Memcache module provides handy procedural and object oriented interface to memcached, highly effective caching daemon, which was especially designed to decrease database load in dynamic web applications.
The Memcache module also provides a session handler (memcache).
More information about memcached can be found at » http://www.danga.com/memcached/.
This module uses functions of » zlib to support on-the-fly data compression. Zlib is required to install this module.
PHP 4.3.3 or newer is required to use the memcache extension.
Esta extension » PECL no esta ligada a PHP. Mas informacion sobre nuevos lanzamientos, descargas ficheros de fuentes, informacion sobre los responsables asi como un 'CHANGELOG', se puede encontrar aqui: » http://pecl.php.net/package/memcache.
In order to use these functions you must compile PHP with Memcache support by using the --enable-memcache[=DIR] option. You may optionally disable memcache session handler support by specifying --disable-memcache-session.
Windows users will enable php_memcache.dll inside of php.ini in order to use these functions. Podeis descargar esta DLL de las extensiones PECL desde la pagina » PHP Downloads o desde » http://snaps.php.net/.
El comportamiento de estas funciones está afectado por los valores definidos en php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| memcache.allow_failover | "1" | PHP_INI_ALL | Available since memcache 2.0.2. |
| memcache.max_failover_attempts | "20" | PHP_INI_ALL | Available since memcache 2.1.0. |
| memcache.chunk_size | "8192" | PHP_INI_ALL | Available since memcache 2.0.2. |
| memcache.default_port | "11211" | PHP_INI_ALL | Available since memcache 2.0.2. |
| memcache.hash_strategy | "standard" | PHP_INI_ALL | Available since memcache 2.2.0. |
| memcache.hash_function | "crc32" | PHP_INI_ALL | Available since memcache 2.2.0. |
| session.save_handler | "files" | PHP_INI_ALL | Supported since memcache 2.1.2 |
| session.save_path | "" | PHP_INI_ALL | Supported since memcache 2.1.2 |
A continuación se presenta una corta explicación de las directivas de configuración.
Whether to transparently failover to other servers on errors.
Defines how many servers to try when setting and getting data. Used only in conjunction with memcache.allow_failover.
Data will be transferred in chunks of this size, setting the value lower requires more network writes. Try increasing this value to 32768 if noticing otherwise inexplicable slowdowns.
The default TCP port number to use when connecting to the memcached server if no other port is specified.
Controls which strategy to use when mapping keys to servers. Set this value to consistent to enable consistent hashing which allows servers to be added or removed from the pool without causing keys to be remapped. Setting this value to standard results in the old strategy being used.
Controls which hash function to apply when mapping keys to servers, crc32 uses the standard CRC32 hash while fnv uses FNV-1a.
Use memcache as a session handler by setting this value to memcache.
Defines a comma separated of server urls to use for session storage, for example "tcp://host1:11211, tcp://host2:11211".
Each url may contain parameters which are applied to that server, they are the same as for the Memcache::addServer() method. For example "tcp://host1:11211?persistent=1&weight=1&timeout=1&retry_interval=15"
There is only one resource type used in memcache module - it's the link identifier for a cache server connection.
| Name | Description |
|---|---|
| MEMCACHE_COMPRESSED (integer) | Used to turn on-the-fly data compression on with Memcache::set(), Memcache::add(), y Memcache::replace(). |
| MEMCACHE_HAVE_SESSION (integer) | 1 if this Memcache session handler is available, 0 otherwise. |
Example#1 memcache extension overview example
In this example, an object is being saved in the cache and then retrieved back. Object and other non-scalar types are serialized before saving, so it's impossible to store resources (i.e. connection identifiers and others) in the cache.
<?php
$memcache = new Memcache;
$memcache->connect('localhost', 11211) or die ("Could not connect");
$version = $memcache->getVersion();
echo "Server's version: ".$version."<br/>\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)<br/>\n";
$get_result = $memcache->get('key');
echo "Data from the cache:<br/>\n";
var_dump($get_result);
?>
Example#2 Using memcache session handler
<?php
$session_save_path = "tcp://$host:$port?persistent=1&weight=2&timeout=2&retry_interval=10, ,tcp://$host:$port ";
ini_set('session.save_handler', 'memcache');
ini_set('session.save_path', $session_save_path);
?>