extindex: --gc: avoid SQLite lock conflict on shard cleanup

Xapian shard cleanup only requires read-only access to
over.sqlite3, so avoid opening it with read-write access since
create_tables will hit lock conflicts on "INSERT OR IGNORE"
statements.

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/PublicInbox/SearchIdxShard.pm b/lib/PublicInbox/SearchIdxShard.pm
index 1598faeb..8635f585 100644
--- a/lib/PublicInbox/SearchIdxShard.pm
+++ b/lib/PublicInbox/SearchIdxShard.pm
@@ -78,8 +78,9 @@ sub shard_close {
 sub shard_over_check {
         my ($self, $over) = @_;
         if ($self->{-ipc_req} && $over->{dbh}) {
-                # can't send DB handles over IPC
-                $over = ref($over)->new($over->{dbh}->sqlite_db_filename);
+                # can't send DB handles over IPC, and use read-only to avoid
+                # create_tables lock conflict:
+                $over = PublicInbox::Over->new($over->{dbh}->sqlite_db_filename)
         }
         $self->ipc_do('over_check', $over);
 }