sub walktimer {
    ## The queue handle is passed in when the thread is started
    my $Q = shift;
    #Sleep for 180 seconds, upon completion execute SQL to change OK_OPEN back to all zero for $showcasenum
    
    ## A hash to remember when things time out.
    my %when;
    
    ## wake up once per second
    while( sleep 1 ) {
        
        ## while there are showcase numbers on the queue
        while( $Q->pending ) {
            ## grab the one at a time
            my $showcasenum = $Q->dequeue();
            
            ## Calculate when the timeout should occur, 
            ## and add the showcase number to the hash to be dealt with at that time
            push @{ $when{ time() + $walktime } }, $showcasenumber;        
        }
        ## find any times that have expired (earlier than now!)
        for my $time ( grep{ $_ < time() } keys %when  ) {
            
            ## And for each showcase number scheduled at that time
            for my showcasenum ( @{ $when{ $time } } ) {
                
                ## Do your db stuff
                my $dbh = DBI->connect('dbi:mysql:alarm:databasehost','username','password') or die "Connection Error: $DBI::errstr\n";
                my $sql = "update Showcases set OK_OPEN=0 WHERE SC_NUM = ?";
                my $sth = $dbh->prepare($sql) or die "Can't prepare $sql: $dbh->errstr\n";
                $sth->execute($showcasenum) or die "SQL Error: $DBI::errstr\n";
                $dbh->disconnect;
            }
            ## and remove the expired time from the hash
            delete $when{ $time };
        }
    }
}