Memcached::addServers

(PECL memcached >= 0.1.1)

Memcached::addServersAdiciona múltiplos servidores ao pool de servidores

Descrição

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

Memcached::addServers() adiciona servidores ao pool de servers. Cada entrada em servers deve ser um array contendo hostname, porta e, opcionalmente, o peso do servidor. Nenhuma conexão é estabelecida com os servidores neste momento.

O mesmo servidor pode aparecer várias vezes no pool de servidores porque nenhuma verificação de duplicação é feita. Isso não é aconselhável; em vez disso, use a opção weight para aumentar o peso da seleção desse servidor.

Parâmetros

array

Array dos servidores a serem adicionados ao pool.

Valor Retornado

Retorna true em caso de sucesso ou false em caso de falha.

Exemplos

Exemplo #1 Memcached::addServers() example

<?php
$m
= new Memcached();

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

Veja Também

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User Contributed Notes 2 notes

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2
Michael Brenden
11 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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2
Aliaser
6 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
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