PHP常用的缓存技术

水深无声 2024-03-27 15:57 51阅读 0赞

**一、数据缓存**

这里所说的数据缓存是指数据库查询缓存，每次访问页面的时候,都会先检测相应的缓存数据是否存在，如果不存在，就连接数据库，得到数据，并把查询结果[序列化][Link 1]后保存到文件中，以后同样的查询结果就直接从缓存表或文件中获得。

用的最广的例子看Discuz的搜索功能，把结果ID缓存到一个表中，下次搜索相同关键字时先搜索缓存表。

举个常用的方法，多表关联的时候，把附表中的内容生成[数组][Link 2]保存到主表的一个字段中，需要的时候数组分解一下，这样的好处是只读一个表，坏处就是两个数据同步会多不少步骤，数据库永远是瓶颈，用硬盘换速度，是这个的关键点。

**二、页面缓存**

每次访问页面的时候，都会先检测相应的缓存页面文件是否存在，如果不存在，就连接数据库，得到数据，显示页面并同时生成缓存页面文件，这样下次访问的时候页面文件就发挥作用了。(模板引擎和网上常见的一些缓存类通常有此功能)。

**三、时间触发缓存**

检查文件是否存在并且时间戳小于设置的过期时间,如果文件修改的时间戳比当前时间戳减去过期时间戳大，那么就用缓存，否则更新缓存。

四、内容触发缓存

当插入数据或更新数据时，强制更新缓存。

**五、静态缓存**

这里所说的静态缓存是指静态化，直接生成HTML或XML等文本文件，有更新的时候重生成一次，适合于不太变化的页面，这就不说了。

以上内容是代码级的解决方案，我直接CP别的框架，也懒得改，内容都差不多，很容易就做到，而且会几种方式一起用，但下面的内容是服务器端的缓存方案，非代码级的，要有多方的合作才能做到。

**六、内存缓存**

Memcached是高性能的，分布式的内存对象缓存系统，用于在动态应用中减少数据库负载，提升访问速度。

这里说下Memcached的例子：

<?php

$memcache = new Memcache;

$memcache->connect("localhost", 11211) or die ("Could not connect");

$version = $memcache->getVersion();

echo "Server"s version: ".$version."\\n";

$tmp\_object = new stdClass;

$tmp\_object->str\_attr = "test";

$tmp\_object->int\_attr = 123;

$memcache->set("key", $tmp\_object, false, 10) or die ("Failed to save data at the server");

echo "Store data in the cache (data will expire in 10 seconds)\\n";

$get\_result = $memcache->get("key");

echo "Data from the cache:\\n";

var\_dump($get\_result);

读库的例子:

<?php

$sql = "SELECT \* FROM users";

$key = md5($sql); //memcached 对象标识符

if ( !($datas = $mc->get($key)) ) \{

// 在 memcached 中未获取到缓存数据，则使用数据库查询获取记录集。

echo "n".str\_pad("Read datas from MySQL.", 60, "\_")."n";

$conn = mysql\_connect("localhost", "test", "test");

mysql\_select\_db("test");

$result = mysql\_query($sql);

while ($row = mysql\_fetch\_object($result))

$datas\[\] = $row;

// 将数据库中获取到的结果集数据保存到 memcached 中，以供下次访问时使用。

$mc->add($key, $datas);

\} else \{

echo "n".str\_pad("Read datas from memcached.", 60, "\_")."n";

var\_dump($datas);

七、PHP的缓冲器、加速器

有eaccelerator， apc， phpa，xcache，这个这个就不说了吧，搜索一堆一堆的，自己看啦，知道有这玩意就OK。

八、MYSQL缓存

这也算非代码级的，经典的数据库就是用的这种方式，看下面的运行时间，0.09xxx之类的

我贴段根据蓝色那家伙修改后部分my.ini吧，2G的MYISAM表可以在0.05S左右，据说他前后改了有快一年。

\[client\]

……

default-character-set=gbk

default-storage-engine=MYISAM

max\_connections=600

max\_connect\_errors=500

back\_log=200

interactive\_timeout=7200

query\_cache\_size=64M

……

table\_cache=512

……

myisam\_max\_sort\_file\_size=100G

myisam\_max\_extra\_sort\_file\_size=100G

myisam\_sort\_buffer\_size=128M

key\_buffer\_size=1024M

read\_buffer\_size=512M

……

thread\_concurrency=8

九、基于反向代理的Web缓存

如Nginx，SQUID，mod\_proxy(apache2以上又分为mod\_proxy和mod\_cache)

NGINX的例子：

<nginx.conf>

\#user nobody;

worker\_processes 4;

error\_log logs/error.log crit;

pid logs/nginx.pid;

worker\_rlimit\_nofile 10240;

events \{

use epoll;

worker\_connections 51200;

http \{

include mime.types;

default\_type application/octet-stream;

sendfile on;

keepalive\_timeout 65;

tcp\_nodelay on;

\# server pool

upstream bspfrontsvr \{

server 10.10.10.224:80 weight=1;

server 10.10.10.221:80 weight=1;

upstream bspimgsvr \{

server 10.10.10.201:80 weight=1;

upstream bspstylesvr \{

server 10.10.10.202:80 weight=1;

upstream bsphelpsvr \{

server 10.10.10.204:80 weight=1;

upstream bspwsisvr \{

server 10.10.10.203:80 weight=1;

upstream bspadminsvr \{

server 10.10.10.222:80 weight=1;

upstream bspbuyersvr \{

server 10.10.10.223:80 weight=1;

upstream bspsellersvr \{

server 10.10.10.225:80 weight=1;

upstream bsploginsvr \{

server 10.10.10.220:443 weight=1;

upstream bspregistersvr \{

server 10.10.10.220:80 weight=1;

log\_format test\_com "$remote\_addr - $remote\_user \[$time\_local\] "$request" "

"$status $body\_bytes\_sent "$http\_referer" "$http\_user\_agent" ";

\#--------------------------------------------------------------------

[\#img.test.com][img.test.com]

server \{

listen 10.10.10.230:80;

server\_name [img.test.com][img.test.com 1];

location / \{

proxy\_pass [http://bspimgsvr][http_bspimgsvr];

include proxy\_setting.conf;

access\_log logs/img.log test\_com;

[\#style.test.com][style.test.com]

server \{

listen 10.10.10.230:80;

server\_name [style.test.com][style.test.com 1];

location / \{

proxy\_pass [http://bspstylesvr][http_bspstylesvr];

include proxy\_setting.conf;

access\_log logs/style.log test\_com;

[\#help.test.com][help.test.com]

server \{

listen 10.10.10.230:80;

server\_name [help.test.com][help.test.com 1];

location / \{

proxy\_pass [http://bsphelpsvr][http_bsphelpsvr];

include proxy\_setting.conf;

access\_log logs/help.log test\_com;

[\#admin.test.com][admin.test.com]

server \{

listen 10.10.10.230:80;

server\_name [admin.test.com][admin.test.com 1];

location / \{

proxy\_pass [http://bspadminsvr][http_bspadminsvr];

include proxy\_setting.conf;

access\_log logs/admin.log test\_com;

[\#buyer.test.com][buyer.test.com]

server \{

listen 10.10.10.230:80;

server\_name [buyer.test.com][buyer.test.com 1];

location / \{

proxy\_pass [http://bspbuyersvr][http_bspbuyersvr];

include proxy\_setting.conf;

access\_log logs/buyer.log test\_com;

[\#seller.test.com][seller.test.com]

server \{

listen 10.10.10.230:80;

server\_name [seller.test.com][seller.test.com 1];

location / \{

proxy\_pass [http://bspsellersvr][http_bspsellersvr];

include proxy\_setting.conf;

access\_log logs/seller.log test\_com;

[\#wsi.test.com][wsi.test.com]

server \{

listen 10.10.10.230:80;

server\_name [wsi.test.com][wsi.test.com 1];

location / \{

proxy\_pass [http://bspwsisvr][http_bspwsisvr];

include proxy\_setting.conf;

access\_log logs/wsi.log test\_com;

[\#www.test.com][www.test.com]

server \{

listen 10.10.10.230:80;

server\_name [www.test.com][www.test.com 1] \*.[test.com][];

location ~ ^/NginxStatus/ \{

stub\_status on;

access\_log off;

location / \{

proxy\_pass [http://bspfrontsvr][http_bspfrontsvr];

include proxy\_setting.conf;

access\_log logs/www.log test\_com;

error\_page 500 502 503 504 /50x.html;

location = /50x.html \{

root html;

[\#login.test.com][login.test.com]

server \{

listen 10.10.10.230:443;

server\_name [login.test.com][login.test.com 1];

ssl on;

ssl\_certificate cert.pem;

ssl\_certificate\_key cert.key;

ssl\_session\_timeout 5m;

ssl\_protocols SSLv2 SSLv3 TLSv1;

ssl\_ciphers ALL:!ADH:!EXPORT56:RC4 RSA: HIGH: MEDIUM: LOW: SSLv2: EXP;

ssl\_prefer\_server\_ciphers on;

location / \{

proxy\_pass [https://bsploginsvr][https_bsploginsvr];

include proxy\_setting.conf;

access\_log logs/login.log test\_com;

[\#login.test.com][login.test.com] for register

server \{

listen 10.10.10.230:80;

server\_name [login.test.com][login.test.com 1];

location / \{

proxy\_pass [http://bspregistersvr][http_bspregistersvr];

include proxy\_setting.conf;

access\_log logs/register.log test\_com;

proxy\_redirect off;

proxy\_set\_header Host $host;

proxy\_set\_header X-Real-IP $remote\_addr;

proxy\_set\_header X-Forwarded-For $proxy\_add\_x\_forwarded\_for;

client\_max\_body\_size 10m;

client\_body\_buffer\_size 128k;

proxy\_connect\_timeout 90;

proxy\_send\_timeout 90;

proxy\_read\_timeout 90;

proxy\_buffer\_size 4k;

proxy\_buffers 4 32k;

proxy\_busy\_buffers\_size 64k;

proxy\_temp\_file\_write\_size 64k;

apache mod\_proxy的例子:

ServerName [jb51.net][]

ServerAdmin [admin@zxsv.com][admin_zxsv.com]

\# reverse proxy setting

ProxyPass / [http://jb51.net:8080/][http_jb51.net_8080]

ProxyPassReverse / [http://jb51.net:8080/][http_jb51.net_8080]

\# cache dir root

CacheRoot "/var/www/proxy"

\# max cache storage

CacheSize 50000000

\# hour: every 4 hour

CacheGcInterval 4

\# max page expire time: hour

CacheMaxExpire 240

\# Expire time = (now - last\_modified) \* CacheLastModifiedFactor

CacheLastModifiedFactor 0.1

\# defalt expire tag: hour

CacheDefaultExpire 1

\# force complete after precent of content retrived: 60-90%

CacheForceCompletion 80

CustomLog /usr/local/apache/logs/jb51\_net\_access\_log combined

</VirtualHost>

十、DNS轮询

BIND是一款开放源码的DNS服务器软件，这个要说起来就大了，自己搜索去，大家知道有这个东西就行了。

我知道的有chinacache等大站就是这样做的，说简单点就是多服务器啦，把同一个页面或文件缓存到不同的服务器上，按南北自动解析到相关的服务器中。

(转自：微点阅读 [https://m.weidianyuedu.com/][https_m.weidianyuedu.com])

[Link 1]: https://so.csdn.net/so/search?q=%E5%BA%8F%E5%88%97%E5%8C%96&spm=1001.2101.3001.7020
[Link 2]: https://so.csdn.net/so/search?q=%E6%95%B0%E7%BB%84&spm=1001.2101.3001.7020
[img.test.com]: https:#img.test.com
[img.test.com 1]: https://img.test.com
[http_bspimgsvr]: http://bspimgsvr
[style.test.com]: https:#style.test.com
[style.test.com 1]: https://style.test.com
[http_bspstylesvr]: http://bspstylesvr
[help.test.com]: https:#help.test.com
[help.test.com 1]: https://help.test.com
[http_bsphelpsvr]: http://bsphelpsvr
[admin.test.com]: https:#admin.test.com
[admin.test.com 1]: https://admin.test.com
[http_bspadminsvr]: http://bspadminsvr
[buyer.test.com]: https:#buyer.test.com
[buyer.test.com 1]: https://buyer.test.com
[http_bspbuyersvr]: http://bspbuyersvr
[seller.test.com]: https:#seller.test.com
[seller.test.com 1]: https://seller.test.com
[http_bspsellersvr]: http://bspsellersvr
[wsi.test.com]: https:#wsi.test.com
[wsi.test.com 1]: https://wsi.test.com
[http_bspwsisvr]: http://bspwsisvr
[www.test.com]: https:#www.test.com
[www.test.com 1]: https://www.test.com
[test.com]: https://test.com
[http_bspfrontsvr]: http://bspfrontsvr
[login.test.com]: https:#login.test.com
[login.test.com 1]: https://login.test.com
[https_bsploginsvr]: https://bsploginsvr
[http_bspregistersvr]: http://bspregistersvr
[jb51.net]: https://jb51.net
[admin_zxsv.com]: mailto:admin@zxsv.com
[http_jb51.net_8080]: http://jb51.net:8080/
[https_m.weidianyuedu.com]: https://m.weidianyuedu.com/