What you're missing is that exec abandons the process after it starts it. So it will only wait until the child dies, which should be right after it starts the database :)

I had reservations about this when I wrote it, and I confirmed them:

#!/usr/bin/perl -w

use strict;
use POSIX ":sys_wait_h";

defined (my $pid = fork()) or die "D'oh";

if ( $pid ) {
  print "$$ gonna wait...\n";
  my $kid;
  do {
   $kid = waitpid $pid, WNOHANG;
  } until ( $kid > 0 );
  print "Ok, done waiting\n";
} else {
    exec 'sleep 10; echo "Done sleeping\n"';
}
[download]

What I had thought it would do was to start the execution of the command and then bail. Well.. it didn't. It waited.

Now go get that dinner.

No dinner for you :)