To expand on what moritz said, you also don't need to copy @row_B to @record_B before taking a reference. I believe fecthrow_arrayref re-uses the same ref, which requires you to copy the data, but fetchrow_array is returning you the list, so if you use my as moritz said, the ref will change each time you pull a record, simplifying.

Of course, if all you want is an array of arrays of the data, look at fetchall_arrayref in the DBI documentation