It's also a possibility that there was a mess up with a perl script that inserted the values in the first place, and that the data in the DB is actually strings of "ARRAY(0x...)". In other words, that the stringification of an array-reference happened *before insert* and not *after select*.

Just another case to investigate, if using Data::Dumper to verify your output data's structure doesn't help. Also, don't forget to read perldoc perlref and perldoc perlreftut if any of this is non-obvious to you.