[otrs] config file location?

[kerneljack]

Hi, I hope this is not a stupid question. I am trying to optimise our
OTRS installation, and I want to change the TicketIndexModule type
from 'RuntimeDB' to 'StaticDB'. In which config file am I supposed to
make this setting? I have added a line to the bottom of the "Load"
subroutine in the Kernel/Config.pm file, but I have no way to verify
if these have taken effect?

I know about the Admin/SysConfig module, and from there if I search
for TicketIndexModule, I get *nothing*. It seems I need to search for
Ticket::IndexModule and then I can change the value, but where is this
value stored, and can I see it and modify it manually?

Thanks.