Session problem

I store session in db as documentation , i dont know why the record in db  after few second are deleted

It should not happen. I don't know why but you did something wrong.

The problem is that doing the same operation sometimes it logout and sometime not , in this operation by confirm with message  i use flash data :

Code:

    public function attivaRecord($id){

        $documento_arrivo_model = new Documento_arrivoModel();

        session()->set('id_documento_arrivo_attivo',$id);

        if(isset($_SESSION['id_documento_arrivo_attivo'])){

             session()->setFlashdata('gestisciRecordOK', 'Attivazione correttamente effettuata');

             return redirect()->to('/user_Documento_arrivo/lista_completa/');

        }else{

            session()->setFlashdata('gestisciRecordBad', 'Problemi Attivazione');

            return redirect()->to('/user_Documento_arrivo/lista_completa/');

        }

    }

 What could it be ?