my @uptimes = qw(1 2 3 4 5 1 2 3 4 1 2 3 4 5 6);

for (0 .. $#uptimes) {
  print "We have a peak value: $uptimes[$_]\n"
    if  $_           == $#uptimes
    or  $_           <  $#uptimes 
    and $uptimes[$_] >  $uptimes[$_+1];
}

##</code><code>##

SELECT uptime_id as uid, uptime_value
  FROM uptime
 WHERE uptime_value > (SELECT uptime_value
                         FROM uptime
                        WHERE uptime_id = uid+1);

##</code><code>##

SELECT MAX(uptime_value) FROM uptime;