isearch: mset_to_artnums: avoid unnecessary ops

We can use DBI's selectcol_arrayref directly (as we do in other
places) to avoid unnecessary arrays and ops on our end.

1 files 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->