At the risk of coming in a little late, I'm pretty much doing the exact same thing you want, with the addition of also using a relational backend.

It goes something like this:

1. Check the cache for the information
2. If it doesnt exist in the cache, get it from the database and put it in the cache
3. If it does, get it from the cache and serve it

The only thing you have to worry about is tuning the expiry time of your cache for optimal performance. I like the previously mentioned idea of serving everything up from the RAM disk, this will also increase your performance.

If you've built your site to generate the pages dynamically, it really is only about 6 extra lines of code to cache it all:

my $cache = Cache::FileCache->new();
my $retcache = get('tvgid');
if (! defined $retcache) {
    # Build your page
    #            cache   content expiry
    $cache->set('tvgid', $page, "5 minutes");
} else {
    # Return your page
}
[download]

Too easy.. :-)

You infer from the OP performance is a concern to you, keep in mind there are many, many ways to optimise your code, from regex fiddling to algorithm design to OS tuning to building your own webserver, to application design.

Make sure you benchmark your code as well as RW response time to make sure you can quantify your "optimisations"