[PATCH 3/7] isearch: mset_to_artnums: avoid unnecessary ops

[Eric Wong <e@80x24.org>]

We can use DBI's selectcol_arrayref directly (as we do in other
places) to avoid unnecessary arrays and ops on our end.
---
 lib/PublicInbox/Isearch.pm | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/PublicInbox/Isearch.pm b/lib/PublicInbox/Isearch.pm
index df940e76..2b45e08e 100644
--- a/lib/PublicInbox/Isearch.pm
+++ b/lib/PublicInbox/Isearch.pm
@@ -69,12 +69,11 @@ sub mset_to_artnums {
 			$range = 'AND xnum >= ? AND xnum <= ?';
 			@r = @$r;
 		}
-		my $rows = $self->{es}->over->dbh->
-			selectall_arrayref(<<"", undef, $ibx_id, @$docids, @r);
+		return $self->{es}->over->dbh->
+			selectcol_arrayref(<<"", undef, $ibx_id, @$docids, @r);
 SELECT xnum FROM xref3 WHERE ibx_id = ? AND docid IN ($qmarks) $range
 ORDER BY xnum ASC
 
-		return [ map { $_->[0] } @$rows ];
 	}
 
 	my $rows = $self->{es}->over->dbh->