PHP : settings memory_limits > 1024M does not work

Question

For bads reasons I need to set memory_limits higher than 1G for a directory, but on my PHP 5.2.17 on Lenny server when I put for example 2048M I get only the php.ini default

Answer 1

ini_set("memory_limit",-1);

This should normally remove limits

Answer 2

The limit of

ini_set('memory_limit', '4095M'); // 4 GBs minus 1 MB 

is related to Operating System, with 32bit OS you must to use this maximum limit.

I resolved an issue memory_limit today using this workaround.

Using a higher limit PHP have strange behaviour, it returns exhausted memory in some public non static method class when class was instanced, but putting a die() in the __construct method (to test the problem)

Answer 3

How are you trying to set the memory limit? phpinfo() shows current PHP reserved memory limit, this is what is available due to php.ini having that set as a memory limit

Writing this to Apache .htaccess in your script directory might work, if your server supports setting PHP commands through .htaccess:

php_value memory_limit 2048M

Since it may be possible that .htaccess commands for setting PHP values are turned off. Then you can also try this from PHP code:

ini_set('memory_limit', '2048M');

If this doesn't work and .htaccess also doesn't work, then you need to contact server administrators.

Answer 4

As describe here : http://www.hardened-php.net/suhosin/configuration.html#suhosin.memory_limit

Suhosin will not let you set a value greater than the one the script started with.

If you set the suhosin.memory_limit to 2048M then you'll be able to increase your memory usage.

Answer 5

I had this same issue where I needed my PHP script to use 4 GBs of RAM. The reason doesn't matter. The goal was to set a 4 GB limit in PHP.

The initial idea was to use ini_set('memory_limit', '4096M'); but I found that this didn't work. I have no idea how or why to be honest, but that wasn't important to me at the time. I'm on a system with 32 GBs of RAM, it has to be possible.

I found that setting a limit 1 MB less acually worked, it's a solution that worked for me.

ini_set('memory_limit', '4095M'); // 4 GBs minus 1 MB

Edit Nov '16: Actually, I've never really played with it before but I've noticed on my system that this value seems to completely remove all memory limits for me. I'm able to use as much RAM as my system possibly provides.