lib/PublicInbox/SearchIdx.pm | 8 ++++++--

diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index 9ba9437d59b9a0baf2631bbffdde7f021d58baa9..69b7a6f6964bef876cfb5e41a62d02764b678b19 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -366,8 +366,12 @@ 	my $doc_id;
 	$mid = mid_clean($mid);
 
 	eval {
-		$doc_id = $self->find_unique_doc_id('mid', $mid);
-		$db->delete_document($doc_id) if defined $doc_id;
+		$doc_id = $self->find_unique_doc_id('Q' . $mid);
+		if (defined $doc_id) {
+			$db->delete_document($doc_id);
+		} else {
+			warn "cannot remove non-existent <$mid>\n";
+		}
 	};
 
 	if ($@) {