0..$$#user seems to go far higher than I'm expecting

I think you're looking for just 0 .. $#$user


As a side note/excercise, try Dumper'ing out the results if you change it to be:

my $users = $db_ref->selectall_arrayref("SELECT last_name, first_name 
+from user", {Slice=>{}}) or die "$!\n";
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You might prefer (hash keys are much more meaningful to read than array indices) the way this then looks:

printf "%s, %s\n", $user->[$_]->{last_name}, $user->[$_]->{first_name}
+ for 0..5;
printf "%s, %s\n", @{$user->[$_]}{ qw/last_name first_name/ } for 0..5
+;  # using a hash slice

# or, if going through all rows:
printf "%s, %s\n", $_->{last_name}, $_->{first_name} for @$user;
printf "%s, %s\n", @{$_}{ qw/last_name first_name/ } for @$user;
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