How To Use 'coremessages' With Cdbmessagesource

I am stuck with coreMessages component which I would like to use with CDbMessageSource. If I add:

'coreMessages'=>array(
  'class' => 'CDbMessageSource',
),

to the config/main.php (in the database there are tables SourceMessage and Message) and call e.g.

echo Yii::powered();

(which calls Yii::t('yii',...) I am getting the memory exhausted PHP error:

Allowed memory size of 134217728 bytes exhausted (tried to allocate 77 bytes) in /yii/framework/YiiBase.php on line 466

If I disable debugging I get:

Allowed memory size of 134217728 bytes exhausted (tried to allocate 32 bytes) in /yii/framework/base/CComponent.php on line 174

Basically, whenever I call

Yii::t('zii',...), Yii::t('yii', ...), ...

I get the memory exhausted error. The database (SourceMessage and Message tables) are inserted correctly since the messaging system for the message component is functioning well. Am I missing sth. with this coreMessages component?