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PHP企业级应用缓存技术详解

时间:2021-07-01 10:21:17 帮助过:24人阅读

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...




  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。

  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。



  <?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);

  ?>



  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



  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:



  <VirtualHost *>

  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>

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