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之前我們?cè)钊氲奶接戇^(guò)PHP緩存技術(shù)，其中主要提到了數(shù)據(jù)緩存。數(shù)據(jù)緩存主要是指數(shù)據(jù)庫(kù)查詢緩存，每次訪問(wèn)頁(yè)面的時(shí)候,都會(huì)先檢測(cè)相應(yīng)的緩存數(shù)據(jù)是否存在，如果不存在，就連接數(shù)據(jù)庫(kù)，得到數(shù)據(jù)， 并把查詢結(jié)果序列化后保存到文件中，以后同樣的查詢結(jié)果就直接從緩存表或文件中獲得。
創(chuàng)新互聯(lián)是專業(yè)的敘州網(wǎng)站建設(shè)公司，敘州接單;提供成都網(wǎng)站設(shè)計(jì)、網(wǎng)站制作,網(wǎng)頁(yè)設(shè)計(jì),網(wǎng)站設(shè)計(jì),建網(wǎng)站,PHP網(wǎng)站建設(shè)等專業(yè)做網(wǎng)站服務(wù);采用PHP框架,可快速的進(jìn)行敘州網(wǎng)站開(kāi)發(fā)網(wǎng)頁(yè)制作和功能擴(kuò)展;專業(yè)做搜索引擎喜愛(ài)的網(wǎng)站,專業(yè)的做網(wǎng)站團(tuán)隊(duì),希望更多企業(yè)前來(lái)合作!
用的最廣的例子看Discuz的搜索功能，把結(jié)果ID緩存到一個(gè)表中，下次搜索相同關(guān)鍵字時(shí)先搜索緩存表。
舉個(gè)常用的方法，多表關(guān)聯(lián)的時(shí)候，把附表中的內(nèi)容生成數(shù)組保存到主表的一個(gè)字段中，需要的時(shí)候數(shù)組分解一下，這樣的好處是只讀一個(gè)表，壞處就是兩個(gè) 數(shù)據(jù)同步會(huì)多不少步驟，數(shù)據(jù)庫(kù)永遠(yuǎn)是瓶頸，用硬盤(pán)換速度，是這個(gè)的關(guān)鍵點(diǎn)。
頁(yè)面緩存
每次訪問(wèn)頁(yè)面的時(shí)候，都會(huì)先檢測(cè)相應(yīng)的緩存頁(yè)面文件是否存在，如果不存在，就連接數(shù)據(jù)庫(kù)，得到數(shù)據(jù)，顯示頁(yè)面并同時(shí)生成緩存頁(yè)面文件，這樣下次訪問(wèn) 的時(shí)候頁(yè)面文件就發(fā)揮作用了。(模板引擎和網(wǎng)上常見(jiàn)的一些緩存類(lèi)通常有此功能)
時(shí)間觸發(fā)緩存
檢查文件是否存在并且時(shí)間戳小于設(shè)置的過(guò)期時(shí)間,如果文件修改的時(shí)間戳比當(dāng)前時(shí)間戳減去過(guò)期時(shí)間戳大，那么就用緩存，否則更新緩存。
內(nèi)容觸發(fā)緩存
當(dāng)插入數(shù)據(jù)或更新數(shù)據(jù)時(shí)，強(qiáng)制更新緩存。
靜態(tài)緩存
這里所說(shuō)的靜態(tài)緩存是指靜態(tài)化，直接生成HTML或xml等文本文件，有更新的時(shí)候重生成一次，適合于不太變化的頁(yè)面，這就不說(shuō)了。
內(nèi)存緩存
Memcached是高性能的，分布式的內(nèi)存對(duì)象緩存系統(tǒng)，用于在動(dòng)態(tài)應(yīng)用中減少數(shù)據(jù)庫(kù)負(fù)載，提升訪問(wèn)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);
- ?>
讀庫(kù)的例子：
- $sql = ‘SELECT * FROM users’;
- $key = md5($sql); //memcached 對(duì)象標(biāo)識(shí)符
- if ( !($datas = $mc->get($key)) ) {
- // 在 memcached 中未獲取到緩存數(shù)據(jù)，則使用數(shù)據(jù)庫(kù)查詢獲取記錄集
- 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;
- // 將數(shù)據(jù)庫(kù)中獲取到的結(jié)果集數(shù)據(jù)保存到 memcached 中，以供下次訪問(wèn)時(shí)使用
- $mc->add($key, $datas);
- } else {
- echo “n”.str_pad(‘Read datas from memcached.’, 60, ‘_’).”n”;
- }
- var_dump($datas);
- ?>
PHP的緩沖器
比如eaccelerator，apc，phpa，xcache等等。
MySQL緩存
這也算非代碼級(jí)的，經(jīng)典的數(shù)據(jù)庫(kù)就是用的這種方式，看下面的運(yùn)行時(shí)間，0.09xxx之類(lèi)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緩存
如Nginx，SQUID，mod_PRoxy(apache2以上又分為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
文章名稱：PHP企業(yè)級(jí)應(yīng)用緩存技術(shù)詳解
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