Persistant connexion never close about cache-bundle

[cryptiklemur]

Do you see any issues with the way its set up to work right now? In the ServiceBuilder class, im setting the first arg of Memcached to a serialized string of the hosts

[faboo03]

I saw that and for me there is no clear mistake on your code, I would have done a pull request otherwise. More research brought me to some people saying that some issues exist with php itself (see comments : http://www.php.net/manual/en/memcached.construct.php).

[cryptiklemur]

Ahh, well that pinpoints it for me. Its adding the servers every time, even if they are already in the list. Not sure how to do a getServerList with the definitions...

[cryptiklemur]

253eede

Does this take care of it? If it does, I'll tag it

[faboo03]

No, doesn't change anything... after 4 refresh I got 200 openned connections with persistent param and maximum 10 without...

[cryptiklemur]

@faboo03 i cant really seem to find anything that fixes this issue...

[cordoval]

hmm weird issue, can someone explain to me please how to replicate it? step by step

[faboo03]

My config is : Ubuntu Desktop 13.04, PHP 5.3.3 with memcached and php-memcached.
I am using the last SF 2.3.
My file config.yml :

aequasi_cache:
    instances:
        default:
            persistent: true #turning it false, solve the problem
            namespace: %app.cache_prefix%
            type: memcached
            hosts:
              - { host: %memcache_host%, port: %memcache_port%, weight: 100 }
    doctrine:
        enabled: true
        result:
            instance: default
            entity_managers: [ default ]
        query:
            instance: default
            entity_managers: [ default ]

Now when I get some pages I check for current_connection using : telnet localhost:11211 and the command stats and I see a crazy number increasing to the crash of my local server.

If you need more informations, don't hesitate !

[cordoval]

have you tried to upgrade your php?

[faboo03]

I have the same problem on my local, inte, preprod and prod env.
They have different configurations and I don't have access on the preprod and prod env. I don't think it's a problem with PHP. I have an access on a php5.4 env, I am trying right now and keep you updated.

[faboo03]

same problem with php5.4...

[ccMatrix]

We experienced this issue after upgrading to a version 253eede and later.

After a rollback to 2.1.5 the servers went back to normal.

We are not using persistent connections since that also leads to the connection increase issue without connections getting closed.

[cryptiklemur]

@ccMatrix rolling back to before that commit should actually give you the issue of your server list being filled with duplicate servers... I'm not really seeing anything in that commit that would cause the connection issue..

[ccMatrix]

I just checked the two tagged versions. I will go through it commit by commit to pinpoint the exact source of the problem.

[ccMatrix]

I found it. In 7186301 you updated the way you instantiate the classes. There you just check for isset on the persistent key. So persistent = false is handled just like persistent = true. This lead to our connection issues.

[cryptiklemur]

K, fixed that in d92144a

[cdaguerre]

I have the same problem.
d92144a doesn't seem to fix the issue for unclosed connections when using persistent connections.
Don't ask me why, but it seems that setting Memcached::OPT_TCP_NODELAY to true fixes the problem.

[cryptiklemur]

@ccMatrix @faboo03, does setting Memcached::OPT_TCP_NODELAY to true do anything for you guys?

[cdaguerre]

Sorry, I got confused. Actually, the problem was not solved by the Memcached::OPT_TCP_NODELAY setting.

The problem is that since v2.1, Memcached::getServerList() does not return the weight of the server anymore as it's not allowed by the Api (refer https://github.com/php-memcached-dev/php-memcached/blob/master/php_memcached.c#L2943). Php documentation is outdated.
Hence, we are still experiencing the problem of servers being added on every script call, although we only notice it when using persistent connections.
Simply removing the weight key in Aequasi\Bundle\CacheBundle\Cache\Memcached::addServer() when iterating over existing servers solves the problem.

In addition, IMO the persistent connection id should be set through a config var rather than a serialized hosts array for the following reasons:
1/ persistent_id should be short as it infringes on maximum key length.
2/ you could want to use same servers and different connection ids wether in dev or prod env and you don't necessarily want your id to change whenever you add or remove a server or change server weight
I think the persistent config var could accept boolean and string values in order not to break BC.

I'd be glad to help if you want.

[cryptiklemur]

@cdaguerre go for it :) I don't remember where I saw it, but the suggestion was to use a serialized array of the hosts. I definitely agree with your points though 👍