一、memcached概述
1、网站架构优化流程:
LNMP架构中网站应用访问流程:
浏览器 (app) → web 服务器 → 后端服务 (php) → 数据库 (mysql)
访问流程越多,访问速度越慢,出现问题的几率也越大。
网站访问流程优化思路:
① 采用高性能的负载均衡设备;
② 页面静态化;
③ 引入缓存层,如使用Redis或Memcached,来缓存频繁访问的数据;
④ 优化数据库本身。
2、mencached介绍:
许多Web应用都将数据保存到 RDBMS (关系型数据库) 中,应用服务器从中读取数据并在浏览器中显示。 但随着数据量的增大、访问的集中,就会出现RDBMS的负担加重、数据库响应恶化、 网站显示延迟等重大影响。
Memcached 是高性能的分布式内存缓存服务器,通过缓存数据库查询结果,减少数据库访问次数,以提高动态Web等应用的速度, 提高可扩展性。
Web01/Web02 => memcached(内存) => MyCAT => MySQL01/MySQL02
3、安装memcached软件:
克隆CentOS7生成一个memcached服务器,修改IP、UUID、主机名、hosts文件,关闭防火墙、selinux和NetworkManager。
(1) 架构图:
(2) 编译与安装:
tar -zxf memcached-1.5.8.tar.gz
cd memcached-1.5.8
yum install libevent-devel -y
yum -y install gcc gcc-c++ autoconf automake make
./configure --prefix=/usr/local/memcached
make && make install
(3) 查看目录:
cd /usr/local/memcahced
bin:memcached 二进制程序文件
include:memcached 依赖库文件
bin/memcached -h:
-p 设置memcached监听的端口,默认为11211
-d 启动一个守护进程deamon(后台运行)
-m 分配给memcached使用的内存数量,单位是MB,默认为64M
-u 运行memcached的用户
-l 监听服务器IP地址,可以有多个地址
-c 最大运行的并发连接数,默认是1024
-P 设置保存memcached的pid文件
(4) 启动memcached软件:
bin/memcached -uroot -d :以root用户启动memcached,后台运行
4、使用Telnet连接memcached:
(1) telnet概述:
Telnet协议是TCP/IP协议族中的一部分,是Internet远程登录服务的标准协议之一。
Telnet协议允许用户通过网络连接到远程主机,并在该主机上执行命令、访问文件、查看系统状态等。
由于Telnet协议的通信内容并未加密,存在安全风险,因此在实际应用中,Telnet通常被SSH(Secure Shell)所取代,SSH提供了加密的通信通道,更安全地实现了远程访问。
(2) 安装telnet并连接memcached:
yum install telnet -y
telnet memcachedd服务器IP memcahced服务端口
回车后看到ERROR说明已经连接上memcached,ERROR是memcached对空命令的报错。
二、memcached常用管理命令
memcached操作的是计算机的内存空间,通过内存来缓存数据,其数据结构是一个key:value的键值对。
1、set命令与get命令:
(1) set 命令:
set key flag exptime bytes
set:set命令,用于设置键值对(存储数据)。
key:键名,必须是唯一的,同名会被覆盖。
flag:数据的标识位,0代表没有特殊标识。
exptime:过期时间,0代表不过期,单位为s。
bytes:存储数据的字节数。
(2) get命令:
get key
get:get命令,用于获取键值对信息(获取数据)。
key:键名,根据提供的键名,搜索指定的数据。
如果 key 不存在,则返回空:
get key1 key2
get 命令可一次获取多个键的值:
2、add命令与replace命令:
(1) add命令:
add key flag exptime bytes
add 命令用于将 value 存储在指定的 key 中,如果 add 的 key 已经存在,则不会更新。(修改键)
set 命令则会直接覆盖旧的 key。
出现NOT_STORED代表系统中已经存在了一个键名为name的键值对。
(2) replace命令:
replace key flag exptime bytes
replace 命令用于替换已存在的 key 的 value。(修改值)
如果 key不存在,则替换失败,响应 NOT_STORED。
3、append命令与prepend命令:
(1) append命令:
append key flag exptime bytes
append 命令用于向已存在 key 的 value 尾部追加数据(尾部追加)。
定义一个key=hw,存储数据hello,然后追加一个world:
(2) prepend命令:
prepend key flag exptime bytes
prepend 命令用于向已存在 key 的 value 前面追加数据(头部追加)。
定义一个name=hema,然后追加一个it到hema的前面:
4、delete命令与flush_all命令:
(1) delete命令:
delete key
delete 命令指定用于删除已存在的key。
(2) flush_all清空命令:
flush_all [time]
time:用于在指定时间后执行清空操作
清空memcached中的所有缓存的数据,生产环境下尽量不要使用。
5、计算命令与stats命令:
(1) 计算命令:
incr key value => 在原有值的基础上进行自增操作
decr key value => 在原有值的基础上进行自减操作
(2) stats命令:
stats命令用来获取memcached的运行信息。
cmd_get => memcached运行以来get获取的次数
cmd_set => memcached运行以来set设置的次数
get_hits => 缓存命中数,对于memcached服务器非常重要的指标
① 缓存命中率:get_hits/cmd_get
如果命中率低,业务代码缓存有问题 ;命中率为0,说明缓存没有起作用 。
② 缓存穿透:数据访问经过缓存,没有获取到数据,再直接访问数据库。
③ 缓存雪崩:数据查询全部没有命中,直接访问数据库,数据压力上升。
④ 解决方案:
当数据库中的数据发生变化时,应该尽快将这些变化同步到 Memcached 中;
合理设置缓存的失效时间,并将它们分布开,确保缓存的过期事件不会集中在某个时间点,避免缓存雪崩。
6、memcached注意事项:
① memcached最大过期时间:
过期时间设置最大为30天 (30x24x60x60=2592000s),超过后,其值无法设置进缓存;
② memcached单个key最大长度:
memcached的key的最大长度是250个字符,是memcached服务端的限制;
③ memcached单个item最大能存储:1M。
三、php安装memcached扩展
1、为什么需要扩展:
PHP默认不支持memcached连接,需要通过memcached扩展程序连接php与memcached。
PHP → mecached.so → Memcached
2、安装PHP Memcached扩展:
(1) 准备软件:
libmemcached-1.0.18.tar.gz :php memcached 扩展的依赖库
memcached-3.1.3.tgz :php memcached扩展
(2) 准备环境变量:
PHP扩展编译安装,需要web服务器支持phpize和php-config。
把php的bin目录配置到PATH中(web01 / web02):
echo 'export PATH=$PATH:/usr/local/php/bin' >> /etc/profile
source /etc/profile
(3) 安装php memcached扩展:
安装libmemcached:
tar xvf libmemcached-1.0.18.tar.gz
cd libmemcached-1.0.18
#指定安装目录编译configure脚本
./configure --prefix=/usr/local/libmemcached
make && make install
安装memcached.so:
tar -zxf memcached-3.1.3.tgz
cd memcached-3.1.3
#刚解压出来的memcached-3.1.3中没有configure脚本,需要运行phpize命令生成所需要的configure脚本
/usr/local/php/bin/phpize
./configure --with-libmemcached-dir=/usr/local/libmemcached --disable-memcached-sasl
make && make install
脚本安装:
#!/bin/bash
echo "====================================="
echo "1)安装libmemcached"
echo "2)安装memcached.so"
echo "====================================="
read -p "Please Input The Number 1 or 2 =>" key
libmemcached() {
echo "Start Install libmemcached ..."
sleep 1
tar -zxf /root/libmemcached-1.0.18.tar.gz
cd libmemcached-1.0.18
./configure --prefix=/usr/local/libmemcached
make && make install
}
memcached() {
echo "Start Install php memcached.so ..."
sleep 1
tar -zxf /root/memcached-3.1.3.tgz
cd memcached-3.1.3
/usr/local/php/bin/phpize
./configure --with-libmemcached-dir=/usr/local/libmemcached --disable-memcached-sasl
make && make install
}
case $key in
1)
libmemcached
;;
2)
memcached
;;
esac
查看是否安装扩展:
/usr/local/php/lib/php/extensions/no-debug-zts-20170708:php扩展库的存储路径
(4) 在php.ini文件中开启memcached.so扩展:
vim /usr/local/php/etc/php.ini
extension=memcached.so #在第909行添加这行扩展
设置完成后,重启php-fpm服务:
service php-fpm restart
(5) 测试PHP Memcached扩展是否安装成功 :
在/home/www/public目录下创建一个demo.php文件:
<?php
phpinfo();
?>
3、使用PHP操纵Memcached服务器:
在web服务器上编写php代码,通过php的memcached扩展与memcached服务器交互。
Web01/Web02的 home/www/public 下创建一个 demo.php:
<?php
$mem=new Memcached(); //创建一个对象,用于与Memcached服务器进行通信
$mem->addServer('10.1.1.20',11211); //指定Memcached服务监听的地址和端口
$mem->set('name','itheima'); //使用set方法将一个键值对存储到Memcached中
var_dump($mem->get('name')); //调试输出,输出 name这个键的内容
?>
先情况memcached内存中所有的key。
访问web服务器ip/demo.php,显示出在memcached服务器中存储的键值,说明PHP已经与memcached交互:
在memcached中可查看到name键值对。
4、memcached_tool:
(1) 作用:
用于查看memcached运行状态、有多少key(item)、内存使用了多少,以及查看缓存命中率等指标。
(2) 配置:
① 上传memcache_tools.php文件到Web服务器中的/home/www/public目录下
<?php
/*
+----------------------------------------------------------------------+
| PHP Version 5 |
+----------------------------------------------------------------------+
| Copyright (c) 1997-2004 The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 3.0 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| http://www.php.net/license/3_0.txt. |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@php.net so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Author: Harun Yayli <harunyayli at gmail.com> |
+----------------------------------------------------------------------+
*/
$VERSION='$Id: memcache.php,v 1.1.2.3 2008/08/28 18:07:54 mikl Exp $';
define('ADMIN_USERNAME','root'); // Admin Username
define('ADMIN_PASSWORD','123456'); // Admin Password
define('DATE_FORMAT','Y/m/d H:i:s');
define('GRAPH_SIZE',200);
define('MAX_ITEM_DUMP',50);
$MEMCACHE_SERVERS[] = '192.168.65.128:11211'; // add more as an array
// END OF DEFAULT CONFIG AREA /
/ Password protect
if (!isset($_SERVER['PHP_AUTH_USER']) || !isset($_SERVER['PHP_AUTH_PW']) ||
$_SERVER['PHP_AUTH_USER'] != ADMIN_USERNAME ||$_SERVER['PHP_AUTH_PW'] != ADMIN_PASSWORD) {
Header("WWW-Authenticate: Basic realm=\"Memcache Login\"");
Header("HTTP/1.0 401 Unauthorized");
echo <<<EOB
<html><body>
<h1>Rejected!</h1>
<big>Wrong Username or Password!</big>
</body></html>
EOB;
exit;
}
///MEMCACHE FUNCTIONS /
function sendMemcacheCommands($command){
global $MEMCACHE_SERVERS;
$result = array();
foreach($MEMCACHE_SERVERS as $server){
$strs = explode(':',$server);
$host = $strs[0];
$port = $strs[1];
$result[$server] = sendMemcacheCommand($host,$port,$command);
}
return $result;
}
function sendMemcacheCommand($server,$port,$command){
$s = @fsockopen($server,$port);
if (!$s){
die("Cant connect to:".$server.':'.$port);
}
fwrite($s, $command."\r\n");
$buf='';
while ((!feof($s))) {
$buf .= fgets($s, 256);
if (strpos($buf,"END\r\n")!==false){ // stat says end
break;
}
if (strpos($buf,"DELETED\r\n")!==false || strpos($buf,"NOT_FOUND\r\n")!==false){ // delete says these
break;
}
if (strpos($buf,"OK\r\n")!==false){ // flush_all says ok
break;
}
}
fclose($s);
return parseMemcacheResults($buf);
}
function parseMemcacheResults($str){
$res = array();
$lines = explode("\r\n",$str);
$cnt = count($lines);
for($i=0; $i< $cnt; $i++){
$line = $lines[$i];
$l = explode(' ',$line,3);
if (count($l)==3){
$res[$l[0]][$l[1]]=$l[2];
if ($l[0]=='VALUE'){ // next line is the value
$res[$l[0]][$l[1]] = array();
list ($flag,$size)=explode(' ',$l[2]);
$res[$l[0]][$l[1]]['stat']=array('flag'=>$flag,'size'=>$size);
$res[$l[0]][$l[1]]['value']=$lines[++$i];
}
}elseif($line=='DELETED' || $line=='NOT_FOUND' || $line=='OK'){
return $line;
}
}
return $res;
}
function dumpCacheSlab($server,$slabId,$limit){
list($host,$port) = explode(':',$server);
$resp = sendMemcacheCommand($host,$port,'stats cachedump '.$slabId.' '.$limit);
return $resp;
}
function flushServer($server){
list($host,$port) = explode(':',$server);
$resp = sendMemcacheCommand($host,$port,'flush_all');
return $resp;
}
function getCacheItems(){
$items = sendMemcacheCommands('stats items');
$serverItems = array();
$totalItems = array();
foreach ($items as $server=>$itemlist){
$serverItems[$server] = array();
$totalItems[$server]=0;
if (!isset($itemlist['STAT'])){
continue;
}
$iteminfo = $itemlist['STAT'];
foreach($iteminfo as $keyinfo=>$value){
if (preg_match('/items\:(\d+?)\:(.+?)$/',$keyinfo,$matches)){
$serverItems[$server][$matches[1]][$matches[2]] = $value;
if ($matches[2]=='number'){
$totalItems[$server] +=$value;
}
}
}
}
return array('items'=>$serverItems,'counts'=>$totalItems);
}
function getMemcacheStats($total=true){
$resp = sendMemcacheCommands('stats');
if ($total){
$res = array();
foreach($resp as $server=>$r){
foreach($r['STAT'] as $key=>$row){
if (!isset($res[$key])){
$res[$key]=null;
}
switch ($key){
case 'pid':
$res['pid'][$server]=$row;
break;
case 'uptime':
$res['uptime'][$server]=$row;
break;
case 'time':
$res['time'][$server]=$row;
break;
case 'version':
$res['version'][$server]=$row;
break;
case 'pointer_size':
$res['pointer_size'][$server]=$row;
break;
case 'rusage_user':
$res['rusage_user'][$server]=$row;
break;
case 'rusage_system':
$res['rusage_system'][$server]=$row;
break;
case 'curr_items':
$res['curr_items']+=$row;
break;
case 'total_items':
$res['total_items']+=$row;
break;
case 'bytes':
$res['bytes']+=$row;
break;
case 'curr_connections':
$res['curr_connections']+=$row;
break;
case 'total_connections':
$res['total_connections']+=$row;
break;
case 'connection_structures':
$res['connection_structures']+=$row;
break;
case 'cmd_get':
$res['cmd_get']+=$row;
break;
case 'cmd_set':
$res['cmd_set']+=$row;
break;
case 'get_hits':
$res['get_hits']+=$row;
break;
case 'get_misses':
$res['get_misses']+=$row;
break;
case 'evictions':
$res['evictions']+=$row;
break;
case 'bytes_read':
$res['bytes_read']+=$row;
break;
case 'bytes_written':
$res['bytes_written']+=$row;
break;
case 'limit_maxbytes':
$res['limit_maxbytes']+=$row;
break;
case 'threads':
$res['rusage_system'][$server]=$row;
break;
}
}
}
return $res;
}
return $resp;
}
//
//
// don't cache this page
//
header("Cache-Control: no-store, no-cache, must-revalidate"); // HTTP/1.1
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache"); // HTTP/1.0
function duration($ts) {
global $time;
$years = (int)((($time - $ts)/(7*86400))/52.177457);
$rem = (int)(($time-$ts)-($years * 52.177457 * 7 * 86400));
$weeks = (int)(($rem)/(7*86400));
$days = (int)(($rem)/86400) - $weeks*7;
$hours = (int)(($rem)/3600) - $days*24 - $weeks*7*24;
$mins = (int)(($rem)/60) - $hours*60 - $days*24*60 - $weeks*7*24*60;
$str = '';
if($years==1) $str .= "$years year, ";
if($years>1) $str .= "$years years, ";
if($weeks==1) $str .= "$weeks week, ";
if($weeks>1) $str .= "$weeks weeks, ";
if($days==1) $str .= "$days day,";
if($days>1) $str .= "$days days,";
if($hours == 1) $str .= " $hours hour and";
if($hours>1) $str .= " $hours hours and";
if($mins == 1) $str .= " 1 minute";
else $str .= " $mins minutes";
return $str;
}
// create graphics
//
function graphics_avail() {
return extension_loaded('gd');
}
function bsize($s) {
foreach (array('','K','M','G') as $i => $k) {
if ($s < 1024) break;
$s/=1024;
}
return sprintf("%5.1f %sBytes",$s,$k);
}
// create menu entry
function menu_entry($ob,$title) {
global $PHP_SELF;
if ($ob==$_GET['op']){
return "<li><a class=\"child_active\" href=\"$PHP_SELF&op=$ob\">$title</a></li>";
}
return "<li><a class=\"active\" href=\"$PHP_SELF&op=$ob\">$title</a></li>";
}
function getHeader(){
$header = <<<EOB
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head><title>MEMCACHE INFO</title>
<style type="text/css"><!--
body { background:white; font-size:100.01%; margin:0; padding:0; }
body,p,td,th,input,submit { font-size:0.8em;font-family:arial,helvetica,sans-serif; }
* html body {font-size:0.8em}
* html p {font-size:0.8em}
* html td {font-size:0.8em}
* html th {font-size:0.8em}
* html input {font-size:0.8em}
* html submit {font-size:0.8em}
td { vertical-align:top }
a { color:black; font-weight:none; text-decoration:none; }
a:hover { text-decoration:underline; }
div.content { padding:1em 1em 1em 1em; position:absolute; width:97%; z-index:100; }
h1.memcache { background:rgb(153,153,204); margin:0; padding:0.5em 1em 0.5em 1em; }
* html h1.memcache { margin-bottom:-7px; }
h1.memcache a:hover { text-decoration:none; color:rgb(90,90,90); }
h1.memcache span.logo {
background:rgb(119,123,180);
color:black;
border-right: solid black 1px;
border-bottom: solid black 1px;
font-style:italic;
font-size:1em;
padding-left:1.2em;
padding-right:1.2em;
text-align:right;
display:block;
width:130px;
}
h1.memcache span.logo span.name { color:white; font-size:0.7em; padding:0 0.8em 0 2em; }
h1.memcache span.nameinfo { color:white; display:inline; font-size:0.4em; margin-left: 3em; }
h1.memcache div.copy { color:black; font-size:0.4em; position:absolute; right:1em; }
hr.memcache {
background:white;
border-bottom:solid rgb(102,102,153) 1px;
border-style:none;
border-top:solid rgb(102,102,153) 10px;
height:12px;
margin:0;
margin-top:1px;
padding:0;
}
ol,menu { margin:1em 0 0 0; padding:0.2em; margin-left:1em;}
ol.menu li { display:inline; margin-right:0.7em; list-style:none; font-size:85%}
ol.menu a {
background:rgb(153,153,204);
border:solid rgb(102,102,153) 2px;
color:white;
font-weight:bold;
margin-right:0em;
padding:0.1em 0.5em 0.1em 0.5em;
text-decoration:none;
margin-left: 5px;
}
ol.menu a.child_active {
background:rgb(153,153,204);
border:solid rgb(102,102,153) 2px;
color:white;
font-weight:bold;
margin-right:0em;
padding:0.1em 0.5em 0.1em 0.5em;
text-decoration:none;
border-left: solid black 5px;
margin-left: 0px;
}
ol.menu span.active {
background:rgb(153,153,204);
border:solid rgb(102,102,153) 2px;
color:black;
font-weight:bold;
margin-right:0em;
padding:0.1em 0.5em 0.1em 0.5em;
text-decoration:none;
border-left: solid black 5px;
}
ol.menu span.inactive {
background:rgb(193,193,244);
border:solid rgb(182,182,233) 2px;
color:white;
font-weight:bold;
margin-right:0em;
padding:0.1em 0.5em 0.1em 0.5em;
text-decoration:none;
margin-left: 5px;
}
ol.menu a:hover {
background:rgb(193,193,244);
text-decoration:none;
}
div.info {
background:rgb(204,204,204);
border:solid rgb(204,204,204) 1px;
margin-bottom:1em;
}
div.info h2 {
background:rgb(204,204,204);
color:black;
font-size:1em;
margin:0;
padding:0.1em 1em 0.1em 1em;
}
div.info table {
border:solid rgb(204,204,204) 1px;
border-spacing:0;
width:100%;
}
div.info table th {
background:rgb(204,204,204);
color:white;
margin:0;
padding:0.1em 1em 0.1em 1em;
}
div.info table th a.sortable { color:black; }
div.info table tr.tr-0 { background:rgb(238,238,238); }
div.info table tr.tr-1 { background:rgb(221,221,221); }
div.info table td { padding:0.3em 1em 0.3em 1em; }
div.info table td.td-0 { border-right:solid rgb(102,102,153) 1px; white-space:nowrap; }
div.info table td.td-n { border-right:solid rgb(102,102,153) 1px; }
div.info table td h3 {
color:black;
font-size:1.1em;
margin-left:-0.3em;
}
.td-0 a , .td-n a, .tr-0 a , tr-1 a {
text-decoration:underline;
}
div.graph { margin-bottom:1em }
div.graph h2 { background:rgb(204,204,204);; color:black; font-size:1em; margin:0; padding:0.1em 1em 0.1em 1em; }
div.graph table { border:solid rgb(204,204,204) 1px; color:black; font-weight:normal; width:100%; }
div.graph table td.td-0 { background:rgb(238,238,238); }
div.graph table td.td-1 { background:rgb(221,221,221); }
div.graph table td { padding:0.2em 1em 0.4em 1em; }
div.div1,div.div2 { margin-bottom:1em; width:35em; }
div.div3 { position:absolute; left:40em; top:1em; width:580px; }
//div.div3 { position:absolute; left:37em; top:1em; right:1em; }
div.sorting { margin:1.5em 0em 1.5em 2em }
.center { text-align:center }
.aright { position:absolute;right:1em }
.right { text-align:right }
.ok { color:rgb(0,200,0); font-weight:bold}
.failed { color:rgb(200,0,0); font-weight:bold}
span.box {
border: black solid 1px;
border-right:solid black 2px;
border-bottom:solid black 2px;
padding:0 0.5em 0 0.5em;
margin-right:1em;
}
span.green { background:#60F060; padding:0 0.5em 0 0.5em}
span.red { background:#D06030; padding:0 0.5em 0 0.5em }
div.authneeded {
background:rgb(238,238,238);
border:solid rgb(204,204,204) 1px;
color:rgb(200,0,0);
font-size:1.2em;
font-weight:bold;
padding:2em;
text-align:center;
}
input {
background:rgb(153,153,204);
border:solid rgb(102,102,153) 2px;
color:white;
font-weight:bold;
margin-right:1em;
padding:0.1em 0.5em 0.1em 0.5em;
}
//-->
</style>
</head>
<body>
<div class="head">
<h1 class="memcache">
<span class="logo"><a href="http://pecl.php.net/package/memcache">memcache</a></span>
<span class="nameinfo">memcache.php by <a href="http://livebookmark.net">Harun Yayli</a></span>
</h1>
<hr class="memcache">
</div>
<div class=content>
EOB;
return $header;
}
function getFooter(){
global $VERSION;
$footer = '</div><!-- Based on apc.php '.$VERSION.'--></body>
</html>
';
return $footer;
}
function getMenu(){
global $PHP_SELF;
echo "<ol class=menu>";
if ($_GET['op']!=4){
echo <<<EOB
<li><a href="$PHP_SELF&op={$_GET['op']}">Refresh Data</a></li>
EOB;
}
else {
echo <<<EOB
<li><a href="$PHP_SELF&op=2}">Back</a></li>
EOB;
}
echo
menu_entry(1,'View Host Stats'),
menu_entry(2,'Variables');
echo <<<EOB
</ol>
<br/>
EOB;
}
// TODO, AUTH
$_GET['op'] = !isset($_GET['op'])? '1':$_GET['op'];
$PHP_SELF= isset($_SERVER['PHP_SELF']) ? htmlentities(strip_tags($_SERVER['PHP_SELF'],'')) : '';
$PHP_SELF=$PHP_SELF.'?';
$time = time();
// sanitize _GET
foreach($_GET as $key=>$g){
$_GET[$key]=htmlentities($g);
}
// singleout
// when singleout is set, it only gives details for that server.
if (isset($_GET['singleout']) && $_GET['singleout']>=0 && $_GET['singleout'] <count($MEMCACHE_SERVERS)){
$MEMCACHE_SERVERS = array($MEMCACHE_SERVERS[$_GET['singleout']]);
}
// display images
if (isset($_GET['IMG'])){
$memcacheStats = getMemcacheStats();
$memcacheStatsSingle = getMemcacheStats(false);
if (!graphics_avail()) {
exit(0);
}
function fill_box($im, $x, $y, $w, $h, $color1, $color2,$text='',$placeindex='') {
global $col_black;
$x1=$x+$w-1;
$y1=$y+$h-1;
imagerectangle($im, $x, $y1, $x1+1, $y+1, $col_black);
if($y1>$y) imagefilledrectangle($im, $x, $y, $x1, $y1, $color2);
else imagefilledrectangle($im, $x, $y1, $x1, $y, $color2);
imagerectangle($im, $x, $y1, $x1, $y, $color1);
if ($text) {
if ($placeindex>0) {
if ($placeindex<16)
{
$px=5;
$py=$placeindex*12+6;
imagefilledrectangle($im, $px+90, $py+3, $px+90-4, $py-3, $color2);
imageline($im,$x,$y+$h/2,$px+90,$py,$color2);
imagestring($im,2,$px,$py-6,$text,$color1);
} else {
if ($placeindex<31) {
$px=$x+40*2;
$py=($placeindex-15)*12+6;
} else {
$px=$x+40*2+100*intval(($placeindex-15)/15);
$py=($placeindex%15)*12+6;
}
imagefilledrectangle($im, $px, $py+3, $px-4, $py-3, $color2);
imageline($im,$x+$w,$y+$h/2,$px,$py,$color2);
imagestring($im,2,$px+2,$py-6,$text,$color1);
}
} else {
imagestring($im,4,$x+5,$y1-16,$text,$color1);
}
}
}
function fill_arc($im, $centerX, $centerY, $diameter, $start, $end, $color1,$color2,$text='',$placeindex=0) {
$r=$diameter/2;
$w=deg2rad((360+$start+($end-$start)/2)%360);
if (function_exists("imagefilledarc")) {
// exists only if GD 2.0.1 is avaliable
imagefilledarc($im, $centerX+1, $centerY+1, $diameter, $diameter, $start, $end, $color1, IMG_ARC_PIE);
imagefilledarc($im, $centerX, $centerY, $diameter, $diameter, $start, $end, $color2, IMG_ARC_PIE);
imagefilledarc($im, $centerX, $centerY, $diameter, $diameter, $start, $end, $color1, IMG_ARC_NOFILL|IMG_ARC_EDGED);
} else {
imagearc($im, $centerX, $centerY, $diameter, $diameter, $start, $end, $color2);
imageline($im, $centerX, $centerY, $centerX + cos(deg2rad($start)) * $r, $centerY + sin(deg2rad($start)) * $r, $color2);
imageline($im, $centerX, $centerY, $centerX + cos(deg2rad($start+1)) * $r, $centerY + sin(deg2rad($start)) * $r, $color2);
imageline($im, $centerX, $centerY, $centerX + cos(deg2rad($end-1)) * $r, $centerY + sin(deg2rad($end)) * $r, $color2);
imageline($im, $centerX, $centerY, $centerX + cos(deg2rad($end)) * $r, $centerY + sin(deg2rad($end)) * $r, $color2);
imagefill($im,$centerX + $r*cos($w)/2, $centerY + $r*sin($w)/2, $color2);
}
if ($text) {
if ($placeindex>0) {
imageline($im,$centerX + $r*cos($w)/2, $centerY + $r*sin($w)/2,$diameter, $placeindex*12,$color1);
imagestring($im,4,$diameter, $placeindex*12,$text,$color1);
} else {
imagestring($im,4,$centerX + $r*cos($w)/2, $centerY + $r*sin($w)/2,$text,$color1);
}
}
}
$size = GRAPH_SIZE; // image size
$image = imagecreate($size+50, $size+10);
$col_white = imagecolorallocate($image, 0xFF, 0xFF, 0xFF);
$col_red = imagecolorallocate($image, 0xD0, 0x60, 0x30);
$col_green = imagecolorallocate($image, 0x60, 0xF0, 0x60);
$col_black = imagecolorallocate($image, 0, 0, 0);
imagecolortransparent($image,$col_white);
switch ($_GET['IMG']){
case 1: // pie chart
$tsize=$memcacheStats['limit_maxbytes'];
$avail=$tsize-$memcacheStats['bytes'];
$x=$y=$size/2;
$angle_from = 0;
$fuzz = 0.000001;
foreach($memcacheStatsSingle as $serv=>$mcs) {
$free = $mcs['STAT']['limit_maxbytes']-$mcs['STAT']['bytes'];
$used = $mcs['STAT']['bytes'];
if ($free>0){
// draw free
$angle_to = ($free*360)/$tsize;
$perc =sprintf("%.2f%%", ($free *100) / $tsize) ;
fill_arc($image,$x,$y,$size,$angle_from,$angle_from + $angle_to ,$col_black,$col_green,$perc);
$angle_from = $angle_from + $angle_to ;
}
if ($used>0){
// draw used
$angle_to = ($used*360)/$tsize;
$perc =sprintf("%.2f%%", ($used *100) / $tsize) ;
fill_arc($image,$x,$y,$size,$angle_from,$angle_from + $angle_to ,$col_black,$col_red, '('.$perc.')' );
$angle_from = $angle_from+ $angle_to ;
}
}
break;
case 2: // hit miss
$hits = ($memcacheStats['get_hits']==0) ? 1:$memcacheStats['get_hits'];
$misses = ($memcacheStats['get_misses']==0) ? 1:$memcacheStats['get_misses'];
$total = $hits + $misses ;
fill_box($image, 30,$size,50,-$hits*($size-21)/$total,$col_black,$col_green,sprintf("%.1f%%",$hits*100/$total));
fill_box($image,130,$size,50,-max(4,($total-$hits)*($size-21)/$total),$col_black,$col_red,sprintf("%.1f%%",$misses*100/$total));
break;
}
header("Content-type: image/png");
imagepng($image);
exit;
}
echo getHeader();
echo getMenu();
switch ($_GET['op']) {
case 1: // host stats
$phpversion = phpversion();
$memcacheStats = getMemcacheStats();
$memcacheStatsSingle = getMemcacheStats(false);
$mem_size = $memcacheStats['limit_maxbytes'];
$mem_used = $memcacheStats['bytes'];
$mem_avail= $mem_size-$mem_used;
$startTime = time()-array_sum($memcacheStats['uptime']);
$curr_items = $memcacheStats['curr_items'];
$total_items = $memcacheStats['total_items'];
$hits = ($memcacheStats['get_hits']==0) ? 1:$memcacheStats['get_hits'];
$misses = ($memcacheStats['get_misses']==0) ? 1:$memcacheStats['get_misses'];
$sets = $memcacheStats['cmd_set'];
$req_rate = sprintf("%.2f",($hits+$misses)/($time-$startTime));
$hit_rate = sprintf("%.2f",($hits)/($time-$startTime));
$miss_rate = sprintf("%.2f",($misses)/($time-$startTime));
$set_rate = sprintf("%.2f",($sets)/($time-$startTime));
echo <<< EOB
<div class="info div1"><h2>General Cache Information</h2>
<table cellspacing=0><tbody>
<tr class=tr-1><td class=td-0>PHP Version</td><td>$phpversion</td></tr>
EOB;
echo "<tr class=tr-0><td class=td-0>Memcached Host". ((count($MEMCACHE_SERVERS)>1) ? 's':'')."</td><td>";
$i=0;
if (!isset($_GET['singleout']) && count($MEMCACHE_SERVERS)>1){
foreach($MEMCACHE_SERVERS as $server){
echo ($i+1).'. <a href="'.$PHP_SELF.'&singleout='.$i++.'">'.$server.'</a><br/>';
}
}
else{
echo '1.'.$MEMCACHE_SERVERS[0];
}
if (isset($_GET['singleout'])){
echo '<a href="'.$PHP_SELF.'">(all servers)</a><br/>';
}
echo "</td></tr>\n";
echo "<tr class=tr-1><td class=td-0>Total Memcache Cache</td><td>".bsize($memcacheStats['limit_maxbytes'])."</td></tr>\n";
echo <<<EOB
</tbody></table>
</div>
<div class="info div1"><h2>Memcache Server Information</h2>
EOB;
foreach($MEMCACHE_SERVERS as $server){
echo '<table cellspacing=0><tbody>';
echo '<tr class=tr-1><td class=td-1>'.$server.'</td><td><a href="'.$PHP_SELF.'&server='.array_search($server,$MEMCACHE_SERVERS).'&op=6">[<b>Flush this server</b>]</a></td></tr>';
echo '<tr class=tr-0><td class=td-0>Start Time</td><td>',date(DATE_FORMAT,$memcacheStatsSingle[$server]['STAT']['time']-$memcacheStatsSingle[$server]['STAT']['uptime']),'</td></tr>';
echo '<tr class=tr-1><td class=td-0>Uptime</td><td>',duration($memcacheStatsSingle[$server]['STAT']['time']-$memcacheStatsSingle[$server]['STAT']['uptime']),'</td></tr>';
echo '<tr class=tr-0><td class=td-0>Memcached Server Version</td><td>'.$memcacheStatsSingle[$server]['STAT']['version'].'</td></tr>';
echo '<tr class=tr-1><td class=td-0>Used Cache Size</td><td>',bsize($memcacheStatsSingle[$server]['STAT']['bytes']),'</td></tr>';
echo '<tr class=tr-0><td class=td-0>Total Cache Size</td><td>',bsize($memcacheStatsSingle[$server]['STAT']['limit_maxbytes']),'</td></tr>';
echo '</tbody></table>';
}
echo <<<EOB
</div>
<div class="graph div3"><h2>Host Status Diagrams</h2>
<table cellspacing=0><tbody>
EOB;
$size='width='.(GRAPH_SIZE+50).' height='.(GRAPH_SIZE+10);
echo <<<EOB
<tr>
<td class=td-0>Cache Usage</td>
<td class=td-1>Hits & Misses</td>
</tr>
EOB;
echo
graphics_avail() ?
'<tr>'.
"<td class=td-0><img alt=\"\" $size src=\"$PHP_SELF&IMG=1&".(isset($_GET['singleout'])? 'singleout='.$_GET['singleout'].'&':'')."$time\"></td>".
"<td class=td-1><img alt=\"\" $size src=\"$PHP_SELF&IMG=2&".(isset($_GET['singleout'])? 'singleout='.$_GET['singleout'].'&':'')."$time\"></td></tr>\n"
: "",
'<tr>',
'<td class=td-0><span class="green box"> </span>Free: ',bsize($mem_avail).sprintf(" (%.1f%%)",$mem_avail*100/$mem_size),"</td>\n",
'<td class=td-1><span class="green box"> </span>Hits: ',$hits.sprintf(" (%.1f%%)",$hits*100/($hits+$misses)),"</td>\n",
'</tr>',
'<tr>',
'<td class=td-0><span class="red box"> </span>Used: ',bsize($mem_used ).sprintf(" (%.1f%%)",$mem_used *100/$mem_size),"</td>\n",
'<td class=td-1><span class="red box"> </span>Misses: ',$misses.sprintf(" (%.1f%%)",$misses*100/($hits+$misses)),"</td>\n";
echo <<< EOB
</tr>
</tbody></table>
<br/>
<div class="info"><h2>Cache Information</h2>
<table cellspacing=0><tbody>
<tr class=tr-0><td class=td-0>Current Items(total)</td><td>$curr_items ($total_items)</td></tr>
<tr class=tr-1><td class=td-0>Hits</td><td>{$hits}</td></tr>
<tr class=tr-0><td class=td-0>Misses</td><td>{$misses}</td></tr>
<tr class=tr-1><td class=td-0>Request Rate (hits, misses)</td><td>$req_rate cache requests/second</td></tr>
<tr class=tr-0><td class=td-0>Hit Rate</td><td>$hit_rate cache requests/second</td></tr>
<tr class=tr-1><td class=td-0>Miss Rate</td><td>$miss_rate cache requests/second</td></tr>
<tr class=tr-0><td class=td-0>Set Rate</td><td>$set_rate cache requests/second</td></tr>
</tbody></table>
</div>
EOB;
break;
case 2: // variables
$m=0;
$cacheItems= getCacheItems();
$items = $cacheItems['items'];
$totals = $cacheItems['counts'];
$maxDump = MAX_ITEM_DUMP;
foreach($items as $server => $entries) {
echo <<< EOB
<div class="info"><table cellspacing=0><tbody>
<tr><th colspan="2">$server</th></tr>
<tr><th>Slab Id</th><th>Info</th></tr>
EOB;
foreach($entries as $slabId => $slab) {
$dumpUrl = $PHP_SELF.'&op=2&server='.(array_search($server,$MEMCACHE_SERVERS)).'&dumpslab='.$slabId;
echo
"<tr class=tr-$m>",
"<td class=td-0><center>",'<a href="',$dumpUrl,'">',$slabId,'</a>',"</center></td>",
"<td class=td-last><b>Item count:</b> ",$slab['number'],'<br/><b>Age:</b>',duration($time-$slab['age']),'<br/> <b>Evicted:</b>',((isset($slab['evicted']) && $slab['evicted']==1)? 'Yes':'No');
if ((isset($_GET['dumpslab']) && $_GET['dumpslab']==$slabId) && (isset($_GET['server']) && $_GET['server']==array_search($server,$MEMCACHE_SERVERS))){
echo "<br/><b>Items: item</b><br/>";
$items = dumpCacheSlab($server,$slabId,$slab['number']);
// maybe someone likes to do a pagination here :)
$i=1;
foreach($items['ITEM'] as $itemKey=>$itemInfo){
$itemInfo = trim($itemInfo,'[ ]');
echo '<a href="',$PHP_SELF,'&op=4&server=',(array_search($server,$MEMCACHE_SERVERS)),'&key=',base64_encode($itemKey).'">',$itemKey,'</a>';
if ($i++ % 10 == 0) {
echo '<br/>';
}
elseif ($i!=$slab['number']+1){
echo ',';
}
}
}
echo "</td></tr>";
$m=1-$m;
}
echo <<<EOB
</tbody></table>
</div><hr/>
EOB;
}
break;
break;
case 4: //item dump
if (!isset($_GET['key']) || !isset($_GET['server'])){
echo "No key set!";
break;
}
// I'm not doing anything to check the validity of the key string.
// probably an exploit can be written to delete all the files in key=base64_encode("\n\r delete all").
// somebody has to do a fix to this.
$theKey = htmlentities(base64_decode($_GET['key']));
$theserver = $MEMCACHE_SERVERS[(int)$_GET['server']];
list($h,$p) = explode(':',$theserver);
$r = sendMemcacheCommand($h,$p,'get '.$theKey);
echo <<<EOB
<div class="info"><table cellspacing=0><tbody>
<tr><th>Server<th>Key</th><th>Value</th><th>Delete</th></tr>
EOB;
echo "<tr><td class=td-0>",$theserver,"</td><td class=td-0>",$theKey,
" <br/>flag:",$r['VALUE'][$theKey]['stat']['flag'],
" <br/>Size:",bsize($r['VALUE'][$theKey]['stat']['size']),
"</td><td>",chunk_split($r['VALUE'][$theKey]['value'],40),"</td>",
'<td><a href="',$PHP_SELF,'&op=5&server=',(int)$_GET['server'],'&key=',base64_encode($theKey),"\">Delete</a></td>","</tr>";
echo <<<EOB
</tbody></table>
</div><hr/>
EOB;
break;
case 5: // item delete
if (!isset($_GET['key']) || !isset($_GET['server'])){
echo "No key set!";
break;
}
$theKey = htmlentities(base64_decode($_GET['key']));
$theserver = $MEMCACHE_SERVERS[(int)$_GET['server']];
list($h,$p) = explode(':',$theserver);
$r = sendMemcacheCommand($h,$p,'delete '.$theKey);
echo 'Deleting '.$theKey.':'.$r;
break;
case 6: // flush server
$theserver = $MEMCACHE_SERVERS[(int)$_GET['server']];
$r = flushServer($theserver);
echo 'Flush '.$theserver.":".$r;
break;
}
echo getFooter();
?>
② 在memcache_tools.php文件中设置memcached服务器地址与相关信息:
ADMIN_USERNAME root #22行,登录memcache_tool的默认用户名
ADMIN_PASSWORD 123456 #23行,登录memcache_tool的默认密码
$MEMCACHE_SERVERS[] ='Memcached服务器地址:11211' #配置memcached服务器地址和端口
登录后可查看memcached服务器的相关信息:
memcached中存储的键值对:
5、Memcached缓存失效机制:
(1) Lazy Expiration(惰性过期)
在Memcached中,惰性过期是一种节省CPU资源的策略。Memcached不会在后台主动检查每个键是否过期,而是当客户端尝试获取一个键时,Memcached会检查该键的过期时间戳,如果该键已经过期,那么它不会被返回给客户端,并从缓存中删除。
(2) Least Recently Used(LRU 替换策略)
LRU策略是一种常用的缓存替换策略,当Memcached的内存空间不足以存储新数据时,它根据数据项最后一次被访问的时间来做出决策。即最近最少使用的数据项将被删除,并将其空间分配给新的记录。
四、session入库
1、为什么需要session入库:
由于负载均衡需要对用户的请求进行分发操作,每个服务器有自己的Session文件存储,如果用户的请求被分发到了之前没有处理过该用户的服务器,那么该服务器就无法找到对应的Session数据,从而导致Session失效。
解决方案:
① 使用负载均衡算法:如Nginx的ip_hash算法,确保来自同一用户的请求总是被分发到同一台服务器上。
② 把Session入库:将所有服务器的Session数据集中存储在一个共享的位置,例如数据库或分布式缓存系统。这样,无论用户的请求被分发到哪个服务器,都可以从共享的位置获取到Session数据。
2、DSShop商城系统中的Session入库:
(1) 修改lB负载均衡器配置文件:
先注释掉在第五节配置过的ip_hash,使负载均衡算法为轮询。
(2) 需要配置session入库的文件:
在需要进行登录操作的界面配置session入库。
home文件夹:用户的前端界面,用户登录;
admin文件夹:管理员的后端界面,管理员登录。
(3) 修改文件:
① 前台:修改/home/下的config.php
vim /home/www/application/home/config.php
添加驱动方式和memcached服务器地址:
查看前端界面的session缓存:
前端界面登录信息的session缓存:
② 后台:修改/admin/下的config.php
vim /home/www/application/admin/config.php
修改方式与前台类似:
● 后台除了修改/admin/config.php文件之外,还需要修改总的配置文件,才能使session共享。
vim /home/www/application/config.php
登录后台:
后台登录信息的session缓存:
五、memcached单机多实例:
在一台机器上运行多个memcached实例,每个memcached设置单独的端口号。
/usr/local/memcached/bin /memcached -uroot -d -p 11211
/usr/local/memcached/bin /memcached -uroot -d -p 11212
/usr/local/memcached/bin /memcached -uroot -d -p 11213