On one of my ultra-high traffic web servers, I switched from eAccelerator to APC today (an opcode/caching system for PHP). So far it seems pretty nice… Especially the ability to disable stat for each PHP request.

I ended up making a datastore class for vBulletin also so I could use it for the forum, so if anyone else is using vBulletin on a server with APC, here you go (if you know what this is for, you will know where it goes :) ).

[code=php]// #############################################################################
// APC

/**
* Class for fetching and initializing the vBulletin datastore from APC
*
* @package vBulletin
* @version $Revision: 0.0.0.1 $
* @date $Date: 2006/05/08 16:51:06 $
*/
class vB_Datastore_APC extends vB_Datastore
{
/**
* Fetches the contents of the datastore from APC
*
* @param array Array of items to fetch from the datastore
*
* @return void
*/
function fetch($itemarray)
{
if (!function_exists('apc_fetch'))
{
trigger_error('APC not installed', E_USER_ERROR);
}

foreach ($this->defaultitems AS $item)
{
$this->do_fetch($item);
}

if (is_array($itemarray))
{
foreach ($itemarray AS $item)
{
$this->do_fetch($item);
}
}

$this->check_options();

// set the version number variable
$this->registry->versionnumber =& $this->registry->options['templateversion'];
}

/**
* Fetches the data from shared memory and detects errors
*
* @param string title of the datastore item
*
* @return void
*/
function do_fetch($title)
{
$ptitle = $this->prefix . $title;

if (($data = apc_fetch($ptitle)) === false)
{ // appears its not there, lets grab the data and put it in memory
$data = '';
if ($dataitem = $this->dbobject->query_first("
SELECT title, data FROM " . TABLE_PREFIX . "datastore
WHERE title = '" . $this->dbobject->escape_string($title) ."'
"))
{
$data =& $dataitem['data'];
}
$this->build($title, $data);
}
$this->register($title, $data);
}

/**
* Updates the appropriate cache file
*
* @param string title of the datastore item
*
* @return void
*/
function build($title, $data)
{
$title = $this->prefix . $title;

if (!function_exists('apc_store'))
{
trigger_error('APC not installed', E_USER_ERROR);
}
$check = apc_store($title, $data);
}
}[/code]

Update

I just found out APC datastore support was added to the yet unreleased vBulletin 3.6. Nice!

Update 2

I’ve since switched back to eAccelerator. APC was causing Apache segfaults under ultra-high loads.