使用mysql-proxy-0.8.5實現MySQL讀寫分離

時間 2020-05-27

標籤使用 mysql proxy 0.8.5 實現讀寫分離欄目 MySQL 简体版

原文原文鏈接

實驗環境：RHEL6.6-x86-64mysql

mysql-proxy-0.8.5-linux-glibc2.3-x86-64bit.tar.gzlinux

mysql-5.6.14-linux-glibc2.5-x86_64.tar.gzsql

爲了減輕數據庫負載，能夠考慮使用讀寫分離來實現。目前實現讀寫分離的方式大約有兩種：
數據庫

基於程序代碼實現vim

在程序代碼中根據select、insert語句進行路由分類。讀寫分別由不一樣Server響應。
bash

基於中間代理層實現負載均衡

代理位於客戶端與服務端之間，代理層接收客戶端請求後，判斷讀寫請求轉發至不一樣Server。 mysql-proxy即是其中一種。它能夠監視，分析，改變它們的會話。他有多種用途，負載均衡，查詢分析，查詢過濾和修改等。ide

MySQL主從搭建，請參考個人另外一篇文章，這裏再也不贅述。ui

安裝mysql-proxy
this

# useradd -r mysql-proxy

# tar xf mysql-proxy-0.8.5-linux-glibc2.3-x86-64bit.tar.gz -C /usr/local/

# cd /usr/local/

# ln -s mysql-proxy-0.8.5-linux-glibc2.3-x86-64bit mysql-proxy

vim /etc/profile.d/mysql-proxy.sh
export PATH=$PATH:/usr/local/mysql-proxy/bin

爲/etc/init.d/mysql-proxy提供參數

# vim /etc/sysconfig/mysql-proxy
ADMIN_USER="admin"
ADMIN_PASSWORD="admin"
ADMIN_ADDRESS=""
PROXY_ADDRESS="0.0.0.0:3306"
PROXY_USER="mysql-proxy"
PROXY_PID=/var/run/mysql-proxy.pid
PROXY_OPTIONS="--daemon"
ADMIN_LUA_SCRIPT="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"
RW_SPLITTING_LUA_SCRIPT=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua
PROXY_OPTIONS="--daemon --log-level=info --log-file="/var/log/mysql-proxy.log" --plugins=proxy --plugins=admin --proxy-backend-addresses=192.168.1.5:3306 --proxy-read-only-backend-addresses=192.168.1.6:3306 --proxy-lua-script=$RW_SPLITTING_LUA_SCRIPT --pid-file=$PROXY_PID --proxy-address=$PROXY_ADDRESS --user=$PROXY_USER --admin-username=$ADMIN_USER --admin-lua-script=$ADMIN_LUA_SCRIPT --admin-password=$ADMIN_PASSWORD"

爲mysql-proxy提供sysv風格腳本

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"
# Check that networking is up.
[ ${NETWORKING} = "no" ] && exit 0

# Source mysql-proxy configuration.
if [ -f /etc/sysconfig/network ]; then
    . /etc/sysconfig/network
fi
# Check that networking is up.
[ ${NETWORKING} = "no" ] && exit 0
# 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 $PROXY_OPTIONS
    RETVAL=$?
    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

爲管理提供lua腳本

vim /usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua
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

# chmod +x /etc/init.d/mysql-proxy

# service mysql-proxy start

鏈接至管理

# mysql -uadmin -h192.168.1.7 --port=4041 -p

查看狀態可看到state是unknown

mysql> SELECT * FROM backends;
+-------------+------------------+---------+------+------+-------------------+
| backend_ndx | address          | state   | type | uuid | connected_clients |
+-------------+------------------+---------+------+------+-------------------+
|           1 | 192.168.1.5:3306 | unknown | rw   | NULL |                 0 |
|           2 | 192.168.1.6:3306 | unknown | ro   | NULL |                 0 |
+-------------+------------------+---------+------+------+-------------------+

鏈接至mysql-proxy

# mysql -uroot -p -h192.168.1.7

插入、查詢各執行幾回

再鏈接至管理查看狀態,可看到狀態是up。

mysql> SELECT * FROM backends;
+-------------+------------------+-------+------+------+-------------------+
| backend_ndx | address          | state | type | uuid | connected_clients |
+-------------+------------------+-------+------+------+-------------------+
|           1 | 192.168.1.5:3306 | up    | rw   | NULL |                 0 |
|           2 | 192.168.1.6:3306 | up    | ro   | NULL |                 0 |
+-------------+------------------+-------+------+------+-------------------+

讀寫分離實現完成。