<PCRFGxSessionSQL>
stores
information about subscribers' Gx sessions in SQL. The Gx session table
has one row for each active session. By default session information is
kept after the session is finished providing history information about all
Gx sessions.<PCRFGxSessionSQL>
implements the interface defined by
PCRFGxSessionGeneric.pm
which allows creating
customised Gx session repositories.