If you are new to PHP or just need to refresh your skills, this is the place to start. This series of tutorials will give you the basic knowledge you will need to create a simple PHP website.

PHP is a reflective programming language originally designed for producing dynamic web pages.[1] PHP is used mainly in server-side scripting, but can be used from a command line interface or in standalone graphical applications. Textual User Interfaces can also be created using ncurses.

PHP Manual
Prev		Next

LXXXV. Memcache Functions

Introduction

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.

More information about memcached can be found at http://www.danga.com/memcached/.

Requirements

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.

Installation

This PECL extension is not bundled with PHP. Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: 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.

Windows users will enable php_memcache.dll inside of php.ini in order to use these functions. The DLL for this PECL extension may be downloaded from either the PHP Downloads page or from http://pecl4win.php.net/

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Table 1. Memcache Configuration Options

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

For further details and definitions of the PHP_INI_* constants, see the Appendix H.

Here's a short explanation of the configuration directives.

memcache.allow_failover boolean: Whether to transparently failover to other servers on errors.
memcache.max_failover_attempts integer: Defines how many servers to try when setting and getting data. Used only in conjunction with memcache.allow_failover.
memcache.chunk_size integer: 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.
memcache.default_port string: The default TCP port number to use when connecting to the memcached server if no other port is specified.

Resource Types

There is only one resource type used in memcache module - it's the link identifier for a cache server connection.

Predefined Constants

Table 2. MemCache Constants

Name	Description
`MEMCACHE_COMPRESSED` (integer)	Used to turn on-the-fly data compression on with Memcache::set(), Memcache::add() and Memcache::replace().

Examples

Example 1. memcache extension overview example


<?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);

?>

In the above 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.

Table of Contents
Memcache::add -- Add an item to the server
Memcache::addServer -- Add a memcached server to connection pool
Memcache::close -- Close memcached server connection
Memcache::connect -- Open memcached server connection
memcache_debug -- Turn debug output on/off
Memcache::decrement -- Decrement item's value
Memcache::delete -- Delete item from the server
Memcache::flush -- Flush all existing items at the server
Memcache::get -- Retrieve item from the server
Memcache::getExtendedStats -- Get statistics from all servers in pool
Memcache::getServerStatus -- Returns server status
Memcache::getStats -- Get statistics of the server
Memcache::getVersion -- Return version of the server
Memcache::increment -- Increment item's value
Memcache::pconnect -- Open memcached server persistent connection
Memcache::replace -- Replace value of the existing item
Memcache::set -- Store data at the server
Memcache::setCompressThreshold -- Enable automatic compression of large values
Memcache::setServerParams -- Changes server parameters and status at runtime

Prev	Home	Next
m_verifysslcert	Up	Memcache::add

You Are At PHP: Memcache Functions - Manual Area