By default, Session stores session data in a collection named 'session' inside the default database. This collection is better to be pre-created with fields 'id' and 'expire' indexed. The collection name can be changed by setting [[sessionCollection]]. The following example shows how you can configure the application to use Session: Add the following to your application config under components: php 'session' => [ 'class' => 'yii\mongodb\Session', 'db' => 'mymongodb', 'sessionCollection' => 'my_session', ] Session extends [[MultiFieldSession]], thus it allows saving extra fields into the [[sessionCollection]]. Refer to [[MultiFieldSession]] for more details. Tip: you can use MongoDB TTL index for the session garbage collection for performance saving, in this case you should set [[Session::gCProbability]] to 0.
Since: 2.0
Author: Paul Klimov (klimov.paul@gmail.com)
Inheritance: extends yii\web\MultiFieldSession
 /**
  * Creates test session instance.
  * @return Session session instance.
  */
 protected function createSession()
 {
     return Yii::createObject(['class' => Session::className(), 'db' => $this->getConnection(), 'sessionCollection' => static::$sessionCollection]);
 }