How to clear APC cache entries?

Question

You can use the PHP function apc_clear_cache.

Calling apc_clear_cache() will clear the system cache and calling apc_clear_cache('user') will clear the user cache.

I don't believe any of these answers actually work for clearing the APC cache from the command line. As Frank Farmer commented above, the CLI runs in a process separate from Apache.

My solution for clearing from the command line was to write a script that copies an APC clearing script to the web directory and accesses it and then deletes it. The script is restricted to being accessed from the localhost.

1. apc_clear.php

   This is the file that the script copies to the web directory, accesses, and deletes.

   <?php
   if (in_array(@$_SERVER['REMOTE_ADDR'], array('127.0.0.1', '::1')))
   {
     apc_clear_cache();
     apc_clear_cache('user');
     apc_clear_cache('opcode');
     echo json_encode(array('success' => true));
   }
   else
   {
     die('SUPER TOP SECRET');
   }
   

2. Cache clearing script

   This script copies apc_clear.php to the web directory, accesses it, then deletes it. This is based off of a Symfony task. In the Symfony version, calls are made to the Symfony form of copy and unlink, which handle errors. You may want to add checks that they succeed.

   copy($apcPaths['data'], $apcPaths['web']); //'data' is a non web accessable directory
   
   $url = 'http://localhost/apc_clear.php'; //use domain name as necessary
   $result = json_decode(file_get_contents($url));
   
   if (isset($result['success']) && $result['success'])
   {
     //handle success
   }
   else
   {
     //handle failure
   }
   
   unlink($apcPaths['web']);
   

I know it's not for everyone but: why not to do a graceful Apache restart?

For e.g. in case of Centos/RedHat Linux:

sudo service httpd graceful

Ubuntu:

sudo service apache2 graceful

This is not stated in the documentation, but to clear the opcode cache you must do:

apc_clear_cache('opcode');

EDIT: This seems to only apply to some older versions of APC..

No matter what version you are using you can't clear mod_php or fastcgi APC cache from a php cli script since the cli script will run from a different process as mod_php or fastcgi. You must call apc_clear_cache() from within the process (or child process) which you want to clear the cache for. Using curl to run a simple php script is one such approach.

If you are running on an NGINX / PHP-FPM stack, your best bet is to probably just reload php-fpm

service php-fpm reload (or whatever your reload command may be on your system)

If you want to clear apc cache in command : (use sudo if you need it)

APCu

php -r "apcu_clear_cache();" 

APC

php -r "apc_clear_cache(); apc_clear_cache('user'); apc_clear_cache('opcode');"