第十一章 读写分离及分布式架构

atlas 实现读写分离

Atlas是由 Qihoo 360, Web平台部基础架构团队开发维护的一个基于MySQL协议的数据中间层项目。

atlas 说明

Atlas是一个位于应用程序与MySQL之间中间件。在后端DB看来，Atlas相当于连接它的客户端，在前端应用看来，Atlas相当于一个DB。Atlas作为服务端与应用程序通讯，它实现了MySQL的客户端和服务端协议，同时作为客户端与MySQL通讯。它对应用程序屏蔽了DB的细节，同时为了降低MySQL负担，它还维护了连接池。

atlas 部署

安装atlas

atlas 安装包下载地址:https://github.com/Qihoo360/Atlas

rpm -ivh Atlas-2.2.1.el6.x86_64.rpm

修改test.cnf配置文件

配置文件说明具体可以看安装后自带的test.cnf文件。

cd /usr/local/mysql-proxy/conf

mv test.cnf test.cnf.bak

vim test.cnf
[mysql-proxy]
admin-username = user
admin-password = pwd
# Atlas后端连接的MySQL主库的IP和端口
proxy-backend-addresses = 10.0.0.55:3306
# Atlas后端连接的MySQL从库的IP和端口，@后面的数字代表权重，用作负载均衡，则默认为1，可设多项，逗号分隔
proxy-read-only-backend-addresses = 10.0.0.51:3306,10.0.0.53:3306
# 用户名与其对应的加密过的MySQL密码，密码使用PREFIX/bin目录下的加密程序encrypt加密
pwds = repl:3yb5jEku5h4=,mha:O2jBXONX098=
daemon = true
keepalive = true
event-threads = 8
log-level = message
log-path = /usr/local/mysql-proxy/log
sql-log=ON
proxy-address = 0.0.0.0:33060
admin-address = 0.0.0.0:2345
charset=utf8

启动atlas

/usr/local/mysql-proxy/bin/mysql-proxyd test start
ps -ef |grep proxy

测试读写分离

[ ~]# mysql -umha -pmha -h 10.0.0.53 -P 33060
读: 
db03 [(none)]>select @@server_id;
写:
db03 [(none)]>begin;select @@server_id; commit;

生产授权用户

例子: '10.0.0.%'
(1) 业务主库中
db01 [(none)]>grant all on *.* to '10.0.0.%' identified by '123';

(2) 将密码加密处理
cd /usr/local/mysql-proxy/bin
[ /usr/local/mysql-proxy/bin]# ./encrypt 123
3yb5jEku5h4=

(3) 修改配置文件
vim /usr/local/mysql-proxy/conf/test.cnf 
pwds = repl:3yb5jEku5h4=,mha:O2jBXONX098=,root:3yb5jEku5h4=

(4) 重启atlas 
/usr/local/mysql-proxy/bin/mysql-proxyd test restart


(5) 用户测试
[ ~]# mysql -uroot -p123 -h 10.0.0.61 -P 33060

atlas基础管理

[ ~]# mysql -uuser -ppwd -h 10.0.0.53 -P 2345
db03 [(none)]>select * from help;
(1) 查帮助:
 SELECT * FROM help;

(2) 查看节点信息
SELECT * FROM backends;

(3) 上线和下线节点
SET OFFLINE $backend_id;
SET ONLINE $backend_id 

(4) 删除和添加节点
REMOVE BACKEND 3;
ADD SLAVE 10.0.0.53:3306;


(5) 添加用户和删除用户
SELECT * FROM pwds;
REMOVE PWD root;
ADD PWD root:123
ADD ENPWD root:3yb5jEku5h4=

(6) 持久化配置
db03 [(none)]> SAVE CONFIG

MyCAT基础架构准备

MyCAT基础架构图 (模拟)

这里为了避免开太多台虚拟机，所以使用了多实例，不代表生产环境

环境准备：

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

删除历史环境：

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

创建相关目录初始化数据

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

准备配置文件和启动脚本

========db01============

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

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

========db02============

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

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

修改权限，启动多实例

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

mysql -S /data/3307/mysql.sock -e "show variables like 'server_id'"
mysql -S /data/3308/mysql.sock -e "show variables like 'server_id'"
mysql -S /data/3309/mysql.sock -e "show variables like 'server_id'"
mysql -S /data/3310/mysql.sock -e "show variables like 'server_id'"

节点主从规划

箭头指向谁是主库

? 10.0.0.51:3307 <-----> 10.0.0.52:3307
? 10.0.0.51:3309 ------> 10.0.0.51:3307
? 10.0.0.52:3309 ------> 10.0.0.52:3307
? 10.0.0.52:3308 <-----> 10.0.0.51:3308
? 10.0.0.52:3310 -----> 10.0.0.52:3308

分片规划

shard1：

? Master：10.0.0.51:3307
? slave1：10.0.0.51:3309
? Standby Master：10.0.0.52:3307
? slave2：10.0.0.52:3309

shard2：

? Master：10.0.0.52:3308
? slave1：10.0.0.52:3310
? Standby Master：10.0.0.51:3308
? slave2：10.0.0.51:3310

开始配置

shard1 配置

10.0.0.51:3307 <-----> 10.0.0.52:3307

db02

mysql  -S /data/3307/mysql.sock -e "grant replication slave on *.* to '10.0.0.%' identified by '123';"
mysql  -S /data/3307/mysql.sock -e "grant all  on *.* to '10.0.0.%' identified by '123'  with grant option;"

db01

mysql  -S /data/3307/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.52', 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='10.0.0.51', 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"

10.0.0.51:3309 ------> 10.0.0.51:3307

db01

mysql  -S /data/3309/mysql.sock  -e "CHANGE MASTER TO MASTER_HOST='10.0.0.51', 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"

10.0.0.52:3309 ------> 10.0.0.52:3307
db02

mysql  -S /data/3309/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.52', 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"

shard2 配置

10.0.0.52:3308 <-----> 10.0.0.51:3308
db01

mysql  -S /data/3308/mysql.sock -e "grant replication slave on *.* to '10.0.0.%' identified by '123';"
mysql  -S /data/3308/mysql.sock -e "grant all  on *.* to '10.0.0.%' identified by '123'  with grant option;"

db02

mysql  -S /data/3308/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.51', 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='10.0.0.52', 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"

10.0.0.52:3310 -----> 10.0.0.52:3308
db02

mysql  -S /data/3310/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.52', 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"

10.0.0.51:3310 -----> 10.0.0.51:3308
db01

mysql  -S /data/3310/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.51', 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"

检测主从状态

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

如果中间出现错误，在每个节点进行执行以下命令(2.9 状态正确,忽略此步骤)

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;"

Mycat的安装

这里只是为了测试搭建Mycat，所以直接将MyCAT服务安装到了DB01服务器上

安装java环境

yum install -y java

上传到/application 并解压

略

文件介绍

conf:
schema.xml 主配置文件
rule.xml 分片策略定义文件
server.xml mycat服务有关的配置
xxxx.txt 分片参数功能有关

启动mycat

[ ~]# vim /etc/profile 
export PATH=/application/mycat/bin:$PATH
source /etc/profile

[ ~]# mycat start 
[ ~]# mysql -uroot -p123456 -h 10.0.0.52 -P8066

测试数据准备

db01:

mysql -S /data/3307/mysql.sock 
grant all on *.* to '10.0.0.%' identified by '123';
source /root/world.sql

mysql -S /data/3308/mysql.sock 
grant all on *.* to '10.0.0.%' identified by '123';
source /root/world.sql

MyCAT 核心配置文件使用介绍(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= "world" />  
    <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="10.0.0.51:3307" user="root" password="123"> 
            <readHost host="db2" url="10.0.0.51:3309" user="root" password="123" /> 
    </writeHost> 
    </dataHost>  
</mycat:schema>

Mycat实现读写分离功能

[ /application/mycat/conf]# cat 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="oldguo1" database= "world" />         
        <dataHost name="oldguo1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">    
                <heartbeat>select user()</heartbeat>  
        <writeHost host="db1" url="10.0.0.51:3307" user="root" password="123"> 
                        <readHost host="db2" url="10.0.0.51:3309" user="root" password="123" /> 
        </writeHost> 
        </dataHost>  
</mycat:schema>

重启生效:

[ /application/mycat/conf]# mycat restart

测试:

[ /application/mycat/conf]# mysql -uroot -p123456 -h 10.0.0.52 -P8066
mysql> select @@server_id;
mysql> begin; select @@server_id;commit;

读写分离+高可用功能

编写配置文件

[ conf]# mv schema.xml schema.xml.rw
[ 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="oldguo1" database= "world" />  
    <dataHost name="oldguo1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1"> 
        <heartbeat>select user()</heartbeat>  
    <writeHost host="db1" url="10.0.0.51:3307" user="root" password="123"> 
            <readHost host="db2" url="10.0.0.51:3309" user="root" password="123" /> 
    </writeHost> 
    <writeHost host="db3" url="10.0.0.52:3307" user="root" password="123"> 
            <readHost host="db4" url="10.0.0.52:3309" user="root" password="123" /> 
    </writeHost>        
    </dataHost>  
</mycat:schema>

真正的 writehost：负责写操作的writehost
standby writeHost ：和readhost一样，只提供读服务

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

测试：

mysql -uroot -p123456 -h 10.0.0.52 -P 8066
show variables like 'server_id';

读写分离测试

mysql -uroot -p -h 127.0.0.1 -P8066

show variables like 'server_id';
show variables like 'server_id';
show variables like 'server_id';
begin;
show variables like 'server_id';

对db01 3307节点进行关闭和启动,测试读写操作

配置中的属性介绍:(了解一下)

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，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。

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

switchType属性

-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

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

MyCAT核心特性 - 切分

数据切分

指通过某种特定的条件，将我们存放在同一个数据库中的数据分散存放到多个数据库（主机）上面，以达到分散单台设备负载的效果。

切分类型

• 垂直拆分
  是按照不同的表（或者 Schema）来切分到不同的数据库(主机)上
• 水平(横向)拆分
  根据表中数据的逻辑关系，将同一个表中数据按照某种条件查分到多台数据库(主机)

分片策略

• 范围 range 800w 1-400w 400w01-800w
• 取模 mod 取余数
• 枚举
• 哈希 hash
• 时间 流水

垂直分表

编写配置文件schema.xml

最好先将配置文件备份一份，

cd /application/mycat/conf/
mv  schema.xml  schema.xml.ha
vim schema.xml
------ 配置文件内容如下
<?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="oldguo1" database= "taobao" />
    <dataNode name="sh2" dataHost="oldguo2" database= "taobao" />
    <dataHost name="oldguo1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="10.0.0.51:3307" user="root" password="123">
            <readHost host="db2" url="10.0.0.51:3309" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="10.0.0.52:3307" user="root" password="123">
            <readHost host="db4" url="10.0.0.52:3309" user="root" password="123" />
    </writeHost>
    </dataHost>
    <dataHost name="oldguo2" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="10.0.0.51:3308" user="root" password="123">
            <readHost host="db2" url="10.0.0.51:3310" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="10.0.0.52:3308" user="root" password="123">
            <readHost host="db4" url="10.0.0.52:3310" user="root" password="123" />
    </writeHost>
    </dataHost>
</mycat:schema>

创建测试库和表

双活状态所以在哪一台服务器操作都可以

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))"

水平拆分

范围分片

（1）修改配置文件

修改如下：

vim /application/mycat/conf/schema.xml
--- 修改内容如下

<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" />

vim /application/mycat/conf/autopartition-long.txt

0-10=0
11-20=1

（2）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);"

（3）测试

重启mycat
mycat restart
mysql -uroot -p123456 -h 127.0.0.1 -P 8066

use TESTDB;
insert into t3(id,name) values(1,'a');
insert into t3(id,name) values(2,'b');
insert into t3(id,name) values(3,'c');
insert into t3(id,name) values(4,'d');
insert into t3(id,name) values(11,'aa');
insert into t3(id,name) values(12,'bb');
insert into t3(id,name) values(13,'cc');
insert into t3(id,name) values(14,'dd');

（4）查看数据存放

mysql -S /data/3307/mysql.sock  -e "use taobao;select * from t5";
mysql -S /data/3308/mysql.sock  -e "use taobao;select * from t5";
mysql -S /data/3309/mysql.sock  -e "use taobao;select * from t5";
mysql -S /data/3310/mysql.sock  -e "use taobao;select * from t5";

11.2 取模分片（mod-long）

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

（1）修改配置文件

vim schema.xml
<table name="t4" dataNode="sh1,sh2" rule="mod-long" />

vim rule.xml
  <function name="mod-long" class="io.mycat.route.function.PartitionByMod">
                <property name="count">2</property>
        </function>

（2）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);"

（3）测试

重启mycat 
mycat restart 

测试： 
mysql -uroot -p123456 -h10.0.0.52 -P8066

use TESTDB
insert into t4(id,name) values(1,'a');
insert into t4(id,name) values(2,'b');
insert into t4(id,name) values(3,'c');
insert into t4(id,name) values(4,'d');

（4）查看结果，分别登录后端节点查询数据

mysql -S /data/3307/mysql.sock 
use taobao
select * from t4;

mysql -S /data/3308/mysql.sock 
use taobao
select * from t4;

11.3 枚举分片

vim schema.xml
<table name="t5" dataNode="sh1,sh2" rule="sharding-by-intfile" />

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> 

partition-hash-int.txt 配置： 
bj=0 
sh=1
DEFAULT_NODE=1 
columns 标识将要分片的表字段，algorithm 分片函数， 其中分片函数配置中，mapFile标识配置文件名称

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

重启mycat 
mycat restart 

mysql -uroot -p123456 -h10.0.0.52 -P8066
use TESTDB
insert into t5(id,name) values(1,'bj');
insert into t5(id,name) values(2,'sh');
insert into t5(id,name) values(3,'bj');
insert into t5(id,name) values(4,'sh');
insert into t5(id,name) values(5,'tj');

分别登录后端节点查询数据

mysql -S /data/3307/mysql.sock -e "use taobao;select * from t5;"
mysql -S /data/3308/mysql.sock -e "use taobao;select * from t5;"

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。
修改配置文件

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

后端数据准备

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

重启mycat 
mycat restart 

测试：
mysql -uroot -p123456 -h10.0.0.52 -P8066

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

分别登录后端节点查询数据

mysql -S /data/3307/mysql.sock -e "use taobao;select * from t_area;"
mysql -S /data/3308/mysql.sock -e "use taobao;select * from t_area;"