Support » Plugin: W3 Total Cache » Fatal error: Call to undefined function apc_fetch

  • Resolved crashnet


    Fatal error: Call to undefined function apc_fetch() in /wp-content/plugins/w3-total-cache/lib/W3/Cache/Apc.php on line 158

    Brought down wordpress after the last upgrade was installed. Some other W3TC enabled sites on the same server running same config (but different plugins and themes) did not break.

Viewing 6 replies - 1 through 6 (of 6 total)
  • Plugin Author Frederick Townes


    To manually change engine you can edit the wp-content/w3tc-config/master.php file and change pgcache/dbcache/objectcache.engine => ‘apc’ to ‘disc’ where applicapble.

    That did not work. After I changed all 3 to disc I get a 500 and it doesn’t even get logged to the vhost or apache’s global error log.

    Also, eventhough I never before used APC caching, apc.ini is set to load but apc remains off.

    PS: I have newrelic installed.

    Plugin Author Frederick Townes


    Remove the config files in wp-content/w3tc-config/ and wp-content/cache/config, then try again. The plugin does not use APC by default so it must be set elsewhere.

    I could be a config value from your old config in wp-content so if you have no issue resetting settings you can rename the old config file for testing purposes. Its called w3-total-cache-config.php.

    I replaced every instance of ‘apc’ for ‘disc’ in all those config files and the plugin started working. I then upgraded to and this time the upgrade didnt break anything.

    I am not sure why decided to switch all caches to ‘apc’


    I faced similier issue. I just deleted the w3 cache then removed the cache directory from wp-content folder and reinstalled the w3 cahce plugin and configured again..That works for me perfectly.

Viewing 6 replies - 1 through 6 (of 6 total)
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