CakePHP2で、特定のモデルでのSELECTでレプリケーションスレーブを参照する方法 AppModel::$useReplicaをtrueにすると、参照先がslaveになる belongsToのモデルもslaveからの参照となる

CakePHP2_Replication.php

// app/Config/database.php
class DATABASE_CONFIG {

	public $default = array(
		'datasource' => 'Database/Mysql',
		'persistent' => false,
		'host' => 'master.mysql.host',
		'login' => 'mysql_username',
		'password' => 'mysql_password',
		'database' => 'schema_name',
		'prefix' => '',
		'encoding' => 'utf8',
	);

	public $replica = array(
		'datasource' => 'Database/Mysql',
		'persistent' => false,
		'host' => 'slave.mysql.host',
		'login' => 'mysql_username',
		'password' => 'mysql_password',
		'database' => 'schema_name',
		'prefix' => '',
		'encoding' => 'utf8',
	);
}


//-----------------
// app/Model/AppModel.php
class AppModel extends Model {

	public $useReplica = false;

	public function beforeFind($queryData) {
		if ($this->useReplica) {
			$this->useDbConfig = 'replica';
			foreach ($this->belongsTo as $btModelName => $btModelData) {
				$this->{$btModelName}->useDbConfig = 'replica';
			}
		}
		return $queryData;
	}

	public function afterFind($results, $primary = false) {
		if ($this->useReplica) {
			$this->useDbConfig = 'default';
			foreach ($this->belongsTo as $btModelName => $btModelData) {
				$this->{$btModelName}->useDbConfig = 'default';
			}
		}
		return $results;
	}
}


//-----------------
// app/Model/Hoge.php
class Hoge extends AppModel {
	public $useReplica = true;
	public $belongsTo = array(
		'Fuga',
		'Foo',
		'Bar',
	);
}

//-----------------
// app/Controller/HogesController.php
class HogesController extends AppController {

	public function index() {
		$this->set('hoge', $this->Hoge->find('all'));
	}
}