t/thread-index-gap.t | 7 +++++--

diff --git a/t/thread-index-gap.t b/t/thread-index-gap.t
index f4e4bd09c3ad3228519e6565be9e78bd09f63df6..83c3707d21d795e55d7023ea67fcedee027524cf 100644
--- a/t/thread-index-gap.t
+++ b/t/thread-index-gap.t
@@ -45,12 +45,15 @@ 		$im->add(PublicInbox::Eml->new("$m\nFrom: x\@example.com\n\n"));
 	}
 	$im->done;
 	my $over = $ibx->over;
-	my @tid = $over->dbh->selectall_array('SELECT DISTINCT(tid) FROM over');
+	my $dbh = $over->dbh;
+	my $tid = $dbh->selectall_arrayref('SELECT DISTINCT(tid) FROM over');
+	my @tid = map { $_->[0] } @$tid;
 	is(scalar(@tid), 1, "only one thread initially ($desc)");
 	$over->dbh_close;
 	run_script([qw(-index --reindex --rethread), $ibx->{inboxdir}]) or
 		BAIL_OUT 'rethread';
-	@tid = $over->dbh->selectall_array('SELECT DISTINCT(tid) FROM over');
+	$tid = $dbh->selectall_arrayref('SELECT DISTINCT(tid) FROM over');
+	@tid = map { $_->[0] } @$tid;
 	is(scalar(@tid), 1, "only one thread after rethread ($desc)");
 }