Magento – PHP memory limit, Magento 2.3

The official system requirements (or rather: recommendations) are:

Increase the PHP memory limit to at least 768MB for normal operation or 2GB for testing.

^{Source: Recommendations for CentOS and Ubuntu}

I would only increase it to a higher value if you encounter problems where the memory limit is hit. Then debug and fix these problems, and set the memory limit back to normal when successful.

2 things you need to remember:

• memory limit is set in basic php.ini file, most often in location like /etc/php/X.X/fpm/php.ini and /etc/php/X.X/cli/php.ini (this varies depending on the system and whether you use php as a service or not). Those settings also tells php whether you can override those default values with your custom ones in php.ini file in your document root folder.

• as you noticed above there are 2 paths for php.ini. If you use php-fpm then you have 2 independent settings for php run via apache/nginx as a response to http request and another set of settings for scripts run from the console (ie. bin/magento or composer).

Now if your system tells you memory limit is 128M then it does not lie. Either your default settings forbids you from settings memory limit in project folder or vhost settings points not to the file you are using to change the settings.