split(/\n/, $data) doesn't work. It removes blank trailing lines.

What is your definition of "doesn't work" here? The dropping of empty trailing fields in the case of the LIMIT parameter being 0 or not specified works as advertised in the split docs.

split(/\n/, $data, -1) doesn't work either. It adds a blank line.

Perl doesn't do this on my system:

>perl -MData::Dumper -e "$_=qq(1\n2\n3); print Dumper split /\n/,$_,-1
+"
$VAR1 = '1';
$VAR2 = '2';
$VAR3 = '3';

>perl -MData::Dumper -e "$_=qq(1\n2\n3\n); print Dumper split /\n/,$_,
+-1"
$VAR1 = '1';
$VAR2 = '2';
$VAR3 = '3';
$VAR4 = '';
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When you read your data from file on the other hand, you have to be careful that your editor does not hide a trailing newline on the display. (E.g. Vim, where you can't tell the difference, other than by an initial [noeol] in the status line.)