Just be aware that even this method will only save you space where your records are longer than (from memory) 12 characters. And if you are having to store another array containing the record length, then you have to factor the size of that array into the argument as well unless you replace each record length with the lvalue ref of the record as you go. The space consumed storing the lengths will depend upon whether the numeric values are loaded and stored as IVs or PVs. Around 20 bytes/length for the former and approx. 50 for the later in addition to that used to store the lvalue ref.

Also, it only makes sense to build an array of refs if you are going to randomly access each (or some) records more than once. Otherwise, it would be better to simply generate and use an lvalue ref for each record as you need it. The trade-off between replacing the lengths with lvalue refs, and generatng them on the fly will depend upon the number and frequency with which you re-access records through the life of the program; how the length are loaded etc.