一、介紹
MySQL代理是一個介於MySQL客戶端和MySQL服務器之間的簡單程序，可用來監視、分析或者傳輸他們之間的通訊。他的靈活性允許你最大限度的使用它，這些包括負載平衡、容錯 、分析查詢和修正等等；
MySQL Proxy就是這麼一箇中間層代理，簡單的說，MySQL Proxy就是一個連接池，負責將前臺應用的連接請求轉發給後臺的數據庫，並且通過使用lua腳本，可以實現複雜的連接控制和過濾，從而實現讀寫分離和負載平衡。對於應用來說，MySQL Proxy是完全透明的，應用則只需要連接到MySQL Proxy的監聽端口即可。當然，這樣proxy機器可能成爲單點失效，但完全可以使用多個proxy機器做爲冗餘，在應用服務器的連接池配置中配置到多個proxy的連接參數即可。
實驗環境：
| 名稱 | IP地址 |
| mysql-proxy | 192.168.100.104 |
| mysql-master | 192.168.100.102 |
| mysql-slave | 192.168.100.103 |
首先，你得先配置mysql主從，可能跳轉至 http://junwang.blog.51cto.com/5050337/1424711有主從配置方法。
二、安裝mysql-proxy
由於源碼安裝和rpm包安裝都需要解決很多依賴關係，所以此處我們就使用二進制安裝包；
1、獲取軟件包與安裝
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.gz mysql-proxy # useradd mysql-proxy // *爲其添加啓動服務用戶；*// # yum install mysql -y // *安裝mysql客戶端； *//
2、爲mysql-proxy提供SysV服務腳本
# 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"
# 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-proxy3、爲服務腳本提供配置文件/etc/sysconfig/mysql-proxy，內容如下所示：
# 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的配置選項大致可分爲幫助選項、管理選項、代理選項及應用程序選項幾類:
--proxy-address=host:port 代理服務監聽的地址和端口；
--admin-address=host:port 管理模塊監聽的地址和端口；
--proxy-backend-addresses=host:port 後端mysql服務器的地址和端口；
--proxy-read-only-backend-addresses=host:port 後端只讀mysql服務器的地址和端口；
--proxy-lua-script=file_name 完成mysql代理功能的Lua腳本；
--daemon 以守護進程模式啓動mysql-proxy；
--keepalive 在mysql-proxy崩潰時嘗試重啓之；
--log-file=/path/to/log_file_name 日誌文件名稱；
--log-level=level 日誌級別；
--log-use-syslog 基於syslog記錄日誌；
--plugins=plugin,.. 在mysql-proxy啓動時加載的插件；
--user=user_name 運行mysql-proxy進程的用戶；
--defaults-file=/path/to/conf_file_name 默認使用的配置文件路徑；其配置段使用[mysql-proxy]標識；
--proxy-skip-profiling 禁用profile；
--pid-file=/path/to/pid_file_name 進程文件名；
4、由於上面的啓腳本中指定了ADMIN_LUA_SCRIPT="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"，而該目錄下又沒有此文lua文件。複製如下內容建立admin.lua文件，將其保存至/usr/local/mysql-proxy/share/doc/mysql-proxy/目錄中
--[[ $%BEGINLICENSE%$
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
02110-1301 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三、啓動與測試
# 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
此處mysql-proxy有兩個監聽端口分表用於不同功能
4041端口用於監控mysql-proxy讀寫分離狀態，此時只能使用 select * from backends 查看後端服務器狀態；
3306端口用於正常連接後端服務器讀寫請求；
# 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)
由於此時沒有通過mysql-proxy這臺服務器操作後端mysql服務器，所以state都爲"unknown";
嘗試對後端主機進行讀或寫操作：
注意，還需要在主服務器上創建可遠程操用的用戶名和主機，這裏我創建了用戶admin,而從服務器會自動同步主服務器的修改操作，所以不需要對從服務器添加admin用戶；
# 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 | +-------------+----------------------+---------+------+------+-------------------+
由於多次單條語句都無法使查詢到從服務器，下面我們使用mysql自帶的一個壓力測試工具mysqlslap來測試：
# 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常用參數詳解：
-u username 指定用戶名；
-p password 指定用戶密碼；
-h host 指定測的主機；
-P port 服務端口；
--concurrency 併發數量，多個可以用逗號隔開，concurrency=10,50,100, 併發連接線程數分別是10、50、100個併發；
--engines 要測試的引擎，可以有多個，用分隔符隔開；
--iterations 要運行這些測試多少次；
--auto-generate-sql 用系統自己生成的SQL腳本來測試；
--auto-generate-sql-load-type 要測試的是讀還是寫還是兩者混合的（read,write,update,mixed）；
--number-of-queries 總共要運行多少次查詢。每個客戶運行的查詢數量可以用查詢總數/併發數來計算；
--debug-info 要額外輸出CPU以及內存的相關信息。
--number-int-cols 創建測試表的 int 型字段數量；
--auto-generate-sql-add-autoincrement : 對生成的表自動添加auto_increment列，從5.1.18版本開始；
--number-char-cols 創建測試表的 char 型字段數量。
--create-schema 測試的schema，MySQL中schema也就是database；
--query 使用自定義腳本執行測試，例如可以調用自定義的一個存儲過程或者sql語句來執行測試；
--only-print 如果只想打印看看SQL語句是什麼，可以用這個選項；