PHP Fatal error: Allowed memory size exhausted

What the message looks like

PHP Fatal error:  Allowed memory size of 134217728 bytes exhausted (tried to allocate 20480 bytes) in /var/www/html/wp-includes/class-wp-image-editor-imagick.php on line 612

Common causes

• memory_limit is too low for the task: resizing large images, a big import, Composer, a heavy plugin.
• A loop or a query loads far too much data into memory at once.
• A memory leak in a long-running script or worker.
• The limit was raised in the wrong php.ini: the CLI and PHP-FPM read different files.
• A hosting panel or pool setting overrides the global value.

Check

1. Which php.ini does the command line use, and what is the limit?
   php --ini; php -r 'echo ini_get("memory_limit"), PHP_EOL;'Copy
2. Where is memory_limit set for FPM?
   grep -rn 'memory_limit' /etc/php/*/fpm/Copy
3. Which line failed? Read the log
   grep -i 'memory size' /var/log/nginx/error.log /var/log/php8.3-fpm.log | tail -n 10Copy

Fix

• Raise the limit in the file PHP-FPM uses, for example memory_limit = 512M in /etc/php/8.3/fpm/php.ini, then systemctl reload php8.3-fpm.
• Per pool, set php_admin_value[memory_limit] = 512M in the pool file.
• On a panel such as Plesk, change the value in the domain's PHP settings.
• For Composer, run COMPOSER_MEMORY_LIMIT=-1 composer install once.
• If the script keeps growing, fix the cause: process data in chunks, free large variables, avoid loading whole tables.

FAQ

Is memory_limit = -1 (unlimited) a good idea?

Not for web requests. One broken request can then use all RAM and bring the server down. Use a fixed value, large enough for your biggest legitimate task.

I changed php.ini but nothing happened.

Most likely you edited the CLI file, or PHP-FPM was not reloaded. Check which file is loaded and reload the service.