mysql-proxy 简介
MySQL Proxy是一个处于你的client端和MySQL server端之间的简单程序,它可以监测、分析或改变它们的通信。它使用灵活,没有限制,常见的用途包括:负载平衡,故障、查询分析,查询过滤和修改等等。
MySQL Proxy就是这么一个中间层代理,简单的说,MySQL Proxy就是一个连接池,负责将前台应用的连接请求转发给后台的数据库,并且通过使用lua脚本,可以实现复杂的连接控制和过滤,从而实现读写分离和负载平衡。对于应用来说,MySQL Proxy是完全透明的,应用则只需要连接到MySQL Proxy的监听端口即可。当然,这样proxy机器可能成为单点失效,但完全可以使用多个proxy机器做为冗余,在应用服务器的连接池配置中配置到多个proxy的连接参数即可。
MySQL Proxy更强大的一项功能是实现“读写分离”,基本原理是让主数据库处理事务性查询,让从库处理SELECT查询。数据库复制被用来把事务性查询导致的变更同步到集群中的从库。
架构示意图
1
2
3
4
5
|
___ master_mysql(10.10.10.3)
| |
mysql-proxy(10.10.10.2) |
|___ |
slave_mysql(10.10.10.4)
|
(一)mysql主从同步
1、mysql-master设置
(1)
1
2
3
|
server- id = 1 //master 端ID号
binlog-ignore-db = // 设置不同步的sql库
binlog- do -db= // 设置同步的数据
|
(2)设置完上面以后重启mysql
(3)添加用户访问主库,并且只有备份权限
1
2
|
mysql > grant replication slave on *.* to 'rsync' @ '10.10.%' identified by '1q2w3e4rys' with grant option;
mysql > flush privileges;
|
(4)锁表,主库数据继续写入
1
|
mysql > flush tables with read lock;
|
(5)记录 master file与position的值,slave库配置同步时候要使用
(6)导出mysql主库数据
1
|
mysqldump -uuser -p databases > databases.sql
|
注:这里有个问题,当主库数据上G,较大时需要做如下操作
1
2
|
--max_allowed_packet=XXX // 客户端/服务器之间通信的缓存区的最大大小;
--net_buffer_length=XXX //TCP/IP 和套接字通信缓冲区大小,创建长度达net_buffer_length的行;
|
注意:max_allowed_packet和net_buffer_length不能比目标数据库的配置数值大,否则可能出错。
首先确定目标库的参数值
1
2
|
mysql>show variables like 'max_allowed_packet' ;
mysql>show variables like 'net_buffer_length' ;
|
根据参数值书写mysqldump命令,如:
1
|
mysql > mysqldump -uuser -p? 数据库名 -e --max_allowed_packet=1048576 --net_buffer_length=16384 > databases.sql
|
(7)master库同步到slave服务器上
1
|
# scp databases.sql root@host:/path
|
2、mysql-slave设置
(1)
(2)登录mysql创建sql数据库
1
|
mysql > CREATE DATABASE `?sql_db?` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
|
(3)导入master库数据到slave库中
1
|
mysql -uuser -p? sql_db < databases.sql
|
(4)登录mysql停止slave
(5)配置从库同步
1
|
mysql > change master to master_host=’10.10.10.2’,master_user=’ rsync ’,master_password=’1q2w3e4rys’,master_port=3306,master_log_file=’mysql-bin.000047’,master_log_pos=107;
|
(6)启动同步功能
(7)解除主库锁表
(8)查看slave同步状态
1
|
mysql > show slave status\G // 多执行几遍,查看数据写入后的状态
|
注:查看上面的Slave_IO_Running: Yes 和Slave_SQL_Running: Yes 2个都为yes则证明主从同步正常,如果有任一个显示NO,则证明同步有问题.可以查看数据库日志文件,里面基本上会显示出错误之处,根据错误一步一步排查,基本上都可以解决的.
(二)mysql-proxy读写分离
1、安装mysql-proxy
(1)
1
2
3
4
|
# wget http://ftp.ntu.edu.tw/pub/MySQL/Downloads/MySQL-Proxy/mysql-proxy-0.8.5-linux-el6-x86-64bit.tar.gz
# tar xf mysql-proxy-0.8.5-linux-el6-x86-64bit.tar.gz -C /usr/local
# cd /usr/local
# ln -sv mysql-proxy-0.8.5-linux-el6-x86-64bit mysql-proxy
|
2、设置mysql-proxy属主属组
(1)
1
2
|
# groupadd mysql-proxy
# useradd -g mysql-proxy -s /sbin//nologin -M mysql-proxy
|
3、配置mysql-proxy
(1)为mysql-proxy提供SysV服务脚本,脚本如下:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
#!/bin/bash
#
# mysql-proxy This script starts and stops the mysql-proxy daemon
#
# chkconfig: - 78 30
# processname: mysql-proxy
# description: mysql-proxy is a proxy daemon for mysql
# Source function library.
. /etc/rc .d /init .d /functions
prog= "/usr/local/mysql-proxy/bin/mysql-proxy"
# Source networking configuration.
if [ -f /etc/sysconfig/network ]; then
. /etc/sysconfig/network
fi
# Check that networking is up.
[ ${NETWORKING} = "no" ] && exit 0
# Set default mysql-proxy configuration.
ADMIN_USER= "admin"
ADMIN_PASSWD= "admin"
ADMIN_LUA_SCRIPT= "/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"
PROXY_OPTIONS= "--daemon"
PROXY_PID= /var/run/mysql-proxy .pid
PROXY_USER= "mysql-proxy"
# Source mysql-proxy configuration.
if [ -f /etc/sysconfig/mysql-proxy ]; then
. /etc/sysconfig/mysql-proxy
fi
RETVAL=0
start() {
echo -n $ "Starting $prog: "
daemon $prog $PROXY_OPTIONS --pid- file =$PROXY_PID --proxy-address= "$PROXY_ADDRESS" --user=$PROXY_USER --admin-username= "$ADMIN_USER" --admin-lua-script= "$ADMIN_LUA_SCRIPT" --admin-password= "$ADMIN_PASSWORD"
RETVAL=$?
echo
if [ $RETVAL - eq 0 ]; then
touch /var/lock/subsys/mysql-proxy
fi
}
stop() {
echo -n $ "Stopping $prog: "
killproc -p $PROXY_PID -d 3 $prog
RETVAL=$?
echo
if [ $RETVAL - eq 0 ]; then
rm -f /var/lock/subsys/mysql-proxy
rm -f $PROXY_PID
fi
}
# See how we were called.
case "$1" in
start)
start
;;
stop)
stop
;;
restart)
stop
start
;;
condrestart|try-restart)
if status -p $PROXY_PIDFILE $prog >& /dev/null ; then
stop
start
fi
;;
status)
status -p $PROXY_PID $prog
;;
*)
echo "Usage: $0 {start|stop|restart|reload|status|condrestart|try-restart}"
RETVAL=1
;;
esac
exit $RETVAL
|
(2)将上述内容保存为/etc/rc.d/init.d/mysql-proxy,给予执行权限,而后加入到服务列表。
1
2
|
# chmod +x /etc/rc.d/init.d/mysql-proxy
# chkconfig --add mysql-proxy
|
(3)为服务脚本提供配置文件/etc/sysconfig/mysql-proxy,内容如下所示:
1
2
3
4
5
6
7
8
|
# Options for mysql-proxy
ADMIN_USER= "admin"
ADMIN_PASSWORD= "admin"
ADMIN_ADDRESS= ""
ADMIN_LUA_SCRIPT= "/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"
PROXY_ADDRESS= ""
PROXY_USER= "mysql-proxy"
PROXY_OPTIONS= "--daemon --log-level=info --log-use-syslog --plugins=proxy --plugins=admin --proxy-backend-addresses=10.10.10.3:3306 --proxy-read-only-backend-addresses=10.10.10.4:3306 --proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua"
|
(4)mysql-proxy配置选项注解
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
|
--help
--help-admin
--help-proxy
--help-all ———— 以上四个选项均用于获取帮助信息;
--proxy-address=host:port ———— 代理服务监听的地址和端口;
--admin-address=host:port ———— 管理模块监听的地址和端口;
--proxy-backend-addresses=host:port ———— 后端mysql服务器的地址和端口;
--proxy- read -only-backend-addresses=host:port ———— 后端只读mysql服务器的地址和端口;
--proxy-lua-script=file_name ———— 完成mysql代理功能的Lua脚本;
--daemon ———— 以守护进程模式启动mysql-proxy;
--keepalive ———— 在mysql-proxy崩溃时尝试重启之;
--log- file = /path/to/log_file_name ———— 日志文件名称;
--log-level=level ———— 日志级别;
--log-use-syslog ———— 基于syslog记录日志;
--plugins=plugin,.. ———— 在mysql-proxy启动时加载的插件;
--user=user_name ———— 运行mysql-proxy进程的用户;
--defaults- file = /path/to/conf_file_name ———— 默认使用的配置文件路径;其配置段使用[mysql-proxy]标识;
--proxy-skip-profiling ———— 禁用profile;
--pid- file = /path/to/pid_file_name ———— 进程文件名;
|
(5)复制如下内容建立admin.lua文件,将其保存至/usr/local/mysql-proxy/share/doc/mysql-proxy/目录中.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
--[[ $%BEGINLICENSE%$
Copyright (c) 2007, 2012, Oracle and /or its affiliates. All rights reserved.
This program is free software; you can redistribute it and /or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; version 2 of the
License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
02110-1301 USA
$%ENDLICENSE%$ --]]
function set_error(errmsg)
proxy.response = {
type = proxy.MYSQLD_PACKET_ERR,
errmsg = errmsg or "error"
}
end
function read_query(packet)
if packet:byte() ~= proxy.COM_QUERY then
set_error( "[admin] we only handle text-based queries (COM_QUERY)" )
return proxy.PROXY_SEND_RESULT
end
local query = packet:sub(2)
local rows = { }
local fields = { }
if query:lower() == "select * from backends" then
fields = {
{ name = "backend_ndx" ,
type = proxy.MYSQL_TYPE_LONG },
{ name = "address" ,
type = proxy.MYSQL_TYPE_STRING },
{ name = "state" ,
type = proxy.MYSQL_TYPE_STRING },
{ name = "type" ,
type = proxy.MYSQL_TYPE_STRING },
{ name = "uuid" ,
type = proxy.MYSQL_TYPE_STRING },
{ name = "connected_clients" ,
type = proxy.MYSQL_TYPE_LONG },
}
for i = 1, #proxy.global.backends do
local states = {
"unknown" ,
"up" ,
"down"
}
local types = {
"unknown" ,
"rw" ,
"ro"
}
local b = proxy.global.backends[i]
rows[ #rows + 1] = {
i,
b.dst.name, -- configured backend address
states[b.state + 1], -- the C- id is pushed down starting at 0
types[b. type + 1], -- the C- id is pushed down starting at 0
b.uuid, -- the MySQL Server's UUID if it is managed
b.connected_clients -- currently connected clients
}
end
elseif query:lower() == "select * from help" then
fields = {
{ name = "command" ,
type = proxy.MYSQL_TYPE_STRING },
{ name = "description" ,
type = proxy.MYSQL_TYPE_STRING },
}
rows[ #rows + 1] = { "SELECT * FROM help", "shows this help" }
rows[ #rows + 1] = { "SELECT * FROM backends", "lists the backends and their state" }
else
set_error( "use 'SELECT * FROM help' to see the supported commands" )
return proxy.PROXY_SEND_RESULT
end
proxy.response = {
type = proxy.MYSQLD_PACKET_OK,
resultset = {
fields = fields,
rows = rows
}
}
return proxy.PROXY_SEND_RESULT
end
|
(6)测试
1
2
|
#mysql -uadmin -padmin -h110.10.10.2 --port=4041
mysql > SELECT * FROM backends;
|
1
2
3
4
5
6
7
|
+-------------+-------------------+-------+------+------+-------------------+
| backend_ndx | address | state | type | uuid | connected_clients |
+-------------+-------------------+-------+------+------+-------------------+
| 1 | 10.10.10.3:3306 | up | rw | NULL | 0 |
| 2 | 10.10.10.4:3306 | up | ro | NULL | 0 |
+-------------+-------------------+-------+------+------+-------------------+
2 rows in set (0.00 sec)
|
本文出自 “阿俊博客” 博客,请务必保留此出处http://ssc4469.blog.51cto.com/6315913/1854011
基于mysql主从同步的proxy读写分离的相关教程结束。