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, %showcase );
    
    ## wake up once per second
    while( sleep 1 ) {
        
        ## while there are showcase numbers on the queue
        while( $Q->pending ) {
            ## grab them one at a time
            my( $cmd, $showcasenum  ) = split ':', $Q->dequeue();
            
            ## If a timer already exists for this showcase
            if( exists $showcase{ $showcasenum }  ) {
                my $when = $showcase{ $showcasenum };
                
                ## remove the timer
                @{ $when{ $when } } = grep{ $_ != $showcasenum } @{ $when{ $when } };
                
                ##  and the pointer to it.
                delete $showcase{ $showcasenum };
                
                ## And if this command is a delete request that's all
                next if $cmd eq 'del';
            }
            
            ## Otherwise its a (re)add, so add the new timer
            ## Calculate when the timeout should occur, 
            my $timeout = time() + $walktime;
            
            ## and add the showcase number to the hash to be dealt with at that time
            push @{ $when{ $timeout } }, $showcasenumber;
            
            ## And remember its there
            $showcase{ $showcasenum } = $timeout;
            
        }
        ## 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;

                ## remove the pointer for this showcase
                delete $showcase{ showcasenum };
            }
            ## and remove the expired time from the hash
            delete $when{ $time };
        }
    }
}