I'm currently using `Symfony 2.1.8` and the built-in `PdoSessionHandler`.

I want to add a `user_id` field in the session table to identify to which (logged-in) user the session belongs. The idea is that I can force the user to log back in destroying his session. In my case it will happen if the privileges of the user are updated.

I had a look to the build-in `PdoSessionHandler` that you can't extends because of those silly private variables.

So I've tried created a new one (copy/paste) and add my column `user_id`.
Now this column can be null if the user is not logged in (anonymous users).

So I want to write this `user_id` in the write method of the handler. The user is already stored in the `$data` so I was thinking that I could check if this user exists, grab its `id` and add it in the insert / update query.

The problem is that `$data` is encoded - I guess by session\_encode() - so I'm not sure anymore this is the best place ever to handle my new field, but at the same time I can't see anywhere else I could do it as I need to update this MySQL query to insert the value of the new field.

So my question is: **where is the best place to handle this additional field? And how to set this user\_id value?**

On another note, somehing really annoying is that `Symfony` is creating a new cookie each time I'm logging in or out. So the database ends up with lots of records for nothing (it's always the same user). Why `Symfony` is not using the same cookie value all the time?