Where to define audit log threshold?

Hi all,
I want to trace some VM logs But the audit log only keeps 30 days. "30 days" is the default and recommended value according to the administration guide, I found it can be modified in postgresql

engine=# select option_value from vdc_options where option_name='AuditLogAgingThreshold';

option_value

30
(1 row)

But I don't know whether the log threshold depends on the sql value or other config files, and if I modify it , does RHEV need restart or not?

Best Regards