+sub max {
+ my ($self) = @_;
+ my $sth = dbh($self)->prepare_cached(<<'', undef, 1);
+SELECT MAX(num) FROM over WHERE num > 0
+
+ $sth->execute;
+ $sth->fetchrow_array // 0;
+}
+
+sub imap_exists {
+ my ($self, $uid_base, $uid_end) = @_;
+ my $sth = dbh($self)->prepare_cached(<<'', undef, 1);
+SELECT COUNT(num) FROM over WHERE num > ? AND num <= ?
+
+ $sth->execute($uid_base, $uid_end);
+ $sth->fetchrow_array;
+}
+
+sub check_inodes {
+ my ($self) = @_;
+ my $dbh = $self->{dbh} or return;
+ my $f = $dbh->sqlite_db_filename;
+ if (my @st = stat($f)) { # did st_dev, st_ino change?
+ my $st = pack('dd', $st[0], $st[1]);
+
+ # don't actually reopen, just let {dbh} be recreated later
+ dbh_close($self) if $st ne ($self->{st} // $st);
+ } else {
+ warn "W: stat $f: $!\n";
+ }
+}
+
+sub oidbin_exists {
+ my ($self, $oidbin) = @_;
+ if (wantarray) {
+ my $sth = $self->dbh->prepare_cached(<<'', undef, 1);
+SELECT docid FROM xref3 WHERE oidbin = ? ORDER BY docid ASC
+
+ $sth->bind_param(1, $oidbin, SQL_BLOB);
+ $sth->execute;
+ my $tmp = $sth->fetchall_arrayref;
+ map { $_->[0] } @$tmp;
+ } else {
+ my $sth = $self->dbh->prepare_cached(<<'', undef, 1);
+SELECT COUNT(*) FROM xref3 WHERE oidbin = ?
+
+ $sth->bind_param(1, $oidbin, SQL_BLOB);
+ $sth->execute;
+ $sth->fetchrow_array;
+ }
+}
+
+sub blob_exists { oidbin_exists($_[0], pack('H*', $_[1])) }
+
+# used by NNTP.pm
+sub ids_after {
+ my ($self, $num) = @_;
+ my $ids = dbh($self)->selectcol_arrayref(<<'', undef, $$num);
+SELECT num FROM over WHERE num > ?
+ORDER BY num ASC LIMIT 1000
+
+ $$num = $ids->[-1] if @$ids;
+ $ids;