for each line
  parse out the date-hour, date-hour-minute, database name, and speed
  add speed to $h{date-hour}{database name}
  add speed to $m{date-hour-minute}{database name}
  $db{database name} = 1 # put database name in hash

loop through sorted keys of %db
  print them as headers, formatted to fit what's coming below
loop through keys of %h (sorted if you want)
  print the key (the date-hour)
  loop through sorted keys of %db
    print $h{$key}{database name}
  print a newline

now do the same with the per-minute hash %m