Memcache::connect

(PECL memcache >= 0.2.0)

Memcache::connect — Open memcached server connection

Опис

Memcache::connect(string $host, int $port = ?, int $timeout = ?): bool

Memcache::connect() establishes a connection to the memcached server. The connection, which was opened using Memcache::connect() will be automatically closed at the end of script execution. Also you can close it with Memcache::close(). Also you can use memcache_connect() function.

Параметри

host

Point to the host where memcached is listening for connections. This parameter may also specify other transports like unix:///path/to/memcached.sock to use UNIX domain sockets, in this case port must also be set to 0.

port

Point to the port where memcached is listening for connections. Set this parameter to 0 when using UNIX domain sockets.

Please note: port defaults to memcache.default_port if not specified. For this reason it is wise to specify the port explicitly in this method call.

timeout

Value in seconds which will be used for connecting to the daemon. Think twice before changing the default value of 1 second - you can lose all the advantages of caching if your connection is too slow.

Значення, що повертаються

Повертає true у разі успіху або false в разі помилки.

Приклади

Приклад #1 Memcache::connect() example

<?php

/* procedural API */

$memcache_obj = memcache_connect('memcache_host', 11211);

/* OO API */

$memcache = new Memcache;
$memcache->connect('memcache_host', 11211);

?>

Примітки

Увага

When the port is unspecified, this method defaults to the value set of the PHP ini directive memcache.default_port If this value was changed elsewhere in your application it might lead to unexpected results: for this reason it is wise to always specify the port explicitly in this method call.

Прогляньте також

Memcache::pconnect() - Open memcached server persistent connection
Memcache::close() - Close memcached server connection

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User Contributed Notes 2 notes

down

geoffrey dot hoffman at gmail dot com ¶

14 years ago

If memcached is working, calling memcache_connect( ) returns an Object instance, not a boolean. If memcached is not working, calling memcache_connect( ) throws a notice AND a warning (and returns false as expected). 

<?php
/* memcache is running */
$test1 = memcache_connect('127.0.0.1',11211);
echo gettype($test1);
// object
echo get_class($test1);
// Memcache

/* memcached is stopped */
$test2 = memcache_connect('127.0.0.1',11211);

/*
Notice: memcache_connect(): Server 127.0.0.1 (tcp 11211) failed with: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
 (10060) in C:\Program Files\Support Tools\- on line 1

Warning: memcache_connect(): Can't connect to 127.0.0.1:11211, A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
 (10060) in C:\Program Files\Support Tools\- on line 1
*/

echo gettype($test2);
// boolean
echo $test2===false;
// 1
?>

There appears to be no way to check whether memcached is actually running without resorting to error suppression:

<?php
$test3 = @memcache_connect('127.0.0.1',11211);
if( $test3===false ){
   // memcached is _probably_ not running
}
?>

down

-4

webysther at gmail dot com ¶

10 years ago

In describing the timeout there is a statement that is not completely correct, increase the timeout does not necessarily preclude or unfeasible memcache, only allows the system to wait for more concurrent connections, which is a large minority of the number of connections, this causes several problems and could simply be corrected if the timeout was increased and perform some tests. 
To prove the concept and show that the connection does not wait if the server goes down:

<?PHP

while ( ++$loop < 10000 ) {
    try {
        $memcache = new Memcache;
        @$memcache->pconnect( "127.0.0.1" , 11211 , 30 );
        $loopset = 0;
        $loopget = 0;
        
        while ( ++$loopset < 50 ) {
            if ( @$memcache->set( "foo" , "bar" ) === false ) {
                echo "Fail!" . PHP_EOL;
            }
        }
        
        while ( ++$loopget < 500 ) {
            if ( @$memcache->get( "foo" ) === false ) {
                echo "Fail!" . PHP_EOL;
            }
        }
        
        if ( $loop % 100 == 0 ) {
            echo "Try: " . $loop . PHP_EOL;
        }
    } catch ( Exception $e ) {
        echo "Fail: " . $e->getMessage() . PHP_EOL;
    }
}

?>

Replace with an invalid host and test the timeout will not make a difference! It serves only for connections to the socket that are occupied.

More detail about troubleshooting timeouts in memcached google code.

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