PHP Memory Limit

I ran into this issue today, while dealing with operations on a 20MB JSON string in a PHP application I was building.

The server responded with 500 internal server error, and the message was:

Allowed memory size of 134217728 bytes exhausted

What in tarnation is this???

I found out that the php.ini file has a memory_limit config variable, and mine was set to 128MB, which is 134217728 bytes.

Somehow, my code was using more than the allowed 128MB, which was kinda expected because 20MB JSON string, duh.

Set memory limit in php.ini

I found you could increase this by setting the value in the php.ini file, so I did this.

php --ini #shows you the location of the file
nano /usr/local/etc/php/7.1/php.ini

I changed the value of memory_limit to 512MB, and it worked.

Set it at runtime

However, I later saw that you could set the value within your PHP code at runtime by:

ini_set('memory_limit', '512MB');

Also, that you could remove the limit by setting the value to -1, which is dope because you’re not restricting the server anymore.

Eat your cake and have it

I decided to try removing the limit just before the heavy work starts, and replacing it after it ends.

$limit = ini_get('memory_limit'); // retrieve the set limit
ini_set('memory_limit', -1); // remove memory limit
// do heavy work
ini_set('memory_limit', $limit);

and there we go … works beautifully!