Refreshing stored data at administrator's signal

[Colin Wetherbee <suppressed>]

Greetings.

I have an application that accesses some relatively static database 
tables to create drop-down <select> lists.  As an example, one of these 
tables is a list of common commercial aircraft.

At the moment (and not in a production environment), every time the 
drop-down list is generated for a web page, the script queries the 
database to retrieve the entire list of aircraft.  I would prefer to 
retrieve the list of aircraft when each Perl interpreter starts and then 
not retrieve it again until the administrator sends a signal.  For this 
particular table, the signal would only occur when new aircraft hit the 
market, like the Boeing 787 will (hopefully) in December of this year.

The most UNIX-ish way to do this, I guess, would be to send SIGHUP to 
each running perl process, causing it to reload its configuration, 
update its stored lists, and so forth.  I'd rather do this in a more 
Perl-ish or Apache-ish way, though, and I'd also rather be specific 
about which list it should update.

At the moment, there are about 10 such lists, and I can see that number 
growing to about 20 before the site goes live.  At a guess, the lists 
average about 300 elements each (with the list of aircraft being one of 
the shorter and less-frequently-updated lists).

My ideal solution would be to have an external application (the 
administrator app or whatever it ends up being) update some flag inside 
each mod_perl process every time they need to update a list, and then 
each mod_perl application would see the flag and perform the update.  I 
could do this relatively easily with a combination of threads and file 
hooks or "update sockets" or something, but I don't plan on adding 
threads or sockets to the application, and I think adding that much 
complexity and overhead for this "simple" feature would be overkill.

Any thoughts?

Thanks.

Colin