Memcached::getServerByKey

    (PECL memcached >= 0.1.0)

    Memcached::getServerByKey — Map a key to a server

    Descrizione

    public Memcached::getServerByKey(string $server_key): array|false

    Memcached::getServerByKey() returns the server that would be selected by a particular server_key in all the Memcached::*ByKey() operations.

    Elenco dei parametri

    server_key

    La chiave che identifica il server su cui salvare il valore. Invece di effettuare li'hashing sulla chiave dell'elemento, si effettua l'hashing della chiave del server al momento di decidere con quale server memcached comunicare. Questo permette di raggruppare gli elementi correlati ad un singolo server ottenendo maggiore efficienza nelle operazioni multiple.

    Valori restituiti

    Returns an array containing three keys of host, port, and weight on success o false in caso di fallimento. Utilizzare Memcached:getResultCode() se necessario.

    Esempi

    Example #1 Memcached::getServerByKey() example

    <?php
    $m     = new Memcached();
    $m->addServers(array(
    array(    'mem1.domain.com', 11211, 40),
    array(    'mem2.domain.com', 11211, 40),
    array(    'mem3.domain.com', 11211, 20),
    ));

    $m->setOption(Memcached::OPT_LIBKETAMA_COMPATIBLE, true);

    var_dump($m->getServerByKey('user'));
    var_dump($m->getServerByKey('log'));
    var_dump($m->getServerByKey('ip'));
    ?>

    Il precedente esempio visualizzerà qualcosa simile a:

    array(3) {
  ["host"]=>
  string(15) "mem3.domain.com"
  ["port"]=>
  int(11211)
  ["weight"]=>
  int(20)
}
array(3) {
  ["host"]=>
  string(15) "mem2.domain.com"
  ["port"]=>
  int(11211)
  ["weight"]=>
  int(40)
}
array(3) {
  ["host"]=>
  string(15) "mem2.domain.com"
  ["port"]=>
  int(11211)
  ["weight"]=>
  int(40)
}

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    User Contributed Notes 2 notes

    up
    5
    zhaoyong dot lc at gmail dot com
    11 years ago
    The parameter server_key is very confusing, it's not a server key for MemCached Server, but it's key,in key-value pair which you stored in server.

    <?php
    $m     = new Memcached;
    $m->addServers(array(
    array(    '127.0.0.1',11212),
    array(    '127.0.0.1',11211)
    ));
    for(    $i=0;$i<10;$i++){
    $key = 'key_'.$i;
    $m->add($key, 1);
    }
    for(    $i=0;$i<10;$i++) {
    $key = 'key_'.$i;
    $arr = $m->getServerByKey($key);
    echo (    $key.":\t".$arr['port']."\n");
    }
    ?>

    key_0: 11212
    key_1: 11211
    key_2: 11212
    key_3: 11212
    key_4: 11212
    key_5: 11211
    key_6: 11211
    key_7: 11212
    key_8: 11212
    key_9: 11211
    up
    1
    morphles
    8 years ago
    Just to clarify (as documentation of memcached, even for C lib, frankly is quite lacking), $server_key is hashed using same method as regular keys for values (I checked C source, as again docs......). So you should be able to see where set($key, $value) goes by using getServerByKey($key) with same key. This can be useful if one does not wish to bother with using/has no need to use *ByKey functions, but still want to know which servers are/should be used with regular keys, for implementing fallback or failure reporting.
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