之前我们曾深入的探讨过PHP缓存技术,其中主要提到了数据缓存。数据缓存主要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。

创新互联是专业的叙州网站建设公司,叙州接单;提供成都网站设计、网站制作,网页设计,网站设计,建网站,PHP网站建设等专业做网站服务;采用PHP框架,可快速的进行叙州网站开发网页制作和功能扩展;专业做搜索引擎喜爱的网站,专业的做网站团队,希望更多企业前来合作!
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。
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。
- $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:
- $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
比如eaccelerator,apc,phpa,xcache等等。
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。
- [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
 
#p#
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:
- #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 500 502 503 504 /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;
 - }
 - }
 - 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:
- 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
 
Copyright © 2009-2022 www.wtcwzsj.com 青羊区广皓图文设计工作室(个体工商户) 版权所有 蜀ICP备19037934号