In web development, we often cache time-consuming operations of our database, but there may be a trap. At the moment when the cache fails, a large number of accesses get cache failure indications, and all go to the backend to query the database, resulting in a large number of databases at the same time. Time-consuming queries may cause problems such as database downtime. This problem is deeply hidden and difficult to find. This project is mainly used to solve the inter-process lock problem of PHP.
Example:
Copy the code The code is as follows:
/**
* Test example, open two pages at the same time, you can find the code that only one page can always enter the lock range at the same time
* @link http://code.google.com/p/phplock/
* @author sunli
* @svnversion $Id: test.php 2 2009-11-24 07:14:27Z sunli1223 $
* @version v1.0 beta1
* @license Apache License Version 2.0
* @copyright sunli1223@gmail.com
*/
require 'class.phplock.php';
$lock = new PHPLock ( 'lock/ ', 'lockname' );
$lock->startLock ();
$lock->startLock ();
//process code
echo "Enter lock
$lock->unlock ();
$lock->endLock ();
echo "Release lock completed
rn";
/**
* cache operation
*
* @return $array
*/
function getCache($key) {
return $cache;
}
/**
* Set cache
*
* @param string $key
* @param array $value
*/
function setCache($key,$value) {
}
$cache=getCache($key);
if (! $cache) {
/The cache does not exist, start locking
$lock = new PHPLock ('lock/', $key);
$lock->startLock ();
$lock->startLock ();
//Try to determine the cache Whether there is data, the cache may have been accessed and rebuilt, so there is no need to query the database again
$cache=getCache();
if(!$cache){
//Database query operation, the code is omitted
; C Setcache ($ key, $ data);
}
// Release locks
$ lock- & gt; unlock ();
$ lock- & gt; endlock ();
Analysis and research on PHP process locking problem
The above introduces bigger than bigger phplockphp process lock v10 beta1, including the content of bigger than bigger. I hope it will be helpful to friends who are interested in PHP tutorials.