Perl arrays and hashtables support nesting (e.g. hash-of-hash-of-array-of-hash etc.), mixed "data types" and slices (a convenient form of indexing). There is also PDL if your data is numeric. Additionally, there is Inline::Python if you want to inline python code you already have (untested by me).

storing millions of rows and hundreds of columns in 2d array if possible

well that's illegal in some states and some of us Perl-ers still work on Spectrums, :)

Update: There's also DBIx::Array which offers this:

foreach my $row ($dbx->sqlarrayhash($sql, @bind)) {
  do_something($row->{"id"}, $row->{"column"});
}
[download]

And there's DBIx::Class as a long-term investment.

bw, bliako