mysql读写分离 mysql-proxy
一、介绍MySQL代理是一个介于MySQL客户端和MySQL服务器之间的简单程序，可用来监视、分析或者传输他们之间的通讯。他的灵活性允许你最大限度的使用它，这些包括负载平衡、容错 、分析查询和修正等等；
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。
实验环境：
名称 IP地址 mysql-proxy192.168.100.104 mysql-master192.168.100.102 mysql-slave192.168.100.103 首先，你得先配置mysql主从，可能跳转至 http://junwang.blog.51cto.com/5050337/1424711有主从配置方法。
二、安装mysql-proxy
由于源码安装和rpm包安装都需要解决很多依赖关系，所以此处我们就使用二进制安装包；
1、获取软件包与安装
wget http://ftp.ntu.edu.tw/pub/MySQL/Downloads/MySQL-Proxy/mysql-proxy-0.8.3-linux-glibc2.3-x86-64bit.tar.gz
# tar xf mysql-proxy-0.8.3-linux-glibc2.3-x86-64bit.tar.gz -C /usr/local
# cd /usr/local
# ln -s mysql-proxy-0.8.3-linux-glibc2.3-x86-64bit.tar.gzmysql-proxy
# useradd mysql-proxy // *为其添加启动服务用户；*//
# yum install mysql -y // *安装mysql客户端； *//
2、为mysql-proxy提供SysV服务脚本
# vim /etc/init.d/mysql-proxy
#!/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
# chmod +x /etc/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：
# 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=192.168.100.102:3306 --proxy-read-only-backend-addresses=192.168.100.103:3306 --proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua"
mysql-proxy的配置选项大致可分为帮助选项、管理选项、代理选项及应用程序选项几类:
--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；其配置段使用标识；
--proxy-skip-profiling 禁用profile；
--pid-file=/path/to/pid_file_name 进程文件名；
4、由于上面的启脚本中指定了ADMIN_LUA_SCRIPT="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"，而该目录下又没有此文lua文件。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
--[[ $%BEGINLICENSE%$
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
02110-1301USA
$%ENDLICENSE%$ --]]
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(" 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
rows[#rows + 1] = {
i,
b.dst.name, -- configured backend address
states, -- the C-id is pushed down starting at 0
types, -- 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
三、启动与测试
# service mysql-proxy start
# netstat -tunlp |grep mysql-proxy
tcp 0 0 0.0.0.0:4041 0.0.0.0:* LISTEN 46219/mysql-proxy
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 46219/mysql-proxy
此处mysql-proxy有两个监听端口分表用于不同功能
4041端口用于监控mysql-proxy读写分离状态，此时只能使用 select * from backends 查看后端服务器状态；
3306端口用于正常连接后端服务器读写请求；
# mysql -uadmin -padmin -h192.168.100.104 --port=4041;
Welcome to the MySQL monitor.Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.0.99-agent-admin
Copyright (c) 2000, 2012, 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> select * from backends;
+-------------+----------------------+---------+------+------+-------------------+
| backend_ndx | address | state | type | uuid | connected_clients |
+-------------+----------------------+---------+------+------+-------------------+
| 1 | 192.168.100.102:3306 | unknown | rw | NULL | 0 |
| 2 | 192.168.100.103:3306 | unknown | ro | NULL | 0 |
+-------------+----------------------+---------+------+------+-------------------+
2 rows in set (0.00 sec)
由于此时没有通过mysql-proxy这台服务器操作后端mysql服务器，所以state都为"unknown";
尝试对后端主机进行读或写操作：
注意，还需要在主服务器上创建可远程操用的用户名和主机，这里我创建了用户admin,而从服务器会自动同步主服务器的修改操作，所以不需要对从服务器添加admin用户；
# mysql -uadmin -padmin -h192.168.100.104
mysql> creat databases mydb;
# mysql -uadmin -padmin -h192.168.100.104 --port=4041
mysql> select * from backends;
+-------------+----------------------+---------+------+------+-------------------+
| backend_ndx | address | state | type | uuid | connected_clients |
+-------------+----------------------+---------+------+------+-------------------+
| 1 | 192.168.100.102:3306 | up | rw | NULL | 0 |
| 2 | 192.168.100.103:3306 | unknown | ro | NULL | 0 |
+-------------+----------------------+---------+------+------+-------------------+
由于多次单条语句都无法使查询到从服务器，下面我们使用mysql自带的一个压力测试工具mysqlslap来测试：
# mysqlslap -uadmin -padmin -h192.168.100.104 --concurrency=100 iterations=1 --create-schema='mydb' --query='select * from tb1' --number-of-queries=1 --debug-info
Benchmark
Average number of seconds to run all queries: 0.222 seconds
Minimum number of seconds to run all queries: 0.222 seconds
Maximum number of seconds to run all queries: 0.222 seconds
Number of clients running queries: 100
Average number of queries per client: 0
User time 0.00, System time 0.04
Maximum resident set size 6828, Integral resident set size 0
Non-physical pagefaults 1328, Physical pagefaults 0, Swaps 0
Blocks in 0 out 0, Messages in 0 out 0, Signals 0
Voluntary context switches 404, Involuntary context switches 107
# mysql -uadmin -padmin -h 192.168.100.104 --port=4041
mysql> select * from backends;
+-------------+----------------------+-------+------+------+-------------------+
| backend_ndx | address | state | type | uuid | connected_clients |
+-------------+----------------------+-------+------+------+-------------------+
| 1 | 192.168.100.102:3306 | up | rw | NULL | 0 |
| 2 | 192.168.100.103:3306 | up | ro | NULL | 0 |
+-------------+----------------------+-------+------+------+-------------------+
2 rows in set (0.00 sec)
mysqlslap常用参数详解：
-u username 指定用户名；
-p password 指定用户密码；
-h host 指定测的主机；
-P port 服务端口；
--concurrency 并发数量，多个可以用逗号隔开，concurrency=10,50,100, 并发连接线程数分别是10、50、100个并发；
--engines 要测试的引擎，可以有多个，用分隔符隔开；
--iterations 要运行这些测试多少次；
--auto-generate-sql 用系统自己生成的SQL脚本来测试；
--auto-generate-sql-load-type要测试的是读还是写还是两者混合的（read,write,update,mixed）；
--number-of-queries 总共要运行多少次查询。每个客户运行的查询数量可以用查询总数/并发数来计算；
--debug-info 要额外输出CPU以及内存的相关信息。
--number-int-cols 创建测试表的 int 型字段数量；
--auto-generate-sql-add-autoincrement : 对生成的表自动添加auto_increment列，从5.1.18版本开始；
--number-char-cols 创建测试表的 char 型字段数量。
--create-schema 测试的schema，MySQL中schema也就是database；
--query 使用自定义脚本执行测试，例如可以调用自定义的一个存储过程或者sql语句来执行测试；
--only-print 如果只想打印看看SQL语句是什么，可以用这个选项；
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