The PHP variable "max_input_vars" was introduced in PHP 5.3.9+ as a security measure to limit the maximum amount of POST variables submitted, by default this limit is set to 1000.
In the Apache error log you will see an error like this:
"PHP Warning: Unknown: Input variables exceeded 1000. To increase the limit change max_input_vars in php.ini."
To resolve, the default value can be increased as per below.
Create or update your .htaccess file and add the following line:
php_value max_input_vars 3000
Note: Your hosting provider may not allow this to be overridden, if this doesn't work then please check with your provider.
There are two ways to achieve this, depending on how many sites you wish to enable it for. The first method is per-site, which means that the setting remains if you migrate the site to a new server. The second is per server, meaning the setting will be applied for all sites.
In Plesk under the tab "Website & Domains" > PHP Settings > add the below to the field "Additional Configuration Directives":
max_input_vars = 3000Note: The field "Additional configuration directives" in Plesk is only available to the Plesk Panel Administrator.
SSH to VPS and add the below to /etc/php.ini:
- Restart Apache to apply.