pressflow a drupal branch for scaling

basicly these guys rebranded drupal with some core hacks that allow it to scale out database reads. i did a diff of the two files a while back and it looked very similar to the following drupal patch.

http://fourkitchens.com/pressflow-makes-drupal-scale/downloads

//database.inc
function db_query($query) {
$args = func_get_args();
array_shift($args);
$query = db_prefix_tables($query);
if (isset($args[0]) and is_array($args[0])) { // 'All arguments in one array' syntax
$args = $args[0];
}
_db_query_callback($args, TRUE);
$query = preg_replace_callback(DB_QUERY_REGEXP, '_db_query_callback', $query);

//load balancing
if(strpos(strtolower($_GET['q']),"admin") !== false)
db_set_active('write'); //its important that all admin gets access to the most recent data
else
if(strpos(strtolower($query),"select") === 0){
db_set_active('read'); //this will not contain any data from the master (write) database untill replication happens
}
else {
db_set_active('write');
}

return _db_query($query);
}

//sites/default/settings.php
//$db_url = 'mysql://username:password@localhost/databasename';

$db_url = array(
'default' => 'mysql://username:password@localhost/databasename',
'read' => 'mysql://username:password@localhost/databasename',
'write' =>'mysql://username:password@localhost/databasename'
);
?>

I got that patch from the following post on drupal.org:

http://groups.drupal.org/node/2147