The Virtuoso HTTP session management consists of functions for session variables manipulation and an ability to define a pre- and post-processing function. The pre and post-processing functions are used to save and restore session data between HTTP posts, usually to and from a session table.

Session management must be enable by settings the flag for persistent session variables in virtual directory mapping. Virtual directory mappings use the persistent_session_variables flag, which when specified, session variables can be used in a post-process function to determine if the session variables content must be stored on to the session table or not.

The post-processing function hook can be any user-defined Virtuoso/PL procedure, it will be executed every time after processing of the active page.