Hi,
When ever user logs in, a session will be created. So for each session the session ID is unique.
https://docs.mendix.com/refguide/tricky-custom-runtime-settings#2-2-general-settings
There are two constants that can be used to manage sessions.
- Session Timeout: value determines, how long the user session is valid
- ClusterManagerActionInterval: determines when the invalid sessions are cleared
So, sessions are persisted but when session timedout, it becomes invalid. And all invalid sessions will be cleared.