It is web application running on mod_perl 1 with apache 1.3. But the classes that implements business objects basically don't care if it runs under mod_perl or from command line. They only need the database with a certain schema.

There could be more than a million record in the cache table. The operation on the table is basically like this (in perl-like pseudocode):

sub search
{
   my ($arrival_date, $departure_date, $number_of_guests) = @_;
   
   validate_search_cache($arrival_date, $departure_date);
   
   my @search_results = ... do SELECT query to get a list of available
+ room-package combination between $arrival_date and $departure date f
+or $number_of_guests ...

   return @search_results;
}

sub validate_search_cache
{
   my ($arrival_date, $departure_date) = @_;

   my @validated_dates = ... do SELECT query that returns a list of da
+tes between $arrival_date and $departure_date having valid combinatio
+ns of room-package ...

   my @invalid_dates = ... look for dates between $arrival_date and $d
+eparture_date that doesn't exists in @validated_dates ...

   foreach (@invalid_dates) {
      initialize_search_cache($_);
   }
}

my @field_list = (
   { 
      name => 'valid_price', 
      op => sub { ... computation to check if price valid on   
                  a certain date ... },
   },
   {
      name => 'available_room_count',
      op => sub { ... calculcation to get the available room 
                  count on a certain date ... },
   },
   ...
);

sub initialize_search_cache
{
   my ($date) = @_;

   my @keys;
   my @values;
   foreach (@field_list) {
      push @keys, $_->{name};
      push @values, $_->{op}->($date);
   }

   my $sth = $dbh->prepare("INSERT INTO (".(join ',', @keys).") VALUES
+ (".(join ',', map "?", @values).")";
   $sth->execute(@values);
}
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I hope that explains how the code works. The queries are mostly simple, except when doing the search for availability.