I use CodeIgniter 2.1.0, i store data session in database ci_sessions, i want after insert data in database get a message like “Your information was successfully updated.” by set_flashdata and flashdata (that these don’t work) now my problem is here that after once click (for insert data in database) store data session in database as following image in two row in first row column user_data is empty but in second row it have data, how can fix it?

Do you use any AJAX requests on your platform. The session id gets regenerated by default on every 300 seconds.
Try setting the cookie for site-wide usage in config.php file and see if the problem persists after that. Don’t forget to delete the browser cookies before trying. Eventually, try setting a prefix