What Is Causing "Unable to Allocate Memory For Pool" in PHP

What is causing Unable to allocate memory for pool in PHP?

Probably is APC related.

For the people having this problem, please specify you .ini settings. Specifically your apc.mmap_file_mask setting.

For file-backed mmap, it should be set to something like:

apc.mmap_file_mask=/tmp/apc.XXXXXX

To mmap directly from /dev/zero, use:

apc.mmap_file_mask=/dev/zero

For POSIX-compliant shared-memory-backed mmap, use:

apc.mmap_file_mask=/apc.shm.XXXXXX

Symfony Unable to allocate memory for pool

This error is usually related to Alternative PHP Cache (APC) related which is a free and open opcode cache for PHP. Its goal is to provide a free, open, and robust framework for caching and optimizing PHP intermediate code. Edit /etc/php.d/apc.ini, enter:

# vi /etc/php.d/apc.ini

Make sure the mktemp-style file_mask to pass to the mmap module is correct and valid one:

apc.mmap_file_mask=/tmp/apc.XXXXXX

Next make sure the size of each shared memory segment, with M/G suffix is set correct as per your requirements. In my case it was set to 8M:

apc.shm_size=96M

You need to adjust the number of seconds a cache entry is allowed to idle in a slot in case this cache entry slot is needed by another entry:

apc.ttl=3600

The number of seconds a user cache entry is allowed to idle in a slot in case this cache entry slot is needed by another entry:

apc.user_ttl=3600

The number of seconds that a cache entry may remain on the garbage-collection list.

Save and close the file. Make sure you adjust the values as per your requirements. Restart the Apache 2 web server:

# service httpd restart

Hide error unable to allocate memory for pool

You can hide the PHP error messages by setting the environment in index.php to testing or production. This turns off all PHP error reporting.

define('ENVIRONMENT', 'production');

The templates for the error messages are in application/errors - you can change the appearance of the messages here.

require_once: cannot allocate memory

It turns out this was a problem with my windows share. Perhaps because Windows 7 is a client OS, it is not tuned to serve large amounts of files frequently (which is happening in my case).

To fix, set the following keys in the registry:

HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache to 1

HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\Size to 3

I have been running my setup with these new settings for about a week and have not encountered any memory allocation errors since making the change.

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