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By Alex on Oct 6, 2008 | Reply

I followed this guide step by step but I can’t store my sessions in memcached. The memcache module is configured (appears in php_info()) but when I try to do a session_start this fails.

By Joao Alfredo on Dec 5, 2008 | Reply

Hello Guillaume,

I was looking for something like memcached to use it with php_sessions.

It looks amazing!

But some doubts arose and I think you can help me.

Do you know if its possible to have control over the sessions in memcached ?

Like to know the number of sessions and the possibilite to kill a session.

Thanks.

By Ruben Vandille on Dec 12, 2008 | Reply

The same considerations are valid for other save_handler settings … the default ‘file’ handler for example:

$dh = @opendir(ini_get(’session.save_path’));
while (false !== ($file = readdir($dh))) {
if (strstr($file, ’sess_’)) {
@unlink(unlink(ini_get(’session.save_path’) . “/$file”));
}
}

By Son on Dec 14, 2008 | Reply

Like Alex, I am not able to get the memcache to work with my session handler. I am currently running two VM’s. One for the memcache and one for the Front-end server. Both VM’s are running Debian Etch with Apache, and php5-memcache installed.

The MemCached VM is located at xxx.xxx.xx.xxx and running on port 11211.

On my front-end server, I have set the session handler in php.ini as below:

session.save_handler = memcache
session.save_path = “tcp://xxx.xxx.xx.xxx:11211″

When I run session_start(), I get the following warning: “Warning: session_start() [function.session-start]: Cannot find save handler memcache”.

Does anyone have any idea why this is happening? Your help is greatly appreciated.

By Son on Dec 14, 2008 | Reply

In addition to my last post:

Strange thing is that it works fine when I use the php’s MemCache api’s.

For example, from my front-end server, I am able to run the following code without any problems:

$memcache = new Memcache;
$memcache->connect(’xxx.xxx.xx.xxx’, 11211) or die (”Could not connect”);

$version = $memcache->getVersion();
echo “Server’s version: “.$version.”\n”;

$tmp_object = new stdClass;
$tmp_object->str_attr = ‘test’;
$tmp_object->int_attr = 123;

$memcache->set(’key’, $tmp_object, false, 5000) or die (”Failed to save data at the server”);
echo “Store data in the cache (data will expire in 10 seconds)\n”;

$get_result = $memcache->get(’key’);
echo “Data from the cache:\n”;

var_dump($get_result);

By Son on Dec 14, 2008 | Reply

Hi Guillaume,

Thanks for the quick reply. At the moment, the VM’s are not in a public domain. Nonetheless, below is the phpinfo that pertains to memcache:

System Linux fe1 2.6.18-6-amd64 #1 SMP Wed Oct 15 10:07:11 UTC 2008 x86_64
Build Date Sep 30 2008 18:29:09
Server API Apache 2.0 Handler
Virtual Directory Support disabled
Configuration File (php.ini) Path /etc/php5/apache2/php.ini
Scan this dir for additional .ini files /etc/php5/apache2/conf.d
additional .ini files parsed /etc/php5/apache2/conf.d/mysql.ini, /etc/php5/apache2/conf.d/mysqli.ini, /etc/php5/apache2/conf.d/pdo.ini, /etc/php5/apache2/conf.d/pdo_mysql.ini
PHP API 20041225
PHP Extension 20060613
Zend Extension 220060519
Debug Build no
Thread Safety disabled
Zend Memory Manager enabled
IPv6 Support enabled
Registered PHP Streams zip
Registered Stream Socket Transports tcp, udp, unix, udg, ssl, sslv3, sslv2, tls
Registered Stream Filters string.rot13, string.toupper, string.tolower, string.strip_tags, convert.*, consumed, convert.iconv.*, bzip2.*, zlib.*

apache2handler
Apache Version Apache/2.2.3 (Debian) mod_python/3.2.10 Python/2.4.4 PHP/5.2.0-8+etch13 mod_perl/2.0.2 Perl/v5.8.8
Apache API Version 20051115
Server Administrator webmaster@local.sandbox
Hostname:Port local.sandbox:0
User/Group www-data(33)/33
Max Requests Per Child: 0 – Keep Alive: on – Max Per Connection: 100
Timeouts Connection: 300 – Keep-Alive: 15
Virtual Server Yes
Server Root /etc/apache2
Loaded Modules core mod_log_config mod_logio prefork http_core mod_so mod_alias mod_auth_basic mod_authn_file mod_authz_default mod_authz_groupfile mod_authz_host mod_authz_user mod_autoindex mod_cache mod_cgi mod_dir mod_env mod_mem_cache mod_mime mod_python mod_negotiation mod_perl mod_php5 mod_rewrite mod_setenvif mod_status

memcache
memcache support enabled
Active persistent connections 0
Revision $Revision: 1.39 $

session
Session Support enabled
Registered save handlers files user
Registered serializer handlers php php_binary wddx

Directive Local Value Master Value
session.auto_start Off Off
session.bug_compat_42 On On
session.bug_compat_warn On On
session.cache_expire 180 180
session.cache_limiter nocache nocache
session.cookie_domain no value no value
session.cookie_httponly Off Off
session.cookie_lifetime 0 0
session.cookie_path / /
session.cookie_secure Off Off
session.entropy_file no value no value
session.entropy_length 0 0
session.gc_divisor 100 100
session.gc_maxlifetime 1440 1440
session.gc_probability 0 0
session.hash_bits_per_character 4 4
session.hash_function 0 0
session.name PHPSESSID PHPSESSID
session.referer_check no value no value
session.save_handler memcache memcache
session.save_path tcp://xxx.xxx.xx.xxx:11211 tcp://xxx.xxx.xx.xxx:11211
session.serialize_handler php php
session.use_cookies On On
session.use_only_cookies Off Off
session.use_trans_sid 0 0

Thanks in advance!

By Son on Dec 17, 2008 | Reply

Thanks. I’ll look into this.

By Son on Dec 17, 2008 | Reply

Guillaume,

I followed your steps and still, I am getting the same results.

Any idea?

-Son

By Lewis Carr on Jan 18, 2009 | Reply

Check that there is only 1 session save path, I had 2 in my php.ini and this caused the problem.

By Laph on May 8, 2009 | Reply

An important side-note: Debian cleans up sessions using a cron job – and therefore disables PHP’s internal session cleanup by setting “session.gc_probability” to 0 (zero). You should set this to something > 0 when using memcached as session storage.

By Lazy on Jun 1, 2009 | Reply

@Laph you shouldn’t set touch that, each record in memcached has its ttl, when it’s reached object is automagicly removed from cache so php has no garbage to collect