql  -S /data/3309/mysql.sock  -e "CHANGE MASTER TO MASTER_HOST=‘192.168.10.54‘, 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"

192.168.10.55:3309 ---> 192.168.10.55:3307 主从搭建

# db05
mysql  -S /data/3309/mysql.sock -e "CHANGE MASTER TO MASTER_HOST=‘192.168.10.55‘, 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"

2.5.2 stard2

192.168.10.55:3308 <---> 192.168.10.54:3308 双主搭建

# db04
mysql  -S /data/3308/mysql.sock -e "grant replication slave on *.* to repl@‘192.168.10.%‘ identified by ‘123‘;"
mysql  -S /data/3308/mysql.sock -e "grant all  on *.* to root@‘192.168.10.%‘ identified by ‘123‘  with grant option;"
# db05
mysql  -S /data/3308/mysql.sock -e "CHANGE MASTER TO MASTER_HOST=‘192.168.10.54‘, 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"
# db04
mysql  -S /data/3308/mysql.sock -e "CHANGE MASTER TO MASTER_HOST=‘192.168.10.55‘, 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"

192.168.10.55:3310 ---> 192.168.10.55:3308 主从搭建

# db05
mysql  -S /data/3310/mysql.sock -e "CHANGE MASTER TO MASTER_HOST=‘192.168.10.55‘, 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"

192.168.10.54:3310 ---> 192.168.10.54:3308 主从搭建

# db04
mysql  -S /data/3310/mysql.sock -e "CHANGE MASTER TO MASTER_HOST=‘192.168.10.54‘, 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"

2.6 检测主从状态

db04

[root@db4 ~]# mysql -S /data/3307/mysql.sock -e "show slave status\G"|grep Yes
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
[root@db4 ~]# mysql -S /data/3308/mysql.sock -e "show slave status\G"|grep Yes
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
[root@db4 ~]# mysql -S /data/3309/mysql.sock -e "show slave status\G"|grep Yes
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
[root@db4 ~]# mysql -S /data/3310/mysql.sock -e "show slave status\G"|grep Yes
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes

db05

[root@db5 ~]# mysql -S /data/3307/mysql.sock -e "show slave status\G"|grep Yes
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
[root@db5 ~]# mysql -S /data/3308/mysql.sock -e "show slave status\G"|grep Yes
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
[root@db5 ~]# mysql -S /data/3309/mysql.sock -e "show slave status\G"|grep Yes
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
[root@db5 ~]# mysql -S /data/3310/mysql.sock -e "show slave status\G"|grep Yes
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes

3、安装MyCat软件

下载地址：http://dl.mycat.org.cn/
安装java环境

[root@localhost opt]# yum install java -y

下载mycat软件

[root@localhost opt]# wget http://dl.mycat.org.cn/1.6.7.6/20210303094759/Mycat-server-1.6.7.6-release-20210303094759-linux.tar.gz

解压安装，加入环境变量

[root@localhost opt]# tar xf Mycat-server-1.6.7.6-release-20210303094759-linux.tar.gz 
[root@localhost /]# vim /etc/profile
export PATH=/opt/mycat/bin:/usr/local/mysql/bin:$PATH
[root@localhost /]# source /etc/profile

启动mycat

[root@localhost /]# mycat start 
Starting Mycat-server...
[root@localhost /]#

连接mycat

[root@localhost /]# mysql -uroot -p123456 -h127.0.0.1 -P8066
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.6.29-mycat-1.6.7.6-release-20210303094759 MyCat Server (OpenCloudDB)

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.

mysql> show databases;
+----------+
| DATABASE |
+----------+
| TESTDB   |
+----------+
1 row in set (0.00 sec)

mysql>

4、配置文件介绍

# conf目录
autopartition-long.txt       # 分片配置信息
auto-sharding-long.txt       # 分片配置信息
auto-sharding-rang-mod.txt   # 分片配置信息
rule.xml                     # 分片策略的定义和使用方法
schema.xml                   # 主配置文件，节点、分片、高可用、读写分离
server.xml                   # Mycat服务配置文件

# log目录
mycat.log   # 系统日志
wrapper.log # 启动日志

4.1 schema.xml 配置文件

[root@localhost ~]# vim /opt/mycat/conf/schema.xml
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
# 逻辑库内容
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="sh1">
        <table name="city" dataNode="sh1"/>      # 取节点sh1的city表
        <table name="country" dataNode="sh2"/>   # 取节点sh2的country表

# 分片定义(dn节点定义)
</schema>
    <dataNode name="sh1" dataHost="dh1" database= "world" />  # sh1数据源是从world库，具体连接配置见dh1
    <dataNode name="sh2" dataHost="dh2" database= "world" />  # sh2数据源是从world库，具体连接配置见dh2

# 数据主机定义(dh1定义)
    <dataHost name="dh1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>

# 两套主从，默认db1写，其它三台只读。
    <writeHost host="db1" url="192.168.10.54:3307" user="root" password="123">  # 主库(Master)
            <readHost host="db2" url="192.168.10.54:3309" user="root" password="123" />  # 从库
    </writeHost>
    <writeHost host="db3" url="192.168.10.55:3307" user="root" password="123">  # 备用主库(standby Master)
            <readHost host="db4" url="192.168.10.55:3309" user="root" password="123" />  # 从库
    </writeHost>
    </dataHost>

# 数据主机定义(dh2定义)
    <dataHost name="dh2" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
      
# 两套主从，默认db1写，其它三台只读。
    <writeHost host="db1" url="192.168.10.54:3308" user="root" password="123">   # 主库(Master)
            <readHost host="db2" url="192.168.10.54:3310" user="root" password="123" />  # 从库
    </writeHost>
    <writeHost host="db3" url="192.168.10.55:3308" user="root" password="123">   # 备用主库(Standby Master)
            <readHost host="db4" url="192.168.10.55:3310" user="root" password="123" />  # 从库
    </writeHost>
    </dataHost>
	
</mycat:schema>

4.2 schema.xml 部分参数说明

以下参数正常使用默认值即可。

<dataHost name="dh2" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
balance # 读负载均衡参数
	1：1w/3r,所有standby writehost、readhost参与select语句的负载均衡。
	0：1rw,不开启读写分离机制，所有读写操作都发送到第一台writehost上。
	2：1rw/3r,所有读操作都随机在wirtehost、readhost上分发。
	
writeType # 写负载均衡参数
	0：1w/3r,默认，所有写操作只发送到配置的第一个writehost，第一个挂了后，切换到第二个还生存的writehsot，重新弄启动后以切换后的writehost为主，切换记录在配置文件：dnindex.properties中。
	1：2w/2r,所有写操作随机发送到所有writehost，般用于双主半同步复制。并不推荐使用。

switchType # 是否自动切换
	-1：不自动切换
	1 ：默认，自动切换
	2 ：基于MySQL主从同步的状态决定是否切换，心跳语句未show slave status

maxCon # 最大连接并发数
minCon # 连接池，mycat在启动之后，会在后端节点上自动开启的链接线程

tempReadHostAvailable = "1" # master宕机后，允许这台的slave继续处理select任务
	这个一主一从时（一个readhost，一个writehost），可以开启这个参数。一般不用。

<heartbeat>select user()</heartbeat> # 监测心跳

5、垂直分片应用

5.1 配置文件准备

[root@localhost ~]# vim /opt/mycat/conf/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="table7" dataNode="sh1"/>
        <table name="table8" dataNode="sh2"/>

</schema>
    <dataNode name="sh1" dataHost="dh1" database= "world" />
    <dataNode name="sh2" dataHost="dh2" database= "world" />

    <dataHost name="dh1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="192.168.10.54:3307" user="root" password="123">
            <readHost host="db2" url="192.168.10.54:3309" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="192.168.10.55:3307" user="root" password="123">
            <readHost host="db4" url="192.168.10.55:3309" user="root" password="123" />
    </writeHost>
    </dataHost>

    <dataHost name="dh2" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="192.168.10.54:3308" user="root" password="123">
            <readHost host="db2" url="192.168.10.54:3310" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="192.168.10.55:3308" user="root" password="123">
            <readHost host="db4" url="192.168.10.55:3310" user="root" password="123" />
    </writeHost>
    </dataHost>

</mycat:schema>

5.2 创建测试数据库

在3307节点创建table7和table9，在3308节点创建table7和table9。

mysql -S /data/3307/mysql.sock -e "create database world charset utf8;"
mysql -S /data/3308/mysql.sock -e "create database world charset utf8;"
mysql -S /data/3307/mysql.sock -e "use world;create table table7(id int,name varchar(20));create table table9(id int,name varchar(20));"
mysql -S /data/3308/mysql.sock -e "use world;create table table8(id int,name varchar(20));create table table7(id int,name varchar(20));"

5.3 重启mycat并检查逻辑库

mycat restart;

mysql> use TESTDB
Database changed
mysql> show tables;
+-----------------+
| Tables_in_world |
+-----------------+
| table7          |
| table8          |
| table9          |
+-----------------+
3 rows in set (0.01 sec)

5.4 写入测试

目前逻辑库TESTDB中存在table7-9三张表。table7为3307节点表，table8为3308节点表，table9为3308/3309共有表。以此结论进行写入测试。

# 在逻辑库TESTDB中对3张表进行数据插入
mysql> insert into table7 values(1,‘a‘);
mysql> insert into table8 values(2,‘b‘);
mysql> insert into table9 values(3,‘c‘);

# 在逻辑库查看三张表数据
mysql> select * from table7;
+------+------+
| id   | name |
+------+------+
|    1 | a    |
+------+------+
1 row in set (0.03 sec)

mysql> select * from table8;
+------+------+
| id   | name |
+------+------+
|    2 | b    |
+------+------+
1 row in set (0.00 sec)

mysql> select * from table9;
+------+------+
| id   | name |
+------+------+
|    3 | c    |
+------+------+
1 row in set (0.00 sec)

# 在3307节点查看数据
[root@db4 ~]# mysql -S /data/3307/mysql.sock -e "select * from world.table7;"
+------+------+
| id   | name |
+------+------+
|    1 | a    |
+------+------+
[root@db4 ~]# mysql -S /data/3307/mysql.sock -e "select * from world.table9;"
+------+------+
| id   | name |
+------+------+
|    3 | c    |
+------+------+

# 在3308节点查看数据
[root@db4 ~]# mysql -S /data/3308/mysql.sock -e "select * from world.table8;"
+------+------+
| id   | name |
+------+------+
|    2 | b    |
+------+------+
[root@db4 ~]# mysql -S /data/3309/mysql.sock -e "select * from world.table9;"
+------+------+
| id   | name |
+------+------+
|    3 | c    |
+------+------+

6、水平分片应用

6.1 拆分概念

6.1.1 分片策略

水平拆分包含了几乎经典业务中大部分的分片策略，mycat已经开发了相应算法，非常方便调用。
范围分片
取模
枚举
日期
HASH 等

6.1.2 分片键

作为分片条件的列，用来做查询条件的列，比较适合做分片键。

6.2 范围分片

对一张表table3进行分片

6.2.1 试用环境

1、表内行数较多(如2000w行数据，可按照范围分为1-1000w，1000w01-2000w分片)
2、数据访问非常频繁，但用户访问较离散。所有数据范围均匀访问。

6.2.2 配置文件准备

修改配置文件，定制分片策略。

# 1、schema.xml 添加：
vim schema.xml
<table name="table3" dataNode="sh1,sh2" rule="auto-sharding-long" />

# 2、定义和使用分片策略
vim rule.xml
<tableRule name="auto-sharding-long">   # 分片策略名称，schema.xml中调用
                <rule>
                        <columns>id</columns>      # 分片键为id列
                        <algorithm>rang-long</algorithm>  # 范围方式(函数)
                </rule>    
                
<function name="rang-long"
    class="io.mycat.route.function.AutoPartitionByLong">
    <property name="mapFile">autopartition-long.txt</property>    # 传参文件
</function>

# 3、定义范围
vim autopartition-long.txt
0-10=0     # id为0-10为0号分片
10-20=1    # id为10-20为0号分片

6.2.3 创建测试表

mysql -S /data/3307/mysql.sock -e "use world;create table table3 (id int not null primary key auto_increment,name varchar(20) not null);"
mysql -S /data/3308/mysql.sock -e "use world;create table table3 (id int not null primary key auto_increment,name varchar(20) not null);"

6.2.4 重启mycat并检查

mycat restart 

mysql> show tables;
+-----------------+
| Tables_in_world |
+-----------------+
| table3          |
| table7          |
| table8          |
| table9          |
+-----------------+
4 rows in set (0.07 sec)

6.2.5 写入测试

use TESTDB;
insert into table3(id,name) values(1,‘a‘);
insert into table3(id,name) values(2,‘b‘);
insert into table3(id,name) values(3,‘c‘);
insert into table3(id,name) values(4,‘d‘);
insert into table3(id,name) values(11,‘aa‘);
insert into table3(id,name) values(12,‘bb‘);
insert into table3(id,name) values(13,‘cc‘);
insert into table3(id,name) values(14,‘dd‘);

# 逻辑库查询结果
mysql> select * from table3;
+----+------+
| id | name |
+----+------+
|  1 | a    |
|  2 | b    |
|  3 | c    |
|  4 | d    |
| 11 | aa   |
| 12 | bb   |
| 13 | cc   |
| 14 | dd   |
+----+------+
8 rows in set (0.03 sec)

# 3307节点查询结果
[root@db4 ~]# mysql -S /data/3307/mysql.sock -e "select * from world.table3;"
+----+------+
| id | name |
+----+------+
|  1 | a    |
|  2 | b    |
|  3 | c    |
|  4 | d    |
+----+------+

# 3308节点查询结果
[root@db4 ~]# mysql -S /data/3308/mysql.sock -e "select * from world.table3;"
+----+------+
| id | name |
+----+------+
| 11 | aa   |
| 12 | bb   |
| 13 | cc   |
| 14 | dd   |
+----+------+

6.3 取模分片

取余数分片方式：分片键（一个列）与节点数进行取余，得到余数，将数据写入对应节点。

6.3.1 配置文件准备

# 1、schema.xml 添加：
vim schema.xml
<table name="table4" dataNode="sh1,sh2" rule="mod-long" />

# 查看和定义分片使用
vim rule.xml
<property name="count">2</property>  # 定义被除数（节点个数）

6.3.2 准备测试表

mysql -S /data/3307/mysql.sock -e "use world;create table table4 (id int not null primary key auto_increment,name varchar(20) not null);"
mysql -S /data/3308/mysql.sock -e "use world;create table table4 (id int not null primary key auto_increment,name varchar(20) not null);"

6.3.3 重启mycat

mycat restart

6.3.4 写入测试

use TESTDB;
insert into table4(id,name) values(1,‘a‘);
insert into table4(id,name) values(2,‘b‘);
insert into table4(id,name) values(3,‘c‘);
insert into table4(id,name) values(4,‘d‘);

# 在逻辑库TESTDB查询结果
mysql> select * from table4;
+----+------+
| id | name |
+----+------+
|  2 | b    |
|  4 | d    |
|  1 | a    |
|  3 | c    |
+----+------+
4 rows in set (0.03 sec)

# 在3307节点查询结果
[root@db4 ~]# mysql -S /data/3307/mysql.sock -e "select * from world.table4;"
+----+------+
| id | name |
+----+------+
|  2 | b    |
|  4 | d    |
+----+------+

# 在3308节点查询结果
[root@db4 ~]# mysql -S /data/3308/mysql.sock -e "select * from world.table4;"
+----+------+
| id | name |
+----+------+
|  1 | a    |
|  3 | c    |
+----+------+

6.4 枚举分片

枚举分片要根据不同的表的情况，选择分片键。如中国表中，是根据不同省进行存储数据，便可根据省名称进行分片。前提是有一个列中存储了省的名称。如bj、sh、hlj等。如下表，可根据name列进行分片。

id	name	teleno
1	bj	1111111
2	sh	2222222
3	bj	3333333
4	hlj	4444444
5	sh	5555555

6.4.1 配置文件准备

# 1、schema.xml 添加：
vim schema.xml
<table name="table4" dataNode="sh1,sh2" rule="sharding-by-intfile" />

# 2、查看和定义分片使用
vim rule.xml
        <tableRule name="sharding-by-intfile">
                <rule>
                        <columns>name</columns>   # 修改分片键(name)
                        <algorithm>hash-int</algorithm>
                </rule>

        <function name="hash-int"
                          class="io.mycat.route.function.PartitionByFileMap">
                <property name="mapFile">partition-hash-int.txt</property>
                <property name="type">1</property>         # rule增加此行，修改type为1。不然默认为0，partition-hash-int.txt文档只支持二进制。bj/sh不生效。
        </function>

# 3、定义范围
vim partition-hash-int.txt
bj=0         # name列为bj，分到0分片
sh=1         # name列为sh，分到1分片
DEFAULT_NODE=1    # 其它非bj,sh，分到默认1分片

6.5 Mycat全局表

如果你的业务中有写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。那么这种表适合设置为Mycat全局表。无需对数据进行切分，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是，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会随机获取一个节点的数据。

6.5.1 配置全局表

# 1、schema.xml 添加：
vim schema.xml
<table name="t_area" primaryKey="id" type="global" dataNode="sh1,sh2" />

6.6 E-R分片

如果业务中有两张表经常做join操作，如可以设置为E-R分片。如

select * from a join b on a.id = b.aid where b.id = 1002;

此策略会按取模分片的方式将两张表的数据分别分片到两个节点内，且相关联的数据会分到同一个节点。
如a，b表：

id	name
1	a
2	b

id	addr	aid
1001	bj	1
1002	sh	2

分片结果会a表的1行和b表的1001行在一个节点，a表的2和b表的1002在一个节点。因为有aid相关联。

6.6.1 准备配置文件

schema.xml添加

vim schema.xml
<table name="a" dataNode="sh1,sh2" rule="mod-long_e-r" >  # 因为rule名称与mod-log重复，复制重命名新增一个，对应rule也需要新增同样名称表定义和函数。
		<childTable name="b" joinKey="aid" parentKey="id" />  # 配置非驱动表
</table>

rule.xml增加

vim rule.xml
</tableRule>
<tableRule name="mod-long_e-r">   # 自定义表定义名称
        <rule>
                <columns>id</columns>
                <algorithm>mod-long</algorithm>
        </rule>


</function>
<function name="mod-long_e-r" class="io.mycat.route.function.PartitionByMod">    # 自定义函数名称
        <!-- how many data nodes -->
        <property name="count">2</property>
</function>

6.6.2 准备测试表

mysql -S /data/3307/mysql.sock -e "use world;CREATE TABLE a ( id INT NOT NULL PRIMARY key auto_increment, NAME VARCHAR ( 20 ) NOT NULL );"
mysql -S /data/3307/mysql.sock -e "use world;CREATE TABLE b ( id INT NOT NULL PRIMARY key auto_increment, addr VARCHAR ( 20 ) NOT NULL, aid int);"

mysql -S /data/3308/mysql.sock -e "use world;CREATE TABLE a ( id INT NOT NULL PRIMARY key auto_increment, NAME VARCHAR ( 20 ) NOT NULL );"
mysql -S /data/3308/mysql.sock -e "use world;CREATE TABLE b ( id INT NOT NULL PRIMARY key auto_increment, addr VARCHAR ( 20 ) NOT NULL, aid int);"

6.6.3 重启mycat