[php] ini_set("memory_limit") in PHP 5.3.3 is not working at all

I had this working before :

echo ini_get("memory_limit")."\n";
ini_set("memory_limit","256M");
echo ini_get("memory_limit")."\n";

That would input this :

32M
256M

on a php script executed by command line. I updated from 5.2 to 5.3, and from now, this directive is not working at all : this gives me :

32M
32M

and then make my script fail with a fatal Error...

I checked the php documentation, and googled it, and I didn't find anywhere that "memory_limit" had been deprecated.

Does anyone have a solution?

Ubuntu 10.04 comes with the Suhosin patch only, which does not give you configuration options. But you can install php5-suhosin to solve this:

apt-get update
apt-get install php5-suhosin

Now you can edit /etc/php5/conf.d/suhosin.ini and set:

suhosin.memory_limit = 1G

Then using ini_set will work in a script:

ini_set('memory_limit', '256M');

Let's do a test with 2 examples:

    <?php    
    $memory = (int)ini_get("memory_limit"); // Display your current value in php.ini (for example: 64M)
    echo "original memory: ".$memory."<br>";
    ini_set('memory_limit','128M'); // Try to override the memory limit for this script
    echo "new memory:".$memory;
    }
    // Will display:
    // original memory: 64
    // new memory: 64
    ?>

The above example doesn't work for overriding the memory_limit value. But This will work:

    <?php
    $memory = (int)ini_get("memory_limit"); // get the current value
    ini_set('memory_limit','128'); // override the value
    echo "original memory: ".$memory."<br>"; // echo the original value
    $new_memory = (int)ini_get("memory_limit"); // get the new value
    echo "new memory: ".$new_memory;  // echo the new value
    // Will display:
    // original memory: 64
    // new memory: 128
    ?>

You have to place the ini_set('memory_limit','128M'); at the top of the file or at least before any echo.

As for me, suhosin wasn't the solution because it doesn't even appear in my phpinfo(), but this worked:

    <?php
    ini_set('memory_limit','2048M'); // set at the top of the file
    (...)
    ?>

If you have the suhosin extension enabled, it can prevent scripts from setting the memory limit beyond what it started with or some defined cap.

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

Here's a list of things that are worth checking:

Is Suhosin installed?

• How to check whether Suhosin is installed?

ini_set

• The format is important ini_set('memory_limit', '512'); // DIDN'T WORK ini_set('memory_limit', '512MB'); // DIDN'T WORK ini_set('memory_limit', '512M'); // OK - 512MB ini_set('memory_limit', 512000000); // OK - 512MB

When an integer is used, the value is measured in bytes. Shorthand notation, as described in this FAQ, may also be used.

http://php.net/manual/en/ini.core.php#ini.memory-limit

• Has php_admin_value been used in .htaccess or virtualhost files?

Sets the value of the specified directive. This can not be used in .htaccess files. Any directive type set with php_admin_value can not be overridden by .htaccess or ini_set(). To clear a previously set value use none as the value.

http://php.net/manual/en/configuration.changes.php

Works for me, has nothing to do with PHP 5.3. Just like many such options it cannot be overriden via ini_set() when safe_mode is enabled. Check your updated php.ini (and better yet: change the memory_limit there too).