search: reopen and retry on updated databases

This seems like a nasty thing which breaks downloads of
large mailboxes.

diff --git a/lib/PublicInbox/Search.pm b/lib/PublicInbox/Search.pm
index d9fbc36c49648204b91808ecdb6cdb7c54b42266..856c8c144c8ea1afcb4d0cae2a736ffad4e955ef 100644 (file)
--- a/lib/PublicInbox/Search.pm
+++ b/lib/PublicInbox/Search.pm
@@ -97,7 +97,7 @@ sub query {
                $opts->{relevance} = 1 unless exists $opts->{relevance};
        }
 
-       $self->do_enquire($query, $opts);
+       _do_enquire($self, $query, $opts);
 }
 
 sub get_thread {
@@ -111,10 +111,26 @@ sub get_thread {
        my $query = Search::Xapian::Query->new(OP_OR, $qtid, $qsub);
        $opts ||= {};
        $opts->{limit} ||= 1000;
-       $self->do_enquire($query, $opts);
+       _do_enquire($self, $query, $opts);
 }
 
-sub do_enquire {
+sub _do_enquire {
+       my ($self, $query, $opts) = @_;
+       my $ret;
+       for (1..10) {
+               eval { $ret = _enquire_once($self, $query, $opts) };
+               return $ret unless $@;
+               # Exception: The revision being read has been discarded -
+               # you should call Xapian::Database::reopen()
+               if (index($@, 'Xapian::Database::reopen') >= 0) {
+                       reopen($self);
+               } else {
+                       die $@;
+               }
+       }
+}
+
+sub _enquire_once {
        my ($self, $query, $opts) = @_;
        my $enquire = $self->enquire;
        if (defined $query) {
@@ -127,6 +143,8 @@ sub do_enquire {
         my $desc = !$opts->{asc};
        if ($opts->{relevance}) {
                $enquire->set_sort_by_relevance_then_value(TS, $desc);
+       } elsif ($opts->{num}) {
+               $enquire->set_sort_by_value(NUM, 0);
        } else {
                $enquire->set_sort_by_value_then_relevance(TS, $desc);
        }
@@ -186,21 +204,12 @@ sub num_range_processor {
 # only used for NNTP server
 sub query_xover {
        my ($self, $beg, $end, $offset) = @_;
-       my $enquire = $self->enquire;
        my $qp = Search::Xapian::QueryParser->new;
        $qp->set_database($self->{xdb});
        $qp->add_valuerangeprocessor($self->num_range_processor);
        my $query = $qp->parse_query("$beg..$end", QP_FLAGS);
-       $query = Search::Xapian::Query->new(OP_AND, $mail_query, $query);
-       $enquire->set_query($query);
-       $enquire->set_sort_by_value(NUM, 0);
-       my $limit = 200;
-       my $mset = $enquire->get_mset($offset, $limit);
-       my @msgs = map {
-               PublicInbox::SearchMsg->load_doc($_->get_document);
-       } $mset->items;
 
-       { total => $mset->get_matches_estimated, msgs => \@msgs }
+       _do_enquire($self, $query, {num => 1, limit => 200, offset => $offset});
 }
 
 sub lookup_message {