Mysql radius.radacct trying to clean up

[Sophie Loewenthal]

Hi,

     Our radacct table in mysql  reached 11 million rows and we don't 
need this information.

Would it be safe if I
     stopped FreeRadius,
     mysql:  truncate radius.radacct;
     started FreeRadius?

How would this affect the active sessions with Radius (e.g those who had 
accounting records sent back after the table had been truncated )?

Versions:
freeradius-mysql-2.1.12-1.el6.x86_64
freeradius-utils-2.1.12-1.el6.x86_64
freeradius-2.1.12-1.el6.x86_64


Kind regards,
Sophie