msgmap: ignore duplicates instead of dying

This prevents public-inbox-watch from dying when reloading
(and thus rescanning) already-imported directories.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/PublicInbox/Msgmap.pm b/lib/PublicInbox/Msgmap.pm
index a49b61e8..7e0f34a4 100644
--- a/lib/PublicInbox/Msgmap.pm
+++ b/lib/PublicInbox/Msgmap.pm
@@ -179,7 +179,7 @@ sub id_batch {
 sub mid_set {
         my ($self, $num, $mid) = @_;
         my $sth = $self->{mid_set} ||= do {
-                my $sql = 'INSERT INTO msgmap (num, mid) VALUES (?,?)';
+                my $sql = 'INSERT OR IGNORE INTO msgmap (num, mid) VALUES (?,?)';
                 $self->{dbh}->prepare($sql);
         };
         $sth->execute($num, $mid);