Yii2 always log application category with $_COOKIE, $_SESSION and $_SERVER (category filter not working properly)

Question

I am new to Yii2 and I need some manual logging to Data Base after some actions has happened. The thing that seems best for me is to filter by category. The problem is that Yii2 always add extra line with information $_COOKIE, $_SESSION and $_SERVER. Is this normal? How can I disable the extra log line?

This is the fronted configuration

return [
    'id' => 'app-frontend',
    'basePath' => dirname(__DIR__),
    'bootstrap' => ['log'],
    'controllerNamespace' => 'frontend\controllers',
    'components' => [
        'user' => [
            'identityClass' => 'common\models\User',
            'enableAutoLogin' => true,
        ],
        'log' => [
            'traceLevel' => YII_DEBUG ? 3 : 0,
            'targets' => [
                [
                    'class' => 'yii\log\DbTarget',
                    'categories' => ['manual'],
                ]
            ],
        ],
        'errorHandler' => [
            'errorAction' => 'site/error',
        ],
    ],
    'params' => $params,
];

And this is the action code:

public function actionTest()
{
    $logger = Yii::getLogger();
    \Yii::info('catalog info', 'manual');
    $logger->flush();
    Yii::$app->end();
}

And this is the result:

Thanks to rkm answer this configuration now works:

[
    'id' => 'app-frontend',
    'basePath' => dirname(__DIR__),
    'bootstrap' => ['log'],
    'controllerNamespace' => 'frontend\controllers',
    'components' => [
        'user' => [
            'identityClass' => 'common\models\User',
            'enableAutoLogin' => true,
        ],
        'log' => [
            'traceLevel' => YII_DEBUG ? 3 : 0,
            'targets' => [
                [
                    'except' => [
                        'manual',
                    ],
                    'class' => 'yii\log\FileTarget',
                    'categories' => ['application'],
                ],
                [
                    'class' => 'yii\log\DbTarget',
                    'categories' => ['manual'],
                    'logVars' => [],
                ]

            ],
        ],
        'errorHandler' => [
            'errorAction' => 'site/error',
        ],
    ],
    'params' => $params,
];

Answer 1

Add 'logVars' => [], in your config to log component like this if you don't need any global variables.

'components' => [
    ...
    'log' => [
        ...  
        'targets' => [
            [
                'class' => 'yii\log\FileTarget',
                'logVars' => [],
            ]
        ]
        ...
    ]
...
]

More info about configuring logging in the docs