user_id getting cleared after User Logout

[sanjay84pal]

Hi
I am using the package and everything seems to work perfectly. I enabled the "log_user" and make the necessary changes to capture the user_id in the "tracker_sessions" table.
-When the user logout then user_id getting cleared from the "tracker_sessions" tables too and if from the same browser another user getting login then-new user_id getting updating against the already existing the UUID.
-In this case, I am not able to retrieve the trace record agent the earlier User
-My requirement is that I want to retrieve the User specifically traceable data in the future.

Pls help or suggest, how can I achieve this.