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
Memcached::getServerByKey
(PECL memcached >= 0.1.0)
Memcached::getServerByKey — Map a key to a server
Descrierea
public Memcached::getServerByKey
( string
$server_key
) : array
Memcached::getServerByKey() returns the server that
would be selected by a particular server_key in all
the Memcached::*ByKey() operations.
Parametri
-
server_key -
Cheia ce identifică serverul pe care se înscrie, sau de pe care se citește valoarea. În loc de a efectua hash asupra cheii nemijlocite a elementului, se efectuaează hash asupra cheii serverului, atunci când se decide cu care server memcached să se comunice. Aceasta permite ca elementele asociate să fie grupate împreună pe un singur server pentru a mări eficiența operațiilor multiple.
Valorile întoarse
Returns an array containing three keys of host,
port, and weight on success or false
on failure.
Utilizați
Memcached::getResultCode()
dacă e necesar.
Exemple
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'));
?>
Exemplul de mai sus va afișa ceva similar cu:
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)
}
add a note
User Contributed Notes 2 notes
zhaoyong dot lc at gmail dot com ¶
11 years ago
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.
