Memcached::addServers

(PECL memcached >= 0.1.1)

Memcached::addServers — Añadir varios servidores a la agrupación de servidores

Descripción

public Memcached::addServers(array $servers): bool

Memcached::addServers() añade servers a la agrupación de servidores. Cada entrada de servers debe ser un array que contenga el nombre de host, el puerto y, opcionalmente, el peso (importancia) del servidor. No se establecerá ninguna conexión a los servidores en este proceso.

El mismo servidor podría aparecer varias veces en la agrupación de servidores, debido a que no se realiza ninguna comprobación de duplicados. Esta característica no es aconsejable; emplee en su lugar la opción weight para aumentar el peso de selección (importancia) de dicho servidor.

Parámetros

array: Array de servidores a añadir a la agrupación de servidores.

Valores devueltos

Devuelve true en caso de éxito o false en caso de error.

Ejemplos

Ejemplo #1 Ejemplo de Memcached::addServers()

<?php
$m = new Memcached();

$servidores = array(
    array('mem1.dominio.com', 11211, 33),
    array('mem2.dominio.com', 11211, 67)
);
$m->addServers($servidores);
?>

Ver también

Memcached::addServer() - Añade un servidor a la provisión de servidores
Memcached::resetServerList() - Limpia todos los servidores de la lista de servidores

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User Contributed Notes 2 notes

down

Aliaser ¶

8 years ago

For a proper FailOver mechanism:

$memcached = new Memcached();
$memcached->setOption(Memcached::OPT_CONNECT_TIMEOUT, 10);
$memcached->setOption(Memcached::OPT_DISTRIBUTION, Memcached::DISTRIBUTION_CONSISTENT);
$memcached->setOption(Memcached::OPT_SERVER_FAILURE_LIMIT, 2);
$memcached->setOption(Memcached::OPT_REMOVE_FAILED_SERVERS, true);
$memcached->setOption(Memcached::OPT_RETRY_TIMEOUT, 1);
$memcached->addServers($servers);

Memcached::OPT_DISTRIBUTION: set it to consistent hashing. If one memcached node is dead, its keys (and only its keys) will be evenly distributed to other nodes. This is where the magic is done. This is really different from removing one server in your ->addServers() call.

Memcached::OPT_SERVER_FAILURE_LIMIT: number of connection issues before a server is marked as DEAD, and removed from the list of servers (default: 5).

Memcached::OPT_REMOVE_FAILED_SERVERS: set it to «true», to enable the removal of dead servers.

Memcached::OPT_RETRY_TIMEOUT: after a node is declared DEAD, libmemcached will try it again after that many seconds. Here I've set it to 1 second, but I'm working on PHP scripts that run for less than 100ms most of the time. That would only be useful for cron/daemonize scripts.

Memcached::OPT_CONNECT_TIMEOUT: the timeout after which a server is considered DEAD. As my servers are on the same LAN, ping is ~0.5ms, so 10ms is large enough to consider the server is DEAD. Note that you have to wait twice that time before a node is marked DEAD, so if it's 1000ms, your script will lock for 2 seconds before ignoring the DEAD server. That may affect your response times a lot, and that's why I've set it very low

Author of this is Yvan from Dugwood

down

Michael Brenden ¶

13 years ago

See the note for __construct()

Important to not call ->addServers() every run -- only call it if no servers exist (check getServerList() ); otherwise, since addServers() does not check for dups, it will let you add the same server again and again and again, resultings in hundreds if not thousands of connections to the MC daemon.

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