php memcached error

Question

Every time I try to use the add() function for memcached, I get the following error:

A PHP Error was encountered

Severity: Warning

Message: MemcachePool::add(): The lowest two bytes of the flags array is reserved for pecl/memcache internal use

Filename: libraries/memcached_library.php

Line Number: 92

What could be wrong? I'm using this library for codeigniter: http://github.com/trs21219/memcached-library

Solution 1

Are you on 64 bits? It looks like it's a recently found bug with pecl/memcache: http://pecl.php.net/bugs/bug.php?id=18567

It seems like it has to do with the compression flag. It can't be a boolean anymore, it needs to be an integer according to this source code

/**
 * The compressed argument on Memcache::add, Memcache::set and Memcache::replace takes
 * an integer not a boolean. Since pecl/memcache 3.0.3 booleans now leads to warnings like
 * The lowest two bytes of the flags array is reserved for pecl/memcache internal use
 */

Solution 2

May be it's your case: some manuals for memcache using, like http://www.codeforest.net/how-to-install-memcached-on-windows-machine, have a mistake:

$memcache->add("key", $tmp, 30);

but correct use of expiration seconds parameter (30 sec here) is:

$memcache->add("key", $tmp, MEMCACHE_COMPRESSED, 30);

or like

$memcache->add("key", $tmp, false, 30);

Sample of manual with correct example: http://zurmo.org/wiki/installing-memcache-on-windows
See also documentation http://php.net/manual/ru/memcache.add.php

For me it was the key.

Solution 3

You can add 'false' as the third parameter, it worked for me.

Warning (2): MemcachePool::add() [memcachepool.add]: The lowest two bytes of the flags array is reserved for pecl/memcache internal use

From:
return $this->memcache->add($name, $value, $expiry);

To:
return $this->memcache->add($name, $value, false, $expiry);

Solution 4

This might be helpful for some, I had downloaded a library for codeigniter that made use of memcache not memcached for sessions. It can be found here: https://github.com/pierskarsenbarg/codeigniter-session-memcached

The problem for me was that when the lib was using

memcache->set()

and/or

memcache->replace()

the third parameter was the expire time and not a valid flag type.

i.e. MEMCACHE_COMPRESSED

Example

Original Code:

$this->memcache->set('user_session_data' . $this->userdata['session_id'], $this->userdata, $this->sess_expiration); 

Changed Code:

$this->memcache->set('user_session_data' . $this->userdata['session_id'], $this->userdata, MEMCACHE_COMPRESSED, $this->sess_expiration);

After changing the third parameter to a correct flag type the error went away.

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Comments

[Matthew]

Perfect. Thanks. I changed compression from TRUE to 0 and everything works fine now.

[Victor Perov]

Yes, Memcache and Memcached methods in the PHP are differs

[FlameStorm]

You answered in fact just the same I do upper, but about codeigniter memcached feature bug. I think it's useful too - upvote.

[kta]

I was using Memcache on windows and facing the same issue. Just to repeat, 'Compression' will be the third argument if passes which need to be 0 to resolve it. Ref:php.net/manual/en/memcache.set.php