PHP缓存技术
普遍缓存技术
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。
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)
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。
内容触发缓存:
当插入数据或更新数据时,强制更新缓存。
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
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:
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
$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:
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
$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);
?>
php的缓冲器:
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
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
代码拷贝框
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
……
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
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
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
#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
server {
listen 10.10.10.230:80;
server_name img.test.com;
location / {
proxy_pass http://bspimgsvr;
include proxy_setting.conf;
}
access_log logs/img.log test_com;
}
#style.test.com
server {
listen 10.10.10.230:80;
server_name style.test.com;
location / {
proxy_pass http://bspstylesvr;
include proxy_setting.conf;
}
access_log logs/style.log test_com;
}
#help.test.com
server {
listen 10.10.10.230:80;
server_name help.test.com;
location / {
proxy_pass http://bsphelpsvr;
include proxy_setting.conf;
}
access_log logs/help.log test_com;
}
#admin.test.com
server {
listen 10.10.10.230:80;
server_name admin.test.com;
location / {
proxy_pass http://bspadminsvr;
include proxy_setting.conf;
}
access_log logs/admin.log test_com;
}
#buyer.test.com
server {
listen 10.10.10.230:80;
server_name buyer.test.com;
location / {
proxy_pass http://bspbuyersvr;
include proxy_setting.conf;
}
access_log logs/buyer.log test_com;
}
#seller.test.com
server {
listen 10.10.10.230:80;
server_name seller.test.com;
location / {
proxy_pass http://bspsellersvr;
include proxy_setting.conf;
}
access_log logs/seller.log test_com;
}
#wsi.test.com
server {
listen 10.10.10.230:80;
server_name wsi.test.com;
location / {
proxy_pass http://bspwsisvr;
include proxy_setting.conf;
}
access_log logs/wsi.log test_com;
}
#www.test.com
server {
listen 10.10.10.230:80;
server_name www.test.com *.test.com;
location ~^/NginxStatus/ {
stub_status on;
access_log off;
}
location / {
proxy_pass http://bspfrontsvr;
include proxy_setting.conf;
}
access_log logs/www.log test_com;
error_page 500502503504/50x.html;
location =/50x.html {
root html;
}
}
#login.test.com
server {
listen 10.10.10.230:443;
server_name login.test.com;
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;
include proxy_setting.conf;
}
access_log logs/login.log test_com;
}
#login.test.com for register
server {
listen 10.10.10.230:80;
server_name login.test.com;
location / {
proxy_pass http://bspregistersvr;
include proxy_setting.conf;
}
access_log logs/register.log test_com;
}
}
<conf/proxy_setting.conf>
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;
mod_proxy的例子:
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
ServerName www.zxsv.com
ServerAdmin admin@zxsv.com
# reverse proxy setting
ProxyPass / http://www.zxsv.com:8080/
ProxyPassReverse / http://www.zxsv.com: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/dev_access_log combined
</VirtualHost>
而SQUID的例子 ,这方面网上有写的太多,大家自己搜索一下
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:http://www.cnblogs.com/softwaredevelop/archive/2010/04/07/1706322.html