Once again, I strongly recommend you move the object constructor outside the while loop. Tux, a.k.a. H. Merijn Brand, the author of Text::CSV_XS, which is the base module you're indirectly using, amplified this suggestion in his reply to your post. He explained that "you create a new csv parsing object for every line read." You really don't want to do this needlessly for 1.7 million records. And Tux's advice to use getline instead of <>/parse/fields is a wise one.

I think you're trying too hard to handle the floating-point weight values. Just be explicit with your tests:

if ($pounds == 0.0 and $grams == 0.0) {
    ...
}
[download]

The right coercions happen automagically. Here's the proof:

D:\>perl -E "say '' == 0.0 ? 'Equals' : 'Does not equal'"
Equals

D:\>perl -E "say '0' == 0.0 ? 'Equals' : 'Does not equal'"
Equals

D:\>perl -E "say '0.0' == 0.0 ? 'Equals' : 'Does not equal'"
Equals

D:\>perl -E "say '123' == 0.0 ? 'Equals' : 'Does not equal'"
Does not equal

D:\>perl -E "say '123.4' == 0.0 ? 'Equals' : 'Does not equal'"
Does not equal

D:\>
[download]

So you didn't like any of the other improvements I suggested in my refactored version of your script?

Jim