We have discussed PHP caching technology in depth before, which mainly mentioned data caching. Data caching mainly refers to database query caching. Every time you access a page, it will first detect whether the corresponding cached data exists. If it does not exist, connect to the database, get the data, and complete the query...
We have discussed PHP caching technology in depth, which mainly mentioned data caching. Data caching mainly refers to database query caching. Every time you access a page, it will first detect whether the corresponding cached data exists. If it does not exist, connect to the database, obtain the data, and serialize the query results and save them to a file. The same query results are obtained directly from the cache table or file.
The most widely used example is the search function of Discuz, which caches the result ID into a table and searches the cache table first when searching for the same keyword next time.
For a common method, when multiple tables are associated, the contents in the attached table are generated into an array and saved in a field of the main table. When necessary, the array is decomposed. The advantage of this is that only one table can be read, but the disadvantages are two. There will be many more steps to synchronize the data. The database is always the bottleneck. Trading the hard disk for speed is the key point.
Page Cache
Every time you visit a page, it will first detect whether the corresponding cached page file exists. If it does not exist, connect to the database, get the data, display the page and generate a cached page file at the same time, so that the next time you visit The page file comes into play. (Template engines and some common cache classes on the Internet usually have this function)
Time-triggered cache
Check whether the file exists and the timestamp is less than the set expiration time. If the timestamp of the file modification is less than the current timestamp minus the expiration timestamp If it is large, then use the cache, otherwise update the cache.
Content-triggered cache
When data is inserted or updated, the cache is forced to be updated.
Static cache
The static cache mentioned here refers to static, directly generating text files such as HTML or xml, and regenerating them when there are updates. It is suitable for pages that do not change much, so I won’t talk about it here.
Memory Cache
Memcached is a high-performance, distributed memory object caching system used to reduce database load and improve access speed in dynamic applications.
$memcache = new Memcache;
$memcache->connect('localhost', 11211) or die (“Could not connect”); getVersion();
Echo “Server's version: “.$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);
?>
Example of reading the library:
$sql = 'SELECT * FROM users';
$key = md5($sql); //memcached object identifier
if ( !($ datas = $mc->get($key)) ) {
// If the cached data is not obtained in memcached, use the database query to obtain the record set
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;
// Save the result set data obtained from the database to memcached for the next access Use
$mc->add($key, $datas);
} else {
echo "n".str_pad('Read datas from memcached.', 60, '_')."n";
}
var_dump($datas);
?>
PHP buffer
Such as eaccelerator, apc, phpa, xcache, etc.
MySQL Cache
This is also considered non-code level. Classic databases use this method. Look at the running time below, it is like 0.09xxx.
[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
Web cache based on reverse proxy
Such as Nginx, SQUID, mod_PRoxy (apache2 and above are divided into mod_proxy and mod_cache)
Example of NGINX:
#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; lay on;
# server pool
upstream bspfrontsvr {
server 10.10.10.224:80 weight=1;
server 10.10.10.221:80 weight=1; 0 weight=1;
}
upstream bspstylesvr {
server 10.10.10.202:80 weight=1;
}
upstream bsphelpsvr {
server 10.10.10.204:80 weight=1;
}
up stream bspwsisvr {
server 10.10.10.203:80 weight =1;
}
upstream bspadminsvr {
server 10.10.10.222:80 weight=1; 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;
server helpsvr;
include proxy_setting .conf;
}
access_log logs/help.log test_com; 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 log s/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
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